help setting valve lash
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
help setting valve lash
Is there anyone in the kaiserslautern, Germany area experienced with setting valve lash on a 94?
I just had the engine rebuilt before shipping it here and it ran fine taking it to Atalnta to be shipped, but as we arrived it developed a "tick", after getting the car here i found that one rocker seems to be hitting the valve cover, its only in the one spot and the car is still running good. I want to try to fix it myself but would REALLY like someone who could assist me--I have never done anything like this before and want to learn.
I just had the engine rebuilt before shipping it here and it ran fine taking it to Atalnta to be shipped, but as we arrived it developed a "tick", after getting the car here i found that one rocker seems to be hitting the valve cover, its only in the one spot and the car is still running good. I want to try to fix it myself but would REALLY like someone who could assist me--I have never done anything like this before and want to learn.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
If the rocker is adjusted, go to a taller (thicker) valve cover gasket.
If it is only one rocker that is hitting the cover, check to see if it is adjusted correctly. Readjust the rocker. Are the studs press in or screw in? If press in studs, it may be pulling out which would give you more play in the rocker than there should be after it was adjusted.
If it is only one rocker that is hitting the cover, check to see if it is adjusted correctly. Readjust the rocker. Are the studs press in or screw in? If press in studs, it may be pulling out which would give you more play in the rocker than there should be after it was adjusted.
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
If the rocker is adjusted, go to a taller (thicker) valve cover gasket.
If it is only one rocker that is hitting the cover, check to see if it is adjusted correctly. Readjust the rocker. Are the studs press in or screw in? If press in studs, it may be pulling out which would give you more play in the rocker than there should be after it was adjusted.
If it is only one rocker that is hitting the cover, check to see if it is adjusted correctly. Readjust the rocker. Are the studs press in or screw in? If press in studs, it may be pulling out which would give you more play in the rocker than there should be after it was adjusted.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
If the studs are screw in you will find the base of the stud with flat shoulders to get a deep socket on so you can torque them to the head. If they are press in, it will look like a straight round rod going into the head.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
All LT1s are screw in rocker arm studs.
Figure out/tell us which valve the rocker in question is on. Depending on the answer you'll rotate the engine to top dead center for either #1 or #6 cylinder in the firing order. After you do that, it'll take you 2 minutes assuming you stop for a drink...
- Loosen the rocker arm nut in question
- Spin the pushrod between your fingers while you tighten the rocker arm nut until you feel interference between the rocker and the pushrod
- Tighten the rocker arm nut another 1/4 - 1/2 turn
- Done
Don't let some around here confuse you like it's rocket science. You have a street engine, not some high strung track engine you're going to beat the &%^## out of every weekend on the track.
Figure out/tell us which valve the rocker in question is on. Depending on the answer you'll rotate the engine to top dead center for either #1 or #6 cylinder in the firing order. After you do that, it'll take you 2 minutes assuming you stop for a drink...
- Loosen the rocker arm nut in question
- Spin the pushrod between your fingers while you tighten the rocker arm nut until you feel interference between the rocker and the pushrod
- Tighten the rocker arm nut another 1/4 - 1/2 turn
- Done
Don't let some around here confuse you like it's rocket science. You have a street engine, not some high strung track engine you're going to beat the &%^## out of every weekend on the track.
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Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
Well, so much for just adjusting it. I pulled the valve cover and found the rocker is broken. It was also turned to the side a little which is what was causing the tapping. I loosened it and repositioned it back where it belongs and the tapping went away. The garage that rebuilt it is going to get me a new rocker.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Now the question becomes "What caused it to break?" You should find the cause to prevent this from happening again.
Can you post photos so we can see where it broke? Are your rockers the Self Aligning versions? I'm willing to bet they are.
Jake
Can you post photos so we can see where it broke? Are your rockers the Self Aligning versions? I'm willing to bet they are.
Jake
pics please
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
Pics are coming, I hope tomorrow if the weather cooperates. I dont know if they are Self Aligning. I just had the Engine rebuilt, there are less than 350 miles on it, and none are hard miles. I dont know what could have caused it to break.
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
here are the pics, it didnt break like i thought. Instead it looks like it slipped off to one side and the whatever it was hitting just wore it down.
http://s812.photobucket.com/albums/z...tte%20Rockers/
http://s812.photobucket.com/albums/z...tte%20Rockers/
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
All LT1s are screw in rocker arm studs.
