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djminkin

Did all ti’s have piano top pistons?

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Pretty sure the early cars through 1969 (as a minimum) had bathtubs,
I have 2 sets on the shelf and just took a look Mahle 081 94 00 (std)
and Mahle 081 94 02 (.020 over), for 2000CS and 2002Ti, 1965-1969, 9.3.1 CR

 

mahle.jpg

Edited by dp
added diagram

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Reason I ask is the head is missing and I have a 68 121ti engine and head from a NK 2000ti engine and it has the piano tops. Would the NK and ti be different?

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39 minutes ago, djminkin said:

Reason I ask is the head is missing and I have a 68 121ti engine and head from a NK 2000ti engine and it has the piano tops. Would the NK and ti be different?

121 head is bathtubs, E12 is piano tops. People would machine 121 heads to clearance the piano tops so they could use available piano top pistons on earlier 121 head engines. Are the pistons that came with your Ti bathtube or piano top?

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Here is what I have in the NK block but I think the ones that came with the engine are flat top

2F38F56C-2E84-4BF9-8DD7-568E657BB407.jpeg

Edited by djminkin

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Here is what came with the dissembled engine but the head was missing so maybe there are not correct. 

C24F60A1-4978-46ED-BA7C-FDA6A6E79096.jpeg

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https://www.bmw2002faq.com/forums/topic/136618-piano-top-pistons-ok-to-use-with-121-head/?tab=comments#comment-20570

 

got the above link in a search of the faq using "piano top" .... there is a picture in it that shows piano top. The extremely crusty black foto you posted is a bathtub. and the line drawing I posted is bathtub. The linked thread also has a pic of the 121 head combustion chamber, I think its next to the piano top piston picture and you can see why its important to match things up.  --30-- 

Edited by dp

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14 hours ago, djminkin said:

Anyone know what the flat top pistons would have been in?

 

Maybe a 2000 sub-model, as opposed to a 2000ti. One source — not definitive, in my mind — states the 1969 2000ti had a 9.3:1 compression ratio.

 

https://www.automobile-catalog.com/auta_details1.php

 

I’d find it impossible to believe a flat top piston with a 121 head could get anywhere near a 9.0:1 compression ratio. I notice, in the same document, that the 1969 2000 had a compression ratio of 8.5:1. Maybe that had a flat-top piston. Maybe...although I’d expect flat tops to be closer to 8.0:1.

 

Sorry, dp! I failed to read the entire thread, and thus failed to see that you had already discussed and resolved this issue (but for the question of flat-top pistons in a 2000 engine)!

 

Regards,

 

Steve

 

 

Edited by Conserv

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