Z22se Postmortem

Muncher

Muncher

Muncher

Soldato
Joined
17 Oct 2002
Posts
7,169
Location
Ipswich
A VX owning mate very kindly gave me his old engine after it went bang in spectacular fashion whilst in Europe so today I stripped it down to salvage a few bits from it and also to have a general play to see if I could work out what went wrong.

The 2 big holes in the block and one in the sump suggested it was quite serious :p

Having fully stripped it as far as I could tell it looks as though one of the conrods snapped, blowing a hole through the block. The piston only made very minor contact with the valves on one cylinder meaning the head is fine.

There was a lot of soot on the pistons which I guess suggests it was using a lot of oil? Everything else from what I could tell seemed fine, the timing chain was fine, the crank bearings didn't look that bad, it just looks as though the conrod snapped in two places...

http://www.muncher.org.uk/z22se_postmortem

There's 70 odd pics there so hopefully enough for the engine gurus to go on...

postmortem%20018.jpg
 
Does this happen often? I mean, have you heard of any similar cases on vx220.org etc?

Europe as in Nurburgring, being driven hard? or was it during normal driving?
 
postmortem%20032.jpg


Where was that cap removed from, the damaged cylinder? The shells don't look to bad to me.

There must have been some MASSIVE forces involved, I haven't seen a rod snap there before :eek:
 
It's not a common problem on the z22se at all, hence why I was interested. Replacement costs can be about 4k including labour but there are quite a few we one hand engines about. It was being driven hard at the time but not on the ring, I think low oil was quite likely but why would that cause that specific failure?
 
Muncher said:
It's not a common problem on the z22se at all, hence why I was interested. Replacement costs can be about 4k including labour but there are quite a few we one hand engines about. It was being driven hard at the time but not on the ring, I think low oil was quite likely but why would that cause that specific failure?
Click to expand...

possibly. do the Z22SE's have oil spray bars?
 
In sufficent oil level means that instead of picking up oil it gets either a froth or no oil.

Even for a split second this can cause the bearing shell to pick up on the crank, spin the shell, sieze to the crank eventually due to the heat and then causes the rod to break near the piston. The conrod then flaps around and destroys everything.

I would have expected some significant knocking noise from that engine if that was the failure mode.
 
Wow, thanks for sharing the photos Munchers, very interesting. I've no great knowledge to add my opinion though I'm afraid.
 
Simon said:
In sufficent oil level means that instead of picking up oil it gets either a froth or no oil.

Even for a split second this can cause the bearing shell to pick up on the crank, spin the shell, sieze to the crank eventually due to the heat and then causes the rod to break near the piston. The conrod then flaps around and destroys everything.

I would have expected some significant knocking noise from that engine if that was the failure mode.
Click to expand...

but in cases like that, dont the shells look very scored?

im having to keep a close eye on my oil lately, it has developed a bad leak that i cant diagnose yet :rolleyes:
 
Just had stumpy (some of you will remember him) look at the pics and he thinks it has just been over revved and thrown a rod.

Edited to add the car already has another second hand engine in it and is back on the road. I just saved this engine from going in the skip really.
 
Last edited:
Matt82 said:
but in cases like that, dont the shells look very scored?

im having to keep a close eye on my oil lately, it has developed a bad leak that i cant diagnose yet :rolleyes:
Click to expand...

The shells for the other cylinders *should* be fine, but the offending shell would be nothing less than mullered.
 
You must log in or register to reply here.
Back
Top Bottom