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Re: You Guys Are Killing Me With This Shimmin RockersTh [Re: 64Post] #378174
07/17/09 10:02 PM
07/17/09 10:02 PM
Joined: Jan 2003
Posts: 32,882
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 32,882
Grand Prairie,Texas
If you don't change the rocker position or the valve position then you haven't changed the geometry. Shaving the heads do neither. You haven't changed where the rocker runs on the valve so shims aren't necessary. All you are doing is bring the head closer to the lifters meaning you possibly need shorter pushrods which is the only thing changed.

Re: You Guys Are Killing Me With This Shimmin RockersTh [Re: 64Post] #378175
07/17/09 10:04 PM
07/17/09 10:04 PM
Joined: Jan 2003
Posts: 25,200
Upper Midwest
M
MoparforLife Offline
Too Many Posts
MoparforLife  Offline
Too Many Posts
M

Joined: Jan 2003
Posts: 25,200
Upper Midwest
Quote:

Quote:

isn't the ideas to have the rocker tip center on the valve stem hence the needs for the shim when you shave the head too much?




Noooooo !!!



Shaving the head will have 0 effect on the center line of the rocker to the center line opf the valve tip.

Re: You Guys Are Killing Me With This Shimmin RockersTh [Re: MoparforLife] #378176
07/18/09 12:11 AM
07/18/09 12:11 AM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
Too Many Posts
383man  Offline
Too Many Posts
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Joined: Jan 2003
Posts: 27,421
Balt. Md
Shims can be a bandaid fix if the plunger in the lifters bottoms out on the cam base circle from decking the block and (or) milling the heads. It can cause the lifter plunger to bottom out and hold a valve slighty open. It happened on my friends car years ago when he started his fresh 383 and it was missing on 3 cylinders. The hydraulic lifter is made to have around .100 to .150 of plunger travel to keep the rocker right at the valve tip and adjusted at all times. If a valve job is done and the valves sink say .020 then the lifter plunger will bleed down or pump up to get the lash at zero. But if the plunger moves all the way down and bottoms out it can now hold the valve open. I like to set my lifter preload about .020. I actually watch and measure the plunger travel as I tighten the rocker shafts. I had to either get adjustable rockers or adjustable pushrods or shims on the 383 that was in my boys Dart. I had milled the heads and the lifter plungers were bottoming out. I was very short on cash so I used the rocker shaft shims. They were in the car for 7 years and worked fine. We raced the car many times and they did the job just fine.

Do you need rocker shims ???
Thats up to you. I would always check my lifter plunger travel and if they bottom out you need to fix it one way or another. The shims are a cheap fix as the best way is to get adjustable rockers and the right lenth pushrods. Just assemble your eng and check the lifter plunger travel. If it does not bottom out and you have some room for movement then you will be ok. Ron

Last edited by 383man; 07/18/09 12:18 AM.
Re: You Guys Are Killing Me With This Shimmin RockersTh [Re: 383man] #378177
07/18/09 12:35 AM
07/18/09 12:35 AM
Joined: May 2006
Posts: 1,225
El Cerrito Ca.
G
gregn96cuda Offline
pro stock
gregn96cuda  Offline
pro stock
G

Joined: May 2006
Posts: 1,225
El Cerrito Ca.
I bought a 64 Fury with a rebuilt 361 (less than 50 miles on rebuild) about 8 years ago. With the car I got the receipts for the rebuild that totaled $1200.
The engine ran like crap, so I did a compression test and found 2 dead cylinders on opposite sides. I pulled one head expecting to find a burnt valve, but the head looked fine. I ended up installing shims, and it ran excellent after my bandaid fix.

Re: You Guys Are Killing Me With This Shimmin RockersThing [Re: MoparforLife] #378178
07/18/09 12:46 AM
07/18/09 12:46 AM
Joined: Jan 2003
Posts: 5,186
Wherever I am.
J
Junky Offline
master
Junky  Offline
master
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Joined: Jan 2003
Posts: 5,186
Wherever I am.
Quote:

Quote:

YOU DO NOT NEED SHIMS. Is that good enough for you?


Short, sweet, and to the point. No you will not need a shim band aide.
Also listen to Dave and Kevin at Hughes, they have forgotten more than most here will ever know or learn.



The engine I run is a 383 out of a 1971 New Yorker, heads shaved 0.030 with 0.20 shims. Cam is a CompCam XE262H, stock stamped steel rockers. No need for shims. Buttoned the engine up and hammered down. Runs great.


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