Can I Shim Hemi Rocker Arm Stanchions ?

Discussion about the Hemi in general.

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Don Nicklason
Posts: 46
Joined: Mon Jan 24, 2005 10:49 am
Location: Roseburg, OR

Can I Shim Hemi Rocker Arm Stanchions ?

Post by Don Nicklason »

My 55 Dodge 270 Hemi only has 7.5 to 1 comp ratio. Would like to mill heads enough to bring it up to 8.5 or 9 to 1. Had cam regound to 3/4 race.
Have Offenhauser 3 duece intake. Tell me why shimming stanchions to get correct pre-load on lifters won't work ?
Don
55 Red Ram Powered 30 A Roadster
345 DeSoto
Posts: 11
Joined: Thu Feb 10, 2005 7:29 am

Post by 345 DeSoto »

First off, you aren't "Dyno" Don Nickelson and trying to fool us all by mis-spelling your last name, are you? To answer your question, I see what you're trying to do, however, there are a few problems involved. The heads are held down by the bolts which hold the rocker stantions down. Washers, unless they are Blanchard ground and hardened AN washers, are not noted for being a uniform thickness and are relatively soft. When the heads are torqued down ordinary washers will deform and this, together with the non uniform thicknesses, will throw your rocker shaft out of alignment. The same thing can be accomplished MUCH better and easier using adjustable push rods which, for the older Hemi engines, is why they were designed....
Don Nicklason
Posts: 46
Joined: Mon Jan 24, 2005 10:49 am
Location: Roseburg, OR

Shimming Rocker Arms

Post by Don Nicklason »

Well, First off, to answer your Question. No, I am not Dyno Don. But we both go back to when he came on the scene. Don't think Dyno Don would have asked my question- LOL!
Being a mechanic since 1949 I know about AN washers, gr. 5, 7 & 8 bolts too. Found out from two phone calls from Pro racing biz. guys. One said I need to take .040" off the heads to get correct preload on lifters, because of 3/4 grind I had put on the cam, which is what I thought too.
They also said I could take another .020" to .040" off & shim the stanchions to suit.
The stock C/R is only 7.6 to 1, would like to get it up to 8.5 or 8.75.
And yes, I know about adjustable push rods & rockers & dome pistons.
Make me a donation & I'll buy what I need.
Seriously, Just building a show & shine street rod & already have a half a ton in it.
Regards;
Don
55 Red Ram Powered 30 A Roadster
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