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Discussion Starter #1
I am rebuilding my motor on my 07 Elise.

Anybody know where to get upgraded pistons? possibly forged ones?

I would rather not use stock as a misfire in piston 1 caused the rings to fail. After my mechanic took apart the motor we discovered that all 4 pistons showed signs of cracking.

FYI, my car has a Katana2 supercharger on it... so I would prefer strong pistons instead of doing this every year.....

Any help would be appreciated.

Thanks.

David.
 

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2007 Lotus Exige S
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Most of the vendors associated with this site carry/sell pistons; you may have to contact them if they are not listed separately on their websites from their complete engines. As long as you are in the rebuilding stages you might want to consider exactly what you want out of your engine and now would be the time to change things like compression ratio if desired. If none of the companies you research carry pistons with the qualities you want there are still options out there. Piston companies like JE will custom make one off pistons but they do cost more.

Maybe people that have actually rebuilt their engines can provide some experience on their rebuilds and additional teardowns.
 

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I've had Mahle, and Wiseco in mine. I've had both break due to manufacture issues. The first Mahle's didn't have a large enough top land, and eventually shattered. The Wiseco's don't have a deep enough recess to clear the oil squirters.

Wiseco worked with me to attempt to correct the issue, and while the new design is better, I still ended up having to bend the squirters slightly to provide clearance.

Mahle re-designed their pistons years ago to eliminate the top land issue. They sent me a sent of 9:1 ones of the new design for my troubles. I've got them unused laying around in the box if you are interested in lowering your compression. Monkey Wrench sells them for $589 plus shipping. I'd sell them for $550 shipped if you are interested. If so just send me a PM.
 

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Now onto the part not mentioned. The MMC coating on the stock bore is intolerant of many pistons. If you go to a Nikasil bore, your options become larger.
 

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Now onto the part not mentioned. The MMC coating on the stock bore is intolerant of many pistons. If you go to a Nikasil bore, your options become larger.
Very good point. Mahle's and Cosworth will work in a stock block, most everything else won't. Mine block has Darton Sleeves, which allows the use of Wiseco's.
 

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Definitely check the condition of your cylinder walls before committing to pistons. If the old pistons and rings were damaged then there is a chance that the cylinder walls were damaged as well. If they're damaged then you can get the block sleeved, nikasil coated (if the damage is very light) or replace it with a new OEM block. I personally prefer the sleeves because they're very durable and will work with any of the available pistons. A plus is that if you somehow damage another piston in the future you can still reuse the block and sleeves, they can be bored +0.5mm over.

Forged pistons will definitely take more beating than the stock cast pistons but if you failed the stock pistons you should take a look at your setup and tune and consider some changes. The stock pistons are fairly tough and generally only fail if there is a problem or if you just run the boost way too high.

If you want to run higher boost as more people are doing with the intercooled supercharger kits you can drop the compression slightly to 10.5:1 for extra safety margin. We carry Mahle and Wiseco in a variety of compression ratios.

As noted above, the support struts in the bottom of the Wiseco pistons do interfere with the piston squirters. A slight tweak of the squirter toward the center of the bore provides plenty of clearance.
 
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