brubaker

I had a mystery tick in my top end of my new motor after about 150 mlies on it. I isolated it down to #7 intake and found a worn out valve guide, today I removed both heads, disassembled them and found that only #7 intake guide worn, no others. I am trying to figure out what caused this. you can rock this valve side to side about .050" compared to the others about .002"! when I built this engine I bought these le2 heads from a friend of mine, they were wraped up and stored in his house for a year or two. before the valve cover was installed I did pour oil all over the valve springs and all of the valve train so nothing would be dry.

SS RRR

there have been others with LE heads that have had valve guide problems.

dangalla

as much as i hate to agree i have to. although mine have just over 3k on them without a problem i have read of at least one other person with serious valve guide problems

NightTrain66

99 % of the LE heads do not get bronze liners in the heads at all and there for no guide work is done. As long as the guides are .0015 or tighter, they are used. Only thing that wears guides is lack of oil or bad geometry (wrong PR length or guide plates not centering roller on valve tip).

Not sure why only 1 is worn but it is possible.

Make sure rockers (especially the one that is worn) are oiling properly and make sure the roller is centered (side to side) on the valve.

The LT1 heads have the guides installed as blanks with no holes and then the holes are drilled in them so the hole is not in the center of the guide. This makes it possible for the correct GM or Trick Flow guide plates to still have 1, 2 or all of the rockers not alligned side to side with the valve tip properly.

If this checks good, move to adjusting the PR length. Use a black marker and color in tip of valve and then adjust the length until the valve leaves the wear pattern on the valve tip that is most centered when rolling motor over by hand. Some need 7.000 and some need a 7.200 length. A 7.150 is what i suggest for people who do not wanna take the time to do it right and just want to order a pushrod without measuring.

When you have the geometry correct and enough oil to lubricate, the guides will last a LONG time.

brubaker

I did notice that not all of the rocker tips were perfectly allighned side to side with the valve tip, in fact #7 intake was the worst, but the roller still kept 100% contact with the valve tip. I am using comp 4808 guide plates, any other recomedations to resolve this problem? all of the rocker oil holes bleed oil well. push rod length is standard 7.2" trick flow chromemoly.

shoebox

Sounds like that could be your problem, right there. Contact and proper geometry are not always the same thing.

brubaker

So whats the cure, ajustable guide plates?

mdacton

Yes. you could probly use different ones too...7808 is not the right guideplate.

I tried to use them along time ago and they are not right.

After using the Isky a few time they are the way to go, so you can get each rocker perfect

Flyin_Z28

I had the same issue a year ago. Poor geometry caused 3 valves slightly worn and 2 guides completely missing . Don't know where they went to!! I'm guessing they made their way out through the exhaust.

Make absolutely sure that your valve/rocker geometry is set correctly since this can cause a serious loss of power and alot of headache down the road.

brubaker

What's the part# for the ajustable guide plates?

mdacton

http://store.summitracing.com/partde...P&autoview=sku

shoebox

Guideplates do not adjust geometry. They are only there for "support" if needed. You get the geometry correct first.

brubaker

I am new to this site and I want to thank everyone for their input, also thank you to lloyd for his time on the phone today, at this point I need to have bronze liners installed, replace some valves, get the ajustable guide plates, then check the geometry, hopefully after that I will have a long lasting and quiet valvetrain. THANK YOU ALL

SStrokerAce

Guideplates are one reason for guides that are worn. There is almost no 100% way to get rocker tips centered over the valves on every valve on a LT1 (or really any SBC motor) without adjustable guideplates. The other issue is pushrod length. Actually the BIG hupla on this board about WORN OUT LE2 GUIDES IS DUE 100% TO THIS!!!!

If you want valve guides to last you need to check PR length, apparently those who don't blame Lloyd for it.

LE2 head:

http://s86.photobucket.com/albums/k1...t=100_0364.jpg



I know that because of the color of the locks, that's the exact part number lock and retainer Lloyd uses on his heads LE2 heads.

We can agree that these are Ai heads:

http://s86.photobucket.com/albums/k1...t=100_0735.jpg


Notice the number on the right side of the head under the valve cover rail "32" and the gold colored locks....

Now notice these

http://s86.photobucket.com/albums/k1...urrent=710.jpg

http://s86.photobucket.com/albums/k1...urrent=705.jpg


Same gold colored locks and "32" on the head, hence Ai heads.

ACTUALLY CHECKING PR LENGTH!

These are from the same persons photobucket page, and one of the only people to have both LE and Ai heads.

7.050" Pushrod is the correct length, while the 7.100" pushrod is too long and even that would side load the valve. Now imagine the pattern for a 7.150"-7.200" pushrod, it would hang the rocker arm way off the end of the valve like is seen in the first pic of the LE heads.....

THAT'S HOW YOU DESTROY VALVE GUIDES IN A SET OF HEADS!

Instead of being a man and admitting that could (well it is) his fault said user wanted the screw up of the heads fixed that he caused then threw a temper tantrum because they were not fixed.

Bret

Side Note: I know a lot of head porters and they will number their heads usually by the number of sets that they have done. If Ai has only done 32 sets of LT1 heads it's no wonder they don't get a lot of people screwing their parts up!