Morris Minor Owners Club

Theoretically (of course )... what would happen if I gave my brother a 1300 head gasket, when I was in a hurry to leave, to fit to the 1098 engine in his car??

*whistles innocently*

I suggest the worse could be you feel a sharp ringing sensation around the ears when you next see him!

Be fair it can't make his engine any worse

Well he fitted it! Lots of steam out of the back and water dribbling down the exhaust manifold :s

well now you know what happens...

Whats a bit annoying the waste of a perfectly good copper gasket... I was sure I had a small bore one (and that was it) but obviously not!

Small bore gasket has egg shape holes - large bore gasket has (larger) round holes. But - since the large bore gasket is used on small bore engine when fitting 940 (or S) head - I'm surprised that it was leaking water!

the holes all seemed to line up except one waterway, the one at the back of the block...

I dont know if the H/G was the problem or not

Yes - there is one waterway - which I plug with a lump of silicon sealer when fitting the 940 head. But (way!) in the past I have done the job without plugging that hole, and had no worries - just a very fast Mini!

But - since the large bore gasket is used on small bore engine when fitting 940 (or S) head - I'm surprised that it was leaking water!

maybe on minis that is correct. The Morris 1098 engine needs a small block gasket. I've fitted 12G940's following the mini boys advice of using the correct gasket for the head - and it leaks water on a Minor 1098 block (done it twice now in 20 years with the same results)

Hmm - same block Ray - anyone I know doing this has used the large bore gasket - the small bore will overhang into the combustion chambers! My 1098 certainly has large bore gasket fitted - and runs fine. It's a very common mod in Mini world - and they ALL use the large bore 1275 gasket.
We've had this discussion/arguement before!

Hmmmmm

the small bore will overhang into the combustion chambers!

I've found a few that were ok - but this was in the good old days when A series head gaskets were made by lots of folks and different ones for each application.

Tested a new small bore gasket on a standard 940 head earlier this evening - it seriously overhangs the combustion chambers at the 4 exhaust valve positions. More than just the rolled edge of the gasket - it wouldn't survive any time at all - and in fact would be in danger of being whacked by the exhaust valves ! It has to be a 1275 head gasket with a 940 head.

Still not sure how he managed to get steam out of it. The fact that you can interchange heads tells you that all the oil and waterways are compatible. and a 1275 gasket would not show on a 1098 block and head

all the oil and waterways are

the oilway is compatible - but not all the waterways are the same.

it seriously overhangs the combustion chambers at the 4 exhaust valve positions. More than just the rolled edge of the gasket

completely agree with you on that one - the one's I used had the rolled edge just in line with the combustion chamber.

Hmm - strange!

As I am preparing to fit the 940 head in the near future, can anybody tell me which waterway should be blocked off?
Thanks
Declan

From memory it's towards the back. The water hole exists in the block - but not in the 1275 gasket or in the 940 head. In the past I have just ignored it - and had no problems. Last time (several years ago now, and engine still going fine - I simply put some silicon sealer in the hole - and allowed it go off slightly while I had lunch - then plonked the gasket and head on the block - and bolted it all down!