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GT40p heads - factory pushrods?

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    #1

    GT40p heads - factory pushrods?

    Hola,

    Did I search but didn't come up with an answer so hoping somebody can help me out. Will the factory pushrods work with GT40p heads and an explorer cam?

    I also plan on putting a new timing chain on it. I know I should do new lifters and rockers. Who sells good factory replacements for lifters / rockers on the cheap? I'm about out of cashola and figured there is probably a good online source for factory replacment type parts... Or would it be worthwhile to step up to a 1.7 rocker, could it even be done economically?

    Motor will be used for towing.

    Thanks,
    JD
    1986 Ford Contry Squire: HO engine swap, 3G alternator, 3.73 gears, rear air springs, Class III 8000 lb hitch... potential tow rig for my Blazer trail toy??
    Tags: pushrod length, pushrods
    #2
    The most economical 1.7 roller is the Crane "Cobra" rocker. It is the set Ford usen in its Cobra OEM application. This needs a different set of pushrods. If you stick with the factory 1.6 rockers, you should be alright with stock NoPo length. Replacement stock rockers are available at AutoZone or any of the other parts stores.

    Comment

      #3
      The pushrods may or may not need to be changed with the Cobra rockers. I'm using stock pushrods, an Explorer cam, and Cobra 1.7 rockers and the lifter preload came out right where it should be, but thats with an E7 head. P heads ought to be the same, but anything is possible. You'd need to check the lifter preload to determine if something needs to be changed. If you're really out of cash, probably someone on here has a full set of used stock stamped rockers and pushrods they could sell you for cheap. I know where several sets are at the moment.
      86 Lincoln Town Car (Galactica).
      5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

      91 Lincoln Mark VII LSC grandpa spec white and cranberry

      1984 Lincoln Continental TurboDiesel - rolls coal

      Originally posted by phayzer5
      I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

      Comment

        #4
        I have had 3 motors all needing different length pushrods when the P heads with the Cobra rockers bolted on.... ANY time you bolt a rocker on, you should be paying attention to preload. It is either within allowable tolerances or it is not.. pretty straight forward...

        Comment

          #5
          Mercracer, were any of the heads milled, or is it just from the tolerance variance of the components?

          Comment

            #6
            Sounds like I'll just have to give the factory pushrods a shot, and if they don't work I'll have to dig up the cashola somewhere to buy new ones.

            Crossing my fingers and hoping I get lucky! Thanks!
            JD
            1986 Ford Contry Squire: HO engine swap, 3G alternator, 3.73 gears, rear air springs, Class III 8000 lb hitch... potential tow rig for my Blazer trail toy??

            Comment

              #7
              Pushrods in Tom's motor were the stock ones. HO cam, Cobra rockers, P heads. Preload came out where it belongs. I will say I don't remember if they were HO engine pushrods or Explorer engine pushrods, or if there is actually any difference. Whatever they were, it was stock production Ford pushrods from something. Engine makes no funny valvetrain noises either.
              86 Lincoln Town Car (Galactica).
              5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

              91 Lincoln Mark VII LSC grandpa spec white and cranberry

              1984 Lincoln Continental TurboDiesel - rolls coal

              Originally posted by phayzer5
              I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

              Comment

                #8
                What did you use for "where it belongs"? Mine were all on the loose side of the range without longer pushrods...

                Comment

                  #9
                  they all came out between 1/2 and 3/4 turn past zero lash, which from my understanding is OK.
                  86 Lincoln Town Car (Galactica).
                  5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                  91 Lincoln Mark VII LSC grandpa spec white and cranberry

                  1984 Lincoln Continental TurboDiesel - rolls coal

                  Originally posted by phayzer5
                  I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                  Comment

                    #10
                    I run my vette at about 1/2 turn past zero lash. Spec is 1 turn, but the less preload on them the less prone to valve float at higher rpms (not that I'm planning on running the motor in my wagon at high rpms.)

                    Still collecting knowledge and parts, but getting more of both each day!
                    1986 Ford Contry Squire: HO engine swap, 3G alternator, 3.73 gears, rear air springs, Class III 8000 lb hitch... potential tow rig for my Blazer trail toy??

                    Comment

                      #11
                      Originally posted by Mercracer View Post
                      I have had 3 motors all needing different length pushrods when the P heads with the Cobra rockers bolted on.... ANY time you bolt a rocker on, you should be paying attention to preload. It is either within allowable tolerances or it is not.. pretty straight forward...
                      Here's a topic I don't know much about .... how does one determine whether lifter preload is appropriate, especially with pedestal mount rocker arms? The info I've had in the past basically says to just bolt stuff back together with stock pushrods and call it good unless shimming of the rockers is needed; it doesn't address what to do when the rockers wiggle and wobble a great deal and you hear funny noises with the engine running.
                      2012 Mazda5 Touring | Finally working on the LTD again!

                      Comment

                        #12
                        Originally posted by gadget73 View Post
                        they all came out between 1/2 and 3/4 turn past zero lash, which from my understanding is OK.
                        That is loose in my book.... 3/4 to 1 1/2 is what I go by.... I have been able to keep them between 1 and 1 1/2.

                        Comment

                          #13
                          Originally posted by 1987cp View Post
                          The info I've had in the past basically says to just bolt stuff back together with stock pushrods and call it good unless shimming of the rockers is needed; it doesn't address what to do when the rockers wiggle and wobble a great deal and you hear funny noises with the engine running.

                          You certainly didn't get that "info" from any official source such as a service manual. Teh internetz is evil... If a pedestal rocker wiggles and wobbles, you are really screwed because you have less than zero lash.... How would you know if shimming is necessary if you just bolt it together without paying attention to preload????? Too much preload you shim and not enough you use longer pushrods.
                          You go by number of turns after zero lash. Zero lash is then there is no end play in the pushrod. It is just resting on the lifter piston but not compressing it yet.. You will still be able to rotate the pushrod as there will only be the slightest of drag on it..

                          Comment

                            #14
                            Ah... now I have a creeping feeling I should have spent more time with that smallblock rebuilding book a friend let me refer to when assembling the thing. I certainly don't recall the Haynes manual going into detail on this stuff, but now I'm realizing that's to be expected. Odd that a well-known Ford engine builder told me once that some wobbledy slop on the rockers is normal ...

                            What are the cheapest sources for custom-length pushrods when one-piece or hardened rods aren't really required?
                            2012 Mazda5 Touring | Finally working on the LTD again!

                            Comment

                              #15
                              Originally posted by 1987cp View Post
                              Odd that a well-known Ford engine builder told me once that some wobbledy slop on the rockers is normal ...

                              What are the cheapest sources for custom-length pushrods when one-piece or hardened rods aren't really required?
                              When the valve is closed, you can grab a rocker and often get it to move some.. Wobbly slop is what I would call bad, but low tension is another thing... It is in teh feel..... The more you do, the better sense you will get for what is "normal". You can visually see during inspection when a rocker is worn out.... Summit or Jegs are sources for pushrods... If you are doing a performance build, why would you look for the worst source for parts?? Cheap = bad. Economy priced quality product = OK.

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