Those who shim up the rocker pedestals, COME IN PLEASE!
06-26-2010, 01:31 PM
#1
Those who shim up the rocker pedestals, COME IN PLEASE! For those of you that have shimmed up your rocker arm pedestals due to milled heads, etc... did you ever think about cutting the pedestals into four pieces to make re-assembly of the valve train easier? I need to make the reassembly process easier.
The only other thing that I could think of that would make this process easier would be to super glue or epoxy the shims to the bottom of the rocker pedestal, but I'd kind of rather just cut the pedestal into fours because i dont know if super glue melts under high temps. I am sure that is bad for your engine if it does melt and starts to travel around your engine.
so.... has anyone ever cut their pedestals into fours to make reassembly easier? I imagine that cutting them into fours would still allow the rockers to automatically be aligned properly.
Let the brainstorming begin!
The only other thing that I could think of that would make this process easier would be to super glue or epoxy the shims to the bottom of the rocker pedestal, but I'd kind of rather just cut the pedestal into fours because i dont know if super glue melts under high temps. I am sure that is bad for your engine if it does melt and starts to travel around your engine.
so.... has anyone ever cut their pedestals into fours to make reassembly easier? I imagine that cutting them into fours would still allow the rockers to automatically be aligned properly.
Let the brainstorming begin!
06-26-2010, 02:48 PM
#7
it sounds like it does not change the valve train geometry.
milling, however, does require new push rods to run a set preload like 50 or 60 thousandths.
so it sounds like instead of chopping up or super gluing junk to my pedestals, i should just buy new push rods.
milling, however, does require new push rods to run a set preload like 50 or 60 thousandths.
so it sounds like instead of chopping up or super gluing junk to my pedestals, i should just buy new push rods.
Trending Topics
06-29-2010, 02:28 AM
#12
my setup right now gives me the preload that i am looking for (~60 thousandths). i am simply shimmed up twenty or thirty thousandths (i think, havent measured myself). the shims are two rectangular "ford" shims stacked on top of another. i dont know how thick each shim is. i will have to measure once i get my hands on some calipers.
jegs says these shims can 30, 60 or 90 thousandths tall.
jegs says these shims can 30, 60 or 90 thousandths tall.
Last edited by jdoyle; 06-30-2010 at 01:17 AM.
06-29-2010, 04:51 AM
#13
Why are you shimming the rockers? Based on the thread, it appears to be for an unsubstantiated reason. You need to verify the swipe on the stock rockers if you have a cam in the car. If you don't keep them at stock height. Milling the heads will not change the rocker geometry. More rocker motion that results from a larger cam will due to the smaller base circle and more rotation from higher lift. Milling the heads will effect the lifter preload. If you knew what the preload was before milling you can get pretty close on the after milled preload without measuring.
Also, roller tip vs. non-roller tip has no impact on "how forgiving" the geometry is. It comes down to side loading on the valve guide and optimum valve opening.
I wouldn't add shims unless you have sound reason to and based on your questions it doesn't appear you have made the measurements to determine the need for shims or the amount of shim required.
Also, roller tip vs. non-roller tip has no impact on "how forgiving" the geometry is. It comes down to side loading on the valve guide and optimum valve opening.
I wouldn't add shims unless you have sound reason to and based on your questions it doesn't appear you have made the measurements to determine the need for shims or the amount of shim required.
06-29-2010, 12:39 PM
#14
Shimming your rockers up are actually going to make your rocker geometry even worse. Milling the heads does not change the rockers sweep in relation to the valve tip. It's mostly just going to change the pushrod length you will need to get the appropriate preload.
06-29-2010, 06:05 PM
#15
11 Second Club
iTrader: (103)
Join Date: Aug 2005
Location: South of West Point Iowa
Posts: 2,633
Likes: 0
Received 1 Like
on
1 Post
i will argue with you about that KCS. If you mill, the head, the pivot point will drop by that distance and therefore the valve will open ever so slightly sooner. I'm not going to draw it out or do the math, but if you keep the same pushrods, you'll open sooner...
06-29-2010, 07:13 PM
#18
Milling the head won't change the rocker geometry, but it does lower the rocker in relation to the lifter. As everyone has already said, that alone would require shorter pushrods to maintain appropriate preload, but I don't think it would open the valve any sooner (unless we get into the dynamics, and then we get into "pump-up") and it doesn't require shimming the rockers to correct the geometry since the rocker's position in relation to the valve never changes.
If anything, I think it just creates more preload in the lifter.
06-29-2010, 07:52 PM
#19
ive never had a swipe issue on any ls camswap. Although i will say this. the contact area these stock rockers have is quite a bit bigger then say a roller tipped one. on the roller style it is easy to c the roller as it contacts the valve along with side load. on a stock style rocker its not as easy to c but is generally to close to spec to even worry about. unless something really drastic has been changed.
Last edited by LTX355; 06-29-2010 at 08:04 PM.
06-30-2010, 01:25 AM
#20
Why are you shimming the rockers? Based on the thread, it appears to be for an unsubstantiated reason. You need to verify the swipe on the stock rockers if you have a cam in the car. If you don't keep them at stock height. Milling the heads will not change the rocker geometry. More rocker motion that results from a larger cam will due to the smaller base circle and more rotation from higher lift. Milling the heads will effect the lifter preload. If you knew what the preload was before milling you can get pretty close on the after milled preload without measuring.
Also, roller tip vs. non-roller tip has no impact on "how forgiving" the geometry is. It comes down to side loading on the valve guide and optimum valve opening.
I wouldn't add shims unless you have sound reason to and based on your questions it doesn't appear you have made the measurements to determine the need for shims or the amount of shim required.
Also, roller tip vs. non-roller tip has no impact on "how forgiving" the geometry is. It comes down to side loading on the valve guide and optimum valve opening.
I wouldn't add shims unless you have sound reason to and based on your questions it doesn't appear you have made the measurements to determine the need for shims or the amount of shim required.
I was kind of in a rush to get my engine back because I had to drive the car to school. the pushrods i have now are the same ones that i gave them when i gave them my engine. perhaps they shimmed the pedestals because they didnt have the correct length push rod in stock when I wanted my engine back? i kind of doubt it because to me, the current 7.4 pushrod, current shim height and current valve stem height is not the same situation as if i were to remove the shim from under the pedestal (lowering the pedestal), and shortening the pushrod by the amount of the shim height because the valve stem height stays the same.
lets say in its current set up the rocker is completely level. now with the shim removed and the pushrod shortened by the height of the shim, the rocker would not be in a completely level position as it was before. it would be lower on the pushrod side than it was before. would this change the wipe/swipe?
Last edited by jdoyle; 06-30-2010 at 01:48 AM.