"White Knight"

I had a hard time with my GM guideplate install, they would do what someone here mentioned they would twist ever so slightly when i torqued them down. I had a hard time getting the valve right in the middle of rocker.

How do you align those GM guideplates anyways, because those holes the studs go through are like twice as big as they need to be. Yes I am exagearating, but come on. How do you align something that has terrible tolerances. I had one I just had to throw away, because no matter what I did I could not get the valve to sit in the middle of the roller tip. Bought a new one and bata bing...right down the middle.

wrd1972

I just measured my the push rods. They are the exact same length as my original to within .001".

So this is not happening due to being too long.

1racerdude

Ya HAVE to check your GEOMETRY to get the right length PR. There is NO magic formula,except to get a length checker and CHECK the pattern.
If ya don't it will tear it up again or wear out the guides.

wrd1972

Update:
14 of the 16 rockers and guide plate slots look great and show the normal amount of wear in the range of .030" or so. One has a tad more wear than normal and the one in the photo is big time destroyed.

I checked several existing push rods and they were all straight.

The geometry looks good using Comp Cams tech sheet.

I have been brainstorming with Thunder and they think it might be a bad rocker arm. The new one is on the way under warranty exchange. I think the wrong size rods have been ruled out.

I also have some high tec chromoly 7.2" push rods coming too along with two new GM guideplates.

I am going to use the existing valve with the rounded stem top the way it is and monitor it for wear very often. Since I trashed the AIR pump the left valve cover comes off in minutes. Worse comes to worse I can pull the head and throw in a new valve or get them ported.

roughneck427

I dunno im using Harland Sharp 1.65 ratio rockers arms i cant see why to different brand of Rockers on 2 different cars are bad i bought mine about 7 months ago also when i first put them on they just didnt look like hardend metal to me like you see black oxidized plates.Im sure in another few months mine would have looked like yours.


Well update these guide plates are NOT hardend

10111771 - Pushrod Guideplate For L98 Corvette Aluminum Head & ZZZ-ZZ4 Heads (Without Self Aligning rocker arms) 10111771

PACE Price Qty
$9.95
Detailed Description
This non-hardened guideplate is used with the Corvette aluminum cylinder head assembly P/N 10185086 and 5.7-liter HO engine assembly P/N 10185072. Use with self-aligning rocker arm P/N 10089648. These guideplates should not be used when using slotted tip rockers.

Why in the hell would the make a non-hardend guidplate one spot it says to use SA rockers and in the title it says not for use with SA

Joe B

IMO, I would NEVER put a new roller rocker on a mushroomed valve tip.....this can cause excess side loads on the guides as well as putting increased pressures on the roller rocker bearings......I would at least get one lash cap on there giving you a perfectly smooth surface for the roller to ride on....I would then use the sharpie marker method to see where the patern is(it may be closer than you think) On previous engines where I had lash caps my patern hardly changed even with a 80thou thick lashcap.........If your patern does need a little different sized pushrod to get it perfect, you can always just buy one slightly different length hi-tech pushrod to match your others you have comming, same with the lashcap, you can just get one for that specific valve stem tip.......about 15 bucks total, and nothing to constantly have to check and worry about....good luck with it....joe

JFR

Do no have bent push rods, but had one fall off. I am going to add push rod guides. My question isid 1995 Lt1 z28, come with push rod guides?
I bought this car used and have no info, but someone has had it apart.
Has 85k on it. Doing a head gasket replacement, and valve job, making sure head is not warped, etc.
Thanks

Daniel6718

no stock guides are built into the head gaskets...prolly the rocker nut backed off...or was too loose..

wrd1972

No guide plates from the factory on stock LT1 heads.

kyle97

Just wanted to add to this thread...

I had the exact same problem with my guideplates, but i noticed it before anything bad happened. I was running comp pro-mag 1.6rr with 7.200 (stock) comp hi-energy hardend pushrods, and GM guideplates.

The wear was fairly bad on about half of the plates. Fortunatley, all my valve stems were still in good shape except for one. The rocker had been cocked to the side pretty far and both the roller tip and the valve stem had some pitting in the metal. Using a pushrod length checker, I determined that my puhsrods actually should have been 7.050. Im not sure if the improper length caused the guideplate wear or if there is still a different problem i havent identified -- i guess ill just have to keep an eye on it once i fix things up.

I got a set of comp lash caps, and re-checked the required pushrod length. Even with the caps, I still needed 7.050, so they dont seem to affect much. I also replaced the damaged rocker and the severly worn guideplates.

I think I needed the shorter length due to the fact that my heads were milled 0.010, I used an impala head gaset (0.026 compressed thickness) and the higher ratio rockers. Also, my crane OE replacement lifters have slightly different cups than stock. They sit about 0.030 higher than the stock lifters.

ta4me

Just a quick question? Those aren't self algining RR are they? You can't use guide plates with SA rockers. They will move side to side and kill the guide plates.

Just wondering?

kyle97

Mine were the NSAs, and im pretty sure wrd1972's were also.

wrd1972

My rockers are Comp pro-mag (full roller) 1.6 ratio NSA 7/16" studs.