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Discussion Starter · #1 ·
Hey guys, i recently installed a trick flow stage 1 cam in my car. Now my car is idling fine but as soon as i put it in gear and start to move it backfires(popping noises from under car). I can Rev the engine in neutral and its fine but as soon as its in gear and goes it starts to backfire. I upgraded my valve springs on my GT40P heads to compensate for the cam and got hardened push rods...though i didn't measure them, i just read people find stocks slightly a little to short so i ordered some that were +.100 longer than stock.(Give me **** for not measuring first time around) So i've cleaned my MAF, TB, IACV, Adjusted my timing, there doesnt appear to be any vacuum leaks. Do you think my pushrods could be the reason i have the backfiring?
I just did the sharpie trick where you color the valve stem, install rockers rotate engine couple times and check the mark. The mark is slightly below the center of the valve. Do you think that is enough to cause my issue? Thanks for your thoughts.
 

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Yes, I do think your randomly spec'd pushrods are the priblem. Search the webb for "How to install bolt-down rockers" and prepare to be amazed.
 

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I was being sarchastic. With .100" longer pushrods, hes probably pretty close to bottoming out the lifter. He,ll realize when he reads an in depth how to, that 3/4 to 1 full turn past zero lash the bolt is supposed to be torqued. He probably had min of two turns or more past zero lash, if he checked at all. Most that have issues like this never check, they just tighten it all down and go, so I am making an assumption on this, and if Im wrong, I apologize. The timing could be way out of wack too, but Im betting if he goes back to stock p/r, and follows the how to adjust bt down rocker procedure off the net, he,ll be close if not dead on.
 

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Discussion Starter · #6 ·
I was being sarchastic. With .100" longer pushrods, hes probably pretty close to bottoming out the lifter. He,ll realize when he reads an in depth how to, that 3/4 to 1 full turn past zero lash the bolt is supposed to be torqued. He probably had min of two turns or more past zero lash, if he checked at all. Most that have issues like this never check, they just tighten it all down and go, so I am making an assumption on this, and if im wrong, I apologize. The timing could be way out of wack too, but Im betting if he goes back to stock p/r, and follows the how to adjust bt down rocker procedure off the net, he,ll be close if not dead on.
Ok buddy so i took your advice and went back to the stock length. Zero lashed and torqued. It took me under 1/4 turn=Too short. So i bought Ford racing shims .30 and .60 size. I'm shimmed my +.100 length rods at .30 and from zero lash it was from 3/4 to one full turn and the .60 shims at zero lash where 1/2 to 3/4 turn to reach the torque specs. Both of these lengths seem right about where the proper length should be? Now ive noticed some of the rockers have excessive play in them with either of the shim sizes installed. Torqued i can wobble them side to side a decent amount? After all this my backfiring issue is still around. Any ideas? Do my pushrods with the shim combo seem to be right? Would loose rockers cause my backfire issue? I have stock E7 heads i can swap the rockers of there and see if there is any difference? Timing? Timing is just hook up light, remove spout connector, start car, loosen nut turn distributor till its at where you want it. Reconnect spout connector, tighten bolt and done. So if that is correct i think my timing is correctly adjusted. Any thoughts guys? Appreciate the info. Im just 20, no mechanic experience and just reading and learning as i go. Gotten this far so i think its going alright for my first cam install. Appreciate any advice and thoughts.
 
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