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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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#27 ·
Sorry yunis, no joke... for once I followed the book as much as I can and got rid of all the bodges on the car.. THEN it decides to blow up :(

John,, Sorry, I'm letting you make too many assumptions.. the rebuild wasn't as simple as all that which i was talking about on here!, my turbo was knackered, so I have also fitted a new turbo(brians old one), I have also upgraded from phase3+ to phase 3.5+, upgraded from my frontera cooler to the EDS "8.1", had my cams reprofiled to pipers fast road setup, upgraded the fuel pump to the bosh 909, and re-wired a direct feed from the battery via a 30amp relay switched off the origional feed.. as well as a couple of lower restriction intake mods.. the old setup used to run 1.5bar overboost dropping to 0.9bar quickly :( it was supposed to hold 1.15bar, but never did.. the new setup runs 1.5bar overboost as intended, however it also held the correct 1.25bar intended right up to about 6k rpm then slowly dropped off to about 1.1-1.15 bar by the 7.5k limiter.

When I origionally started setting the car up, i was getting misfires badly at 4 and 5k rpm, so I installed new rotor/cap/plugs @ 0.6mm... the misfire seemed to dissapear all but a very occasional erm.. hesitation i wouldnt even call a miss @4k (nothing i would even worry about, but does suggest something was not 100%) perhaps it was just the old plugs/rotor etc... or perhaps it was just a case of "new plug syndrone" masking the problem and it might have returned a few more miles down the road..

I do still have the origional gaskit somewhere.. i will measure its compressed thickness asap :) am i right in thinking a stock gaskit is 1.1mm?
No, i didnt fit it myself, this rebuild was the first time i've pulled an engine apart and the first time in my ownership the calibras head has been off.


Thankyou all for the support and help... keep it all coming, I am now a little less depressed about the whole thing and plan to get it back on the road asap rather than let it stay in storage again for a while.. so I want to work out what went wrong!!
I'll be binning my injectors and FPR for an ajustable and higher flow injectors before I run it again, and i'll also check the crank timing mark hasnt slipped! I'm beggining to think now thats quite likely, it is quite an aged pully setup.. A shame the problem has not been made more common knowledge
 
#28 ·
It's easy to get the timing marks wrong you know. You stick them where you think they're fine, turn the engine a couple of turns and then both cams are off by a full tooth! Sometimes it's the cambelt tensioner that plays silly boogers (I assume that the cambelt is new of course)
IMO you need to double and triple-check the timing marks before you start puting things back together. Turn the engine by hand a few times, check and check again. It can't hurt.
As for bigger injectors, remember that the phase chips were meant to work with stock yellows. If you're not running beyond those limits, why spend more money and risk electric incompatibilities with the ECU?
 
#29 ·
Yeah, i did turn the crank pleny before running :( everything lined up, gotta check that mark on the crank vbelt pully, see if it still aligns with the crank cambelt pully mark and actual tdc..

I know what your saying about injectors.. I've allways said the same myself, I will get my FPR checked out and injectors re-flow tested, they were fine before i fitted the phase3, i will also try to verify the new fuel pump is working properly, spec wise its good... but doesnt mean i dont have a duff one.. I'm going to contact EDS with detailed spec of my build.. see if they have any advice with reguard to potential issues and thoughts on uprating the injectors etc etc...

decided i definately want to rebuild it again, its too much of a fun project car to scrap and i couldnt get squat for it resale... time to have a real play with it..

If anyone has any pictures of the cam marks at tdc properly setup that would be good... :) im 99% certain it was right.. having never done it before i even made sure i had help to do it, so there were two sets of eyes over it.. and we hand cranked and rechecked plenty enough.. it really is all a little bit vauge though...
 
#30 ·
Something is wrong mechanically, I can't see how you can get 250psi otherwise...
Cam timing does affect the Comp testing figures, you'll see that if you start playing with different cam timing settings.
If your old gasket measures roughly like a stock one (and the car ran OK before) then cam timing would be the first suspect I'd think...
 
#31 ·
I will double check the crank timing marks tomorrow... not a lot i can do about the cam pulleys now tho, its all apart again...
Is there any way i can verify the cams themselfs??? they were not my origional cams, they were sent from a trustworthy third party to piper for reprofiling then sent to me(my cams were shot).. it is entirely possible that somewhere along the way they could have been mixed up... to me, a cam is a cam.. it looked like what i took out, and went in ok.. the rest i can but trust was done correctly by piper etc.. wouldnt have a clue where to start looking to verify the correct machining etc has been done... presume its not really something i can do?? they DID loose the cams for a few days!!! however that was delt with quite quickly when they realised I was not the sender, so i dont think they got mixed up or anything.. just left to one side as they did not know what they were as the sender name had no relevance to any orders they'd recieved...
 
