Cost effective 331 stroker base Windsor 5.0 or Cleveland 351?

[xctasy]

This is a stroker 331 rod ratio post.

Real quick. Even a 0.875" compression height 331 sroker won't make a better than 1.75 to 1.73:1 rod ratio with a Chevy or Holden style 5.70 or 5.63" long rod. But swapping to a common 351C/302C Aussie or US block will allow a guy to make a 331 stroker with a 2:1 rod ratio easily.

The 331 stroker D.S.S builds uses a 5.4" rod, and whatever 1.163 compression height piston with 3.25" crank stroke and 30 th over pistons for a 1.66:1 rod ratio.

Level 10 D.S.S 331 5.0 EFI stroker with Trickflow 185 CNC heads, Trickflow Upper and Lower intake. It is a Non induction limited engine. There are two cam specs Ethyl Cat liked, and I'd like to baseline them with a 2:1 rod ratio.

I'd then like to do two runs with optimised cams to suit the 2:1 rod ratio.


Ethyl Cat's two best cams with my tall deck Cleveland engine combination, with just the rod ratio being the difference. In pactice, I'd use more shallow 1.09" deck 347 pistons to keep eveything the same, or use copper head gaskets to get the deck to the same as the D.S.S. 331 stroker, and use Mitsubishi rods bused to 0.927" to get the 2:1 rod ratio with a 6.5" rod and a 3.25" stroke.



I get my cam profiles from a cam grinder in New Zealand, and another in Australia. I am interested in how many horsepower one can liberate by lengthening rods and reducting piston compression height.

In New Zealandand Australia, the total amount of 5.0 HO or Explorer engines are limited. But we've got 10 times more old 302C and 351C's around. So to me, its easier to bore and stroke a 302C to 331 and package all the 5.0 HO or Explorer parts into Cleveland block.


The Cleveland block takes Windsor heads, and is 1" taller than the 302W block. Its got 2.75" main bearings and 2.311" big ends, but it can take downsized 302W sized bearings by made up spacers, and to create a 3.25" stroke, you can either offset grind a 302c or 351c crank to get there. So no new crank. In the siprit of creating a level playing field, I'll horse trade the main bearing specfications on these two engines.


In another post, tonysilver82, was given by Ethyl Cat some very expensive advise on selecting an ideal area under the curve cam for a 331 stroker an EFI 5 speed Mustang with gears, for free, and he backed it up 100%. The two best cam profiles were trialed from four prospects, and a full complement of electronic dyno runs were made to prove/disprove the ideal choice. All on EC's normakl pacakge.

In engine building, it’s like anyone can learn to haul a trailer, but not everyone can back it up. Ethyl Cat has backed it up. I'd like to add that by saying I trust 100% the method of packaged electronic horsepower/lb-ft. calculation..I've actually been using a copy one version of Engineer Analyser back in 2002 when I started trialling my own cams to suit my I6. As you change the rod ratio with a thinner compression height piston, all else being equal, your top end power grows progressively, but it happens because of other things you optimise. And that is where the engineering science comes into play with cam selection.


The reason I don't use it and would rather use Ethyl Cat's assessment is from years of working with computer programs in Civil Engineering. So I'd like to affirm Engine Specialists like Ethyl Cat to the whole team at FEP. I don't use EA anymore because I'd rather spend 200 dollars and buy a cam master with an engine run attached to it than cheap out on buying an off the shelf cam without a computer verification.




For me, it’s about locking down what rod ratio change does to a stoker 331, and how to offset it with other cost effective options. I actually learned all this on Holden 5.6" rod 308 "331" stokers in 1988, and Brad Girdwood in Australia taught it in a 253-308 and 302-351 Rebuilds series by Australian Street Machine. In all cases the changes Brad recommended were the same as Ethyl Cat's does, basically due to cost being the key factor.

[xctasy]

Basically, using a US 351c block to make a reverse stroker 331.

Or an Aussie/US 302c block to make a positive stroker 331. They can be casting coded as late as 1982 passenger car engines, with base block emissions which can be over ridden by the 5.0 hardware.

The blocks are more like shallow deck 351 Windsors. All block cooling passages except the front squre holes line up with a 5.0/5.8 Windsor block.

They have 1/2 head bolts, that inch taller than 5.0 deck, 300 thou less than 351W deck, square holes in the front of the cylinder head to flow the water through (these just need to be plugged up). They are common paper weights, able to be found fairly easily. Early ones were often four or three speed manual, colored a funny orange

https://www.youtube.com/watch?v=pmMf74IqvkY

https://www.youtube.com/watch?v=BP5TGuQDIHw

So, using eveything D.S.S 331, except the block and rods, and comparing the flywheel hp and lb-ft differences only due to the rod ratio.

For 302c info see. http://www.aus-ford-uk.co.uk/html/engines.html

With the October, 1970 introduction of the XY Falcon and ZD Fairmont range of cars, the Cleveland progressed beyond its performance image and 250hp, two barrel carburetored, 2V versions were offered as the top option on both models. The 300hp, four barrelled, 4V version of the engine was only offered on the XY GT and GTHO. Both these engines were still imported, but Ford Australia was keen to build its own and had tooled up to provide locally manfactured 351C and 302C engines. Why tool for a 302C engine when they had been using the 302W ? Well, it provided economies of scale, being able to use all of the ancilliary parts from one engine on another, and all for the sake of a different crank and rods.

And so the March, 1972 introduction of the Australian designed XA Falcon range also saw the debut of Australian built 351C and 302C in two barrel carbed, 2V form. There have been some reports that 302C’s were fitted to Brisbane built, December, 1971 XY Falcons. Brisbane cars have the letter ‘H’ as the second leter of their VIN. For the moment, the four barrel, 4V engines were imported, but by the early/middle of 1973 Ford Australia had developed their own four barrel fed 351C but used their own 2V style heads on the engine.

This is where the 2V and 4V descriptive terms become somewhat entwined. The distinct separation that applied in the U.S. between 2V and 4V ensured that a 2V Cleveland had a two barrel carb and inlet manifold, small inlet and exhaust ports and an enlarged chamber volume, while the 4V Cleveland had a four barrel carb, large inlet and exhaust ports and reduced size chamber volume which created a higher compression ratio. Now the Australians introduced a 2V head that took either a two or a four barrel carb inlet manifold, and had a large, but not as large as the U.S. 2V, open chamber size, plus, for further confusion, they introduced a 302C engine that had 2V heads which had a two barrel carb but a chamber volume smaller than anything the U.S. had offered, even on their highest performance Clevelands.

