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  1. #1

    Default Setting Up Your Valvetrain on a GT40P 302

    So, here's what I've got. It's a new rebuilt shortblock 306 with my previous GT40P heads I had on my old engine. We're going to a new Flowtech cam, new beehive valve springs, and Scorpion pedestal mount roller rockers. So, we need to figure out how long of pushrods I need, how to get proper rocker arm geometry, and shim the rockers for the consistent/balanced lifter preload. I tried starting with rocker geometry using the Half Lift method, outlined in this video:

    https://www.youtube.com/watch?v=o5is9BsH5OU

    BUT, when I would go to try and get the rocker level with the valve retainer, I could barely even make that happen with the rocker mounting bolt just barely biting. It may not have even been level at that point, I'm not sure. But anyway, I moved on from there. Half lift on my cam is .275". Thread pitch on the 5/16-18 bolts is .055. So that comes out to 5 turns of the bolt. When I turn the bolt 5 turns (which really isn't enough thread biting), the rocker is a good .130" from the pedestal.



    Every video I've seen of this method uses stud mount rockers. Is this even a thing you can do with pedestal mount rockers? Do stud mount rockers not even sit down on something? Do they just sort of float there on the stud? I wouldn't know, I've never even seen them in person, let alone worked with them. Two more handy videos on pushrod length, but with stud mount rockers:

    https://www.youtube.com/watch?v=76wbtu9l09A

    https://www.youtube.com/watch?v=5MjAxnGeGKw

    Setting up where the middle of the rocker sits with pedestal mount rockers (with shims) seems to be more about getting proper lifter preload at mounting bolt torque than at what angle it does what, like in this video.

    https://www.youtube.com/watch?v=pJSj-3XS8ts&t=1s

    That guy seems to already have to correct pushrods to work with, lucky bastard. So, there's another nice technique that I don't feel like I can rely on because my situation is different.

    Apparently if I had a small block chevy though, figuring out my pushrod length would be as easy as slapping on of these guys on there...

    https://www.youtube.com/watch?v=UBO-Mgp0Og8

    But again... the easy way is not for me. According to a customer question on Summit, these DO NOT fit Fords. Of course they don't.

    I am still early in the process, but I have tried rolling a couple of patterns on the valve tip.


    The first was too low on the tip, as well as too long (the roller rolled too far). I did this one with the .130" in shims (too much) the Half Lift method told me I needed. According to the pedestal rocker video above, Ford says you can only have up to .090" total in shims on a roller rocker. On a whim, I thought I would also try rolling one with a not so crazy .040" shim in there. For the pushrod length, I lengthened it until it was at zero lash with the rocker snugged down and then torqued down the rocker. For that test, I got a nice pattern right on the middle of the valve, but it was still too long. I should mention too, I was using a solid lifter for these. The pedestals have not been machined, they are stock height, and I believe the valves are stock height for the intake, and very close to the same for exhaust. The installed height of the springs is 1.825. I was using check springs for the tests though.

    Then I thought with that setup I could try a piston to valve test. I got .230" for intake. Does that sound reasonable? I know my pistons have some pretty big valve reliefs...

    Anyway, what would you do in my place? How would you figure out your pushrod length? I should mention the original pushrods will not work. They are too short (which is weird too). I just hate the fact that the Half Lift method got me results that are far from what they should be. Today I was at the point where I was just trying things at random....
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  2. #2

    Default

    I emailed Scorpion about my confusion. They had this to say:

    "We only use the half lift method to verify proper geometry on solid lifter and shaft/stud mount applications. With regards to pedestal mount rocker arms, we recommend checking for proper lifter preload, as well as checking the witness mark on top of the valve (left by the roller). To do this, just blacken the valve tip with a sharpie/permanent marker, install the rocker (with a lifter pumped up) and roll the engine over several times, remove the rocker and check the witness mark. The witness mark should be no larger than 0.080", and should be close to centered on the valve. The best way to determine proper pushrod length (to achieve the required lifter preload and pattern on valve) is to use an adjustable checking pushrod. You can purchase these through any retailer (Jeg's, Summit, etc.), and they are relatively inexpensive. You will have to remove a valve spring and install a checking spring (included with some adjustable pushrod kits, also sold by themselves in pairs), full spring pressure can bend the adjustable pushrod tool, as they are made of aluminum. You can also start with a stock length pushrod and see where that puts you as far as preload and pattern on valve. Just let us know if you run into problems with this method, or if something checks out of spec."

