From the GRM Vault: The Secrets of Cylinder Head Modifications

This article comes from all the way back in 2000, so we had to march back to our archives, pick out the magazine, and dig out the scanner.

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Secrets of cylinder head modifications


Secrets of cylinder head modifications


Secrets of cylinder head modifications


Secrets of cylinder head modifications


Secrets of cylinder head modifications














































































































































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Comments

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oldeskewltoy
oldeskewltoy UltraDork
6/7/18 10:30 a.m.

looks fancy... and I'm "sure" improvements were made...  but no views of the ports... no flowbench before and after...  

stylngle2003
stylngle2003 Reader
6/7/18 12:28 p.m.

I miss Mike Kojima's writing in my mailbox every month.  But MotoIQ is my most-visited website, and has been for about the last 6 years or so, so it's not all bad.

white_fly
white_fly Reader
6/7/18 2:25 p.m.

Is that really what a factory 4A-GE head looks like? That casting looks exceptionally poor unless that head has been mishandled.

oldeskewltoy
oldeskewltoy UltraDork
6/7/18 3:12 p.m.
white_fly said:

Is that really what a factory 4A-GE head looks like? That casting looks exceptionally poor unless that head has been mishandled.

They found one that had been sitting... likely with water in it....  you can tell by the valve seats... they are pitted.  a bit like this one

 

 

This is more typical

 

white_fly
white_fly Reader
6/7/18 3:48 p.m.

In reply to oldeskewltoy :

Thanks. That looks more like what I would've expected.

te72
te72 Reader
6/7/18 9:18 p.m.

Would be interesting to read a follow up focusing on the modern world of "turbo all the things!"

 

Of particular interest to me, having a (as far as I know) well ported 1jz head in my Supra. Only point of comparison I have is that it made bout 40whp more than a comparatively stock head on the same dyno, on otherwise stock engines.

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