While the home grown four barrel, 2V 351C was introduced on automatic XA GTs towards the end of its life, the last of the imported, high compression, big port, 4V U.S. engines lasted only through to the first few months of XB GT production, again mostly, but not exclusively, in manual transmission cars, and by January, 1974, they were gone and all 351C engines that followed were Australian made.

The 351C ran through till the middle of the XE Falcon’s life before, to howls of protest, Ford killed off their V8 in 1982. In its later life it suffered compression ratio cuts, emissions equipment additions and a swap to Carter carbs to keep it clean and healthy

http://fordsix.com//viewtopic.php?f=95&t=18418&start=50

The 1969-1970 XW engine codes
H = 351 4V HO (Windsor or Cleveland 300 hp engine)
T = 351 4V, 290 HP, GT 4-dr and Police Pursuit Falcon engine

The 1971 XY engine codes
T = 351 4V HO (Cleveland 300 hp engine)
K = 351 4V, 290 HP, GT 4-dr and Police Pursuit Falcon (Cleveland engine)

The 1971 XY, 72XA, 73-76 XB engine codes
T = 351C 4V HO (Cleveland 300 hp engine)
K = 351c 4V, 300 HP, GT 4-dr and Police Pursuit Falcon engine
There was a delete option 351 2V 2-bbl 260 hp and 3514V 2v head 4-bbl engine with 290 hp, no codes known
Y = 302W 2V, 200 HP (Initally Winsor to Feb 1972, but some after December Brisbane state XY Falcon had 240 hp 2-bbl 302C's with H subcode)
Y = 302C 2V, 240 HP (After Marchy 1972, the 302 Cleveland engine, an extra 10 hp with dual exhaust)

The 1976-1979 XC engine codes
T = 5.8 Cleveland 4V 2V head 216 hp SAE net dual exhaust
P = 4.9 Cleveland 4V 2V head 195 SAE net single exhaust, 207 HP SAE net dual exhaust

The 1979-1980 XD engine codes
T = 5.8 Cleveland 4V 2V head 200 hp DIN net single exhaust
P = 4.9 Cleveland 4V 2V head 188 hp DIN net single exhaust

The October 80 XD engine codes
T = 5.8 Cleveland 4V 2V head 200 hp DIN net single exhaust
P = 4.9 Cleveland 4V 2V head 188 hp DIN net single exhaust, 207 HP SAE net dual exhaust

The New South Wales Emmision XD engine codes
H = 5.8 Cleveland 4V 2V head 200 hp DIN net single exhaust
B = 4.9 Cleveland 4V 2V head 188 hp DIN net single exhaust, 207 HP SAE net dual exhaust

The XE leaded 97 RON engine codes
T = 5.8 Cleveland 4V 2V head 200 hp DIN net single exhaust
P = 4.9 Cleveland 4V 2V head 188 hp DIN net single exhaust, 207 HP SAE net dual exhaust


The New South Wales Leaded RON 97 Emmision XE engine codes* undisclosed HP loss
H = 5.8 Cleveland 4V 2V head 200 hp DIN net single exhaust
B = 4.9 Cleveland 4V 2V head 188 hp DIN net single exhaust, 207 HP SAE net dual exhaust

Lastly, Any 335 won't easily take a serpentine drive due to the stupid Lima 385 style integral front cover
For mustangxtreme's Black Magic 400 Capri,
It required a Lincoln 5.0 28 Oz serp harmonic balancer
3.8 Power steering intermediate bracket,
Custom power steering bracket
3G alternator.

His 400 is much taller and wider but still 335 Cleveland based with same engine mount base and front cover hard demensions.

If you use headers for a 5.8 windsor with 5.0 heads then you'll fit everything in. You'll have to try real hard to have a tensioned serpentine belt hookup like a factory 5.0, but most of what you need, you can do with the 302C/351C block.


see from our beloved Dave der mustangxtreme http://vb.foureyedpride.com/showthre...ck-Magic/page3

Here's the weekend update.... Here's how it sits for the night.

[FUKAZ28]

[Walking-Tall]

FYI, all the 331's I see at DSS have 5.315" rods in them.

This will be interesting...

[xctasy]

Okay, 1.635:1 verses 1.96:1 then.


I've got some Buick Skylark 350 rods at 6.375" whiich I could bush down to give 1.96:1 for an even 20% L/R improvement. If its offset ground down, you can weld a cast iron crank to get the right stroke, and use the same diameter as 5.0 conrod big end.

So its actually a straight calculative effort in matching the existing data with the new L/R ratio verses the cam choices. I'm happy to pay Ethyl Cat on the basis that he might have to spend time doing work. Again the rub for me is that I can build up an engine like this in New Zealand, baseline it as the best perofrmance compromise for a 331, sell it, and then fiddle around with my I6. We've got access to everything, but what we are missing is the L/R improvment. I've discussed ths for 10 years and am prepared to put my last dimes where my mouth is.


I'll get the cam data from my other two sources, with their estimates, and we'll post the data. The point I'm making is that I've said, based on the details from other engines, that there is a linear advantage in torque out put from down low to up high power when optimising the cam for a given improving of what SAE engineeers call L/R or lambda. I expect 10 % extra power, but the independent sources need to corroborate this on an engine that isn't induction air flow limited. BMEP should go up converstant with inertial ramming and friction reduction, which are critical load imputs.


This is basic stuff which I've trialed in air flow limited engines, if tha's the correct term.

On non air flow limited, I'm still convinced of a better result conversant with half the algebric improvement. Australian Touring Car and NASCAR race cars with with inferior peak power figures have won races on the basis of having other parts of the top end power curve covered. We don't race dynonmaeters, we race transient load conditions.

On an engine making 460, I'd expect to see an extra 46 peak horsepower due to pumping losses, ring loads, inertial ramming. On the top end of the curve, the area under the curve and its shape will tend toward providing over rev power without a sharp drop off.

[Ethyl Cat]

I think I am beginning to grasp what your intentions are and what you need me to do.

BUT.... There are some things at play here with your design that kind of make this an uneven comparison. The main one being deck height.

Increasing deck height will 100% lengthen the intake runners, changing wave pulse tuning.

