I need pistons 3.248/3.75 and I have the choice of sealed power or offenhauser (from speedway) or the speedway piston (looks the same as the offenhauser). Whats is the better choice?
Offenhauser does not make pistons, I believe that’s just an agreement ($$$) so Speedway can use their name.
Somebody beat me saying the ones I bought were made in India. I couldn't find anything wrong with them, though.
Last I knew, Sealed Power is owned by Mahle. Mahle is a major player in the automotive industry with plants on several continents. I vote Mahle.
I bought a set of 3 5/16 X 3 3/4 pistons from Speedway on closeout (pistons, rings and pins for $109.95) because of the price. I had my machinist look them over and he said they seemed fine. They were 4 ring pistons and he installed them without the fourth ring after balancing the engine. The engine runs great. I'd do it again (at that price).
It's unneeded and just causes extra drag. As I understand it, early on in the flathead era, there was a real problem with excess oil consumption. Some "hired gun" engineers ( I have heard they were either from Studebaker or Oldsmobile) decided that an easy fix would be to add the fourth ring. With the advances in piston ring technology, the three usual rings are fully adequate to control the oil these days. I had numerous discussions, both here and on "The Ford Barn" and the overall conclusion was to just leave the fourth ring off. I talked to my machinist about it, and he could see no reason to use the fourth ring, so we left it off. So far, it seems to have been the right thing to do. Some have argued that leaving the fourth ring off destabilizes the piston in the bore. Those folks do not understand the functions of the pistons and rings. The stability of the piston in the bore is controlled by the proper fitting of the piston to the bore. A new engine with new rings built with excessive piston to bore clearance can still have "piston slap". Actually, the piston supports the rings, which are meant to control oil and compression.
I'd have to say that it depends on your intended use. If you're going to be doing some serious racing, you probably want forged pistons with metric rings. For a mild street engine, they would be overkill and probably a waste of money (and probably noisy when cold as well). That being said, I think that brand is important. The problem is that these days, good old American "name brands" no longer mean much in many cases. I "took one for the team" and used the Speedway pistons and found them to be satisfactory. I wonder how many guys that said "Mahle!" have actually purchased and installed them? There are too many "knee jerk" anti-this and anti-that opinions these days. I believe you are doing the right thing and asking. on this forum. I might try asking on "The Ford Barn" as well, as there are a lot of very knowledgeable "flathead gurus" there.
Not in a flathead, but we used literally millions of Mahle pistons in production Diesel engines over the years. They were, at the time sourced from Mahle domestic and European plants. Low volume pistons for obsolete engines like flatheads would obviously come from plants worldwide that are tooled for lower volumes. They are a world cl*** source.
Sealed Power used to be owned by Federal Mogul. I was not aware that they were owned on Mahle but for all I know Federal Mogul could be owned by Mahle. They have been an affordable quality piston for a long while. I would not be afraid to use them today. I am not aware that Speedway owns a foundry or a forge. I would probably want to know who makes the pistons I was ordering before I bought them. Not to say that they are selling an inferior product just that I would like to know what I was buying. That is just me and in no way do I expect anyone else to do that.
I recall reading on the FordBarn, fella (who I think p***ed away so I won’t venture to recall his name) was an engine builder/machine shop owner, I think he worked with his son. Anyways, he had dyno results of engines without the bottom ring, his claim was impressive, like 20-25 more HP? Do you recall the thread. It’s been a 8-10 years since I was a FB guy, so at least that long ago.
I think you're referring to Gary ("GOSFAST") on the Barn. I seem to remember this, but a quick search didn't find the exact thread. As I remember it, It wasn't removing the fourth ring from a stock piston that caused that increase in power, but replacing the four-ring stock-type pistons with forged units with 3 Moly rings did. I don't think just removing the ring would do anything close to that. And guys, I'm not knocking Mahle or anyone else. I am just relating my own experience to a guy who has asked a legitimate question. Also, I am advising against blanket judgements, especially in this day and age.
Back 30+ years ago there were only 2 piston forging sources for roughs and blanks. 1 was TRW/Sealed Power and even the custom big name pistons had their forge symbol on the inside, but they did their own thing for sizing and shape. The forged slugs I bought were less than .0005 difference outta 8. They all weighed the same, to the gram. Cast pistons? I dunno. I have to believe each seller is also limited to raw material sources especially in a global industry. What are you getting for the $$$? Pop quiz, were the pistons I bought: A-Ross B-JE C-Diamond D-Sealed Power 500 bonus points for the 1st right answer
As in TRW and 1 other company (who's name escapes me) were the only 2 doing blanks for forged pistons. Logically that actually makes sense considering the enormity of such a gig, yes? If you mean others, they would source raw blanks and cut and size to their designs for dome, ring spacing, blag blah blah.
Up to 1994, the other company making forged piston blanks would have been Alcoa at their Vernon Works facility in Los Angeles. Alcoa shut that plant down in 94 over a wage dispute and no longer made forged piston blanks. A group of former Alcoa employees with knowledge of the forging process started Performance Forge and went into production in 96. They started with making piston forgings and over time have expanded into other aluminum forgings as well. FWIW, Mahle does not own Sealed Power. Sealed Power is a part of DRIV which is a Michigan based company that is a division of Tenneco. From the literature, it appears that all Sealed Power pistons are now made in India.
I have been using Mahle pistons since the 1980's. Yesterday I drove my wife's car, it has Mahle pistons. Today I drove my car, it has Mahle pistons This weekend I will ride my motorcycle, it has Mahle pistons.
Thanks for the replies. I will get the sealed power pistons. What rings work best with these pistons?
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