Whats eating my Roller Rockers?
02-22-2005, 10:20 PM
#1
Instructor
Thread Starter
Whats eating my Roller Rockers?
I am uncertain if its a bad valve adjustment or something else? After I found the first one (i heard an internal squeek) I replaced all the pushrods (same length) and the damaged rocker. The other day I heard a minor squeek and found another damaged rocker and have since replaced it. Am I setting my rockers too loose? I have a solid cam and was told adj .24 int and .28 exh. was spec. by original engine builder. Should I be going a little tighter?
I just installed a MSD unit with a rev limiter. Perhaps I over rev the poor bastard with my new 4 speed? Other than that car runs great!
I just installed a MSD unit with a rev limiter. Perhaps I over rev the poor bastard with my new 4 speed? Other than that car runs great!
02-22-2005, 10:27 PM
#2
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if the cam mfg said those are the specs, then not much you can do...also check the rockers....there is a machined recess in the fulcrum, the machined recess is on top, thats for the adjusting nut to sit....it may be possible you installed the fulcrum upside down
02-22-2005, 10:40 PM
#3
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Originally Posted by GDaina
if the cam mfg said those are the specs, then not much you can do...also check the rockers....there is a machined recess in the fulcrum, the machined recess is on top, thats for the adjusting nut to sit....it may be possible you installed the fulcrum upside down
100% UNLESS YOU ARE ADJUSTING THE VALVES WRONG
02-22-2005, 10:49 PM
#4
Instructor
Thread Starter
Originally Posted by GDaina
...it may be possible you installed the fulcrum upside down
02-22-2005, 10:55 PM
#5
Racer
Originally Posted by ferndog4
I am uncertain if its a bad valve adjustment or something else? After I found the first one (i heard an internal squeek) I replaced all the pushrods (same length) and the damaged rocker. The other day I heard a minor squeek and found another damaged rocker and have since replaced it. Am I setting my rockers too loose? I have a solid cam and was told adj .24 int and .28 exh. was spec. by original engine builder. Should I be going a little tighter?
Is your builder's recommendation "hot" or "cold" and are you running aluminum heads? Aluminum heads "grow" when hot and can open up your lash up to 0.007". . .But it appears that your adjustment nuts are coming loose. The set screw and the retaining nut need to be turned together that last 1/4 turn to "lock" the lash setting.
02-23-2005, 12:09 AM
#6
Instructor
Thread Starter
Fbody, your right .028 and .024 are the correct settings. That was what I am using on the feeler guages I just miss typed. Anyways, Aluminum Heads, I wish. I am using good ol fashion hogged out Cast Iron "492's." I will take your advice and re-lock all the nuts to make sure none come loose.
02-23-2005, 01:30 AM
#8
Instructor
Thread Starter
Originally Posted by i885744
I can't see very well from the pictures. Are those self aligning rockers or do you have guideplates?
02-23-2005, 08:29 AM
#9
Race Director
Looks like the rocker is moving all over the place probably because they are too loose. Get the part number for the cam and look up the manufacturers lash setting. Also are you setting the lash hot or cold ?
Also check that your method of adjusting the valves is correct
Also check that your method of adjusting the valves is correct
02-23-2005, 09:03 AM
#10
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Me thinks, as someone mentioned above, the set screws are not tightened, and the polylocks are loosening. I assume that longer rocker arm studs are used.
02-23-2005, 09:17 AM
#11
Le Mans Master
Originally Posted by GDaina
Me thinks, as someone mentioned above, the set screws are not tightened, and the polylocks are loosening. I assume that longer rocker arm studs are used.
How are you tightening the nuts/set screws? It is important that you do it the right way. 
Check the rocker studs to see if they are torqued down tight. The guideplates could be moving around causing that damage.-Mark.
02-23-2005, 09:24 AM
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Originally Posted by ferndog4
02-23-2005, 10:27 AM
#14
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[QUOTE=page62]Not to hijack the thread...but isn't your distributor a notch out of whack???
I suppose its off a tooth but timming this thing was a pain. I really dont want to have to go through that again for some time. Any timming shortcuts to straighten it out?
I suppose its off a tooth but timming this thing was a pain. I really dont want to have to go through that again for some time. Any timming shortcuts to straighten it out?
02-23-2005, 10:34 AM
#15
Instructor
Thread Starter
Originally Posted by MotorHead
Looks like the rocker is moving all over the place probably because they are too loose. Get the part number for the cam and look up the manufacturers lash setting. Also are you setting the lash hot or cold ?
