Fixing poor leakdown, Cyl 1 leaks at 50%, rest are cool. |
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Fixing poor leakdown, Cyl 1 leaks at 50%, rest are cool. |
VaccaRabite |
Oct 24 2007, 07:00 AM
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#1
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En Garde! Group: Admin Posts: 13,554 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
So, at the Sterling meet I did a leakdown test on my motor, and found a problem with Cylinder 1. 45% leakdown, but 120 lbs of compression. Was tempted just to let sleeping dogs lie, but pulled the head off.
What was going on was clear as soon as we did that, the head was not totaly sealed to the cylinder, off by a very small amount. Instead of having the head recut, I decided to try and lap the two of them together. So, last night I hand lapped them, using ground graphite to check for even contact. I got good contact after the third round of hand lapping (lap, clean, check). Now I need to get the jug back on the block. I have a ring compressor on the piston, but I can't ficgure out how to get the head back on. Do I have to take the piston head off the rod? If so, how do I get it off. It looks like that tis a spring keeper that needs to be removed. Is there anyhting on the rod the needs to be loosened before I can pull the pin out to remove the piston head? Obviously, if there is a trick to getting the jug back on without pulling off the piston head, I'd like to do that. Zach |
davep |
Dec 31 2007, 07:54 PM
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#2
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914 Historian Group: Benefactors Posts: 5,195 Joined: 13-October 03 From: Burford, ON, N0E 1A0 Member No.: 1,244 Region Association: Canada |
Well, it appears most of your problem was the extra base shim on cylinder 2. However, you said the gap was .005 to .007 and you took out .010 . So you should still have an error of .003 to .005 even though the cylinders are .002 different. Wow, lots of tiny errors all over.
What I would try at this point would be to clamp the cylinders down and remeasure the evenness of the two cylinders in place. If you get an error, then try switching the cylinders. One combo should be the the better of the two, so use that combo and assemble. Then do the leakdown test again. |
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