Piston selection: S65 94mm on Alusil bores

[deansbimmer]

I'd like to learn up on sources and tech for an engine build I'm starting. I’ve built stock S65’s but this is the first time I'm going to need custom pistons made.

I have a remanufactured S65 block with original AluSil cylinders that Dinan bored and honed to 94mm. Other than the increased bore, my plan is to assemble it mostly stock while addressing the engine's weak spots (rod/main bearings, valve springs, etc). It is going in a 2011 E93 M3 I'm putting together for my wife so I want to be confident in the components.

Therefore I need to source some pistons, which probably won't be an off the shelf product. Of Mahle, CP, and JE, so far I've only got an estimate on a set from JE (forged alloy w/ ferro coating) at $3k and 3 weeks, per VAC. I don't know what Dinan can offer for their block because they have been impossible to contact and don't return messages (Very frustrated at them right now).I would prefer Mahle but don't know who has experience in ordering them for the S65.

What other knowledgeable sources could I contact? Do any of the forum's engine experts have any input or advice? This is the only component I have to lock down before I can start assembly. Thanks in advance

[OM VT3]

Dinan sell a 94mm rebuild kit i think

[Green-Eggs]

We can order Mahle pistons for any custom configuration you like. We also have experience having Mahle custom make pistons when your block is already bored and honed. Usually you have the block bored to the pistons, not make the pistons made to fit the block. We can help either way. PM me for details.

[deansbimmer]

Originally Posted by Green-Eggs

Usually you have the block bored to the pistons, not make the pistons made to fit the block. We can help either way. PM me for details.

Understood. That's partly why I'm so frustrated at Dinan. They have the specs from the block job so Pistons could be ordered later. I've been trying to get ahold of the guy (or anybody) for almost 2 weeks now with no luck. Pm sent.

[KawBoy]

Very old thread, but it would be nice to know which way you ended up going.

[Jbonly21]

Originally Posted by Green-Eggs

We can order Mahle pistons for any custom configuration you like. We also have experience having Mahle custom make pistons when your block is already bored and honed. Usually you have the block bored to the pistons, not make the pistons made to fit the block. We can help either way. PM me for details.

Hi, I know this is a really old post. But can you guys still order 94mm Mahle piston for S65? Thanks

[tdott]

Originally Posted by Green-Eggs

We can order Mahle pistons for any custom configuration you like. We also have experience having Mahle custom make pistons when your block is already bored and honed. Usually you have the block bored to the pistons, not make the pistons made to fit the block. We can help either way. PM me for details.

I always wondered what is the best solution to avoid piston slap when cold. Which seems to be a problem with stroker engines using forged pistons.

Would it be better to go with a non-forged piston similar to OEM composition but sized for the larger bore?

[spammysammich]

Originally Posted by tdott

I always wondered what is the best solution to avoid piston slap when cold. Which seems to be a problem with stroker engines using forged pistons.

Would it be better to go with a non-forged piston similar to OEM composition but sized for the larger bore?

I have a stock piston on my work bench and it has Mahle cast onto it. In a brief search, I didn't see anyone offering a hypereutectic cast piston in custom sizes for this car. Given the relatively small volume, I doubt there is one. I would love to be wrong.

[Jbonly21]

Originally Posted by spammysammich

I have a stock piston on my work bench and it has Mahle cast onto it. In a brief search, I didn't see anyone offering a hypereutectic cast piston in custom sizes for this car. Given the relatively small volume, I doubt there is one. I would love to be wrong.

Been searching and the only ones I found so far is the VAC but it’s ment to go with their sleeve.
https://store.vacmotorsports.com/je-...ker-p4235.aspx