wrong head gasket

Post by **Matt** » Wed Apr 08, 2009 7:13 pm

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*

Post by **paulk** » Wed Apr 08, 2009 7:37 pm

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

Post by **Matt** » Wed Apr 08, 2009 8:03 pm

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

Post by **rayofleamington** » Wed Apr 08, 2009 9:09 pm

well now you know what happens...

Post by **Matt** » Wed Apr 08, 2009 9:40 pm

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!

Post by **bmcecosse** » Wed Apr 08, 2009 11:15 pm

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!

Post by **Matt** » Wed Apr 08, 2009 11:18 pm

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

Post by **bmcecosse** » Wed Apr 08, 2009 11:24 pm

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!

Post by **rayofleamington** » Wed Apr 08, 2009 11:26 pm

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)

Post by **bmcecosse** » Wed Apr 08, 2009 11:36 pm

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!

Post by **d_harris** » Wed Apr 08, 2009 11:48 pm

Hmmmmm

Post by **rayofleamington** » Thu Apr 09, 2009 8:32 pm

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.

Post by **bmcecosse** » Thu Apr 09, 2009 11:25 pm

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.

Post by **Peetee** » Fri Apr 10, 2009 12:51 am

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

Post by **rayofleamington** » Fri Apr 10, 2009 10:39 am

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.

Post by **bmcecosse** » Fri Apr 10, 2009 10:47 am

Hmm - strange!

Post by **Declan_Burns** » Sat Apr 11, 2009 12:54 pm

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

Post by **bmcecosse** » Sat Apr 11, 2009 10:50 pm

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!

Morris Minor Owners Club

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