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Grrr.. killed it already. gaskit?

2K views 50 replies 13 participants last post by  JohnA 
#1 · (Edited)
Grrr.. killed it already. *edit* terminal this time..

Well last night while settin up boost I blew me engine up again.. At long last, I have found something I am good at!! lmao

After litterally five hours hunting for my compression tester and finding it hiding under the sofabed :confused: heres what i got..
Belt still lines up by marks, but i've only just noticed the threed to suggest the mark on the type of pully i have can be off :eek:

Anyway... just after new rings/bearings/lifters/cams etc etc... z20Let gaskit...
brummm brumm.. booost boostt.. sweet :D put put.. smoke smoke.. not sweet :( sounded like it was running on 3, but drove ok the 200meters back home, i gave it a quick blatt to investigate the smoke situation, its not too bad at all, just looks like a Escort RS turdo on boost.. pick one any one..
by the time i pulled into my drive the car was wanting to stall and soundling like a bit of a tank :p

cold engine and dry, all plugs out.

200 205 40 50

GRRRRR ffs.. :D so can a gaskit loose that much? or is the head likely fubar somehow also? it doesnt sound metalic or anything turning..

tried oil down 3, went to maybe 45-50psi, tried putting a plug in 4 while doing 3, i expectet that to go up then, but it didnt, only about another 5psi... are the valves on 4 open fully or soemthing then?

Obviously gotta come off.. but thoughts on such low?? just headG or something else too??

What gaskit should i put back on?? I dont fancy that one again.. should i go back to stock? or another? I know 200 is high comp... but it started at 250 before the run in, so i expect it to drop to 190 or less after a few more miles.. If it ever runs again lmao
 
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#2 ·
Sounds like a breached head gasket.

That is exactly what happend on my nova last week.

Compresion on 1 and 2 was fine but 3 and 4 where down to roughly 25 PSI each.

Took head off to find a bit of gasket missing on the thinest part between cylinder 3 and 4.

Sounds like a new gasket kit, head bolts and skim the head to me.

Possible problem with the block but doubt it.

May not need skimming depends on the condition of the head, if in doubt, do it.
 
#3 ·
i'd use the std gasket buddy. these z/let gaskets arent faring too well on here over the last couple of days (tom stickland?)

get the head skimmed again & lube the head bolt threads b4 fitting just to make sure you are using all the torque in the bolt & not wasting it in friction.

are ure injectors clean. its prolly not the same but ive blown 4 head gaskets in a year on my nova cos the injectors were in a poor state.

now the block is cracked.......... :(
 
#5 ·
Well it doesnt matter anymore..

For years i've bodged the car, phase 3 on a frontera cooler, standard fuel pump with known poor wiring, fubar turbo... now i go put a 909 pump on with direct feed, eds cooler.. spend lots of money..

Buggered... no.3 melted :( taken out cylinder.. nice.. :rolleyes:

Its gone at 3 oclock right next to where gasket gone, probably took it out tbh..

Anyone got a block/pistons anywhere??

So the big question is why???? I have done all this work to uprate the fueling/cooling of the car, and NOW i have the problem??

We kinda presumed my gauge was screwed when it origionally showed 250psi compression after the rebuild.. i guess it really was 250 :( like i say, 1 and 2 are still showing 200..

but why??? what would make it genuinely so high? the car showed normal compression (but a bit duff cos of rings etc) before the rebuild.. the only work i did not do myself was re-profiling of some LET cams to piper fast road.. and the head rebuid, I told them i'd rather not have it skimmed and to only do it if absolutely nessacary and then the smallest skim they could get away with.. it came back skimmed, but i dont know how much..

could incorrect cam profiling or excessive skimming raise it this much??
whatever it was has killed my car.. its a write off, i just cant afford to spend another penny on it.. another one bites the dust huh... :cool:
 
#7 ·
Fark, gutted mate. If I can help with anything let me know.

You can measure the head to see how much has been skimmed off, not sure what it should be or where exactly to measure, its in the haynes I think.

So has piston 3 melting broken the bore into cylinder 4?

I'm really paranoid about mine now....
 
#9 ·
no.. thats the strange thing, the cylinder hasnt melted its just scraped to buggery, it might be ok with a rebore, but its already 0.5 over. i dont understand why 4 is also so low.. i cannot see a headgaskit breach like that dropping 150psi

I dont know what i'll do with it yet.. early days... look out for a new cylinder block/pistons or think about rebore i dunno... need cheap/free solutions at the moment.. out of work again :(
 
#11 ·
Cheers for the offer bri..

I will have to investigate my block properly, i just saw the piston and walked away tbh.. not entirely happy about it as im sure you can immagine.. My current pistons are 0.5 oversize, im fairly sure the block will at least need a rebore again, so then i'd need the next size up, but if i can find a stock block somewhere then i'll give you a shout, that would be very good of you indeed :) I'd like to get it back on the road again, after sitting for the last 8 months to do the same again or longer would be a shame..

Sorry for the picture, camera out of charge only phone avaliable...
 
#13 ·
Does anyone have a haynes? i dont :( i didnt think it covered the let
i have an early 92' KS head.. i said i didnt want it skimmed, and to only do it if absolutely nessacary and very very fine.. i just measured the head either end 3 times.. removed the bigest and smalest value and averaged the other 4.. i dont know where your supposed to measure, but logic says it should be flat :p and i cant get the verniers over anywhere else..

