Piston/Ring Question

[n2omike]

A question:

I have a set of Mahle 4032 alloy pistons with 1.5/1.5/3.0 mm rings and a standard tension oil ring.
The newer ones come with 1.0/1.0/2.0 mm rings, can be had in 2618 alloy, and I believe can be ordered with low tension rings.

The engine is a 363 Ford (8.2 deck) that will be assembled this summer. I've also added a vacuum pump to the mix. Engine will spin around 7800 rpm and make 620-640 hp. It will also see up to 200hp worth of nitrous.

What kind of power is to be gained by upgrading to the new piston with the thinner rings and a low tension oil ring? The engine has already been balanced. The pistons 'look' the same, but not sure how close they will weight match.

Thanks!

[swampbuggy]

I'll break the ice and estimate 15 H.P. Mark .

[dannobee]

We just had this discussion in the Advanced Engine section. Since you're already starting out with thinner rings and likely a low tension oil ring, I doubt you'll see very much difference. Maybe 5 hp over what you already have.

viewtopic.php?f=15&t=63226

[n2omike]

We just had this discussion in the Advanced Engine section. Since you're already starting out with thinner rings and likely a low tension oil ring, I doubt you'll see very much difference. Maybe 5 hp over what you already have.

viewtopic.php?f=15&t=63226

Thanks. I hadn't clicked on the Advanced section for a while. Looks like it's likely 10hp or less.
Mahle pistons use to have 1.5/1.5/3.0 mm rings, and then then went to the thinner 1.0/1.0/2.0 mm package. I acquired the pistons a long time ago, and they have the thicker rings, and I believe standard tension oil rings. Was wondering if it was worth buying new pistons, but it looks like it's probably not worth the effort. The thinner rings and low tension oil ring would have been nice with the vacuum pump, but is pretty expensive for what I'm looking to do. Will see about just using some low. tension oil rings. May test actual piston/ring drag first and see what I'm working with.

[Mark O'Neal]

A 3.0 mmm oil ring maxes out at about 13lbs, compared to 20 to 23 for a 3/16 std tension oil. They all back off a bit after they get hot.

If you want, you can run a 9 lb oil ring....but there's really no point.


The Total Seal Set for 4.125_1/16 1/16 3.0 is CR1002 and ships with an 11lb oil ring.

Kevin told me something about converting them all to Napier seconds, but I forgot what he said.

[n2omike]

A 3.0 mmm oil ring maxes out at about 13lbs, compared to 20 to 23 for a 3/16 std tension oil. They all back off a bit after they get hot.

If you want, you can run a 9 lb oil ring....but there's really no point.


The Total Seal Set for 4.125_1/16 1/16 3.0 is CR1002 and ships with an 11lb oil ring.

Kevin told me something about converting them all to Napier seconds, but I forgot what he said.

Thanks for chiming in Mark. I appreciate the information!