#32 ·
Ok.. I have just been out for a quick look

I put piston 1 to tdc.. then about half way between the point it stopped going up and started going down.. put the vbelt pully back on where it was.. and the pointer lines up perfectly... so thats that ruled out..

the head gaskit was hard to measure, its a german one tho, i can read oben/top or whatever it is where it is on the vaux ones..
on the other end , still readable is "8098" on the rear.. and "AF45" on the front.. the measurements were about 1.3mm around the ouside.. very hard to measure, so i put the verniers on the metalic ring, which reads about 1.2.. i think the outer material has swelled from the damp/oil from the pit floor where i just picked it up from :p

arnt stock gaskits 1.1mm compressed? so its thicker gaskit :( i just measured the steel Z20 i took off and got 1.12, i'm guessing its probably 1.1compressed but because of the air gaps between the layers with no compression force on it..

as the head has been skimmed again since, its probably fair to say then up to another .2-.3 mm perhaps?? so i should have had a 1.4-1.6mm gaskit maybe :( would this half mili less stroke be the cause for the 20-30psi higher compression?? (my 1 and 2 cylinder are showing 200-205psi now after bedding). Or do i need to continue the investigation into the cams and timing setup??

looks like i'll have to fit a thicker (more expensive booo hoo) gaskit on the rebuild..

thoughts?
 
#33 ·
ok im having trouble measuring the head and pistons..
I dont have a pipette or anything, where can i get one?? are there any other ways to do it? i've just tried with me cooking measuring spoon :p
but i seem to get about 50cc for the head and 17cc for the piston....

TBH, im still not sure what im supposed to do with them to work out the comp ration :D hehehe.. anyone else fancy doing it for me? had a Z20 gaskit on, and 0.5mm oversize pistons...

I'm thinking its definately detonation thats overheated the cylinder and melted it down... I seem to have identified a couple of minor issues which i think have all added up to make the major issue we've seen here..

current plan is to get new block in, std pistons, gotta skim the head again to sort the damage out :( so re-check the volumes accurately, then slightly thicker head gaskit and slight skim off the pistons to correct back to the right comp ratio...
What the opinion on here of light skimming on pistons?? I know its normally frowned against on here and everyone goes for the thicker gaskits, but why?? I think i will need to make up too much ground to go for a thicker gaskit alone..

quite a way off yet anyway...
 
#35 ·
ahhhh.. good thinking!!! i think i have one somewhere.. not a medical one but it will do, old inkjet refil one :) i'll have to have a search see if i can find it...

Brian, im currently trying to sort out a standard Xe block... are you sure you dont need your pistons? if i can get the block then they'd be appreceated very much :)
 
#36 ·
hi stu

the pistons are yours if you want them, they have been looking very lonely for a while now.....feel sorry for them (bless their little valve cut outs)

yep, get the block and as long as its not in need of a rebore then all is good

id like to offer the block i have cheap but it would need a rebore and that would mean new pistons mate

regards, brian
 
#37 ·
yeah no worries about the block mate, i understand that :) the pistons are more than i could expect :) cheers..

My block might have even been ok after a quick hone and a skim, im not certain whether the damage is wear or buildup!! but i have 2 dead pistons so cant afford the skim/hone and 2 pistons.. got to be cheaper this way, i can then rebore my block to a 4litre when money becomes avaliable :p lol... if only you actually could rebore these blocks a reasonable ammount.. could be quite fun :D
 
#38 ·
Stupink said:
... so i put the verniers on the metalic ring, which reads about 1.2.. ..
arnt stock gaskits 1.1mm compressed? so its thicker gaskit :(
Nah, it's practically the same.
For the sort of pressures you had, you're looking for a couple of millimetres thickness missing, maybe more:eek: not tenths of a mill:(

If the cams prove to be OK and the timing marks were OK, then I'd start verifying what these people did with your cyl head.:rolleyes:
 
#39 · (Edited)
well the timing was ok, I don't know what i can do with the cams though?? how on earth can i get them checked other than to send them back to piper? who lets face it, are hardly likely to say oops our bad they blew your engine up heres a new set.. lol..

the head was visually examined by an independant engineer, but he didnt have time to do any tests, visually he didnt think that much had been removed though, im dropping it back down to the origional people who will measure the volume accurately, I was speaking to them again today and he is confident it was only a light skim so if its missing that much then its due to a few too many skims rather than one big one, the rings have probably been shaggered ever since i had the car so i doubt they ever sealed properly.. that and my held boost issues probably meant i just got lucky in the past!!

