Rocker shims?

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Kevin D.

Kevin D.

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I am going to have to use some rocker arm shims that I got from Mancini is there anything special I have to do for the rocker arm oil holes the ones under the shaft on the pedastal or anything else? Thanks Kevin
 
rocker shims or shaft shims, are these mag heads. never heard of rocker shims for a shaft style rocker. but do have instructions for shaft shims if you want me to post.
 
Non magnum they are j heads.These are the shims that raise your shafts .015 off the head pedastals I believe. my concern is the oiling hole for shafts.Help please.Thanks Kevin.
 
You should be fine, but you'll want to make sure there is enough room around the rocker bolt where the oil feed comes up from the block. That should be the 2nd from the front on the driver's side, and 2nd from rear on the pass side IIRC.
 
only if you stack them you have to do anything. but wont hurt to look at the oil passage and make sure its clear.

hughes.jpg


hughes (2).jpg
 
Are these shims you got tapered? If not (and even if they are) I feel there is a better way to do what I think you're needing to do.

Adjustable PUSHRODS. They will go shorter than stock. So if you're using stock rockers and the block and/or heads have been shaved necessitating the shims to adjust lifter preload and/or maintain rocker geometry, I prefer adjustable pushrods. You accomplish everything in one simple step.

However, if you aren't running stock rockers and had the block and/or heads cut.....then you're on your own.

Just make sure the shims are tapered for a proper fit.
 
68 Sedan said:
Are these shims you got tapered? If not (and even if they are) I feel there is a better way to do what I think you're needing to do.

Adjustable PUSHRODS. They will go shorter than stock. So if you're using stock rockers and the block and/or heads have been shaved necessitating the shims to adjust lifter preload and/or maintain rocker geometry, I prefer adjustable pushrods. You accomplish everything in one simple step.

However, if you aren't running stock rockers and had the block and/or heads cut.....then you're on your own.

Just make sure the shims are tapered for a proper fit.
Click to expand...

Pushrod length don't affect rocker arm geometry on a shaft mount system. You can only change geometry on a shaft mount system by moving the shaft up or down. Pushrod length only affects lifter preload on a shaft mount system.
 
Ran shims from Hughes on my bracket racing 360 for 5 yrs,,., cranking 6500 rpm on each pass..

cam was a Hughes 256/265 with Hughes 1.6 rockers...lift was somewhere around .630 gross...
took them off and on a couple of times and never paid attention as to how they went on...
 
The one thing I'd like to point out in the pics... The reduced contact area between the factory saddle and the shims when stacked... That is a lot of instability. I have stacked a couple times on close to stock stuff... but if you really need more than .030 in shims, you should be fixing the issues that cause it. Because the shafts are MUCH more prone to flex, stressing rockers and pushrods and reducing lift the valve sees. The fact we can do it, doesn't really mean we should in terms of rocker shims.
 
The .015 are seeming to work okay installed last nite. Did not fire but will today and then re-adjust. The reason I did this push rods were to long not enough adjustment. It looks good so far. Kevin.
 
Yeah, .015 is almost nothing. I use them to adjust preload on some engines to avoid new pushrods. They definately have their place.
 
I'd have milled the rocker stands and used rocker support blocks instead of the saddles as it allows much more adjustability in the rockertrain.
 
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