RickDraper

I know this is not a ford engine but i bet some of you lads have seen similar failures in the past.

The engine is a Vauxhall C20LET running a 7.2cr and a cometic gasket, head studs and lots of other mods. All was going fine, i met Mark Shead at brunters and i had sorted out a suitable wastegate spring to hold 2.2 bar boost (and managed to keep the boost hose's on). We managed one sighting run with Mark making adjustments to the map then on the second run the head gasket went, blowing all the water out of the header tank.

Upon inspection this is what i found:




Its only on the one cylinder that there are any signs of damage to the gasket.

Any help is much appreciated

scoooby slayer

iTrader: (4)

what type of headgasket was it ?

Rab

Cometic. I've heard people have had issues before. Correct me if I'm wrong? Where's Chip when you need him

RickDraper

Spoken to a few people on the vauxhall forums and none have ever seen a cometic fail in this way. Unfortunatly there are not many other options when looking for a uprated head gasket for a C20LET though.

Calibras and Cav's were hardly prolific in the WRC world! Last time i saw one compeating it was in the world barge pulling championships.

Fiecos Dan

Were the head and block re-faced before the cometic gasket was fitted?


Were the head bolts std or uprated items and retorque'd after runup?


What coolant temps and pressure were you seeing before it went?



Also what turbo, and rough power were you running?

RickDraper

Both the block and head were refaced when the gasket was fitted, the head is fitted with head studs that were checked after the engine was first ran up. Not sure what pressure or temps we were seeing, temps were showing normal on my dash but i would have to check with mark to see if he can remember what he was seeing on the laptop.

I am running a GT30 turbo and seeing about 500bhp at 2.2 bar.

Fiecos Dan

i take it your on Autronic if Marks mapping.


Your running same sort of spec/power as my cossie, and i've never had a issue with the cometic h/g.


Where EGT's monitored?

What does Mark think?

RickDraper

Yes its on Autronic and the egt is on a gauge in my dash. They are not getting that high either. Mark has said the damage is similar to what happened to rod's on the dyno a few months back when the block twisted.

Fiecos Dan

Any pic's of the engine bay?


i dont know anything about the Vaux engine, do they issue's normally @ that spec?

rapidcossie

is that a chip out of head and block?

mk2rstaff

looks like the head has a chip out of it and that would be the reason why the head gasket has failed in that area, has it had some sort of repair work done to it before hand to cause that to fail, other than that it looks ok in the pics just that big bit of metal missing and then leaving that small amount to try and contain all that boost pressure a new head may be in order there

Chip

iTrader: (3)

Ive already spoken to him over on vauxsport, but TBH im none the wiser.

Id not seen the picture of the damage to the head itself, only the gasket, and I thought perhaps it was corrosion from where its been stood for ages, but looking at that damage to the head it looks almost like its been previously repaired or some sort of foreign body has got in there.

Certainly doesnt look like a mapping fault, as NO sign of det there.

I did mention to Rick a couple of years ago I was nervous about the block he has used (ive actually got the same block in a heavily modified calibra I bought secondhand) the reason being that althoguh the bottom of the XEV block is substantially stronger, the top of it is a lot more open than the LET block that people normally use for big power, so I was worried abuot the possibility of movement.

That seems to echo what Mark said, but Im surprised if its happened at as little power as Rick was running so far (under 500bhp as far as im aware)

Daveysaff

iTrader: (9)

The cometic that was on my saff when I got it went the same way, was rusty between the waterways when I took it off
So, in my very limited experience, i'd say they're shite

Fiecos Dan

i think cometic gaskets get alot of slack for other causes to be honest.

As you look at any one or tuner that uses them alot dont have no issue's,
but some tuners wont touch them due to issue's when being devoloped.

Daveysaff

iTrader: (9)

I think it was more to do with the monkeys that fitted it tbh.

JonnyBravo

Daveysaff- Who fitted it ?

Rick - Is there any signs at all that the head may of had a repair ?

RickDraper

Nope the head had not been repaired prior to this.

Chip its pushing about 500bhp now with the new spring.

Daveysaff

iTrader: (9)

'Twas a well known tuning firm, the previous owner had the gasket fitted. I'm 99% sure the block wasn't decked before the cometic hg was fitted, and thats what caused the failure.

RickDraper

Anyone else?