Uregent: Why does this happen to this head gasket.

[vrooom]

[pic]http://www.jay.copperstream.co.uk/ooooorgasket.jpg[/pic]

I fitted new MG head, enlarged ports, and smoothened throat. etc. just your typical modifed mg head on A-series.

I have blocked water bypass on water pump, drilled my themostat. temp ran ok.... until this.

torqued it down. 50lb on each nut. did in sequence. drove it around 30 miles.. until this happen. Water went everywhere.... engine stil ran ok but no power...

ANY idea why it happened ??????????

jay

[KITT]

Were there water ways where those exploded sections are? If so, my guess is some kind of leaking between the cylinders and the water which allowed the cylinders to explode the gasket. Total guess mind!

[Incorrigible]

It looks like the cylinder pressure has forced the gasket failure (difficult to tell from the photo) and as it failed at both ends I'd suspect the head or block wasn't flat (slight warp)

How did you check that before fitting ??

[Andrew Noakes]

vrooom said:

engine stil ran ok but no power

I'm not surprised!

Did you tighten the head nuts progressively or did you torque up no.1 to 50lbft, then no.2, then no.3...?

[vrooom]

I did 25lb stage 1 1, 2,3 to 9 in sequence, then did stage 2, which is 50lb. in sequence same again.

Is head not tight enough to cause blowby ?

Jay

[Pigeon]

11-stud gasket on 9-stud engine?

[stevieturbo]

Thats a massive blow !!!!

I'd think the gasket mustnt have been clamped at either end. Due to warped head/block, or simply loose studs ???

11 or 9 stud wouldnt make any odds IMO.

Ive blown dozens between cylinders before, but nothing like that !!!

[Mutant Rat]

stevieturbo said:

Ive blown dozens between cylinders before, but nothing like that !!!

Ditto.

I'd be inclined to get that one framed and hang it on the garage wall, if I were you!

[vrooom]

Changed to metal payen gasket instead of rubber/metal gasket. it works now. even ran it 30 min although rough running. No water leaks etc!

Let hope it stays same.

I have modifed my cooling system. i blocked the water pump bypass to cylinder head. so i drilled my themostat to get water flow when it cold. as this modifed head dont have bypass hole to water pump bypass.

I will be handing this head gasket on my wall, in frame

[stevieturbo]

If I recall correctly, Payen AF470 ??? Or BK 450 was the gasket I preferred. Its been a few years... I even have a spare BK450 in my garage !!!!!!!

Basically it was a proper OE Metro turbo listing. It lasted longer on my mini engines than any gasket I tried.

The newer BK450 had copper rings around the front coolant passages, whereas the earlier AF gasket didnt. Not that it ever blew there on me anyway.

I always used ARP studs too. Although one actually broke in the block when I was torquing them once!!!