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Discussion Topic:
Flat head v8 pistons
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Cobra Jet |
03-03-2021 @ 1:59 PM
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Member
Posts: 2
Joined: Mar 2021
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I have the 4 ring pistons. Can I leave the bottom oil ring off and run with the top 3 rings?
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nelsb01 |
03-03-2021 @ 7:12 PM
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Senior
Posts: 983
Joined: Oct 2009
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I am not an expert --- but years ago when I had my engine rebuilt, the rebuilder asked if I wanted 3 ring or 4 ring pistoms. I knew that Ford used 3 ring -- and he said that the modern replacements would be 4 ring and more modern technology. So, my engine has 4 rings. I personally think it is better, and an improvement over the technology that was available back in the day. All I know is that engine runs fine with 4 rings.
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RICKS2L |
03-04-2021 @ 5:32 AM
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Member
Posts: 13
Joined: Jan 2012
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No you cannot leave the bottom ring off.
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TomO |
03-04-2021 @ 6:43 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Why would you want to leave the 4th ring off? It not only helps to control oil consumption, but it also stabilizes the piston in the cylinder. I would not leave it off.
Tom
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Cobra Jet |
03-04-2021 @ 11:00 AM
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Member
Posts: 2
Joined: Mar 2021
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I had read that the 4 ring piston with 2 oil rings didn't allow enough lubrication which results in increased cylinder wear.
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TomO |
03-05-2021 @ 9:34 AM
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Senior
Posts: 7256
Joined: Oct 2009
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I don't have any information on excess wear caused by the 4 ring piston, so I cannot comment on it. I doubt that the extra ring would make much of a difference in wear on a hobby car. If you are concerned about it, order some 3 ring pistons for your bore size. With today's technology on ring and piston design, a 3 ring piston can control oil consumption just as well as a 4 ring piston. A 4 ring pisto is deigned to use that 4th ring and leaving it off could lead to adverse effect on the engine, such as piston slap and excess oil consumption.
Tom
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MG |
03-05-2021 @ 11:01 AM
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Senior
Posts: 1260
Joined: Nov 2009
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3 vs 4 Ring Pistons - 3 Ring types have less drag / friction and so are generally more efficient. If you are determined to go with 3 ring pistons, you should buy/use new 3 ring pistons. This, to avoid 'piston slap' by using the pistons you have without the forth ring....
This message was edited by MG on 3-5-21 @ 12:26 PM
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37RAGTOPMAN |
03-06-2021 @ 10:58 AM
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Senior
Posts: 1962
Joined: Oct 2009
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what I have seen that FORD used I guess they were trying to see what worked best ? 1 cast iron pistons, 3 rings, 2 aluminum pistons with 4 ring pistons, 3 then went to 3 rings pistons, years of engines determined what pistons were used, they changed them though the years I used 3 ring pistons with 3 rings, best is to use new pistons, with 3 rings, my 2 cents 37Ragtopman ALSO Warning do not use the press on CAM GEAR,!!! if you are rebuilding the engine,!!!! If it fails you will have to tear the heads of the off, all valves, and the intake and the grill out, pull the cam out, press off the old gear and press on the new one, BIG JOB, use the bolt on cam and gear, A lot less work
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