Valve collision problem |
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Valve collision problem |
thomasotten |
Jun 30 2018, 08:03 PM
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#1
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Senior Member Group: Members Posts: 1,544 Joined: 16-November 03 From: San Antonio, Texas Member No.: 1,349 |
I am having a bit of a problem with my latest 2 liter build. Basically, valves are colliding with pistons after warm up during break in. A valve got stuck and the pushrod actually fell off the rocker.
The heads were redon by RIMCO. After the problem happened, I pulled the heads, and there was clear indication of valve collision, and I had a valve stuck open. The head with a problem was sent back to RIMCO. Reinstalled. What happened this time is the engine start up from cold, runs fine. But then I can hear the taping of collision again. The taping is accompanied by a chirping sound that sounds like something is dragging. I think it must be the valves dragging and closing too slow. I have a deck height of .065. This is essentially a stock build, stock camshaft, etc. Any ideas? Is this perhaps a valve stem lubrication issue? |
thomasotten |
Jul 1 2018, 11:21 AM
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#2
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Senior Member Group: Members Posts: 1,544 Joined: 16-November 03 From: San Antonio, Texas Member No.: 1,349 |
Photo of the stuck valve. When this happened to
the other head, I removed the spring, and gave the valve a little tap and it came right out. I then put it back in the guide and it was smooth. There was some evidence of fine brass flakes, but on a different valve spring. Someone suggested possibly lifter catching. I checked them all, and if you press down on the lifter when pulling you can feel a small catch, but I think this is because the lifter is crossing a chasm in it’s travel in the case. I will probably replace them all. Cam off by one tooth? I usually triple check, but at this point anything is possible . I don’t know maybe I should just tear the whole case apart. Looking over the sales receipt from Rimco, they reamed the guides on both heads originally. When I sent the other head back, they replaced the guides rather than reeming. So perhaps there is something with their reaming process ? Attached thumbnail(s) |
thelogo |
Jul 1 2018, 02:50 PM
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#3
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Senior Member Group: Retired Members Posts: 1,510 Joined: 6-April 10 Member No.: 11,572 Region Association: None |
Photo of the stuck valve. When this happened to the other head, I removed the spring, and gave the valve a little tap and it came right out. I then put it back in the guide and it was smooth. There was some evidence of fine brass flakes, but on a different valve spring. Someone suggested possibly lifter catching. I checked them all, and if you press down on the lifter when pulling you can feel a small catch, but I think this is because the lifter is crossing a chasm in it’s travel in the case. I will probably replace them all. Cam off by one tooth? I usually triple check, but at this point anything is possible . I don’t know maybe I should just tear the whole case apart. Looking over the sales receipt from Rimco, they reamed the guides on both heads originally. When I sent the other head back, they replaced the guides rather than reeming. So perhaps there is something with their reaming process ? Gotta give you major credit for turning your own wrenchs But man this just affirms the fact rebuilding you're engine takes a certain amount of skill that i dont have. (IMG:style_emoticons/default/wub.gif) |
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