How can i tell if i need to re-shim my roller rockers?

[OrangeMustangGt]

my car seems to be making more noise from the valve train area, and i think that maby i will have to remove the shims under my rockers, but ho wcan i be sure they need to be removed, besides a dial gauge? maby i will just take em out and see...i dont know, it gets louder when the engine gets hot, go figure

 

[Joes95GT]

You don't want to remove shims just because they're making noise. It's inherent of some rocker arms, especially aftermarket pieces, to make noise.

What's the contact patch on the valve tip like? What about geometry? 90* angle at half lift? These questions are going to be the answer of whether or not you need to remove or add shims.

Out of curiosity, how much have you shimmed the rockers?

Joe

 

[OrangeMustangGt]

whell, i used some 3.500 length pushrods, that i needed for my cam, i dont remember what shims i used to get the .30 preload? (i think). All i know is this: i switched over to fox valve covers cause they were hitting the covers, now the sound is back, it actally may be hitting the covers somewhere with the fox covers, but i dunno, when it gets hot, it gets tickey, dam it sounds like s chevy.

 

[Joes95GT]

whell, i used some 3.500 length pushrods, that i needed for my cam, i dont remember what shims i used to get the .30 preload? (i think). All i know is this: i switched over to fox valve covers cause they were hitting the covers, now the sound is back, it actally may be hitting the covers somewhere with the fox covers, but i dunno, when it gets hot, it gets tickey, dam it sounds like s chevy.

I'm assuming you meant to type 6.500 as the pushrod length and that's just a typo. I'm also assuming that you put 0.030" preload on the lifter, not 0.30. Further, shimming isn't going to allow for any more/less preload. Shimming is only going to act like a bandaid for the pushrod length.

Instict tells me that your pushrods are about .200" too long. Having worked on and pulled apart a P-headed/cammed car (my own), I think that's where the problem is. I believe my pushrods were 6.250". This was with the stock roller rockers though.

Why don't you cover the inside of the valve cover with marking compound and let the motor run until the ticking starts. If it's hitting the valve cover, you'll know it.

What kind of rockers are you using? If they're a no-name brand, that could also be your problem. Poor design that is inherent with cheap rockers makes them incredibly noisy (for the most part).

You still didn't answer the original, and most important question: What's the geometry like?

Joe

 

[RIO5.0]

6.500??? wow, thats some long ones considering stock lenght....i run 6.300 TF prs shimmed .005-.010. im actually to long by .010...i run Scorpion 1.6s and their a tad "chevyish" shall we say.. ...i frigged with mine like 6 times over...i scored the 6.300 and knew they'd be in the ballpark...

If your louder when its up to temp then somethings wack...that would tell me the geometrys off right there...you run studs or peds???...check your valve tips for a centerline pattern...that'll tell you if your out...

 

[Joes95GT]

i run Scorpion 1.6s and their a tad "chevyish" shall we say..

I actually laughed when I read this. I pulled my valve covers a few weeks ago just to go through the rockers one last time and my Dad was standing by and he said "Are those Ford or Chevy rockers?"

Maybe the old guys know something about that, Andy...

Joe