You guys who need to shim your stock rockers for better geometry should check these out. They are from Ford Racing(i know sacrilege) but these really worked out well for me. Part number is M-6529-A302.

The package i got comes with 16 .030 and 16 .060 thickness shim which can be put together to get you to .090 which is what i used. I ended up gluing mine to the bottom of my rocker stands with a very thin film of gasket maker just so i would not be fighting with them sliding around.


Whats great about these is that there length of the shim is about the same as the width of the rocker stand and the width of the shim is the same as the width of the actual rocker pedestal it goes under neath so when torqued its fully supported. another great feature is that the holes in them are exactly the same as the ones on the rocker stand.


Just figured i share that in case anyone was having a problem figuring out where to get shims from. i got mine from a local speed shop but online they can be had for only 9 bucks

Joe

 

great info . i've been looking with no luck. thanks.

 

I getting ready to add milled heads to a short block and was wondring if anyone could tell me how to tell if I would need to shim. Thanks

 

Bump. Can anyone tell me when you need to shim? I am just curious if milling a lot would make this necessary. When is shimming needed?

 

Shiming is needed when yourgeometry changes or whenever you need to change the wipe pattern on your valve tip. Pushrod length is what determins preload on our setups. When you get your heads milled you should get a pushrod that is shorter depending on how much you milled...I pushrod checker is always a good idea

 

I have a PR checker on the way. I was just wondering if this is a step I will need to address. I have not yet had the heads milled but I will be milling a lot.

 

A smaller base circle and more lift will alter the wipe pattern. The only way to correct the wipe pattern with a fixed mount rocker is to either raise (shim) the rocker stands or lower them. If lowering, then there are other options available.

I commend the OP for doing this, most guys bolt in the parts and go not realizing this is a critical step in the setup.

 

Well I would like to do this right the first time if I have the means. I had not considered having to raise the rockers if needed. I will be running milled heads not sure what cc yet (62-57) and TSPs TV3 and am getting ready to measure for PR length. The wipe is the contact of the rocker to the valve right. If I need to shim how can I tell?

 

Search and read about wipe pattern and all your Q's will be A'ed. Srsly

 

http://www.hardcorels1.com/vbulletin...ghlight=rocker

I'd read this...

 

Why did you have to shim your rockers .090"?

 

cause im using stock rockers with the comp trunion upgrade on my trickflow as cast heads. no need to go with aftermarket roller tip rockers that are heavy and weak when the stock ones will do just fine when set up properly. Thanks to thunder racing for the info i needed to get my stock rockers to work

 

That doesn't explain why you had to shim them up .090". Do the TFS heads have longer valves or something?

 

......

He raised them to get a correct wipe pattern, are you asking what caused the wipe pattern to be so far off?

 

I'm asking why he raised them. If it was just a higher lift cam, raising them is the wrong direction.

 

its to correct wipe pattern thats all. after i raised them is mesured for the correct pushrod. on these motors your should never use shims to set your preload...pushrod length does that and if you need more adjustability then get some adjustable rockers.

 

I'm trying to ask you why you think raising the rockers will correct the geometry as opposed to lowering the rockers.

Did you actually check the wipe pattern? I'm curious to know if you did, and how you determined if it got any better or worse considering the design of that rocker tip. It doesn't leave a nice clean wipe pattern like a roller tip does...

 

Well?

 

My heads were milled .058, the valve pockets were cut deeper to maintain piston to valve clearance. Also switched to the hollow Z06 valves which are slightly longer. These mods raised the valve tip which alters the rocker geometry. A .025 to .030 shim gets me back to the original geometry.

 

The only thing that altered the geometry was the longer valves. Milling the heads and cutting the valve pockets don't alter the rocker's fulcrum in relation to the valve tip height.