    I also found this on Stangnet:

    https://www.stangnet.com/mustang-for...er-rockers.28/

    Here's an except from the pedestal mount roller rockers instructions section:

    "Step 5: Turn the bolts by hand until there is no clearance between the roller and the valve stem (make sure the pushrod is seated in the rocker arm cup). Slowly torque the bolt to 18-20 FT-LBS. Since you are pushing down the plunger in the hydraulic lifter as you torque the bolt, it will probably take a minute or two to complete the procedure. The bolt should have turned between one-quarter to one full turn to reach the torque setting. This will give the correct lifter preload of .020" to .060". If the bolt turned more than one turn, you will have to shim the pedestal (use Ford Racing Performance Parts shim kit M-6529-A302). NOTE: M-6500-A301 anti-pump-up lifters only need .020" to .030" preload. If the bolt turned less than ", you will have little or no lifter preload. The solution for this is longer pushrods. These are available from a number of companies, such as Crane Cams Tech Line (904) 258-6174. There are many modifications that may have been made to the engine which will change the lifter preload, such as valve jobs, different cams, different thickness head gaskets, head milling, etc. It is a good idea to check the rocker arm pattern on the valve stem tip. Use a felt tip marker to “paint” the tip. Then, with the rocker arm in place, turn the engine through two revolutions. Remove the rocker arm and inspect the pattern. It should be nearly centered on the tip. If it appears to be too close to the edge of the tip, call the Ford Racing Tech “Hot Line” for assistance. Note: The lifter preload may be different between the intake and the exhaust or between one side of the engine and the other. Therefore, you must check lifter preload on each rocker arm. "

    Another major consideration here is that I ran these heads before with stock pushrods and rockers with no problems. The pedestals and valves have not changed since that time. This rocker geometry thing just has me overwhelmed at this point mostly because I'm getting results I shouldn't be. It just doesn't make sense, and it keeping me from figuring out anything else.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  3. #3
    FEP Power Member qikgts's Avatar
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    Default

    The response from Scorpion seems to be self explanatory. They make the rockers so I'd go with their method here and it sounds like they are willing to assist too. Are your stock pushrods too short to get proper preload? Seems like you need the right pushrods or at least some that are pretty close to get moving forward.
    '85 GT

  4. #4
    Moderator wraithracing's Avatar
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    What is the actual length of your current pushrods? If my memory is correct, I believe the OEM roller cam motors used a 6.250-6.272 length. Non roller cam motors used a length of 6.800-6.930.

    Most of the information I have found shows the aftermarket roller rollers using somewhere around 6.400" long pushrod, but again there are all kinds of variables such as engine deck height, cylinder head milling, head gasket thickness, etc. just to name a few.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Ongoing RestoModification
    1984 SVO Awaiting Restoration
    1986 GT Wrecked by PO, but still want to save!