Increasing deck height to build your design will decrease the line of site air flow into the cylinder, regardless that the cylinder head is the same. If the engine goes up the intake goes down to fit it in the car. That is a bad thing.

Non performance issues would be engine overall weight, overall size vs packaging restraints. Also you are putting in 80 plus grams of connecting rod to lose 20 grams or so of piston weight. I am not too sure that the increased bobweight is worth it.

None of my software asks me what deck height I am putting all of these parts in so assumptions are in place that disregard what I listed above but I can tell you though that these things will and do affect things.

That said, JUST changing the rod length of the 331 to 6.5" in the software the results are as follows:

Software 1= Loss of 4 lb/ft at peak no change in peak power
Software 2= Loss of 1-2 lb/ft up to about 3000 rpm equal number up to a peak tq 1-2 lb/ft higher. Same total and average hp. Same average tq
Software 3= Loss of 7 hp and loss of 6 lb/ft

That rod ratio increase you so badly want deceases the pull the piston has on the intake runner as it leaves tdc. In a low rpm engine this is a bad thing if your goal is to fill the cylinder quickly and trap the most mass at IVC.

This shows up in every simulation as a reduction in TQ at either low end or all together.

It is a good thing though for an induction limited cylinder head to delay peak demand on the port until later in the intake stroke.

[PaceFever79]

The most cost effective build should be to go get one of those plentiful Aussie 351 Clevelands and just do a performance rebuild? It's not hard to get 450 HP from a 351c with iron heads. Granted you'd need to get the Fox chassis headers and oil pan, but even then you'd be ahead of an exotic stroker 331 hybrid (cost wise). Maybe it was a rhetorical question? Or maybe I'm missing something? Like, I wish 351 Clevelands were still a dime a dozen here in the states.

[Ethyl Cat]

Here is an example of what happens when rod length increases .

One pic is of the 6.500 rod and the other is 5.400 rod. You can see that the demand on the port lessens as the rod lengthens. The average speed has to be the same but the max speed and when that speed occurs is very different. The long rod gets to 5701 FPM @ 76.7 degrees ATDC and the short rods reaches 5777 FPM @74.5 degrees ATDC.

Based on just that data alone. If you can feed it (meet the demand) it will make more power.

[Walking-Tall]

Based on your flow differences, EC, "it" being the shorter rod, with more of a draw on the intake port due to increased piston speed, right?

Recalling the words of an article by or with Vizard, I remember emphasis of longer rods being high on the benefits of TDC dwell time, the squeeze, and it's benefits for higher compression and lower octane fuel... and a longer rod has the result of lowering piston G's / connecting rod tension.

[brianj]

Like, I wish 351 Clevelands were still a dime a dozen here in the states.

I have a 351C, with 50k miles on it, i can have for free. I just can't justify the expense vs a 351W or a hot little 5.0.

[Ethyl Cat]

Based on your flow differences, EC, "it" being the shorter rod, with more of a draw on the intake port due to increased piston speed, right?

Recalling the words of an article by or with Vizard, I remember emphasis of longer rods being high on the benefits of TDC dwell time, the squeeze, and it's benefits for higher compression and lower octane fuel... and a longer rod has the result of lowering piston G's / connecting rod tension.

There are benefits to the longer rod as you listed, but the one under the magnifying glass is the power increase that Xctasy is speaking of.

The draw comes from the rate at which the piston accelerates away from the head. Not too convinced that the "dwell" does much beneficial.

On the rod tension statement, going 1.1 inches longer with the rod reduces tdc tension by 100g's. short rod is 2537 g's and the long is 2437 g's

[Walking-Tall]

There are benefits to the longer rod as you listed, but the one under the magnifying glass is the power increase that Xctasy is speaking of.

The draw comes from the rate at which the piston accelerates away from the head. Not too convinced that the "dwell" does much beneficial.

On the rod tension statement, going 1.1 inches longer with the rod reduces tdc tension by 100g's. short rod is 2537 g's and the long is 2437 g's

Yep...

[xctasy]

Okay. I'm with you all on average overall hp and lb-ft, no net change, and a loss at low end, perhap a minor gain possible at peak power if optimized. It affirms your engine builder D. Morgans summary in terms of averages. I did expect a 10% hp growth if the cam was optimized to bring the critical loads to the same percentage of the short rod engine.

There are benefits to the longer rod as you listed, but the one under the magnifying glass is the power increase that Xctasy is speaking of.

The draw comes from the rate at which the piston accelerates away from the head. Not too convinced that the "dwell" does much beneficial.

On the rod tension statement, going 1.1 inches longer with the rod reduces tdc tension by 100g's. short rod is 2537 g's and the long is 2437 g's

I conceed that without some kind of very astute optimization of other parts of the engine and cam profile specs, there is not the net gain I've claimed. Although the rollover degradation of peak power is very important. Over rev capability is a key feature of good race car engines, but is not often a priority on steet engines. That loss of low end torque is a major issue. and cam optimization doesn't look like it will peal it back.



For everyone here, the terms of reference are 331 stroker engines. Although I've said "Cost effective 331 stroker base Windsor 5.0 or Cleveland 351", its only 3.25" stroke owner created versions I speak of.

I know what a 351C with 2V or 4v heads can do...if its block has enough metal in it, it will make 850 hp with the right parts, even 4V iron heads, rev to 9000 rpm, and swallow Windsors whole. Its simply Fords most enigmatic, psychotic small block ever. But its all about 331's with downgraded, but still crazy, TFS 185 heads.



Re the intake design due to block deck, it is totally an issue. Click 360° View in the links below. The taller 351W intake has the relief for the distribtor, the 5.0 doesn't, and is way shorter, with less runner volume.


See http://www.summitracing.com/int/part...0004/overview/ verses http://www.summitracing.com/int/part...0003/overview/



TFS use a unified lower intake, 03 suffix for 302/5.0, 08 suffix for the whole kit



04 suffix lower intake for 351/5.8 Windsor, 09 suffix for the whole kit


Each has a different runner arrangement by simple geometric needs. The 302 and 351 Cleveland is depending on year, 77 to 79 % of the 351 Windsors deck height gain over the 5.0. You can "cut and shut" the 04/09 351w intake to suit a 302c/351c deck with reasonable ease if its downgraded to the Windsor style TFS heads. But its never gonna be apples verses apples.