TIS says.. 135.58 to 135.68, but im not sure if thats new spec, or tolerance.. im guessing new spec.. sadly my average came out 134.74mm :( would this be soley responsible for the 200+ compression??? or should i continue the investigation further?

so anyone know the definitive limits? shouldnt that be measured by engineers after they skim :(
 
#14 · (Edited)
You 100% sure they are LET pistons, u never know?, i had 2 xe engines with pistons that look identical to them, maybe they made a mistake when u brought them, if u did buy them. Could also explain the high compression, my head has been skimmed a few times and i aint had no problems using Z20LET gasket with P2 software.
 
#16 ·
they were in teh car when i bought it, i have no information at all... i only re-ringed it for the rebuild..
looking at them just now though, compared to miles the other day, the pistons appear to stick margionally proud of the cylinder block opposed to level :( stretched rods? or would this be the wrong pistons??

how to i measure the crown volume?? wouldnt have a clue how to go about that!! sounds like soemthing worth doing though, i have to admit when i got the head back, thinking back now, i seem to be rather unimpressed because the valves looked v close to the mating surface!!! but i had so much going on then i didnt think that much abou it or the consiquesnces.....
 
#17 ·
LET and XE pistons should sit proud of the block (deck) by 0.4mm according to TIS.

The best way to measure crown volume is with a burette or pipette and a piece of perspex with a small hole in it. Petrol and parafin are a bit more accurate than water. Fill the crown with the valves and a spark plug in place noting how much fluid you've used.
 
#18 ·
Stu,

Sorry to be reading this, what a fecking disaster. I can only assume the fuelling was non existant or the knock sensor is duffer. The pistons look like LET ones I must admit, typically XE pistons are flat in the centre. The head has had around 29 thou taken out of it in its time and TBH this shouldnt cause devastation like that. Under fuelling seems more likely as its the typical cylinder 3/4 arrangement thats melted. The fuel comes in here so fuel pressure is lowest here.
On another note, reading some of the comments in here. What is wrong with people? The Z20 Gasket is NOT a problem on the LET engine. We have done around 6 cars with this gasket and never had a problem with one of them (1 of the 6 is an XE as well which the guy canes everywhere).
 
#20 ·
they certainly were john, SOOO high, that i obviously now regretably assumed a gauge fault, based on the fact the engine turned no harder than it did before the rebuild.. 250psi should have been audibly more demanding starting.. you live and learn.. some people do anyway :) i just keep plodding away.
Its looking to be pointing towards lean mix, while i have since uprated the fuel system greatly, the boost also increased tremendously, i was only running say .7-0.8bar by rev limit before, but was holding 1.1bar + at 7.5k on the new setup :(
my afr, which used to show max was flickering from penultimate up to max, in theory not an issue.. but that assumes accurate readout in the first place.. robs offered to help verify the fueling on the new setup if/when i ever get it back on the road :)

your right tho' i've allways been the same.. risk first cry later.. more often than not you get away with it :)
 
#21 · (Edited)
Re: Grrr.. killed it already. *edit* terminal this time..

Stupink said:
Well last night while settin up boost I blew me engine up again.. At long last, I have found something I am good at!! lmao

After litterally five hours hunting for my compression tester and finding it hiding under the sofabed :confused: heres what i got..
Belt still lines up by marks, but i've only just noticed the threed to suggest the mark on the type of pully i have can be off :eek:

Anyway... just after new rings/bearings/lifters/cams etc etc... z20Let gaskit...
brummm brumm.. booost boostt.. sweet :D put put.. smoke smoke.. not sweet :( sounded like it was running on 3, but drove ok the 200meters back home, i gave it a quick blatt to investigate the smoke situation, its not too bad at all, just looks like a Escort RS turdo on boost.. pick one any one..
by the time i pulled into my drive the car was wanting to stall and soundling like a bit of a tank :p

cold engine and dry, all plugs out.

200 205 40 50

GRRRRR ffs.. :D so can a gaskit loose that much? or is the head likely fubar somehow also? it doesnt sound metalic or anything turning..

tried oil down 3, went to maybe 45-50psi, tried putting a plug in 4 while doing 3, i expectet that to go up then, but it didnt, only about another 5psi... are the valves on 4 open fully or soemthing then?

Obviously gotta come off.. but thoughts on such low?? just headG or something else too??

What gaskit should i put back on?? I dont fancy that one again.. should i go back to stock? or another? I know 200 is high comp... but it started at 250 before the run in, so i expect it to drop to 190 or less after a few more miles.. If it ever runs again lmao
man tell me this is a wind up?? ****!! :confused: :(

Stu, man that is so sad...u were looking forward to pod and all...bad luck bud!
 
#22 ·
CraigGreen said:
i'd use the std gasket buddy. these z/let gaskets arent faring too well on here over the last couple of days (tom stickland?)

get the head skimmed again & lube the head bolt threads b4 fitting just to make sure you are using all the torque in the bolt & not wasting it in friction.

are ure injectors clean. its prolly not the same but ive blown 4 head gaskets in a year on my nova cos the injectors were in a poor state.

now the block is cracked.......... :(
i have always said they are a hack!! just look the holes dont even line up..

buy a cometic gasket and be done with it..oh and some head studs would be handy!!
 
#25 ·
Stupink said:
...Its looking to be pointing towards lean mix, while i have since uprated the fuel system greatly, the boost also increased tremendously,
These two don't exactly go together --- if you're running dangerously lean then boost doesn't "increase tremendously". If anything it won't be boosting properly and you'd be getting clicks and pops.

Do you still have the old head gasket lying around?
It would be interesting to measure it's thickness. If it wasn't yourself that had fitted it, maybe it was abnormally thick (or double) in order to compensate for overzelous previous skimmings of cyl head/block
I had once bought a car like this:rolleyes: and only found out when I had the head off.
 
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