340valve train noise with new head gaskets

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dgoplen

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i just put new felpro 8553 pt head gaskets in.now all my rockers are loose,they rattle on the flat side of the cam.and the push rods rotate freely.what kind of preload should be on the lifters .these are factory non adjustable hydraulics.napa called felpro tech and he gave excuses,i know there are thinner gaskets out there .did i make a mistake buying the felpro gaskets or am i doing something wrong? lifters never left bores rockers are l and r facing them and all are torqued down,also whats right way to block heat crossover i have a m1 dual plane and antifreeze cam out around heat croosover area only on both sides.
tks for any help
 
The standard Felpro replacement head gasket is .054" thick. The Felpro 1008 is .035" thick which would put more preload on the lifters. You probably had thinner head gaskets on there and now the thicker gaskets reduced the preload to the point you have slack in the valve trane. You probably lost a bunch of compression too.
 
Humm.... I've replaced stock gaskets with the 8553's before and never had that problem. I wonder if someone in the past replaced the pushrods with shorter than stock rods?
 
Everybody says different on what the compressed thickness of this or that gasket.

1008 advertise at .039

regular perma torques 8553 'for me' measured about .045 after being compressed and run, found that measurement during tear down.
 
my pushrods are 7.50 long so if i bought the 7.550 length would that take care of the slack? without changing head gaskets again? i think the gaskets that were in it before were mopar performance.i never saved them just assumed felpro would make them stock .the felpro tech line said they make them thicker in case you plane the heads.wish they would say that before selling them.
 
dg - sorry, i got the note last night but fell asleep with the pc on...
have you run it yet with the new gaskets?
 
Does it make noise as soon as you start it, or when it warms up? Could be short push rods, or lifters collapsing.
 
i ran it with the gaskets and it sounds like a rattling noise,when it revs up its much quieter.its loudest at idle,i rolled the motor ove today and checked each pushrod on the flat side.they all spin easily and the rockers slide side to side easily,shouldnt the pushrods be tighter ?as the lobe comes up they get tight and dont spin at all.the pushrods lenght are 7.50 inches.
 
dgoplen said:
my pushrods are 7.50 long so if i bought the 7.550 length would that take care of the slack? without changing head gaskets again? i think the gaskets that were in it before were mopar performance.i never saved them just assumed felpro would make them stock .the felpro tech line said they make them thicker in case you plane the heads.wish they would say that before selling them.
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You might get lucky and 7.55's will work but you really need to measure and see exactly what length you need. If you have an old pushrod you can cut it in half and thread each piece and re-assemble it with a coupling nut and lock nuts to make an adjustable pushrod to check for proper length. Or buy an adjustable checking rod.

dgoplen said:
i ran it with the gaskets and it sounds like a rattling noise,when it revs up its much quieter.its loudest at idle,i rolled the motor ove today and checked each pushrod on the flat side.they all spin easily and the rockers slide side to side easily,shouldnt the pushrods be tighter ?as the lobe comes up they get tight and dont spin at all.the pushrods lenght are 7.50 inches.
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Lifters generally bleed down pretty fast and makes it impossible to tell what's what by just rolling it over. Use a remote starter button to spin the engine over for 45 seconds or more to make sure the lifters are pumped up then quickly get the engine rotated so it's on the bottom of the lobe and then you can tell if their loose or not. That doesn't tell you how much pre-load they have though. Just if their loose or not.

BTW: How much oil pressure does it have?
 
The worst part about guessing on the push rod length it's going to cost you close to $100 each time.
 
jefflock said:
The worst part about guessing on the push rod length it's going to cost you close to $100 each time.
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So true...I've got some very nice custom chro-mo push rods...assorted lengths and brand new...:-D:bootysha::snakeman:
 
On one of my cars, a number of years, ago I used adjustable push rods.

I think they were made by Crower...that would be an alternative to guessing on push rod length. If I recall I did it because it was less expensive than adjustable rocker arms..my "toy" cars are always on a tight budget.

Paul
 
As long as you have .020" to .060" pre-load you should be quiet. Unless you were on the way low end of pre-load before you changed the gaskets, and say you had the .025" MP thin gaskets on there, going to the 8553's would give you about .020-.025" less pre-load so that may be the problem.
 
AS was said, I think you need to verify you have enough preload. I personally can't tell by feel. I have to pull the intake and look. Stock type lifters require more, and if you have sloppy bores or some miles on them, you may need more anyway. I aim for .040-.050 when I'm setting things up.
 
i talked to a guy at the mopar tech line and he told me to just check and see what length i need.same thing at smith brothers pushrods.the peole at felpro and summitt just couldnt find any answers ,at least summit referred me to mopar all felpro did was make excuses he didnt even have an idea to try changing to thinner gaskets .i have a push rod length checker coming .thanks for everyones ideas. it just sucks that when you try to do something right and make it better all these problems come up.
 
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