49 ford flathead question

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lowandratty

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Ok flathead guy's, is there any pros or cons when rebuilding a 49 flatty with using the old 4 ring style or the new 3 ring style pistons. Is one better than the other ?, thanks for any help on this. Thanks in advance Ken.
 
Thank you, I just want to build a good running engine I can count on with no problems, with a little more power, I figured this would be the best place to ask about the flatty engine.
 
19Fordy said:
It is my understanding that 3 ring pistons are used more for racing.
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Not really true, most vehicles in service today have the "3-ring" setup, and most of these aren't "racing"??

Just a tip though, when building ANY type engine, the more internal (frictional) HP you can free up, the more power available at the flywheel. This really counts when you are working with 100 HP (nominal) units. The fact that there is one less ring "along for the ride", the better.

Thanks, Gary in N.Y.

P.S. There are "3-ring" racing ring sets available which are also fine for "drivers" such as the ones we use with the Ross line of pistons. These are usually of the "metric" sizes, 1.5. 1.5., and 3.0.
 
I'm just in the process of freshening up my 59A engine, it's a stocker but has been totally reconditioned in the past using 3 ring solid skirt pistons. They're .045" over, so they're not racing pistons.
 
My favorite V8 core motors to find are the ones w bad pistons …. I find quite a few w bad cast 4 ring pistons.
 
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It is all about the oil ring. The design and effectiveness of oil rings has greatly improved since Ford specified four ring pistons for the flathead. Now one modern style oil ring is really all you need, and as GOSFAST stated, you will free up some needed power.
 
There is a good 3-ring piston available that is not forged type but they only make them in large oversizes like 3 5/16". If yours is already out that far, then they would be more streetable than the Ross types plus you don't have to size the fit so loose as you do with forged pistons.
 
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Now I understand why the old pistons had 4 rings, the orignal rings were just a hope and prayer they would just slow the oil down. Thanks everyone. Ken.

Now Anybody got a good 4" merc. crank for sale ?
 
I don't know if anyone would agree with me, but when you think about friction and horsepower, it really doesn't make any sense. If there was any significant friction between rings and cylinder walls, do you actually think rings would last over 50,000 miles? You have friction on start up, but when an engine is running, and at operating temperature, the amount of friction is negligible. It's just another example of over thinking the basic flathead. I do believe oil control and compression with new verses old ring technology is a valid issue, but friction, come on guys.
 
Ok. Thanks. I stand corrected. I thought 3 ring pistons would "rock" more in the cylinder bore and were looser.
 
Russ/40 said:
I don't know if anyone would agree with me, but when you think about friction and horsepower, it really doesn't make any sense. If there was any significant friction between rings and cylinder walls, do you actually think rings would last over 50,000 miles? You have friction on start up, but when an engine is running, and at operating temperature, the amount of friction is negligible. It's just another example of over thinking the basic flathead. I do believe oil control and compression with new verses old ring technology is a valid issue, but friction, come on guys.
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Actually the oil control rings are a fairly high component of ring friction loss. They generally have a higher wall tension than the other rings because their job is to scrape the oil away and they function pretty much the same through all four cycles, Compression rings, on the other hand, are designed to have max sealing on the firing stroke and take more of a ride on the other strokes. So yes, I think there is a noticable difference between 3 and 4 ring friction amounts. especially that big old cast iron bottom ring on the flathead.
 
Not persuaded. Friction means wear. How much ring, and cylinder wall disappears after 50k miles? I contend the rings, bottom oil ring included, are oil sweepers, and ride on an oil film for the most part.
I would agree, the oil ring has the most friction, but, not relevant from any practical standpoint when it comes to horsepower lost. That is my point. You can choose to go to three from four, but it is not going to give you any measurable power. JMHO
 
I think the major friction with the rings is in inital start up of a NEW engine, The wrings will ware in, crating a better seal. as for the forth ring, it's comes form past piston and ring design. when the 3 piece pil ring was invented it provided enough oil control rhat a fourth one wasn;t needed. Also piston desigh allowing a tighter piston to cylinder wall clearance. Pistons rock when the clearance is larger waiting for the piston to heat up and expand. Forged pistons are racing pistons and can be used in street engines, but there are better options. I've been using Egge 3 ring pistons for years they can be fit tight and are lighter than stock pistons. This places a lighter load on the lower end. I think they start at .060" over not sure I know they have then in 3 5/16. +.020,+.030" with Metric rings. at least that's what came in the last set i bought.
 
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