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Hypereutectic Cast Pistons


RedFive

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Hey guys,

 

I've been searching for hours. I'm trying to find a set of hypereutectic cast pistons (i.e. sealed power, etc) and molly rings for an L28et. I found some molly rings here and there, but I only find traces of the pistons. People post saying they've got them installed in their car, but no reference to where they purchased them. I'm just looking for something simple like 20 or 40 over, nothing crazy.

 

Any ideas?? Thanks!

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Hypereutectic pistons work very well for modest forced inducted engines.

 

I had a set in my turbo 3.2L V6 in my '85 GMC Jimmy, well over 20,000 HARD Kms, and when I pulled them out, other than the typical grunge that's on a piston they looked like new, I know there was some detonation too, since I didn't have it tuned well, but they too the beating, and I ended up selling them to someone else that has used them for a long time.

 

"Forged" is not always the answer. On a street and/or daily driven engine I wouldn't use Forged.

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"Forged" is not always the answer. On a street and/or daily driven engine I wouldn't use Forged.

 

Great point. On a 'street' engine that puts out enough power that you have to run forged pistons, making sure the engine gets to operating temp before it's driven is always a must. However, on a real street engine, cast pistons are the way to go. They aren't as flexible as forged (which is why forged pistons are used in race applications, they can handle adverse conditions [read detonation] better than cast can) but they do substantially better than forged units during cold start and winter driving.

 

... Could be why I don't ever understand people that think they need a 1000hp daily driven car.

 

 

Anyway, if you cant find ITM's, 1 fast z sells good cast pistons, and I think he may have the turbo CR as well. His company is B&M Machine, iirc.

 

Also, keep an eye here on the classifieds, a set came up about a month ago of NIB ITM L28ET pistons.

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Good points Mag58. Thanks for the tip on 1 fast Z, I messaged him. As far as the debate goes with forged/cast, I don't see that there is any debate. All you have to do is read about the pros/cons of each and keep in mind what your goals/budget are and it's easy to choose.

 

Some good reading with regards to this can be found here:

http://www.motorcycleproject.com/motorcycle/text/cows-pistons.html

 

And just in case 1 fast Z doesn't have anymore, I'm still looking for alternate sources so please feel free to post them. Thanks!

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I've been trying to find ITM pistons for the turbo all afternoon. Everybody is out of stock and ITM doesn't know if they'll be getting any more.

 

I just bought a new set of 86.5mm ITM cast L28et pistons off eBay not more than a month ago, for under $200. I would keep looking there, they pop up all the time.

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I just bought a new set of 86.5mm ITM cast L28et pistons off eBay not more than a month ago, for under $200. I would keep looking there, they pop up all the time.

 

I emailed the guy on eBay who has all the ITM stuff and he said he doesn't have any turbo pistons and doesn't know when he'll be getting them. :(

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I got my ITM pistons from www.coolparts.com. They drop ship directly from ITM. When I bought my set, they were all out of 40 overs and only had stock and 20 overs. This was in June though.

 

Yeah, I talked to them on the phone Friday and they called ITM while I was on hold. No more turbo pistons and ITM doesn't know when they'll be getting them.

 

So...I'm still stuck. :(

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Wouldn't using ceramic coatings on the pistons also be beneficial for using hypereutiectic cast pistons? I mean I know it would be beneficial in almost any situation, but it seems it would be especially beneficial on a mild boosted setup, probably could help the pistons deal with more adverse conditions. Would be interesting to see how much power could be handled on hypereutectic cast pistons with a ceramic coating as well.

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To the OP:

 

You do realize there is no special difference, other than thinner rings, (means thicker ring lands) between the 1975-78 pistons, and the Turbo pistons?

 

Same diameter, same material, same pin height, same dish. The only difference is they were cut with narrower grooves for narrower rings, to allow for a slightly stronger ring land.

 

regular N42-type pistons are not going to make much difference, so why not use them?

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You dont think a thicker ring land is going to make a difference? Ive sunk ring lands on turbo pistons rather easily i dont want to know what would happen with a weaker ring land.

 

To the OP:

 

You do realize there is no special difference, other than thinner rings, (means thicker ring lands) between the 1975-78 pistons, and the Turbo pistons?

 

Same diameter, same material, same pin height, same dish. The only difference is they were cut with narrower grooves for narrower rings, to allow for a slightly stronger ring land.

 

regular N42-type pistons are not going to make much difference, so why not use them?

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I've run N42 stock Nissan Pistons in my turbo car for over 40K miles...

 

If you are sinking rings and lands, it's NOT the pistons' fault!

 

I've run 21psi on the stock N42 pistons, though most of the time I'm running in anywhere from the 12 to 17psi range. The engine started at 12psi, and it's the lowest boost it's seen since startup. This is a JDM engine, that came out of a car, so it's not like these were new parts I was starting with, either.

 

I think the point XNKE makes is valid. Sometimes people get blinders on to the forest, and then can't see it because of all the trees in the way!

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No, I think a weaker ring land does make a difference. But in this case, the ring land is .4mm thicker on a turbo piston than a N/A piston. Wow. I am amazed that nissan re-tooled to cut those pistons for thinner rings, unless the move was made to thinner rings across the board, as well.

 

Not trying to be sarcastic, just realistic. If a .4mm heaver ring land is all it takes to keep your pistons intact, maybe it would just be easier to drop 1psi of boost? In the end, still don't think the turbo pistons are any stronger than the N/A pistons. Just different enough to be hard to find.

 

Anyway, if you still want the thicker ring lands, measure a set of Z22 or Z24 pistons, I *think* they have the thicker ring lands as well. Not 100% on that, though. Z22S stock diameter is 87mm, L28 crank and L24 rods put you at the stock deck height, and they have a 9.32CC dish in them. Still plenty of those pistons in stock from ITM last I checked, and they are what i am going to run as soon as I get my head reassembled.

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