Seriously what could cause this? (Lifter issue)
Sep 28, 2010, 11:22 PM
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Seriously what could cause this? (Lifter issue)
Alright so heres the whole story from day one with my car (Im hoping giving you the insight will help diagnose the issue)
My car had the timing belt skip a tooth when the accessory belt snapped and hit the timing belt (Oh yeah my car is a road race only car) causing the pistons to hit the valves. I had new guides and valves installed professionally. But I decided to keep the OEM springs and retainers since Im running stock cams and they were low mileage. For a year now (the car doesnt get driven that often) Ive been battling one of my intake rockers falling off at high RPM (above 7K: drivers side cyl #2) So I recently installed new HKS valve springs and titanium retainers thinking maybe the spring was just wore out but that did not fix it. I was then told to check the tightness of the retainer but I cant find any info on how to do that. I noticed that there was a slight scratch on that cam lobe so I put on new (to me) cam's thinking that this would solve my issue. While doing so I noticed something very odd. Please note the picture below.
Can you see how the lifter on the left is higher than the other one? Thinking this was a fluke I pulled the cam back off and swapped that lifter/ rocker with a different one as well as cleaned out and checked for any debris that might be down there (none was found). After installing that cam again I noticed the same issue! Here is a pic again comparing both lifters on the same cylinder
I took my micrometer to check the gaps. The taller lifter was at .35 while the correct height lifter is at .22 which is what all the other lifter are at. So what would make this one the odd man out?
My car had the timing belt skip a tooth when the accessory belt snapped and hit the timing belt (Oh yeah my car is a road race only car) causing the pistons to hit the valves. I had new guides and valves installed professionally. But I decided to keep the OEM springs and retainers since Im running stock cams and they were low mileage. For a year now (the car doesnt get driven that often) Ive been battling one of my intake rockers falling off at high RPM (above 7K: drivers side cyl #2) So I recently installed new HKS valve springs and titanium retainers thinking maybe the spring was just wore out but that did not fix it. I was then told to check the tightness of the retainer but I cant find any info on how to do that. I noticed that there was a slight scratch on that cam lobe so I put on new (to me) cam's thinking that this would solve my issue. While doing so I noticed something very odd. Please note the picture below.
Can you see how the lifter on the left is higher than the other one? Thinking this was a fluke I pulled the cam back off and swapped that lifter/ rocker with a different one as well as cleaned out and checked for any debris that might be down there (none was found). After installing that cam again I noticed the same issue! Here is a pic again comparing both lifters on the same cylinder
I took my micrometer to check the gaps. The taller lifter was at .35 while the correct height lifter is at .22 which is what all the other lifter are at. So what would make this one the odd man out?
Sep 29, 2010, 08:57 AM
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Measure your valve heights. I'll bet the valve in question is .12mm shorter than the others.
P.S. could you measure your cam journal sizes for me?
P.S. could you measure your cam journal sizes for me?
Last edited by JonDSM; Sep 29, 2010 at 11:34 AM.
Oct 2, 2010, 09:51 AM
#5
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Your professionals cleaned up the old valves, checked them for straightness, probably reused several, one of the bent ones got mixed with the good.