Re critical loads drop off with longer rods. I saw this with Brads Speeds Shop (Australia) in the 1988 Budget Buildups series where improved verses existing % of critical loads were charted from an early Engine Analyser program. The long rod allows potential reduction in critical loads if you use up the percentage difference in making extra power. Included were the degrees at maximum piston speed, the idealized intake, critical intake, ideal and critical exhaust dia &primary and secondary length.

On all the weird Cleveland block combos, 5 years after the official death of the Aussie Clevelands 1982 shut down (they recommisioned it for a last run of US DeTomaso engines in 1985), there were guys doing Clevor A3 headed engines, and even Keith Root heads on Cleveland blocks. Lots of work was done becasue of the potential Nascar illegal Yates Heads out cry, and the prospect of Windsor Cleveland 351WCP stamped SVO blocks.

In Australia, a stroked 302 is very cheap. A stock 351c is likely to be the expensive option. In the US, its the reverse. In a Fox, the 351C is ackward, but not hard. A Boss 302 would be easier.

There is a reason I've focused on the non 335 head. Standard observations below. Zone out if you think this is not relevant.


Ford excluded further work on this head after 1974; so have I. Ford tried to hobble the race horse in the US and Australia to get some economy back.

The Cleveland engine has never been an engine that looses power past its peak rpm, even with the standard 256 degree at lash cam. It was always an engine you could use the extra rpm on past 4700 rpm. On the 260, it didn't like the extra rpm past 4700rpm, but the 289 and 289 HP, 5.0 roller cam M code, and especially the H code 4v 351 W, they loved to rev past 6000 rpm. Ford US used the K code and Cobra jet style cam profiles and better rod ratios to overcome CFM breathing restrictions. The issue has always been, the canted valve head makes the Windsor based Boss 302 a rough engine, and its difficult to emissions and CAFE tame that engine. Ford used the 335 head as a bandaid to going to a big block, getting breath-taking power under wide open throttle in automatics by allowing upshifts to be at very high rpm on the 4V variants. They progressively toned it down for the 400 2v and later 351m engines, starting with 5200-5600 rpm rpm upshifts for 285 hp 4V's, then moving down to 4000 rpm for the later 2V's. Although the 400 and the last 1983 351M Bronco and F150's survived the Clevleand executioners death notice of the 1973 model year, the emissions package development stalled.

The 351 C and the 351m/400 is a realatively rough engine verses the 351w. The engine has noisy combustion with incipient detonation very early on. It has the potential of better cfm figures, with a modest intake runner size gain over the Windsor wedge. The Windsor's wedge head, or variations of the wedge windsor, are smoother, and all the EFI intakes have been designed. No body bothered with the Cleveland. The A3 and B3 SVO heads, CHI's heads and intakes, all too little too late. Ford Australia pensioned off the Motorcraft 4350 4-bbl and replaced it with the Chrysler derived plastic Thermoquad 9800 series carb, but then used the 256 degree 2V cam, and 2V heads, and a 4v intakebut with dropped to 4000 rpm full throttle upshifts and no 2350 rpm high stall FMX and C4 converter anymore on the 1974 engines, with over rev capabilty on those engines stil allowing 120 mph plus top speeds and better excelleration with rpms well above the new 4800 rpm rev limit. It always showed the 2800 rpm torque hump gain where the intake runner sized allowed a lovely thump in the back in these engines from fairly poor low speed response.

Henry Ford II made the 335 series engine decision in 1978 from feedback from the long term crystyl ball gazers, and he told the Australians the bad news in 1979 while driving the 1979 model year cars with his son Edsel Ford II. It may have taken six years for Ford Oz to obey, (the last 351C Bronco and F100 was 1985), but SVO USA was still listing the Aussie XE and pillow blocks and closed chamber 57 cc 2V 302 heads as an SVO cataloge item till 1988.

[PaceFever79]

I'm enjoying reading the back and forth about long rod stroked Windsors. But the real enigma is the silly rap that the 351 Cleveland got as the aftermarket ramped up all these awesome go fast parts and technologies to make a Windsor go fast, faster than most competitors. But the simple fact remains that nothing can touch a 351c for HP per cubic inch on the track, or HP per $ spent on the street. The racing heritage is unquestioned, Clevelands dominated and had to be weight handicapped in order for the competitors to be competitive. This includes the mighty Mopar Hemi. On the street, nothing from that era (pre DOHC, LS era) could touch a warmed up 4V 351 Cleveland on the street. Like I said, it's not hard to get a mild 351c 4V to make a very streetable 450+ HP with bolt on parts. Back when I was a teenager working as a mechanic at the local gas station, my '67 Fastback with a stock 4 bolt main block / 4v head / 351c budget build with a 4 speed and 4.11 gears ran high 11s, and it was my daily driver!

Just sayin

Back to long rod stroker talk....

[Ethyl Cat]

I did expect a 10% hp growth if the cam was optimized to bring the critical loads to the same percentage of the short rod engine.


I conceed that without some kind of very astute optimization of other parts of the engine and cam profile specs, there is not the net gain I've claimed.

The reality here is that with this combination there is no optimization to be done. I can change ICL, LSA, lift , etc and with these heads every move is backwards. In this case the best cam is the best cam for both.

Now if this was a limited induction engine, I feel it would have needed two different profiles for long and short rods as I have stated in the past.

[Ethyl Cat]

Also that Box R disappointed me.

It flows less than a prepped Systemax intake.

It looks great until you look at the true flow path. It can be fixed though with some work.

[xctasy]

End of long rod argument in this case for an inlimited induction engine.

What do you want for the free information you gave?

[Ethyl Cat]

End of long rod argument in this case for an inlimited induction engine.

What do you want for the free information you gave?

So it was a short long rod discussion?

I do not want anything.

Maybe we can run the numbers on something that IS induction limited and see what can be done internally and with the cam to help maximize performance.

If you are interested, do you have a baseline engine design that you want to look at that has good reliable information we can use or that you can supply?

[xctasy]

Etyhl Cat, 9 months since I started on more air flow limited research.

I've got two basline engines, the 302c 4bbl and the 351c 4bbl, which isn't air flow limited.And the 200 and 250 2-bbl Weber 34/34 ADM with 27 and 29 mm chokes x-flow alloy head, which is.