Figure out/tell us which valve the rocker in question is on. Depending on the answer you'll rotate the engine to top dead center for either #1 or #6 cylinder in the firing order. After you do that, it'll take you 2 minutes assuming you stop for a drink...
- Loosen the rocker arm nut in question
- Spin the pushrod between your fingers while you tighten the rocker arm nut until you feel interference between the rocker and the pushrod
- Tighten the rocker arm nut another 1/4 - 1/2 turn
- Done
Don't let some around here confuse you like it's rocket science. You have a street engine, not some high strung track engine you're going to beat the &%^## out of every weekend on the track.
Figure out/tell us which valve the rocker in question is on. Depending on the answer you'll rotate the engine to top dead center for either #1 or #6 cylinder in the firing order. After you do that, it'll take you 2 minutes assuming you stop for a drink...
- Loosen the rocker arm nut in question
- Spin the pushrod between your fingers while you tighten the rocker arm nut until you feel interference between the rocker and the pushrod
- Tighten the rocker arm nut another 1/4 - 1/2 turn
- Done
Don't let some around here confuse you like it's rocket science. You have a street engine, not some high strung track engine you're going to beat the &%^## out of every weekend on the track.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
As mentioned above those are screw in rocker studs.
Looks like the rocker just jumped off the stem for whatever reason....could be as simple as it was never adjusted or had preload applied. Was the poly lock still tight when you went to remove the rocker?
The rocker's stud still looks straight but the rocker is destroyed. Pull the pushrod and roll it on a piece of glass to ensure that it is still straight. You'll need a replacement roller rocker at a minimum. Some valve train checks are also in order.
Looks like the rocker just jumped off the stem for whatever reason....could be as simple as it was never adjusted or had preload applied. Was the poly lock still tight when you went to remove the rocker?
The rocker's stud still looks straight but the rocker is destroyed. Pull the pushrod and roll it on a piece of glass to ensure that it is still straight. You'll need a replacement roller rocker at a minimum. Some valve train checks are also in order.
Thread Starter
Instructor
Joined: May 2009
Posts: 180
Likes: 5
From: Williamstown, wv
As mentioned above those are screw in rocker studs.
Looks like the rocker just jumped off the stem for whatever reason....could be as simple as it was never adjusted or had preload applied. Was the poly lock still tight when you went to remove the rocker? The rocker's stud still looks straight but the rocker is destroyed. Pull the pushrod and roll it on a piece of glass to ensure that it is still straight. You'll need a replacement roller rocker at a minimum. Some valve train checks are also in order.
Looks like the rocker just jumped off the stem for whatever reason....could be as simple as it was never adjusted or had preload applied. Was the poly lock still tight when you went to remove the rocker?
The rocker's stud still looks straight but the rocker is destroyed. Pull the pushrod and roll it on a piece of glass to ensure that it is still straight. You'll need a replacement roller rocker at a minimum. Some valve train checks are also in order.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
To help avoid this from happening to others here's what I'd do.:
I'd get down low at the front of the car in a position where I could see how the underside of the rocker arm clears the valve spring retainer. If unable to get a GOOD look, I'd get a mirror and use it to see.
What you'll be looking for is any indication that the body of the rocker arm is touching the valve spring retainer BEFORE the roller contacts the valve stem tip. You need .060" or more clearance between the rocker body and the retainer.
An additional check would be to remove the rockers, one at a time, and look at the underside. If the rocker body had been touching the retainer you'll see witness marks. Should you find that the rocker bodies are touching, you're bound to have a repeat of what you just found - failure. So a change of the retainers or perhaps going to a longer pushrod will be in order.
Jake
I'd get down low at the front of the car in a position where I could see how the underside of the rocker arm clears the valve spring retainer. If unable to get a GOOD look, I'd get a mirror and use it to see.
What you'll be looking for is any indication that the body of the rocker arm is touching the valve spring retainer BEFORE the roller contacts the valve stem tip. You need .060" or more clearance between the rocker body and the retainer.
An additional check would be to remove the rockers, one at a time, and look at the underside. If the rocker body had been touching the retainer you'll see witness marks. Should you find that the rocker bodies are touching, you're bound to have a repeat of what you just found - failure. So a change of the retainers or perhaps going to a longer pushrod will be in order.
Jake
