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Registered
Join Date: Mar 2007
Posts: 66
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Should I re-ring
Last year I built a 2.4 that smoked from the git go. After about 1,500 miles I finally had the chance to tear it down to find out why.
The problem was the valve guides. I could move a few of them 1/8 of an inch. The machine shop where I had the heads done, said at the time, that the valves and guides were in spec. (They have had some help problems recently and the guy that did my heads was fired) So I got screwed. I did a leakdown and all the cylinders were @15% cold. It seamed like all the air noise was coming from the sump. But a few percentage points had to be from the valves. My question is: Should I re-ring while I'm in there. I'm not sure the rings took a good set because of all the oil. They are cast cylinders and I have a ball hone. The rings that are in it are Goetze, but I have a set of Deeves on the shelf. Should I make a few passes with the hone and replace just the top ring? Replace them all? Leave it alone? Thanks
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03-08-2008, 03:36 AM
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Registered
Join Date: Jul 2000
Location: So. Calif.
Posts: 19,910
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Your leakdown test revealed most of the air leakage was from the rings. Without adequate compression, the engine won't produce the power you expect.
The correct rebuilding procedure would be to clean, inspect and measure the pistons and cylinders; measure piston-to-cylinder clearance, cylinder taper and ring groove wear. If okay and within spec, replace all the rings. If you're not familiar with the proper technique for honing the cylinders, ask a knowledgeable shop to perform this. If the valve guides are worn, replace them and re-seat the valves. Reassemble and run the engine so the rings seat properly. Sherwood |
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03-08-2008, 08:38 AM
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Join Date: Dec 2007
Posts: 65
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If I head the heads off I would definately re ring. Rings are really cheap, compared to the stress that you will habe in not knowing if they were done right. I think that I would do all of the measurements and if they check out then just simply rering. Also I beleive that the leakdown needs to be done when hot. What are the compression numbers. I always try to keep in the back of my mind the simple fact that cold comprssion is what starts a car. But every manual and all resources say to do the leakdown and compression when the car is warm.
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03-09-2008, 07:15 PM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,117
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Ditto Crashly
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03-10-2008, 08:15 AM
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