HELP does 1.8i head works on stock NK 1800 mahle pistons?

[Highgrade]

I just got a brand new set of NOS Mahle pistons and I'm not sure they will have a good CR with the 1.8i e30 head or if the valves will hit the pistons?

Thanks

[rey949]

I am not an expert, but if you can see what type of combustion chamber a 1.8 head has then you can look at the following linnk and figure it out...I think...Either piano or bathtub, but you need to know what the 1.8 head has...

http://www.bmw2002faq.com/content/view/46/32/

[Highgrade]

Thanks Rey

I have a 85mm bore for my NOS 3rd oversize NOS mahle pistons, and I found a 118 head from 1980 that probably has the combustion chamber for 89mm bore will that be alright? or should I look for an earlier 118 head?

Thanks

[rey949]

Sorry for the delay in my response. I think you need to speak to your machinist.

What is the engine for ???an early 1800 or a 1600? Or ?

I am not sure on your comments about an 85mm piston size. I think as long as your block is bored correctly and the piston combustion chamber matches your head you should be ok. Make sure the clearances work with your valves etc...a good machine shop should be able to tell you if it will all fit together. You also need to ensure you use the correct pin placement and rod length so make sure you talk to someone really knowledgeable.

Where did you get the pistons? With 85mm pistons you must be bulding a 1600 or 1800 engine....you need to double check the rod length and pin placement...as far as the 1.8i head ....make sure the combustion chamber matches and the valve clearance is correct......devil is in the details... , but again i am no expert...good luck

[Highgrade]

Hi Rey,

I'm in fact rebuilding an early 1967 NK 1800, with the longer stroke and smaller bore (85mm 3rd oversize) I got lucky and found some NOS mahle pistons for my application, an ebay seller called Linea Veloce has few in store and at good prices, I got mine for 290$.

http://stores.ebay.com/lineaveloce

I'm changing the 1,8i head with a 118 korman stage 2 head, also found on ebay that has the matching combustion chambers for my piano pistons.

Thanks

Omar

[tjones02]

Just a little tip. Your 118 head and 1800 piston tops are "bathtub" style not "piano".

What makes you think the head is for an 89mm bore? A 118 head is exactly that, a 118 style head, no matter the production date. Unless, the combustion chambers have been modified, it would have the same combustion chamber shape and size as a 118 head with a 1960's production date.

Cheers and Hope This Helps,

[Highgrade]

Hi Tom,

Thanks for the tip, as i got a bit confused with size of the bore and combustion chamber, if i understand well 118 head from any year has the same size and combustion chamber shape which is for bathtub pistons of smaller bore (84 to 85) did i get it right?

Thanks

[tjones02]

Well, actually the late NK 1800's starting with the 1969 model year had the short stroke of the 1600 but with the 89mm bore topped with a 118 head. Same as the 1802, which used the 118 head till the end of production in 1975. It's simply that there are no variations in the combustion chamber size or shape. They are 118 heads, whatever bore block they were bolted to, whether 84 or 89mm.