| mike39 | -- 01-21-2013 @ 5:29 PM |
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Building a flathead V8 for my 39 truck. Have new 4 ring pistons and Hastings rings. I was told not to use the oil ring on the bottom of the piston. Is the oil ring just above the wrist pin enough ? Mike
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| deuce_roadster | -- 01-21-2013 @ 5:34 PM |
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When the cylinders are honed to fit the pistons proplerly, and the ring gap is proper, it is true, you don't need the bottom oil ring. It is just a lot of extra friction.
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| supereal | -- 01-22-2013 @ 6:58 AM |
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Use all the rings as designed, but be sure that the end gaps are proper, and the gaps are staged at 120 degrees apart when installed. If the cylinders haven't been rebored, check the ring gap at several places in the bore. Never re-ring an engine without honing the cylinders to break the glaze and provide a "diamond" pattern, or it will delay or prevent ring seating. Also, if provided, be sure the oil ring expanders are properly installed, and that all rings are facing the right direction.
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| TomO | -- 01-22-2013 @ 8:49 AM |
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Mike, Super is correct, use all of the rings. If you only want to use 3 rings, get 3 ring pistons. The skirt design on 3 and 4 ring pistons are different and leaving out the bottom ring could cause piston instability in the bore. Tom
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| mike39 | -- 01-22-2013 @ 6:00 PM |
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deuce, Yes its bored .060 and honed properly.
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| mike39 | -- 01-22-2013 @ 6:02 PM |
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Looks like some of you say use them and some say leave em out.................
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| supereal | -- 01-22-2013 @ 9:18 PM |
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TomO is right. Omitting the bottom ring on a four ring piston will likely result in "piston slap". The bottom oil ring was adapted to reduce oil consumption. Any reduction in friction would be minor if left off.
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| supereal | -- 01-22-2013 @ 9:18 PM |
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TomO is right. Omitting the bottom ring on a four ring piston will likely result in "piston slap". The bottom oil ring was adapted to reduce oil consumption. Any reduction in friction would be minor if left off.
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| TomO | -- 01-23-2013 @ 7:40 AM |
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Mike, The engineer that designed the 4 ring pistons that you bought designed the piston skirt to use the 4th ring. The piston will not control oil or operate correctly in the bore without that 4th ring. You have 2 lungs, what would you think of a doctor that performed open heart surgery and left out one of your lung, because you could still breathe with one lung? Tom
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