I know that the fourth ring creates more drag and robs some power . Would it really hurt all that much,,,,or would it be offset by less oil on the cylinder walls to contaminate the incoming fuel charge ? Also,,,,would the extra ring at bottom help stabilize the piston in the bore better ? Since most street engines will not produce an enormous amount of power,,,,,and live most of their lives at a lower rpm anyway,,,,what would it hurt ? Any real world experience,,,or ideas to the contrary ? Tommy
<a href="https://www.jalopyjournal.com/forum/threads/ford-piston-questions.981079/#post-11048862">Ford Piston questions</a> Ford Piston questions Jack E/NJ
I was thinking the 4 th ring could be left out if need be,,,,,no big deal I think . From what I was reading in other posts,,,,,would not hurt anything to leave it off . Tommy
No kind of expert here, but I've built 2 flatheads recently. Left the bottom ring out of both of them, and see absolutely no problem. Saving up to do #3 and I'll leave the 4th ring out of it, too.
Have put together many flathead Motors over a 55 year period——probably 20 or so for myself——noticed a large amount of “drag” if using all 4 rings——also noticed I don’t get 10,000 miles out of those engines b4they start “smoking” pretty bad and time to tear down and re-do over. This latest engine was a .020 bore and 4 in crank—-thought I would try using all 4 rings—-best running engine with 160 psi in all cylinders. I think 4rings definitely helps to control “piston rocking” which in theory will wear the bore quicker if assembled using only 3 of the 4 rings.. note I am 73 years young and run my hot rod “pretty hard”——so hard I gave up using early Ford trans and banjo rears over 35 years ago.My heavy foot requires Chevy 4 & 5 spd trans and 9 in Ford exclusively! Generally 3 ring pistons are for racing—-Jahn’s & Ross come to mind. My 32 Henry cabriolet runs 80 in the 1/8 but is driven nearly every day because of mild weather in s. Texas.
The history of the 4 ring piston starts with the three ring allowing some oil to be consumed. Ford hired an ex-Oldsmobile engineer to design a different piston for the 59A series and he came up with the 4th lower ring and extended skirt. It cured oil consumption but also cut down oil ll to the other rings. Pull down almost any 4 ring equipped engine with some miles on it and you will find rings that have overheated and destroyed ring lands, broken and the pieces crawled over each other. I have built lots of 4 ring motors after seeing this and reading a report in an old Cars and Parts magazine many years ago. I run the piston because it is more stable in the cylinder that the 3 ring. BUT, I never install the 4th ring. Then engines run fine and consume marginal amounts of oil, not enough to worry about, and when torn down with many miles on them, no ring overheating and breaking. My advice is to run the longer 4 ring piston for stability but not the 4th ring. I wish I still had that article to bolster my argument. I use 3 ring pistons on big bore engines.
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