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See if you can call Mahle and get them in a "low drag" set. Then they'd be worthwhile.

Low drag doesn't mean oil usage either. Unless the cylinder walls are trashed and in that case nothing would seal properly.

I personally like Mahle's stuff...especially their powerpak piston sets with the 1.5-1.5-3mm rings. Had a set of those in flat top versions in my old Mustang. Light, strong, low drag...revs quickly, decelerates quickly, etc. Was able to get around 28-29 mph out of it with zero tuning...so somethign was working good. 5.0 (.030) 9.1 comp, EFI (stock MAF style) with the stock tune and nothing else. Also had AFR165 heads.
 

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Discussion Starter #3
That's some killer gas mileage!

I've run Speed Pro low tension oil rings in this motor before, but it smoked. I suppose a low drag set has nothing to do with the oil rings?

I'll look around.
 

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That's some killer gas mileage!

I've run Speed Pro low tension oil rings in this motor before, but it smoked. I suppose a low drag set has nothing to do with the oil rings?

I'll look around.
the low drag set from S/P is the oil ring tension
 

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Like any other ring pack, the manufacturer wants to see a particular hone grit. Mahle ultra-low-tension (what I have in my 438), they wanted a 600 grit hone. The custom Wiseco's I had in the old 408 (2 ring, 1.5mm) they wanted a 400 grit.

The cylinder wall and concentricity of the bore is what dictates oil usage more than anything else. There are other factors as well but if the bore is round and not tapered, with the right hone "grit", even a 2 ring piston won't smoke. And no I did not use a vacuum pump or dry sump.

If the bores are oval and tapered, a guy could put a ring in there with 50 lbs of tension and it, too, would never seal. It'd wear the bores out in no time though and that's one reason we see the 302's of old with trashed bores and a ridge 1/16" deep at the top. The rings were 5/64" thick and after installing all 8 (new rings, fresh bore) it would take 75 lb-ft of torque to turn the motor. Once it broke in (which took forever...enough to wear the bores some more so the rings would free up), they were ok. But many folks still are stuck in days of old with the old "high tension" rings and TRW pistons (no offense...I understand bugets), but the newer stuff is light years ahead for only just a few bones more.

Back in the day, the materials were such that there was no way a 1mm ring was ever going to go over a piston without breaking. Now it's commonplace and we see them on motorcycle engines that run 100's of thousands of miles, and routinely spend time north of 10-12,000 RPM. Even autos are coming with 1.5mm ring packages, right out of the factory. Some of the single cylinder high revving MX bikes are 2 ring design. One compression ring and an oil ring. And a piston that weighs around 110g at 3.8" bore size (it's only about 3/4" tall...we call them ring holders with pin stuck through it).

BTW the 438" that is in my car now, it took 11 lb-ft to turn the engine over without the valvetrain. Brand new block, 600 grit hone, 4.125" bore and 4.100 stroke. I am not impressed with it myself, but I know what's ailing it. Just don't have the time/money/motivation to make it "right"
 

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Discussion Starter #6
Thanks for the reply.

My motor had bad valve guides too. They were pretty much gone. I wonder if the smoking problem was the valve guides. I would get a puddle of oil that would gather in the throttle body (EFI car)

How far can hone the bores out before you need to go with a larger piston?
 
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