Different cylinder heads!!

[mint6]

Hi,

I'm in the process of port and polishing my Jspec V6 mx6. On removing the intake manifolds I found the ports on each of the heads are a different shape! The front head ports are rounder looking and the rear ones are more square looking. From looking at the gaskets, that are almost square shaped, I'm thinking the front cylinder head may have been replaced at some point.
Unfortunatly I have little or no history of work completed on the car since it has been in the UK.
Does anyone know if they are suppose to be the same or not, and would it matter if i opened them out to the same size? Or should i even be running two different heads if they are found to be from different specs??
Cheers

[Tex_Mx]

Hi M8. I think you might have a uk spec head on the front.The j-spec ones are more square.And they should look the same on both heads.

Your heads will have some numbers on them that will be easy to see now you have the intake off.Have a look and post them on here and someone should be able to tell you which ones you have.

It might be the front had been changed at sometime.That might mean your cams have been swapped as well.

But as for running it shouldnt hurt anything that I can think of.

Good luck and let us know how you get on.

Roy

[Oddball]

Deffinately sounds like you have a DE front cyl head... to see if it was a head swap. check the front cams for the following stap .. KL-31 .. should be the same as the rear cams. if you have KL-31 cams in the front head, then yes, its been swapped out and by somebody who knows no better ..
The rounded corners of the DE head will be causing a slight flow restiction from the inlet manifold. As ZE heads are not that easy to come by, and you are actually porting and flowing, then i you could port the head to match, using the inlet gasket, will take a few hours with a dremmel or similar, but it is possible to square up those corners, i did so to a set of de heads a few months back, pic in my photo link in my sig.

Oddy.

[mint6]

Thanks for your help guys.
The cams I have on the car are stamped as follows;
Rear head -rear cam KL 01 (4)
-front cam KL 01 (2)
Front head -rear cam KL 01 (3)
-front cam KL 01 (451)

The numbers in brackets are smaller numbers on each cam.

So I'm thinking that as these numbers are the same then the cams are the originals!?

Dan

[Oddball]

Sorry to tell you this Dan, but those cams are DE spec.. the ZE Cams are marked KL-31 ... looking like a suspect motor

Paul.

[Tex_Mx]

Hi Dan.

Did you get the numbers off the heads as well?
A couple of other things...Like do you have a long neck manifold?If you have the heads off what does the top of the pistons look like?
Might be that the whole engine has been swapped at some point.If you could post some picts it might be helpfull.
Roy

[mint6]

Hi Guys

Got some more numbers off my engine if your interested, I'll list them out:

Rear cylinder head KL 31-101
Front cylinder head KL-1A1

Throttle KL-30

Valve Covers Front KL01-L2
Rear KL01-R4

I have tried attatching a picture of my engine i took a while back but cant seem to attatch the damn thing!! But the intake manifold throttle comes out at a right angle like other j-spec 6's I've seen.

The works on hold at the mo as I have put a hole in my hand when working on the car......................5 stitches.

Dan

[N0DDY]

Ouch! Hope you're okay, just make sure that you dont lose the stitches or get it infected or anyhing! You'll need to your pics on the web somewhere and link them in on a post. Someone'll no doubt be along shortly to explain what all those numbers should be from.

[Oddball]

Sorry to hear about your hand Dan, if you email me your pictures i'll host them and put them up in the thread until you get sorted..

Now then.. the rear is definately a ZE Head, the front a DE and the throttle body is a DE. If the heads are still off the engine can you get a picture of the top of the pistons too please, the only way to tell if its a ZE bottom end or not.

Paul.

[Einstein]

I reckon it will be a J-Spec engine, that had a fault (maybe warped) front head... the garage that replaced it, used a DE model..

John