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
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  5. #5
    FEP Supporter Broncojunkie's Avatar
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    I'm following this thread because a buddy is going through the same thing. He switched from E7's to GT40P's and the stock pushrods seem too short. He's using the stock rocker arms.
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    86 coupe - rotbox roller
    86 coupe - working on 408w, c4
    88gt - 302 efi, t5

  6. #6
    FEP Power Member STL79Coupe's Avatar
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    By Flowtech cam I assume one from Ed Curtis? What does Ed suggest? My last setup I got from Ed he had me use stock length PR 6.250, but I was using AFR 165's and was back in 2000.
    Keith formerly STLPONDS
    '79 V8 coupe in the works!
    Build thread http://vb.foureyedpride.com/showthread.php?t=89153

  7. #7

    Default

    Quote Originally Posted by STL79Coupe View Post
    By Flowtech cam I assume one from Ed Curtis? What does Ed suggest? My last setup I got from Ed he had me use stock length PR 6.250, but I was using AFR 165's and was back in 2000.
    Yes. I haven't asked him specifically about setting up rockers and stuff, but he did tell me the cam I ordered has a slightly smaller base circle than the stock HO cam I had before. That, combined with the difference of the roller rockers, must be what's causing my old stock pushrods to be too short. I tried measuring them with a ruler and they do seem to be stock length 6.250".

    On a side note, here's another thing that can happen with P heads. P heads come from the factory with 2 different height valve springs between intake and exhaust, meaning the distance from the keeper groove to the tip. Exhaust valve springs had rotators too. BUT, my heads had been prepped before I bought them. Rotators were removed and all new valves were installed, the intake valves were enlarged to 1.9. I bought a set of beehive valve springs to match my new cam for P heads. When I went to install them, I found that it came with keepers meant for the stock setup that would place the retainer too high on the exhaust valves. I had to order another set of keepers the same as the intake side ones because my valves are all the same. So, lesson for the kids out there, make sure you measure your valve spring installed height.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  8. #8
    Moderator wraithracing's Avatar
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    Between the small base circle camshaft, the new heads, the different valves, springs, retainers, etc. You have very little that is what you can consider "stock" Ford. Unfortunately this seems to be the same situation I put myself in most of the time too.

    I think at this point an adjustable pushrod to help you determine the correct pushrod length is the best option. I would recommend no shims at all so you hopefully don't have to use any if everything works out correctly. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Ongoing RestoModification
    1984 SVO Awaiting Restoration
    1986 GT Wrecked by PO, but still want to save!

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Underway
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  9. #9

    Default

    Quote Originally Posted by wraithracing View Post
    new heads, the different valves,
    Same heads, different engine block, same valves. I mean same as I ran with stock rockers and pushrods.

    I know what you mean though. And I do have an adjustable pushrod length checker... rod.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  10. #10

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    Have you made a lifter solid to check with? That way you rule out the "play" you might introduce with the hydraulics. Also, are you using checker springs? You do not need a ton of force to check the pushed length and pattern.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  11. #11

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    Quote Originally Posted by Haystack View Post
    Have you made a lifter solid to check with? That way you rule out the "play" you might introduce with the hydraulics. Also, are you using checker springs? You do not need a ton of force to check the pushed length and pattern.
    I'm using LMR's mockup solid lifter. As far as I can tell, it's identical to the hydraulic ones, just not hydraulic. I plan to do a few measurements just to see though. And yes, I'm using checker springs. I know you can buy whatever from the hardware store, but I wanted something I knew would do what I needed, so I bought the correct ones. I'm more "cheap" with my time and sanity than I am with my money.

    Definitely looking like I'll have some car time tomorrow, so I should have more details for you.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  12. #12

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    Good luck man. Sounds like you have all the right tools, you got this.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  13. #13
    FEP Senior Member OX1's Avatar
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    I don't believe proper valve geometry is possible with Ford pedestal heads.
    I spent a lot of time trying to get my GT40X heads right. Ended up with
    TW170's on both mine and my dad's rides.

    https://forums.corral.net/forums/5-0...correctly.html
    Last edited by OX1; 07-19-2019 at 06:46 PM.
    86 Capri, 5.0, 5Spd, A9L QH/BE, 47 lb Inj PMAS 3" MAF, Single T44 Turbo, Front Mount IC, TW170,
    Stock Cam, Explr Intake/TB, 1.7 Rockers, CF dual friction clutch, 3" DP, 2.5" full Exh, 3.27, 11.932 @ 115.78
    84 LTD, 331-10:1, TW170/Exprl Intake, 47 lbs inj/80 mm LMAF, Full Duals, Quarterhorse, Vortech 7PSI, Lentech AOD, 5 lug Mk VII brakes/rear, Eibach Sway bars, Cobra HB (dads ride, but I fix it )