All 1982 XE Falcon engines that I've spent a lot of time behind from 1982 to 2003. My boss in Alexandra had both a 1977 Fairlane 351 4-bbl, an XE Fairmont 302 auto Station wagon and another workmate with a 351 auto Station wagon, and myself and our neigbour in Dunedin had a pidgeon pair of 200 abd 250 GL Falcons with the same engine blocks. There was another 302, I drove extensively in a 1979 XC Fairmont auto. Blairs 375 HP 351 XY I never drove. But I sat in it in a 1/8 mile dash, and it is the most insane small block I've ever experienced.

All the details I'll post if you'd be good enough to run it through your program.

Before I start.

Got two questions now. Question two down a bit.


Question 1. What, in your opinion, constitutes an air flow limited engine. Is it flow net peak critical air speed going over 265 feet per second, or is it a venturi area, port area warning in your assement program?


Your information was entirely correct and pivotal, as not many 4-bbl Ford V8 engines are ever deamed to be 'airflow limited", as they are short stroke, large bore engines with plenty of port area, the 351C the most oversized ports for the capacity of nearly any Detriot engine design.

Remember, I'm a 100% Ford Cleveland V8 guy who just happens to have gotten his hands dirty on
1-bbl GM 2.2, 2.6 and 3.3 liter non cross flow sixes from 1958 to 1973
Ford SOHC 1993cc Pinto EAO's
then Kent bowl in piston Cross flows
SU carbed A series 998/198/1275,
Cologne 2294 cc V6's
and then a brace of 200, 221 and 250 generally single carb in line Falcon sixes with a range of log head, 2V, or cross flow intake port configurations.

If ever there were air flow limited engines, it would be the A series, the GM L6 sixes and especially Ford small I6. If ever there was an engine with less air flow restriction than the Bob Pinnel spec forged piston, NASCAR blocked 2V headed 4-bbl 351C and the production 114 hp 2.3 liter 2-bbl Solex 34 Colgone V6's, I've yet to see them. Both engines reved out to 7000 rpm without a hint of distress.


I studied early 1960's Ed Pinkerton rod ratio work, who did Morse testing of FE engines on work at Ford’s Scientific Research Organisation. And then rechecked every reference to half lambda ratio peak power increases. That is, if, say, David Vizard claimed a 2 hp increase due to using a set of longer rods, at what lamda ratio improvement was that, and is the engine "Air flow limited"

There are actually plenty of them, and its very relevant to the restricted engine formula's US racing polices for cost reduction reasons.

Any references to rod ratio power gains indeed fall under "air flow limited" and for this reason, need qualification. But there are plenty in addition to what I've historically listed!



https://www.youtube.com/watch?v=ow5cGV7bXCw

in the 2 minutes out of 2hrs with David Vizard A Series from 1 min 47.18 to 1 min 49.24sec

This was a 1.8:1 rod ratio small bore 2.78 to 2.95 " long stroke 3.2" stroke engine with 5.75" rods. Add the rare Cooper 970S 6.00" rods, and rod ratio improves 4.2% to 1.875. Gain was about 2 hp on what is normally a 100 hp engine at the modified 1275 to 1435 cc level. Its air restricted because it won't operate under Independent runner conditions, even with the best carburation, due to the siamesed intake ports.

Now I've driven many, many long rod 200 cross flow and 302C 2v engines which both have 2:1 approx rod ratios and short strokes, and they put out better specific power than the bigger 250 and 351 engines. They aren't lethagic, they are smoother as fast for top speed, and while they certianly have 25 to 16% less torque, the 1/4 mile times drop from 17.9 seonds as a 200 to 17.6 seconds as a 250, and from 16.9 seconds as an auto 302C 4-bbl to 16.5 seconds as a 351c 4-bbl auto.The 1982 3.3 could do 111 mph, the 250 109 mph. The 302 auto, 118 mph, the 351 auto, the same.

The figures, DIN net, are 121 hp and 188 hp compared to 131 hp and 200 hp. Each bigger engine is down 20 hp on its idelised 25 and 16% smaller brother with the same bore, carburation, compression ratio. Just stroke rod ratio, and piston dish or chamber changes. Same camshaft (256 degrees SAE duration, same cam each ran since 1970 in the cooking model sixes and Cleveland V8's)


Question 2. in your Engine anaylser opinion, was critical air speed the reason for the specfic power out put drop?

Same with the 300 Ford verses the 240. Data is more diffcult, becasue there was no comparison to the 145 or 155 hp 240 in a fullsize sedan with a smilar 300 Big six. Fuel consumption tradeoff and acceleration tradeoff is equal to that lamda verses horsepower figure.


Now, what is porported in this article from "Ford Cleveland 335-Series V8 engine 1970 to 1982 - The Essential Source Book" is interesting.



http://www.veloce.co.uk/shop/product...=Sample%20Text

Bold font is mine.

