Head ID?

[Jason240z]

Howdy.

My 'other' head.

Its been worked, large valve seats(I measure 38/44).  casting mark has been ground off.

there's a machining stamp, 0.020, CC's measure about 42 with one small valve in, so nearer 40-41.

Maths make it about 3.6cc removed, so N42?  Looks right from pics of a stock one?

Any thoughts?  I was going to perform the same to my e31, however that can wait till the future.

 

Edited August 18, 2018 by Jason240z

[Zed Head]

Not so sure of that combustion chamber shape.  And the valve measurements are supposed to be of the valve heads themselves, as I understand things, not the seats.  It does look like a non-squish or open chamber though.  Maybe another E88 or E31.

Here's my bona fide N42 head.  Look at the area by the plug, and between the valves.  Looks like yours has more space between the valves even though you're measuring a bigger exhaust valve value.  And the plug area looks different.  That would be a lot of aluminum dust.  Who knows.

[Jason240z]

to me it looks very similar, looks like its been unshrouded, possibly the skim also altering the look compared to standard.

[Jason240z]

looks like the last n42 pic here?

 

http://www.atlanticz.ca/zclub/techtips//headporting/index.htm

[Zed Head]

Could be.  A lot of dust to create that space.  Maybe it's the actual head in the atlanticz pictures.  After removing all of that material the chamber would be larger.  So the head would need shaving to shrink it down.  What's the head width, top to bottom?  And still, probably 35 mm valves.  There's not an extra 1.5 mm between the valves, I think.

Post a full length shot of the head and the coolant passages can be compared.  There are differences, I think.  Causes lots of head gasket confusion.

One of the valves is flipping us the bird...

[Jason240z]

6 minutes ago, Zed Head said:

Could be.  A lot of dust to create that space.  Maybe it's the actual head in the atlanticz pictures.  After removing all of that material the chamber would be larger.  So the head would need shaving to shrink it down.  What's the head width, top to bottom?  And still, probably 35 mm valves.  There's not an extra 1.5 mm between the valves, I think.

Post a full length shot of the head and the coolant passages can be compared.  There are differences, I think.  Causes lots of head gasket confusion.

One of the valves is flipping us the bird...

I'll grab one tomorrow.  the way I measured the valves, i've got a 44mm valve that fits the way I measured, i'll double check though.

the CC measurement stacks up if it is 0.020 off, however it might have had that off before.  head width 107.18mm

[Jason240z]

top shot, other head is an e31....

close up of the e31

[rturbo 930]

Wouldn't an N42 head have reliefs for the injectors on the intake ports?

[Zed Head]

That's too easy!

[Jason240z]

I believe they do, however not all of them.

[Jason240z]

I'm now leaning towards an early e88, or e31, looks amazingly similar to my e31.

[Zed Head]

33 minutes ago, Jason240z said:

I believe they do, however not all of them.

Did you get your parts from Europe or the states?  You're right, EFI was mostly a states thing, for emissions.  I think I've read about mysterious no injection notch N42's before.  I had forgotten.

I put my N42 on top of your E31.  They look the same, cooling passage wise.  The bores look different though.  Might be another clue.  The N42 would match an 86 mm bore.