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Seriously what could cause this? (Lifter issue)

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Old Sep 28, 2010 | 11:22 PM
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crazy_ugly_coyo's Avatar
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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?
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Old 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?

Last edited by JonDSM; Sep 29, 2010 at 11:34 AM.
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Old Oct 1, 2010 | 10:16 AM
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Did you measure your valve heights yet? The valve in question even looks lower in the picture.
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Old Oct 1, 2010 | 09:05 PM
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Pulled the head off today, Bent Valve is what caused it. But would cause only ONE valve to bend?!?!?!?!? Grrrrrrrrrrrrrrr
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Old Oct 2, 2010 | 09:51 AM
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Originally Posted by crazy_ugly_coyo
Pulled the head off today, Bent Valve is what caused it. But would cause only ONE valve to bend?!?!?!?!? Grrrrrrrrrrrrrrr
Your professionals cleaned up the old valves, checked them for straightness, probably reused several, one of the bent ones got mixed with the good.
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Old Oct 2, 2010 | 05:50 PM
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Good news! I can buy a nakamura intake valve for a 4g63 for $6. if it were exhaust it would be much more expensive.

p.s. have you measured your cam journals?
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Old Oct 17, 2010 | 06:51 PM
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if your t belt skipped a tooth might have belt valves
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Old Oct 17, 2010 | 07:05 PM
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So, its safe to assume that you don't have a timing belt cover then? This is a good reason for me to put mine back on.
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