In the very early 1960s, Engine Engineer, Ed Pinkerton, worked for Ford’s ‘Scientific Research Organisation,’ located opposite the EEE building on Oakwood Boulevard, where Car Styling and Body Engineering was housed, which afforded him the opportunity to work on various theoretical and practical engineering matters, beneficial to the company’s future projects. Ed Pinkerton carried out significant experimental work, in order to separate fact from fiction, and to determine the ideal connecting rod-to-stroke ratios, in a quest to obtain optimum engine efficiency. Much of his investigation involved a single-cylinder test engine, and, later, the FE NASCAR engines, resulting in the production of a range of interchangeable connecting rod and piston combinations, specifically for these tests. The sets of connecting rods were approximately 0.030in/0.75mm different from each other, in centre-to-centre length. They were used in conjunction with pistons, with the gudgeon pin re-positioned to compensate, allowing the overall piston crown to remain constant. Using the same two cars and engines, all combinations were track-tested, resulting in irrefutable conclusions.
The 1.68:1-1.72:1 connecting rod-to-stroke ratio combinations worked most effectively, and although the horsepower and torque remained more or less constant for all engines, there was a significant difference in the rate of acceleration off or out of a turn in a test car.
The problem with connecting rod-to-stroke ratios larger than 1.72:1 is that, as the combustion pressure increases when the piston is at top dead centre and just past it, the connecting rod is technically pushing down vertically onto the crankshaft. The longer the connecting rod, the longer the time it is effectively too vertical, and, as a result, the combustion pressure energy is not being used to maximum efficiency to turn the crankshaft in the direction of rotation; essentially it is trying to push the crankshaft out of the bottom of the engine.
The experiments carried out by Ed Pinkerton concluded that, generally, for all current Ford engines, a connecting rod centre-to-centre distance to crankshaft stroke ratio between 1.68:1 and 1.72:1 was the requirement, with the latter regarded as optimum. The centre-to-centre distance of the connecting rod is divided by the stroke of the engine, which is sometimes referred to as the ‘L over R’ of an engine. Pinkerton noted that if the connecting rod-to-stroke ratio was less than 1.68:1, this factor did not necessarily result in an engine lacking responsiveness, however it did start to affect the piston skirt service life; the shorter the connecting rod, the higher the rate of piston skirt/bore wall wear.
Ford sometimes went beyond the ideal connecting rod-to-stroke ratio of 1.72:1 for other reasons, notably for the 1969 and 1970 Boss 302ci Trans-Am racing engines, that used its Indianapolis racing engine connecting rods, with a 5.312in centre-to-centre distance. This was coupled with the 3in stroke, which, quite coincidentally also resulted in a ratio of 1.77:1. In this instance, it was exceeded to keep the piston weight down, as 0.157in of connecting rod ‘I’ beam cross sectional area weighed less than 0.157in of aluminium piston skirt mass, but, this ratio was regarded as the absolute upper limit. In the 1960s, car engines were not reaching such high rpm levels as today, where current NASCAR V8 engines are turning 9000rpm, and, based on experimentation and the subsequent results, all have connecting rod-to-stroke ratios in the vicinity of 1.77:1-1.81:1.
To increase the capacity, nowadays, various types of long-stroke crankshafts are fitted to V8 engines, and as a result, the connecting rods are becoming shorter and the pistons designed more squat to fit into the block. Although this procedure is quite acceptable, due to the loading, the bore wall and piston skirt life can be greatly reduced. Therefore, it becomes a matter of obtaining a larger capacity with a reduced service life expectancy over stock, and possibly, an engine with less than ideal engine performance characteristics.
The original low-deck USA-made 1970-1974 351ci-2V and 351ci-4V engines used 5.778in centre-to-centre distance length connecting rods, as did the Australian-made 351ci-2V and 351ci-4V engines between 1972 and 1982. However, the 302ci engines manufactured at the Australian Geelong Engine Plant between 1972 and 1982 used components with a centre-to-centre distance of 6.020in, specifically to allow them to employ the 351ci piston. This move, while allowing Ford Australia to use a common part, reduced engine performance capability, as the connecting rod-to-stroke ratio was well above the ideal range.


When the 351ciM-2V engines came on stream in the mid-1970s, they were used to power trucks and many cars. Mrs Lee Iacocca had a car fitted with one of these engines which cut out on the over-run, leading up to a roundabout. When the engine stalled, there was limited power assistance for the steering, and she careered straight over the roundabout and into a fruit stall in a market place, before coming to a halt. Fortunately, no one was injured, but on hearing of the accident her husband, President of Ford, Lee Iacocca, demanded the problem was fixed immediately, as it was unacceptable for expensive Lincoln cars to stall in this way.

Engine Engineering engineer Bill Barr was assigned to investigate the problem, and when testing the cars, could not believe how sluggish they were in comparison to the earlier USA 351ci Cleveland engines. He subsequently made enquires into the differences between the two versions. When he was given the data, he recalled remarks made by Ed Pinkerton at a lunchtime discussion in 1963, during the Indy engine programme, regarding connecting rod-to-stroke ratios. He noted the long connecting rod aspect of the 351ciM-2V engine and extra weight of the internal components, in comparison to the 351ci US Cleveland. The connecting rod-to-stroke ratio of the USA 351ci Cleveland was 1.65:1, versus 1.88:1 of the 351ciM.
For low-deck block 351ci racing engine applications, changing the original stock-connecting rod centre-to-centre distance length from 5.778in to 6.020in, in conjunction with the stock 351ci stroke, results in an increase in a ratio from 1.65:1 to an ideal 1.72:1.

Connecting rod-to-stroke ratios
Engine Connecting rod-to-stroke ratio
302ci low-deck 2.01:1
351ci low-deck 1.65:1
351ci tall-deck 1.88:1
400ci tall-deck 1.65:1

[Ethyl Cat]

Not ignoring you Xctasy, just trying to figure out the best way to answer you without writing a book.

[xctasy]

Thanks EC

Yeah, don't rush it. LOL.


You are probably aware that I've gotten it wrong,wrong, wrong for 13 years. Despite having the best teachers in the world from these US forums.

I think it took the last 9 months to figure out what the difference between "unlimited airflow" and "airflow limited" is in ways I can understand. Traditional cam selection is based on inlet flow availability versus dispaced cylinder volume. On a good 351 4V, its over 100%, on a 200 six, its about 60%.


To me, for the last 13 years, I've effectively been making a query as to why limited airflow engines "seam" to show a specific loss in hp per cubic inch.



Phil Irving had a hp per rpm per cube table, which has forced production based engine block endurance racers like Larry Perkins, and Holden Australia, Ford Australia in there V8 Supercar 5 liter engines to push the long rod engines for endurance 600 mile race environmnents.

The bigger 2002 stroker 8.206" deck 5.0 Ex T3 Ford Falcon FTE 5.6 strokers and and the last Holden 8.9" deck, 4 by 3.48" 5.7 liter (VS GTS Commodore, VS Senator 215i, VT GTS Series 1, VT Senator Signature 220i was also a Holden 304 to Chev 350 stroker engine) were used to optimise production engine blocks for the market which really wanted 335 hp of more engines. The Holden 5.7 stroked 5.0 engine fall flat on its face over 4000 rpm, the Ford so called stock bore 347 stroker engine just ate up everything from 4000 to 6000 rpm.

Each wasn't limited by the traditional Stan Wiese idealized PLAN hp per cubic inch correction, they were designed to use rod ratio to optimise power with the planned cam duration. .

I had the same video David Vizard explaination in 1988 in his third A Series Mini engine book, but like lots of things David Vizard, he gives the SPECIFIC answers but its very specific to application, and its possiable to over simplify a response to that is caused by other things. A 1293 cc As eries In line four is not a 331 stroker V8, and none of the tuning solutions result in the same power increases even on a percentage basis, because everything else has changed.

Same as recomended cam lobe center angles

https://fordsix.com/viewtopic.php?f=...512487#p512487

You have to really watch the stuff that follows David Vizards articles, write-ups and books. there are some liberties taken that do not necessarily apply globally in all instances.

