The Golden Rules - break at your own peril

vocky

Please remember the golden rules set by General Motors, they designed the z22se and do know what they are talking about.

<u>CONNECTING RODS</u>
GM recommend that the connecting rods be upgraded because stock Z22SE / L61 rods are not designed for power levels over 250 hp.

<u>PISTONS</u>
The stock Z22SE / L61 pistons have been tested to power levels approaching 300 hp by GM.
However these pistons should be replaced with a stock forged-type piston for applications over the 250 hp level.

JE, Wiseco and Diamond offer pistons in various compression ratios that work for most applications.
GM recommend a compression ratio of 9:1 or less for blown gas applications, and 10-11:1 for normally aspirated with premium fuel.

now for some graphic pics, those with a weak heart or other serious health problems look away................

:sick:

the sump may contain some odd things notsure.gif

the block may suffer some damage dunno..

techieboy

Oh, sh!t. That really isn't too healthy looking, is it?

FLD

That looks like an LS1/7 hybrid I was asked to look at that had suffered detonation. Was that just a simple rod failure?

JohnnyN

Gee thanks Neil! Something else for me to worry about now then!

vocky

I'm not 100% sure exactly what caused the destruction, but I do know.....

the oil system was not to blame - all bearings are in good condition, even the bearings on number 1 conrod with snapped
both cams are fine
all the cam followers are fine
one inlet cam lifter had a tiny crack, the others are all fine
one inlet valve head had snapped off - but only had minor damage - caused by flying debris
one exhaust valve head had snapped off - also had only minor damage - caused by flying debris
the other number 1 valves were both bent - otherwise minor damage - caused by flying debris
all four valve guides are cracked
three valve seats are damaged, one is fine
the piston is totally destroyed
the block is beyond repair
the conrod snapped below the gudgen pin and then went through the block before finally snapping above the big end
the cylinder head suffered minor damage
the cylinder head combustion chambers showed it was running rich, not lean
the plugs also confirmed it was running rich rather than lean

so I suspect the conrod failed and took out everything in it's path

robo22sri

oh my! that is ruined! who's 2.2 was it neil?

Daniel

dont think that be running any time soon lol

alanoo

How is the cyl sleeve ?

Could be a pin lock failure

winstar

is that MAXR's bottom end? Though his failure was due to the fuel pump being on it's last legs and going lean?

You need to remember all the stg 2 SC conversions are pushing about 280 hp through the crank when you account for the SC parasitic loss.

vocky

alanoo said:
How is the cyl sleeve ?

Could be a pin lock failure

the cylinder sleeve is....... well it's........ hmmm........... :sick:

'dead' might be the answer :lol:

I will get a pic of the other block damage

winstar said:
is that MAXR's bottom end?

no, it's not

winstar said:
You need to remember all the stg 2 SC conversions are pushing about 280 hp through the crank when you account for the SC parasitic loss

very true

vocky

here is a pic of the liner, apart from the debris damage there was nothing to suggest there was a problem with the liner or piston before the failure.

JohnnyN

Well, if that happens to mine then it will be the end.

Surely this doesn't happen under normal driving conditions? Is this a failure whilst on a track day or something?

FLD

Any chance of a pic of the piston esp round the top ringland. I've seen one run rich (black deposits) but then lean out and detonate causing very similar looking results. The top ringland area will give this one away.

vocky

JohnnyN said:
Well, if that happens to mine then it will be the end. I would have no intention of rebuilding or replacing.

Surely this doesn't happen under normal driving conditions? Is this a failure whilst on a track day or something?

the failure occurred at 4000 rpm driving along a public road

I would suggest you replace the conrods with steel items Johnny dunno..

FLD said:
Any chance of a pic of the piston esp round the top ringland. I've seen one run rich (black deposits) but then lean out and detonate causing very similar looking results. The top ringland area will give this one away.

the piston is shown in the very first picture, seriously thats all thats left of it :wtf:
the big chunk is actually the liner wall not part of the piston

I can take a pic of the other pistons as they are all fine, no damage whatsoever

JohnnyN

Would my lower compression ratio be a saving factor. Mine is 8.5:1??

For the amount of conversions that are out there and there are quite a few, this appears to be an isolated case. Obviously there's the 1st Vectra that's been running for years now and also the Astra and not only is that an everyday driver along with the Vectra, the Astra is also used on the track.

Is this catastrophic failure a home build?

Muncher83

I have a set of new forged eagle rods for sale if anyone is getting a twitchy ringpiece :p

vocky

Is this catastrophic failure a home build?

this catastrophic failure was because the bhp exceeded the con rods capability, simple as that 🙁

FLD

The problem I had manifested as a broken rod (V8). Turned out the duty on the injectors reached full duty and it ran lean. Was running rich until then with the black deposits. It detonated badly and this showed as pin holes round the top ring land of the piston. The piston took a battering but survived. It was a top notch forged one though. I'm guessing by the number of pieces that was a stock one! Still always a shame to see that happen though 🙁

winstar

was it cylinder 1or 4 that went? due to the way the flow exits a eaton SC, at 60 degrees rather than 90, cylinder 4 will get more air flow than the others

vocky

it was cylinder number 1 which suffered conrod failure.