Head gasket question--535i with M30 motor

[Dash01]

Should the holes for coolant in the head gasket match the holes in the head and block?

The replacement HG sold to me has much smaller and round holes than the corresponding triangular ones on the head and block on the intake side.

On the exhaust side, the HG holes are round and offset, with relatively little overlap of the rectangular holes in the head and block.

Is this proper, or did they sell me the wrong HG?

I'll try and post pics later this evening.

[Martin in Bellevue]

This has been discussed before. The restricted coolant holes keep the coolant volume in the head. This is a good thing, as the head is more evenly temperature regulated. The holes on the exhaust side are for oil return to the pan. You can leave the headgasket uncut for installation.

As an aside, check the old headgasket between cylinders 5 & 6. I caught my headgasket before it let go, in a pre-emptive headgasket replacement with new valve guides & a mild cam regrind. There was significant decay between 5 & 6 on the old head gasket.

[Dash01]

This shows headgasket vs. block on intake side. Holes are much smaller on HG.



HG laid in position over head.



HG vs. head on exhaust side of block.


SO, IS THIS THE PROPER HEAD GASKET FOR THE M30 BLOCK, OR DID THEY SELL ME THE WRONG ONE?

[genphreak]

This has been discussed before. The restricted coolant holes keep the coolant volume in the head. This is a good thing, as the head is more evenly temperature regulated. The holes on the exhaust side are for oil return to the pan. You can leave the headgasket uncut for installation.

As an aside, check the old headgasket between cylinders 5 & 6. I caught my headgasket before it let go, in a pre-emptive headgasket replacement with new valve guides & a mild cam regrind. There was significant decay between 5 & 6 on the old head gasket.

How were your coolant holes at the very bac of the block? I think these are the most at risk from blocking with any cludge.

If you can, post some good pics of the block surface before you put your HG on, you could get some very salient advice

[genphreak]

WRONG WRONG WRONG. Gasket is all wrong dude.

Geee- pics were posted fast! I wrote a reply and then they were there!

Nice looking head though- who did such a great job on that? Is it new??? Engine is in nice nic too!

Need a decent pic of the head surface (no gasket) and coolant galleries though. Just a nice one for the archives would be good if you can...

[Mr Project]

WRONG WRONG WRONG. Gasket is all wrong dude.

You sure? I think it looks a lot like the one I did on my M30. Couple years ago, though, my memory could be a little fuzzy.

[genphreak]

You sure? I think it looks a lot like the one I did on my M30. Couple years ago, though, my memory could be a little fuzzy.

Check out the last pic, the galleries above the exhaust manifolds. I am sure mine was open. Unless it's round the wrong way in that pic, but I don't think it is. Might check my own pics to be sure... hang on

[genphreak]

Check out the last pic, the galleries above the exhaust manifolds. I am sure mine was open. Unless it's round the wrong way in that pic, but I don't think it is. Might check my own pics to be sure... hang on

Yes it is wrong. But it's confusing-even the right one seemed wrong, in that it seemed to have the wrong sized holes.

Here is a pic of the right one;

[Blitzkrieg Bob]

On the exhaust side, the HG holes are round and offset, with relatively little overlap of the rectangular holes in the head and block.

That's what it looks like. Swiss cheese is cheaper to cut than a full gallery profile

[Dave M]

Great catch guys. I guess this is what the board is for

Dave M