[Ethyl Cat]

I found this interesting in the Pinkerton article:
"The 1.68:1-1.72:1 connecting rod-to-stroke ratio combinations worked most effectively, and although the horsepower and torque remained more or less constant for all engines, there was a significant difference in the rate of acceleration off or out of a turn in a test car."

I am unsure of what you are saying about the engines here:
"Now I've driven many, many long rod 200 cross flow and 302C 2v engines which both have 2:1 approx rod ratios and short strokes, and they put out better specific power than the bigger 250 and 351 engines. "

Based on the power numbers you gave the 200 six makes .605 hp/in3 and the 250 makes .75 hp/in3. The 302 V8 makes .43 hp/in3 and the 351 makes .57 hp/in3.

On thing DV says in his books is that given everything else is the same, an increase in displacement of 1 cubic inch equals one HP. In the case of both these comparisons it holds true and then some if they are truly similar in all other aspects except stroke. 67 hp on the sixes and 69hp on the V8s

I think the long rod in the 302c was a means to an end just like the info states. A way to hook the 3" crank to a shelf piston. The lack of performance came from a relatively big runner and valve for the engines displacement. The Cleveland head is a 190cc runner and a 2.04" valve compared to the GT40p at around 150cc runner and 1.85 diameter valve. SAME airflow capabilities! Which one do you think works better? If they did not change the cam then it was most likely the wrong cam for the displacement. Many, many things most likely affected the performance but rod ratio is last in line. I wish I had some detailed info on all 4 powerplants.

On the Lee Iococca passage, the 351M sucked pond water for a bunch of different reasons (as most mid 70's engines did) but I feel the rod ratio was not one. In my opinion the absolute last thing I would use on evaluating an engines success or failure in a given arena is the length of the connecting rods.

On the long rod helping a weak head:

If you compare a 6" rod 331 with a 5" rod 331, for the first 90 degrees of the intake stroke the short rod creates about a 3.5% (4.1% being peak) harder pull on the intake runner compared to the 6"rod. For the second half of the stroke however the LONG rod pulls harder to the tune of 5.5% with a peak of 9%.

If your port is weak and you can slightly delay the hard pull until the valve is far enough open it could benefit cylinder fill. If you have a ICL of 108 your valve is near peak lift right when the long rod late pull begins. This in turn can enhance near and post BDC flow.

I have the words may and could in there because it is just my thoughts on this topic and I do not have an empirical evidence that it is true or total bull honky.
There is no way I will ever be able to afford to do any A-B-A testing of something like that.

As far as an increase of cylinder pressure around TDC on the power stroke with long rods, in the simulation the difference between a 5" rod and a 6" rod in a pump gas 331 was about 10 psi more for the long rod out of 930psi total or about 1.1%.

Fun facts:
The 427 NASCAR engines in the article ran about 7000 rpm. A ported Tunnel port FE head flows about 320 cfm and the piston demand on that port at that rpm is 363cfm.

A 358 NASCAR small block turns around 9500 rpm and a ported R07 head flows 410 cfm at the same lift as the FE and more at higher lifts up to 460cfm at 1.0" lift . The piston demand on that port at 9500 rpm is ........ wait for it.........410 cfm

Which one would you consider a flow limited engine? Which one has a 2.0:1 rod stroke ratio? (Hint: the article says the FE has a 1.72 ratio.)

Do you think the NASCAR builder did that for power from cylinder pressure or air induction? Friction? Reciprocating mass? Your guess is as good as mine.

Lastly, Buddy Rawls has forgotten more than I will ever know about this stuff. Tons of respect for him. Read all of his posts every time you see one.

All done.
Xctasy hope I answered something. Your questions always send me on a quest for answers to the questions they create. Thanks for that.

[xctasy]

Yes, all done.Thanks so much.

A couple of extra appendums to show you how I used the Phil Irvings Aspirations Index method of power assesment, with a response from BR.


Since I didn't make it too clear,

3.3 is 121 hp, 4.1 was re-rated by Ford Australia to 131 hp in March 1983 for all XE 4.1 passenger cars. That is, 0.607 hp per cube vs 0.525 hp per cube .

The 4.9 passenger engine was 188 hp, the 5.8, 200 hp, or 0.623 hp per cube vs 0.568 hp per cube.


I am totally comfortable that air flow limited is based on cylinder deamand verses port air flow. That's all the info I really needed.



Without trying to make it too complicated due to "scum sucking metrics and German DIN net horspower readings",


the Aussie 3.3/200 and 4.1/250 were DIN Net rated at 121 hp, 177 lb-ft, and and 131 hp and 225 lb-ft. Just a 10 hp increase, just an 8.2% increase.



Despite having the same 9.38" tall block, the 3.3 had a 3.126" stroke and 6.275" rods, the 4.1 had a 3.91 inch stroke and 5.88" rods.



So the capacity increase due to stroking it was exactly 3.91/3.126, or 25%. The hp per cube was based on the real engine capacities being 3269 cm3 or 199.5 cubic inches, and 4089 cm3, or 249.5 cubic inches. Why only aan 8.2% power increase?

The 1982 press figures were wrong, Ford admitted it at the 1983 press release that the 105 kW /310 Nm rating was the less emissionised F100 engine figure. The same thing happened from 1976 to 1985, with the 207 hp 302 or 216 hp 351 options in the F100 and Bronco missing out on the updated emissions equiment of the passenger cars. .


The 351 is 3.5/3.0 bigger, 16.7% bigger. After 1978, all sedans had more emissions gear, and 188 hp in the 4.9, and 200 hp in th 5.8. The 254 lb-ft torque figures was rasied to 306 lb-ft. The power increase was only 6.4% from a 16.7% capacity increase.


In both cases, the specfic power dropped off with shorter L/R, longer stroke engines in the same block. Torque was, off course, proportiona to capacity increasel, and at a lower rpm figure.


What I am saying is the aspirations index, as I described to Buddy Rawls on Sep 11, 2011

https://fordsix.com/viewtopic.php?f=...508236#p508236

Your factored relationships are essentially an inlet capability versus displaced cylinder pumping volume ( CID and rpm) relationship. You have established a criteria or fudge factor to address the actual port velocity issue (which is super important to the process), which is critical to the big picture. One end of your spectrum is very restrictive motors ran at high rpms (extreme port velocities), the other end of the spectrum is very flow capable inlet inlets running at low rpms (slow port velocities). I do not use multiple curves based on the level of modification, I go straight for the actual inlet and outlet parameters in comparison the displaced cylinder 'pumping' volume using a single set of equations, regardless of the build level. Three quick examples, using your A? relationship, in my direct experience (camshaft customers) are an FIA 289 build that mapped to a 4550 AI, a 360 cid outlaw street car (nat asp) that mapped to around 3600 AI, and a stock headed 125cc 289/302/E7 head on a 306 that ran around 5700 AI . I have never used such a rating system, but it is cool to see how it fits in your criteria.

