Pushrod concern
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Pushrod concern Hello all, as you can see I am very new to the site, first post actually.
Im currently in the process of doing a MSIII cam swap into my friends 2000 Trans AM. The car had always had a very very odd Cylinder #2 dead misfire, that I tried to diagnose, and said it was most likely engine mechanical internal. As I was disassembling the right hand side of the motor and got the valve cover off, I proceeded to inspect cylinder #2's intake and exhaust pushrods. What I found has me very concerned. The exhaust pushrod is not where it should be, as in it is lying on its side in the cylinder head. I noticed that on the pushrod guide hole, it was elongated to about 1.5 time original size. My question is, is there any aftermarket pushrod guides that can be installed here, or do we need to get a set of heads? We need to take the heads off anyways for new gaskets and LS7 lifters, so thats not an issue.
BTW for anyones information, I have recently graduated the GM ASEP program and this is my first side job... I love the engineering of this motor platform!
Thanks for all your guys help, I can get a picture of the damage if anyone would so like.
Im currently in the process of doing a MSIII cam swap into my friends 2000 Trans AM. The car had always had a very very odd Cylinder #2 dead misfire, that I tried to diagnose, and said it was most likely engine mechanical internal. As I was disassembling the right hand side of the motor and got the valve cover off, I proceeded to inspect cylinder #2's intake and exhaust pushrods. What I found has me very concerned. The exhaust pushrod is not where it should be, as in it is lying on its side in the cylinder head. I noticed that on the pushrod guide hole, it was elongated to about 1.5 time original size. My question is, is there any aftermarket pushrod guides that can be installed here, or do we need to get a set of heads? We need to take the heads off anyways for new gaskets and LS7 lifters, so thats not an issue.
BTW for anyones information, I have recently graduated the GM ASEP program and this is my first side job... I love the engineering of this motor platform!
Thanks for all your guys help, I can get a picture of the damage if anyone would so like.
"The exhaust pushrod is not where it should be, as in it is lying on its side in the cylinder head. "
Need to see this. You mean the pr was not even sitting on the lifter or did it slip to the side of the rocker?
Need to see this. You mean the pr was not even sitting on the lifter or did it slip to the side of the rocker?
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Well I took the rocker arms off the cylinder head, and the #2 Exhaust pushrod was not present as in not located between the lifter and rocker arm, had a heck of a time finding the damn thing, and happened to see it lying on its side in the head. I must say it was one of the more bizzarre things I have seen, My fear is that if we use the head again, the pushrod could drop again. Ill get pics up tonight if needed.
Sounds like the pushrod bent then broke and was laying in the lifter tray under the head. You may be OK but photo's would help as we are all guessing. Guide plates aren't required if everything is setup correctly.
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Ok will do. Ill get the heads off before the weekend is out and take pictures for you guys, Im thinking that at some point the lifter collapsed, and created excess lash in the valvetrain, and that is what started the whole downhill process.
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I had a bad misfire and could only count 15 pushrods. Needless to say one of them had broken in half. the pushrod pieces were a bitch to fish out with the pen magnet. and the inside of the cylinder head where the pushrod goes had been scored up. I replaced it with another stocker and changed the oil to get any shavings. All was fixed..
Pushrod dropped below the surface. Got wedged below it and forced up breaking the lower corner of the head casting off. What allowed it to drop down that far? Possible lifter failure? I know when checking my pushrod length with the tool when it was closed at 6.800 it was able to drop down below the head's surface. This was done by mistake of course and the heads were not trq'd down for good but some info for this sitaution anyway.
First, fish out the pieces and post photo's. Second, try to examine the lifter from the top and see if the plunger is in the correct location. From the picture, the head looks OK but then again you need to look around down the hole by eye. I wouldn't panic yet until you have all the facts.
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Yeah thanks vettenuts Im pulling the heads off tomorrow, for the LS7 lifters to go in along with the cam and such I will extensively post progress pictures as well as anythign that appears incorrect.
Was the rocker bolt loose ? If not , I would say the lifter is bad which allowed the PR to drop from the rocker arm . I would say the head would be fine to re-use . The pushrods are not supposed to contact the walls of the holes in the head anyways, so I don't think there will be any problems with re-using the heads .
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Ok thats what I was thinking. But as a progress report, got the heads off today found both pieces of that pushrod. Everything else seems to be good to go. Thanks to all of you for your information.
The pushrod was probably bent and was ran until it finally broke after wearing against the head for so long. Bent pushrods are common on these engines and usually occurs from an over rev. It would be a good idea to have the valves reseated and make sure none are bent while the heads are off. The rocker arms are a self aligning design and do not require guideplates, so the hole in the head being waddled out is not a concern.