Also check that your method of adjusting the valves is correct
Also check that your method of adjusting the valves is correct
I set the lash warm. From what I read to set the hot lash you need to do that minutes after the engine shuts down. Its too damn hot in their! Even whith Mechanix gloves. Maybe I will pay someone to burn their hands, not me. Do you think the pushrods are too short? The roller hits the center of the valve like its suppose too. I think i might just need to set the locks?
02-23-2005, 10:49 AM
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Is there any damage to the inside oval of the rockers? Is there any sign of the rockers hitting the guide plates? Also the rocker roller should be closer to the outside edge so when the rocker moves the roller will move from the outside edge to inside edge. Check to see when they are on the ones that are at full lift.
Dumb question but your setting the lash when the lifters are seated on the base circle of the cam?
Keep at you will find the problem.
Dumb question but your setting the lash when the lifters are seated on the base circle of the cam?
Keep at you will find the problem.
02-23-2005, 11:13 AM
#17
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When the balancer and the #1 cylinder are at TDC, the rotor should point towards the #1 cylinder. You may have to pull the distributor and use a long screwdriver to turn the oil pump slot about 1/8 turn clockwise. The drop the distributor back in, but with the rotor moved over a notch clockwise as you go in.
For the rest of the procedure, download a copy of Lars timing paper at www.corvettefaq.com
For the rest of the procedure, download a copy of Lars timing paper at www.corvettefaq.com
02-23-2005, 12:23 PM
#18
Race Director
IF you set it warm it should be close enough if the specs are correct. To check the valve train geometry ( to see if you have the correct pushrods)
rotate the motor by hand and watch the travel of one of the rollers over the tip of the valve, it should start at one side travel and travel about the same distance on the other, if it doesn't do this your pushrods are too long or too short.
Another thing to check is the pushhrod hitting anything, usually the head below the guide plates. Check a pushrod it should have about a .3in rubbed spot where it goes thru the guide plate and should not have any other worn spots on it. Also check the alignment of the guide plates make sure they are not unessarily deflecting the rocker one way or the other if they do they need to be adjusted.
rotate the motor by hand and watch the travel of one of the rollers over the tip of the valve, it should start at one side travel and travel about the same distance on the other, if it doesn't do this your pushrods are too long or too short.
Another thing to check is the pushhrod hitting anything, usually the head below the guide plates. Check a pushrod it should have about a .3in rubbed spot where it goes thru the guide plate and should not have any other worn spots on it. Also check the alignment of the guide plates make sure they are not unessarily deflecting the rocker one way or the other if they do they need to be adjusted.
02-23-2005, 01:14 PM
#19
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The valve lash is only a starting point. You can tighten it up .010 without a problem. This is from Comp Cam. If you want less noise and more duration set them at .018 or even a little tighter.
I set mine cold and a little tighter then specs and never had a problem.
It looks like the rocker is comming loose and allowing the push rod to walk all over the place.
I set mine cold and a little tighter then specs and never had a problem.
It looks like the rocker is comming loose and allowing the push rod to walk all over the place.
02-24-2005, 12:06 AM
#20
Instructor
Thread Starter
Originally Posted by MotorHead
IF you set it warm it should be close enough if the specs are correct. To check the valve train geometry ( to see if you have the correct pushrods)
rotate the motor by hand and watch the travel of one of the rollers over the tip of the valve, it should start at one side travel and travel about the same distance on the other, if it doesn't do this your pushrods are too long or too short.
Another thing to check is the pushhrod hitting anything, usually the head below the guide plates. Check a pushrod it should have about a .3in rubbed spot where it goes thru the guide plate and should not have any other worn spots on it. Also check the alignment of the guide plates make sure they are not unessarily deflecting the rocker one way or the other if they do they need to be adjusted.
rotate the motor by hand and watch the travel of one of the rollers over the tip of the valve, it should start at one side travel and travel about the same distance on the other, if it doesn't do this your pushrods are too long or too short.
Another thing to check is the pushhrod hitting anything, usually the head below the guide plates. Check a pushrod it should have about a .3in rubbed spot where it goes thru the guide plate and should not have any other worn spots on it. Also check the alignment of the guide plates make sure they are not unessarily deflecting the rocker one way or the other if they do they need to be adjusted.