The AI aspirations index for the 200 is 199.5*4100/121, or 6760. For the 250, 249.5x 3800/131 or 7237. The specfic power for every rpm is 7.0% less with the 50 cube bigger engine. In terms of hp per cube, 0.607 vs 0.525


The aspirations index for the 302 is 301.6*4500/188, or 7219. For the 351, 351.9x 4300/200 or 7566. The specfic power for every rpm is 4.8% less with the 50 cube bigger engine.

In terms of hp per cube, 0.623 vs 0.568.

In both engine families, the short rod, longer stroke engine is power compromised compared to an idealised one % power for one % capacity increase.

[Ethyl Cat]

Ahhh, so I got the numbers mixed up. Thanks for clarifying.

That is an interesting formula, thanks for sharing.

Looking at that engine info, I believe that you are trying to use racing engine design philosophies on a passenger car engine. A HP increase was never Fords intention when creating the bigger engines. If it were they would have changed different or additional components.

Do you get a longer lever to lift MORE (HP) things or to lift HEAVIER (TQ) things? If we move to the torque numbers it is obvious what Ford wanted to do.

Peak hp does not get a car rolling stoplight to stoplight. Peak hp does not affect cruise MPGS.

If we apply one of my favorite engine efficiency formulas to these engines maybe it will show what I mean. BMEP- Brake mean effective pressure

The short definition is that this indicates the average pressure applied to the piston during the power stroke.

150.8 * TQ / CID
I converted the torque numbers to SAE:

200 six= 178.7 psi 237 lb/ft
250 six= 184.6 psi 306 lb/ft 25% increase in displacement and a 29% increase in torque=win

302= 163.8 psi 328 lb/ft
351= 175.7 psi 409 lb/ft 16% increase in displacement and a 25% increase in torque=win #2

These all used peak tq numbers as opposed to peak hp. So with an increase in displacement the engine can run the same amount of cycles to perform its job better and with nearly the same fuel economy. If it makes more torque it needs less throttle, less throttle =less fuel consumption. Also since the rpm ranges are similar Ford did not have to redesign anything (trans/diff) to make it happen because the engines
operate in the same parameters

You can see that adding a short stroke crank to the 351 ruined its efficiency ( 8%). Therefore the decision to make that engine was purely based on money. The long connecting rod was the way to get it done.

You can also see that out of all the engines, the 250 six is the most efficient one

So again, I think you are confusing yourself using race engine evaluating techniques on passenger car engines. Apple to oranges.

Fun conversation!

[xctasy]

I am totally on board with torque and how it produces a resultant power curve when a speed factor is applied.


I'd say no to an extra 45 lb-ft if it gives the same acceleration with better fuel economy.

If we eliminate my focus on peak power, and go back to a Simpsons Rule apprach of determiing area under a torque curve, that is work done.




You'll find that the peak values per rpm aren't what should be looked out, is total area under a curve. The loss of 1000 to 2500 torque from a better rod ratio is then squared off against the gain in 2500 to 4800 rpm.

Its not a steady state, the vitality of an engine is based on its abilty or willingness to make power.


I'm lucky, I look at dyno curves, and go back to good old Imperial torque plots, see the Simpsons rule, not the peak power. I use peak power, but peak power is only a measure for the abilty to do work at a certain rate.

Ford publicly states great info like this


But I pull it appart, and see only this, the crimson torque line.



A classic example is the loss of 9% in torque when the 346 Chevy LS1 replaced the 350 cubic inch Holden V8. The 1998 Holden engine made 288 hp and 350 lb-ft with a 1.616 Golden Ratio rod ratio. The 1999 Chev LS-1 lost its area under the curve torque from 1000 to 3500 rpm, the peak torque loss was a massive 21 lb-ft, with just 329 lb-ft, with only another 7 hp at the top end. It then gained it above 3500 to the 5252 rpm unit, and gained power to 6600rpm. Rod ratio was 1.68:1, and it had a reduced bore and increased stroke. Again, not apples verses apples, but proof that torque isn't the only thing that Detriot uses for Raod Car performance.


In so doing, it gained fuel efficency, peak acceleration, and smoothness, despite having a wide lobe sepration. It offset any torque gain by running very high compression and detonation preventative measures like high swirl head that snarled up peak cfm for the sake of mixture motion. And in so doing, it carried more revs on the roadin every situation, yet got better fuel consumption.

Based on detontation, I think the rod ratio was the facilitator to getting the high end torque to operate as the sweet spot. If torque was only the measure, then they would have stayed with the earlier engine. Its not, its brake specfic fuel consumption and real world peformance are the measures.

This is getting back to what people like Larry Widmer have been saying said,

After spending time on an engine dyno trying to optimize power and finding out there was more to it than this, I realized that these engines only spend a short time in the upper rpm ranges. Most importantly, they must be able to accelerate through a range of rpm. With the possible exception of a superspeedway engine that operates in a comparatively narrow span of rpm, an engine must be built to move quickly through whatever range of engine speed is being used, under load. Stated another way, it must not only make torque, but do so as quickly as possible.

http://www.hotrod.com/articles/ctrp-...e-past-to-now/

So we focus on tqrque, and dyno runs, but an engine isn't subject to a 600 rpm per second dyno pull. It must have an ability to use the torque as an impulse.


I've driven all four engines 200/250/302/351 engines extensively, and I'm at the point where I think the set form of looking at torque only is part of the problem. The outworking of it all is Engine Masters verses NASCAR. The 3.3 and 4.9 were standout economy engines that lost very little in acceleration over the bigger 4.1 and 5.8. I'd say no to an extra 45 lb-ft if it gives the same acceleration with better fuel economy.

In fact, the 3.3 was faster and quicker than the 4.1, despite having less torque.

The 1982 3.3 and 4.9 were such a sweet engines, each had ecconomy which was supperior, and its rev range on each smaller engine could be extended to 5500 rpm over the normal 4800 rpm rev limit for the bigger engines.