One thing we did notice today, is that cylinder 3, and cylinder 4 on one side has piston marks on the head :O so the pistons are running VERY close to the head, is that normal?? we are fairly certain its only the liquified piston thats bridged the gap to make them meet, as 3 is the duff cylinder and its hit both sides, 4 has small melt and its only toutched on one side, 1 and 2 are fine and they havne melted or lost the gaskit at all..

I'm definately going to check the compression ratio, get it back to near normal with a thicker gaskit and piston skim... a bit of both should get close.. cant afford low comp pistons, and dont want to be going fitting too thick gaskit.. just dont like the sound of that...

I'm also now running plugs 2 grades colder than stock, initially i was running one grade colder... so perhaps that caused some damage(was missing like a pig).. i think with the colder plugs, the pistons and the thicker gaskit it should all be ok, I also thought i could hear a slight air leak somewhere before, like i said initially i did the spray test, and coudnt find anything re-torqued everything and coudlnt find anything, but i WILL remove every pipe and gaskit again and make 100% certain its all airtight.. on boost it shouldnt matter that much as its only going to loose air on boost making it richer, but i guess on lift-off it might run lean and do some nasty damage... I'm fairly sure its just normal intake noise tho, i would have found the leak otherwise.. will see when its rebuild if its still there...

I guess i will have to return the cams and get them checked otu anyway :( no big deal... few quid for postage got to be worth verifying, they could have made a mistake easy..
 
#40 ·
Stupink said:
.. how on earth can i get them checked other than to send them back to piper?
You can measure the timing with a dial gauge. It's not 100% accurate, and only cylinders 1 and 4 would be straightforward (due to clearance problems, with my gear at least)
This would show any major discrepancies.
Your compression figures were so off the scale, that you'd need the cams to be off by 2 teeth or more - so we're looking for something major here.
the head was visually examined by an independant engineer, but he didnt have time to do any tests, visually he didnt think that much had been removed though,
You can't tell these things just by looking at the head. At the very least you'd need another head next to it for comparison.
.. the rings have probably been shaggered ever since i had the car so i doubt they ever sealed properly..
That wouldn't affect the figures you saw


so the pistons are running VERY close to the head,
of course they are, how else would you get 250psi?
I'm also now running plugs 2 grades colder than stock, initially i was running one grade colder... so perhaps that caused some damage(was missing like a pig)..
the NGK iridiums I have on my site work very well

few quid for postage got to be worth verifying, they could have made a mistake easy..
I remember someone here who was sent the wrong cams by Courtnenay...
 
#41 ·
Ok, i've been on the phone to piper, and we have confirmed they are the right cams, measured the lift and it came out 9.4mm for the inlet and 9.34 for the exhaust, he said turbo's are around 9.5 and the xe etc would be over 10. and that theres only one program on the machine that would run on a set of turbo cams..

Still trying to find out the head volume, then i'll get it measured acurately and we'll see just what the heck they've done to the head..

John, what do you mean by the old rings being knackered wouldnt effect the figures i saw? i dont understand.. What i meant by my statement is that if the compression from the head skims etc might have allways been high, but being compensated for by dodgy rings(they were BAD!!!).... which might be why it never melted before..

I am now thinking back to another post i made.... about the turbo spooling up MUCH later than my old setup... with a lack of overboost... who can spell air leak :( that hiss must have been something... I've checked everythign again, still nothing, but its all coming apart and going to get 100% seal whether it likes it or not before the rebuild ;)

Would it be possible for the piston to melt on idle/light throttle when it was running vacuum?? it happened after a long boost run.. so maybe the temperature got there then, and then on lift off when i cam off the carriageway the resultant lean mix finished the job :(

If anyone knows the head volume for certain please let me know, i'm trying to get hold of chris at regal to see if he knows, got to be easier than asking vauxhall.. lol.. who else might i be able to find it out from?
 
#42 ·
Correct me if I am wrong here but to work of the compression ratio you just take the Compression test result and divide it by 14.7

You can then use this against your measured volumes to see how good all your seals are.

If your engine was reading 250 PSI on the compression test then that would work out at an effective copression ratio of 17.01 to 1

200 PSI would be 13.6 to 1 which would be a lot safer but in my opinion still too high on a turboed engine.
 
#44 ·
Yeah, its a kind of guide, but not as exact or accurate as measuring from what i've been told. I also want to try and work out where the compression is coming from more importantly.., it sounds like the engineers took too much off the head, i would like to be able to determin that or disproove it one way or another.. I'm not sure i'd ever get anywhere with it tbh, but heck even if they just did the head/piston machining i need doing free/cheaper that woudl all help me out here.. yet again chris at regal is getting back to me with the figures, then i'll get it all measured up and see where i can go from there.