  14. #14

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    Quote Originally Posted by OX1 View Post
    I don't believe proper valve geometry is possible with Ford pedestal heads.
    I spent a lot of time trying to get my GT40X heads right. Ended up with
    TW170's on both mine and my dad's rides.

    https://forums.corral.net/forums/5-0...correctly.html
    There's a definite point worth consideration. Is it even possible!

    And then the question becomes, are these expensive rockers going to hold up to not necessarily having proper geometry? I just had a friend tell me he's had a couple of sets of Scorpion rockers blow up on him and kill a couple of engines. I'm building this engine to drive often and put some serious miles on for many years to come, not just to have some fun with it for a season or two and then get bored and pawn it off on some poor sap who doesn't know the engine is a ticking time bomb.

    (SIGHHHHHHHHHH) What to do?
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  15. #15

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    Dang, so sorry to hear Brad. I'm certainly paying attention though. I however won't be changing as many things in the valve train (stock springs and stock rockers), but I am certain I will run into a number of my own head scratchers. I hate when you've purchased a part (in your case the scorpions) only to then find out the concerns on the forums. I've had a few of those for sure.

  16. #16

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    Brad,

    I would start by reading through the thread linked in post 13 above. It has a lot of good information in it. In that thread, post #5 is the key.

    If the angle of the rocker arm and the ratio of it are not correct, you will never be able to get the valvetrain setup optimally.

    In my experience, the best way to do this is to accurately measure the rocker arm and cylinder head. Put all of the geometry into a CAD program. Then in the CAD program you can look at what needs to be moved around to get things setup as best as possible. The most difficult trick here is accurately measuring the rocker arm geometry. This will require calipers, pin gauges, a 5/16" steel ball and small straight edges to do properly.

    If you can't do all of this, here is some general advice.

    Doing what is required in the setup geometry to make the roller scrub a smaller distance across the face of the valve will give the engine the highest possible rpm potential before valve float happens. This is because the lift at the valve will most resemble the cam profile without any added jerk.

    Doing what is required in the setup geometry to get the average position of the roller in the middle of the valve tip, will give the engine the longest valve guide life.
    Jack Hidley
    Maximum Motorsports Tech Support

  17. #17

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    Do you have a comp cams psuhrod length tool? You have to get the pushrod length right or you will never be able to shim it right. Basically two points and be changed rod length and rocker height. Get those two correct and you win.

  18. #18

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    Looks like your rods are too short by the picture. You do want the centre of the valve stem to contact the roller like others have said.

  19. #19
    FEP Power Member gmatt's Avatar
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    "I don't believe proper valve geometry is possible with Ford pedestal heads."

    If this statement is true, then I suppose lifter preload is the only thing to worry about along with a pushrod length that's in the ballpark. Millions of engines with millions upon millions of miles. Mostly with the stamped steel rockers, which are not nearly as friendly to the valve guide(side loading). Am I wrong to think this? At least with relatively low lift cams and lower spring pressures. You wouldn't want to use pedestal rockers with an aggressive high lift cam anyway.

  20. #20

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    Quote Originally Posted by 78futura View Post
    Do you have a comp cams psuhrod length tool? You have to get the pushrod length right or you will never be able to shim it right. Basically two points and be changed rod length and rocker height. Get those two correct and you win.
    I do have an adjustable pushrod length thingy. I don't think it's Comp though. It came with the LMR kit.

    https://lmr.com/item/SVE-PTVTOOL/sve...ing-tool-85-95

    But yeah, it's exactly that sort of thing that keeps me pretty much paralyzed in regards to the valvetrain every time I do get a little car time. The "can't do this until you do that; can't do that until you do this" stuff. I always prefer to spend my time doing other things I KNOW I can accomplish like putting the transmission back together or getting the headers ready for new gaskets. I'm going to run out of those things before long though, so I'll have no choice but to chip away at this.

