Air Fuel Ratio

[Ethyl Cat]

Blowby can only come from the rings.

Hopefully you oriented the top and second ring correctly and they are in the right groove.

If piston to cylinder wall is really .030" that is your problem. Surely you wrote it wrong?

Maybe the cylinder walls got washed out from the rich low end.

Do a cylinder leakage test.

[80Merccapri]

Yea I wrote that wrong it was supposed to be .0030 but mine was .028 so yeah I think it's time to bore it out. Top ring was the moly one and the second ring was installed with the dot up like the packaging said. Why were my cast Pistons fine with wall clearance and now the forged 3.780 bore one side clearance so far out?

[Ethyl Cat]

It is already bored out it sounds like.

Maybe you assumed it was standard but it was not when you ordered pistons?

[80Merccapri]

I'll check my old Pistons. The forged ones that are in there now wiggle around a lot in the cylinder. new Pistons are 3.780 though. If there the same size as my new ones what could cause them to be that far off? Could the cylinder of wore that much?

[80Merccapri]

The old ones are 3.750 diameter. So they must be worn out pretty bad

[xctasy]

I'm not going to tell you why, it'd just confuse you.

You need an e tube with less holes at the top when viewed upside down. 61440.166 or F2 will do it. That will instantly richen your high end rpm. The DG 38 series 250 needle and seat will do the rest.


First, Apply a new needle and seat, and re-adjust the float level to spec. You never, ever even start tuning a HW unless the fuel float level and fuel control equipment are in triple AAA+ spec.


Then recheck idle corrector.



Everyone else who puts a HW 5200 in a six cylinder engine richens the idle.

When you cam up and turbos a stock 4 cyl engine, you find you now have:-

Too little fuel up high above 4000 rpm.

Probably too much down low.

At the very least, you should block up the F5's top holes when viewed upside down, to richen up high rpm air fuel.


So you need less holes up top, and and maybee more holes down low to reverse the situation.

The master list for these tubes is the Weber 61440 xxx Fx emulsion tubes They use xxx numbers, not Weber Fxx Numbers.

Interchange below has the lengths as well, laid out in landscape so you can compare them. You view them from the right side of the page, so that the e tubes are upside down.




Stock lengths choices are 34.5 mm, best to avoid resetting your float level, and just use those lengths.

61440.166 is the Capri 2.8 liter US emulsion tube, an F2, and its richer up top.

The F7 (61440.226) is different than the F70 (61440.197).

An F50 is radically different to an F5, but they do the same thing

You'll find F78's in most Weber ICH/ICT 34 carbs we use for VW's and 200 Ford Offy/Edelbrock Tripower set ups, although its taller, and has an integrated air corrector.

Your 34.5 mm 61440.xxx series e tube choices are:-
166 (F2)
181,182, (F3, F5)
196,197, (F4, F70)
211, 212, 213, 217,218, 219, 223 (F6,F8,F24,F53, F56,F57,F80)
216,224 (F50,F81)
220,222 (F66,F7
226 (F7)
229 (F87)
488 (F25)


There is a F30 which is 33 mm, close enough, i'd guess, and others are valid as long as you use the recommended float level with them.

Your F5 Emulsion Tubes needs more holes to lean it down low, and less holes to richen it up high. Ford used F5 or F50, F6 and F66 emulsion tubes on 2.0 and 2.3 engines with this carb. he 2.8 uses the right e tube you need. Maybee the Turbo 2.3'S 974 well tube will do the same thing.


You need to add holes down low, and take holes out up top.

You can solder and drill the brass tube. Like swanson 454 did on his 245 cube Jeep, and Airbert on Fordsix Pefromance did with his 1961 Falcon 200. .

Turn the stock issue F5 or F50 e tube upside down with Main jet at top and air corrector at the bottom.

The normal F5 is pretty much the same operationally as the F50, but its a different section width and has an external as well as internation section change, plus different holes.




Upside down E tubes. Left hand side, F50, which is near enough to your F5.

Then F6 then, far right, his custom F7.


He then turned it into the F This



F6's and F66's are other common replacements. Airbert (Mr Neuman) found an F56 too

[xctasy]

Go to a library, and get this book if you can.



http://www.amazon.co.uk/Tuning-Briti.../dp/0854297324


Tuning British Leyland's 'A' Series Engine Hardcover – Aug 1989

The problem with your high rpm air fuel ratio swing is blow by.


The way to fix it is to remove it by an evacusump system, two 5/8" PCV valves to the intake manifold from the rocker cover.


And then two anti back fire valves flowing in excess of 18 cfm each from the lower turbo manifold flange to a dedicated rocker cover catch can.

David Vizard described on in pages 398 and 399 of his second edition of modifying BMCs A series engine, and discussed Turbo applications specfically. Diagrams 15.2a, and 15.2 nail the sysyem down.



