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Old 12-07-2018, 12:34 AM   #26
jamal
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Uh, I don't think it matters what rings or pistons you use, .0045" p/w clearance isn't going to go well. And nowhere does mahle say that. Their recommended clearance for the subaru 4032 pistons is .0022 to .0030, and I like to keep it on the close side.
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Old 12-07-2018, 03:02 AM   #27
stu
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Rings defiantly matter. These were drop in 99,5 pistons back in 05. They were extremely loose on a new oem block .0045 and when I reached out to them they said that was normal. The ring Pack they used were also loose right out the bag top ring was close to .0035 top and second, (but Rings don't matter) a few years later they changed the forging and made a tighter fitting piston and came out with new specs.
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Old 12-07-2018, 11:13 AM   #28
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Originally Posted by stu View Post
Rings defiantly matter. These were drop in 99,5 pistons back in 05. They were extremely loose on a new oem block .0045 and when I reached out to them they said that was normal. The ring Pack they used were also loose right out the bag top ring was close to .0035 top and second, (but Rings don't matter) a few years later they changed the forging and made a tighter fitting piston and came out with new specs.
I think 'that's normal' and that's ideal have very different meanings. Yeah, .0045 for a 4032 on a street car is stupid. It should have been half that. That and the monster ring gap certainly didn't help either

One of the more overlooked and constantly developing things is the cam on the skirt profile. That is the black magic part to the public in terms of good skirt wear and reduced piston noise. It's also hard to put that profile into comparison with words on a forum.
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Old 12-07-2018, 11:36 AM   #29
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Originally Posted by Homemade WRX View Post
CP-Carrillo's parent company is Pankl. When they leave the race engine world, it's only to work with Ducati, Koenigsegg, Porsche (996/997 GT3 I know), etc...

Good to know.
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Old 12-07-2018, 04:09 PM   #30
jamal
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Going to stick by the specific rings not mattering when you have huge gaps and p/w clearance.

Here is my actual point:

Say I take mahle's 2618 2.0 piston and rings, and put them in one motor. Then use manley's in another. Same p/w clearance, same ring gaps, same everything else in and attached to the motor. Would anyone be able to notice the difference?
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Old 12-07-2018, 06:50 PM   #31
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Well both:
1.) drill oiling holes (broaching is less prone to cracking)
2.) use skirt coatings

Mahle
1.) Mahle pulls oiling off of the ring groove to feed it which is a compound drilling. Can anyone confirm is modern Manley's do this?
2.) Mahle has the Graphal coating all over the piston (hardened surface)
3.) Mahle uses an anodized top ring so to avoid micro-welding from the top ring

Due to that alone, I'd spend a bit more and go Mahle, choosing between the two.

If doing my own thing: I'd electroless nickle plated JE pistons and a 9310 tool steel wrist pin...
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