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How to determine if a P90 head has been shaved?


Samurai7one

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  So, I got a couple of parts motors (L28s) Ive been sitting on and waiting (3 years) to get to a point in my life where I can start to build my motor.  I guess I have reached that point, so I have started to tear down the two motors. I have two L28s, one has a spun bearing BUT, it also has a wealth of desirable parts on it.  Such as: a Kameari timing chain tensioner,  adjustable cam gear, lightweight flywheel,  cast aluminum oil pan, flat top pistons, and what looks to be reworked or like new P90 head.  Because of the specific parts this motor has on it, I am expecting that the head was probably shaved in order to increase the compression ratio.  Why would anyone put all of those parts on a NA motor and not spend a few dollars to shave the head (maybe future turbo plans)?

  So I guess what I am looking for is an easy way to determine if the head has been shaved.  I know I can CC the combustion chamber, but is there a more simple method, such as measuring the height of the head itself?  Pictures are attached, maybe some of you guys can just take a look at the chamber shape/size and tell.

Thanks in advance! :cheers:

post-29602-0-76902700-1423707412_thumb.jpegpost-29602-0-21580000-1423707397_thumb.jpeg

Edited by Samurai7one
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, but is there a more simple method, such as measuring the height of the head itself?  

That seems to be the method.  The number is out there somewhere, I've seen it.   If you post your number someone can probably tell you if it's shaved.

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You should a have little over 1.5 mm below that P90 stamp on the right front of the head, at the bottom.  My head is shaved .080 (2 mm) and it just cuts into the bottom of the numbers.

Edited by Kash
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^^^^ That is a quick practical check for anybody thinking about a head in the junkyard. Basically like a 'Lincoln Head Penny Check' on tire tread, if you can't fit two credit cards on top of the head gasket and the bottom of the numbers on the head, it's been worked to some extent. A Credit Card is generally 0.040" (1mm) thick.

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