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Volkann

Need Help, M10+S14

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Hi ,

I have a 1502, last year I bored the 1.6L m10 block to "89" 2002 pistons size, I put 2002 crank, rod, pistons, 121TI C.head, and DCOE Webers.

2 weeks ago I sold all the parts except the block.

Like some of you I have a dream to build a M2.

I have M10 block, S14 cylinder head with ITBs on, and S14 cranckshaft.I'm planing to use S14 rods also.

I did some search and some say it is ok to use "93.40" S14 pistons in M10 block, some say No because of the overbore.

What is your opinion? If I can't use S14 pistons, what are the alternatives ?

I will definetly be using the S14 head.

I REALLY NEED HELP.

THANK YOU !

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I wish I have a S14 block or I can find one. It is also impossible for me to use S14 block because of legal issues. I must work on M10. No other chance.

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If you are thinking about using the 1502 M10 block I don't believe there is enough cylinder wall thickness to go much past 89mm. You are talking about a 9.5mm overbore! I have taken a couple of 2 liter M10 blocks to 92mm (that is a 3mm overbore) but only after I have had them sonic checked to see how thick the cylinder walls were. I have seen enough core shift in a couple of blocks that would have made even 92mm risky. I agree if you want a 2.3 liter S14 do the hole thing and use a S14 block, you already have the really expensive part (the head) blocks are a lot easier to find than good heads.

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An S14 head on an M10 block is an engineering nightmare , for example there is an oil return from the S14 head that is not present in the M10 block. Going the other direction is much easier (S14 block with M10 head).

Honestly, I'd sell the head and contact Kari about his twincam M10 head since you are tied to the block - http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,289146/

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If you are thinking about using the 1502 M10 block I don't believe there is enough cylinder wall thickness to go much past 89mm. You are talking about a 9.5mm overbore! I have taken a couple of 2 liter M10 blocks to 92mm (that is a 3mm overbore) but only after I have had them sonic checked to see how thick the cylinder walls were. I have seen enough core shift in a couple of blocks that would have made even 92mm risky. I agree if you want a 2.3 liter S14 do the hole thing and use a S14 block, you already have the really expensive part (the head) blocks are a lot easier to find than good heads.

Before I bore, I have to check as I see. I wish I can use S14 block, but its imposibble. I have to stick with M10.

By the way, I have 3 S14 heads, one of them is never used :)

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An S14 head on an M10 block is an engineering nightmare , for example there is an oil return from the S14 head that is not present in the M10 block. Going the other direction is much easier (S14 block with M10 head).

Honestly, I'd sell the head and contact Kari about his twincam M10 head since you are tied to the block - http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,289146/

Thanks ! I contacted to Kari. I have 3 S14 heads, I want to use them.

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Sure, you're going to have to weld the combustion chamber domes smaller and then re-machine/polish, then enlarge and fit the oil passages, then deck the head, then machine parts to get the timing chain to line up and fit.

After all that, check clearances, re-machine as needed. You're going to need custom pistons, as the stroke will be slightly different.

May I suggest machining a billet aluminum m10 block, with unobtanium sleeves?

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May I suggest machining a billet aluminum m10 block, with unobtanium sleeves?

No way--way too heavy. What you need is a carbon fiber block!

http://www.thecarbonfiberjournal.com/?p=770

BTW, would be interested to know why using an S14 is not allowed for your purpose. What competition organization and racing class are you building for? Are you limited by displacement, so want to build a small-displacement 4-valve engine? I agree with the point above that you will run into all kinds of issues using a block with small bores and a head made for larger bores--but perhaps you have the machining know-how to do all of this.

Fred '74tii & '69GT3

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May I suggest machining a billet aluminum m10 block, with unobtanium sleeves?

No way--way too heavy. What you need is a carbon fiber block!

http://www.thecarbonfiberjournal.com/?p=770

BTW, would be interested to know why using an S14 is not allowed for your purpose. What competition organization and racing class are you building for? Are you limited by displacement, so want to build a small-displacement 4-valve engine? I agree with the point above that you will run into all kinds of issues using a block with small bores and a head made for larger bores--but perhaps you have the machining know-how to do all of this.

Fred '74tii & '69GT3

In my country, the engine block number must be same with the one in the legal papers. We have to take the cars to TUV stations for the general control of the condition. They check block number also.

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M42?? Wouldn't that be easier?

In the end I have to rebuild the M42 engine because it will be at least 150.000 miles.

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Hi Volkan.

S14 head on m10 block has been done - so it's possible. The oil return can be made outside the block. I don't know details but it can be done.

If you go past 89mm you need to use 2 liter block. I would get custom s14 pistons for something like 90...92mm bore. I don't believe there's any problems with head chambers. You can use tii head gasket if you remove the cutting ring or with 90mm bore as it is.

Is it ok for you to use 2-liter block? Or change block at all if you say the number should match?

Tommy

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Hi Volkan.

S14 head on m10 block has been done - so it's possible. The oil return can be made outside the block. I don't know details but it can be done.

If you go past 89mm you need to use 2 liter block. I would get custom s14 pistons for something like 90...92mm bore. I don't believe there's any problems with head chambers. You can use tii head gasket if you remove the cutting ring or with 90mm bore as it is.

Is it ok for you to use 2-liter block? Or change block at all if you say the number should match?

Tommy

Hi Tommy !

I hope u are OK. Long time since we last talk. Nice to hear from u :)

Today I was looking to the Finnish Drag cars with S14's. They are using S14 head & M10 block with 90mm bore. You know their cars much better then me. So it seems 90mm or 92mm is fine with S14 Head chambers.

Who do you think is the best for the custom pistons? There has to be shapes and cutting on the top, who do you think can do all this engineering?

Will I be loosing too much power because of the smaller pistons? What is your opinion?

I have a spare 2 liter block registered to me also. No problem with using that block.

Thanks :)

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Hi Tommy !

I hope u are OK. Long time since we last talk. Nice to hear from u :)

Today I was looking to the Finnish Drag cars with S14's. They are using S14 head & M10 block with 90mm bore. You know their cars much better then me. So it seems 90mm or 92mm is fine with S14 Head chambers.

Who do you think is the best for the custom pistons? There has to be shapes and cutting on the top, who do you think can do all this engineering?

Will I be loosing too much power because of the smaller pistons? What is your opinion?

I have a spare 2 liter block registered to me also. No problem with using that block.

Thanks :)

I'm great, Volkan! We're actually having a baby in couple of months so it'll be quiet with car projects in near future. But I did run few races this summer.

Yes they have used M10 blocks actually because they can take more boost than S14 block. That's also why they use "only" 90mm bore. You have the head, so measure the chamber diameter. You have the block also so it's not that hard to test fit and see what it takes to mate them together. What I've heard, it shouldn't be that bad job.

Making S14 pistons for 90mm bore shouldn't be a problem for any of the suppliers that makes custom forged pistons. Ross, Arias, Wössner, JE,... they are all good. You just need to find a good reseller to work with.

I wouldn't worry about losing performance because of bore size. You still have huge benefit of the 16 valves and the stroke.

Tommy

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