Chris seems to suggest 160psi is about ideal for a turbo running the setup i have, heh. whats 40psi between friends..

He also commented on the valve spring issue considering i had non-standard cams, suggesting the springs might be too weak and letting the exhaust gasses back into the chambers overheating it all, im a bit ****ed off about that because when they upgraded to my 3.5 kit with them and didnt hear anything about washers, i phoned them up and actually queried them about it.. Is there any way i can check if this has been happening?? obviuosly with the head off now its ideal time to do something about it if nessacary, any suggestions?

Does anyone know where i stand legally? having asked for a light skim only if nessacary, would there be any come back if their over keen skimming had been the cause of this high compresion?
 
#45 ·
Well I was useing roughly 14.7 PSI to one Atmosphere.

Atmospheres are fractionaly less the Bar.

If 9.0 -1 is the ideal compress ratio then if you where only compressing air the it would be at 9 Atmospheres at TDC which is the same as 132.3 PSI.

I guess the difference is the fact that you are not just compressing air you are also compressing fuel (but I doubt the fuel compresses)

What is the ideal air to fuel ratio????
 
#47 ·
Stupink said:
...he said turbo's are around 9.5 and the xe etc would be over 10.
XE cams have 9.5mm lift when new. I would expect piper people to know their figures, but hey...
.. What i meant by my statement is that if the compression from the head skims etc might have allways been high, but being compensated for by dodgy rings(they were BAD!!!).... which might be why it never melted before..
Ah, gotcha now.
Yeah, this makes sense in theory.
But in practice if the piston rings were leaking *this* bad, then your bonnet would have an inside dent from the dipstick, and your turbo would be smoking like hell because the crankpressure wouldn't let the turbo oil drain.
Plus the inside of your bores would probably be very worn, needing to go oversize.
..Would it be possible for the piston to melt on idle/light throttle when it was running vacuum??
not really
A serious intake leak might do some damage, but not this bad (you would have heard it hissing, and idle would probably be affected too)
 
#49 ·
Stupink said:
..Chris seems to suggest 160psi is about ideal for a turbo running the setup i have, heh. whats 40psi between friends..
170 perhaps.
I thought you originally had 250 mate
He also commented on the valve spring issue considering i had non-standard cams, suggesting the springs might be too weak and letting the exhaust gasses back into the chambers overheating it all,..
Your cam lift is not that far off XE cams, and in any case that would only happen at high revs.
How high would you rev during break-in, anyway?
I've got the new valve spring hight on my site I think.
Knackered valve springs are always shorter.
 
#50 ·
This was after run in john, I had swapped over to fully synth a while ago and was faffing around setting it up, had already slowly increased the rpm over the last few days running in and was doing up to near the limiter..

Yeah, i did have 250psi, that was just after the rebuild.. with no miles on it at all.. after the run in it was down to 200. heh.. donw to 200.. hmmm...

I will look at the spring measurements and check them against mine then... I might swap them out anyway, but whether they need to be stronger than stock or additional washer... anyone got experience of this? regal were talking of 1 or 2mm washers depending on the strength, but he didnt really seem to know tbh.. sounds like its all just left up to the mechanic to do..

Re piper, we were talking about reprofiled cams, so i presume that is what he is talking about, if mine were indeed mixed up for reprofiled xe cams that they would have been in excess of 10mm lift.. I am only making assumptions though.. he did seem to be very helpfull and know what he was talking about.

Miles, i guess your right, all i have to support the theory are my personal compression figures before and after.. unfortunately that will mean squat, and i never thought to meaure the head before :( Only if they were responsible for checking the head dimensions were still within vaux spec etc would it have given me any chance :( but from what i've seen not a single engineer place has the spec.. im having to get it from vauxhall myself.. lol...
 
#51 · (Edited)
Stupink said:
Yeah, i did have 250psi, that was just after the rebuild.. with no miles on it at all.. after the run in it was down to 200. heh.. donw to 200.. hmmm...
200 is XE territory
I will look at the spring measurements and check them against mine then... I might swap them out anyway, but whether they need to be stronger than stock or additional washer...
this 'washer' theory is for high-boost/high-rev operation.
You were just running it in...

regal were talking of 1 or 2mm washers depending on the strength, but he didnt really seem to know tbh.. sounds like its all just left up to the mechanic to do..
If they knew what they were talking about, they wouldn't be what they are, would they?lmao

The cyl head thickness (sealing surface to sealing surface) should be:
135.58 ~ 135.68mm

maximum variation of the sealing surface: 0.05mm

Hope it helps:beer:
 
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