Damaged/modifed e31 head - opinions wanted..

[franky240z]

A quick story....

 

I decided to use my L24 instead of a L28, mainly as I like the fact it's still on its original engine, it ran well with no knocks but always had a little bit of white smoke even when warm, compression results were all good but I knew something wasn't right.

 

I pulled the head off and found this.

 

 

Looks like a slight leak on between the coolant and bore:unsure: Gasket told the story when looking underneath.

 

Upon close inspection I found on one cylinder cracks/splinters around the spark plug, No worries I thought, I could grind them back so there's no sharp edges/stress points for cracks to start from. Would we agree this is a fair point? I understand that i'd increase the size of the chamber slightly which i'd try to duplicate on the others, good or bad?

 

Next I cut back, hardly removing any meat at all. Once given a wipe over I noticed that the chamber on this pot has been altered...

 

 

 

An unmodified chamber

 

 

1: the spark plug hole/mount has been cut back

2: the shape isn't the same as others

3: I can feel that the shape isn't smooth and without machine marks the others have.

 

Is is the e31 head off my 1970 240. I'd like to keep/use it however I'm prepared to listen to some wise suggestions. Subject to pressure testing is it ok to go ahead and use it? I can't work out the effects of having a chamber 1 or 2cc larger compared to others.

 

Strange thing is that the rest of the head is untouched, its not had any 'porting' or anything I can see done.

 

I'm also not sure if detonation has been the cause of the problems. Valve sizes are 33/42mm.... I take it that these are the standard size?

 

My plan was to have have hardened seats fitted, new valves/stem seals build engine with;

 

10.5:1 - 11.0:1 compression ratio

Piper 285 grind cam

dynamic balance on the crank with ATI harmonic damper

+50 bore with new pistons+rings

triple 40's

nice exhaust

4lb off the fly wheel.

full rebuild, obviously not making new history for 240z engines but a nicely thought out fun engine.

 

It did involve this head, I'd like it too still if possible.

 

Failing that has anyone got a e31 head knocking around?