ABY - what blows first

[adam g]

Whilst being really stupid today and going flat out on an engine that I hadnt had remapped since a 4 bar MAP sensor upgrade, I unsurprisingly blew it up.

The good news is there isnt a rod hanging out the block but the massive smoke plumes (that accompany the massive misfire) come out of both the engine bay and exhaust.

This suggests head gasket to me but I thought a head gasket would be eaten by mild detonation over time rather than a sudden 30psi blast. Also arent they metal on the ABY so should be pretty robust so mabey its a holed piston. Could it be something else I havent thought of?

I intend to start pulling it apart tomorrow.

[driftin jo]

Your rods are probably bent.

[madpugger]

Knackered bore/piston I'd say...

[adam g]

Possibly but it still got me the 8 mile journey home. I would have thought bent rods would be an engine siezer.

[martinws]

Where was the smoke coming from under the bonnet? what colour was the smoke?

[driftin jo]

Possibly but it still got me the 8 mile journey home. I would have thought bent rods would be an engine siezer.

No, it wouldn't necessarily seize the engine.

[SteveH]

I badly bent three rods and the car still ran. Apart from a loud knocking there were no smoke or oil issues.

[rs200]

bent rods 100%.
same symptoms have my 3b before engine rebuilt !
good luck !

[JariP]

Maybe a blown head gasket and melted cylinder head between two cylinders.

[adam g]

I guess it makes sense that the ali head might melt before the gasket. Ar*e, this could be an expensive, me and my impatience.

The smoke is coming from somewhere under the exhaust manifold so hard to see but assume from between the head and block. The smoke was grey/blue and reeked of oil.

I'll start with compression check. How big a job is the head removal on these. Ive done a 10v URq head recon a few times. Is it a similar nightmare of a job on the ABY?

[JP]

Twice as bad as double the valves and half the space

[QuattroFever]

What reg aby is it. Didn't some early ones still come with the paper gasket.

[adam g]

Not sure of the year of engine as I bought it 2nd hand, its a conversion into my urq.

However, from the small piece thats visible it looks like a metal gasket.

A bigger job than the 10v then, awe bugg*r

[djh]

taking the head off ain't too bad on these, i'd rather do one of these than a 10v.

[DJones]

taking the head off ain't too bad on these, i'd rather do one of these than a 10v.

Ditto^^