Its also covered in




How-to-Modify-Ford-s-o-h-c-Engines-David-Vizard

http://www.scribd.com/doc/26804743/H...-Vizard#scribd




In the A series 2ND Edition book, DV said that blow by from valves and pistons collectively defines remaining engine life. An Evacusump system should pull 1.85 to 2.65 inches of Hg suction at operating temperature. When the figure drops below that, it only has 15 to 30 minutes more operation time at full load.

[80Merccapri]

I will have to check for that book this week. But drilling the power valve solved all my issues for now on 9 pounds off boost. I got the blow by to almost completely stop. I had a vented an fitting in the valve cover added and it was leaking out of that I believe even though it was baffled and could install anywhere. Blocked some of it off and it stopped 90 percent of it I'm gna try blocking it completely and see if it will stop it completely. Piston to wall clearance was fine no more than 3 thousands. Piston does move in the cylinder slightly. I took pics of my plugs today so you can look at them, air fuel never goes past 12.5 under wot. Mostly around 11.8. the an fitting is on the side of the valve cover so I'm guessing it was leaking from there even though it's baffled and not over any oil holes. But my catch can would fill up 3/4 full in 2 or so miles than after I plugged it off a little it wasn't even showing on the marker after ten miles of fairly hard driving. Car never ran so strong so there is no way my rings aren't seating or any thing is to far out. i had the stock filler cap and the an fitting to a catch can and than it was vented to the air from there. I'll pay pics of plugs when I can't though. Thanks for the help I'm gna need those books for my carb when I increase boost most likely.

[xctasy]

Cool.

Just a note. The removal of blow by is based on the dyamic leak down rate of 3 cfm at 5000 rpm overall for a Formula 5000 or TransAm or AVESCO 630 hp 302 SB Ford or Chevy making 450 lb-ft of torque at 5000rpm. Thats 3/8ths of a cfm per piston for an engine making about 630 hp at 7500 rpm.

David Vizard allowed for a heck of a lot more blowby than most Americans would be confortable with. The 1275 would have to have a 37% leakdown rate to pass 18 cfm of blow by, but that is how the evacusump system is oversupplied by the suction force of the exhaust, and that gives depressions of 1.85 to 2.60, and the vaccum really unloads the rings to reduce flutter.

Or your engine making, say, 135 hp stock with cam, then maybee 215 hp turboed, then perhaps 315hp with a turbo and nitrous. Blowby is proportiona to torque gain under nitrous as well, so it will go up 50% with nitrous, balooning the normal wear environment on the piston, and pehaps making 2.25 cfm total in good shape, 9/16ths of a cfm per piston. As the rings and bore wear, blowby will go up as the static leakdown rates (measured under a 24 hour or overnight test pressure) drop from 80 to perhaps 65% for an engine getting really tired.


I'd expect a static leakdown of 80% to yeild those kind of 2cfm figures at about 4000 to 5000 rpm under the giggle gas. . Engine health is best measured by blow by pressure if Evacusump, as the rings are unloaded by the system. The life remining can be drastically increased by having a little think, and then deciding to incorporate some kind of Evacusump stratergy.

Like everything, its your car, and you don't have to incorporate a xctasy grocery list of wack job ideas...but it sure as heck is an awesome indicator of engine health, a barometer which if used, will allow you to confidently lean a little harder on your 2.3.


See http://performancetrends.com/Blowby_...owby-CFM-Table

[Bymguate]

Had a similar issue. Heres what i found and fixed my problem. It was a simple float needle calibration with the nitrofill floats...

https://www.youtube.com/shared?ci=tDdomH56-mY

[80Merccapri]

Needle and seat were way to small. Not allowing the bowl to fill up fast enough. Drilled one out with success but after increasing the boost and what not I decided to go with a Holley 350 street avenger. Parts are easy to find and cheap and jets are easy to change. Made a world of diffidence. Car is cranked up on boost and everything is happier all around. After modifying the carb a little of course. If I could go back I wouldn't waste my time on the 5200 carb.

[xctasy]

Holley 2300 series 7448 350 cfm and 4412 500 cfm carbs will always get good results right off the shelf. The carbs are not claibrated via air restriction as the Holley Weber and Weber 32/36 and 38's are.


The US Holley Weber has specific well tubes (emulsion tubes) and its not just a 32/36 DGAV copy, its a 32/36 DFAV copy, so everthing requires a lot more work.

If you have starvation, you have to rework the main fuel supply at the float.

So if you can find it, a turbo 2300 will work right off the bat with a Holley 350 cfm carb. If its non turbo, a Holley 350 cfm carb often won't work well, because of the ball cehck valve issues. On a turbo, the Holley's tendancy to go full rich is just fine.

Webers are lean carbs, and you wust not ever run a turbo out of fuel at Wide Open Throttle.

[80Merccapri]

Yeah the 350 took some work to get right. But it is a lot easier to make quick changes for tuning. And the master jet kits make it very easy to pinpoint the perfect air fuel. The 5200 I modified worked good for ten or so pounds and worked great on the bottle. Just climbing well over 20 pounds now. Was planning to stay at 15 but after the carb worked so well I went up one pound at a time until I got mid 20s.