    It's definitely my plan to try to get a nice pattern on the valve tip. We'll see how that goes. I'm not just going to slap it together. I'm far too paranoid for that.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  21. #21

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    Quote Originally Posted by Jack Hidley View Post
    Brad,

    I would start by reading through the thread linked in post 13 above. It has a lot of good information in it. In that thread, post #5 is the key.

    If the angle of the rocker arm and the ratio of it are not correct, you will never be able to get the valvetrain setup optimally.

    In my experience, the best way to do this is to accurately measure the rocker arm and cylinder head. Put all of the geometry into a CAD program. Then in the CAD program you can look at what needs to be moved around to get things setup as best as possible. The most difficult trick here is accurately measuring the rocker arm geometry. This will require calipers, pin gauges, a 5/16" steel ball and small straight edges to do properly.

    If you can't do all of this, here is some general advice.

    Doing what is required in the setup geometry to make the roller scrub a smaller distance across the face of the valve will give the engine the highest possible rpm potential before valve float happens. This is because the lift at the valve will most resemble the cam profile without any added jerk.

    Doing what is required in the setup geometry to get the average position of the roller in the middle of the valve tip, will give the engine the longest valve guide life.
    I will definitely do that.

    Yeah though, I think that's been part of my problem with the rocker geometry thing. I'm not sure I'm even measuring it right. Getting the rocker sort of level with the valve spring retainer is just so imprecise and leaves so much margin for error, when you need to get it right down to the thousandths of an inch! I don't have access to CAD or any of those fancy tools, but I will certainly shoot for a good pattern on the valve tip, like I said. Thanks!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  22. #22

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    Quote Originally Posted by Str8sixfan View Post
    Dang, so sorry to hear Brad. I'm certainly paying attention though. I however won't be changing as many things in the valve train (stock springs and stock rockers), but I am certain I will run into a number of my own head scratchers. I hate when you've purchased a part (in your case the scorpions) only to then find out the concerns on the forums. I've had a few of those for sure.
    Yeah, that's the worst. Scorpion is really the only choice for pedestal mount now. Most companies have stopped making them probably because of all the really good aftermarket heads out there that come pre-machined for stud mount rockers. I guess there are some steps I can take to help mitigate possible disaster. My friend says he's had decent luck soaking the rockers in oil for a day or so, and then use break in oil on first start-up.

    At least in your case, using the stock rockers will take a lot of the guesswork out of it!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  23. #23

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    Quote Originally Posted by ZephyrEFI View Post
    Yeah, that's the worst. Scorpion is really the only choice for pedestal mount now. Most companies have stopped making them probably because of all the really good aftermarket heads out there that come pre-machined for stud mount rockers. I guess there are some steps I can take to help mitigate possible disaster. My friend says he's had decent luck soaking the rockers in oil for a day or so, and then use break in oil on first start-up.

    At least in your case, using the stock rockers will take a lot of the guesswork out of it!
    with the exception of, the stock rockers were meant for a car with roller lifters, whereas I have solid lifter. So I assume the pushrod length for sure will be different. I hope that it's not any more B.S. than that.

  24. #24

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    Quote Originally Posted by Str8sixfan View Post
    with the exception of, the stock rockers were meant for a car with roller lifters, whereas I have solid lifter. So I assume the pushrod length for sure will be different. I hope that it's not any more B.S. than that.
    Yep, I've seen it stated they are different between roller motors and flat tappet.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

  25. #25

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    Well, I decided to hire the guy who did my intake porting to come out and help me get this valvetrain going. I'll report back here with how we end up setting it up! Pressure's off, and I can't wait!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Transit Connect Titanium LWB
    '14 Ford Fusion SE Manual

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