head gasket problem

[nodrog]

due to my cordy bending all 4 exhaust valves, i thought id upgrade its internals, so its now got all new performance valves, springs, tappets and cam, had the head skimmed, de-coked, polished and gas flowed, and have had a custom induction kit+pipe fitted .

the only thing is, ive had no luck gettin the head to seal, all the timing is correct(had it re-tuned), the bolts are tightened by the book and hasn't been reved above 4k rpm,was ok for a couple of days, but has now blowen at the front of the engine

i dont understand why, its been done properly(ive got 3years of experiance), seat want £378 excluding VAT, and the only garage that will do it wants £300 excluding VAT and the gaskets


help anyone ???????????

 

[goble]

what has it blown??????? more info reqd .the gasket?

 

[nodrog]

the gasket has blown at the front edge of the engine, it emptied a full tank of oil in around 15mins of me driving it, but is not creaming the oil cap

 

[goble]

before u refitted the head did u blow out the block where headbolts go into???

 

[nodrog]

yes, used an 2bhp compressor and air gun, was all bone dry

 

[goble]

then take the head off again inspect the gasket if it looks ok you have got a buggered head or block

 

[nodrog]

hopefully the gasket was dodgy, the heads fine, and the block is smooth and level.iv got a new gasket on its way, and also got some head sealent aswel, so should work this time round.

 

[hopkinsgm]

Potentially stupid question but is this the first time the head has been skimmed? And how much did you have taken off it?

 

[nodrog]

the cars done 98200miles, but the company that rebuilt it said before they skimed it, it was at its origional depth, not sure how much they took off,. should i get it re-skimmed?

 

[hopkinsgm]

I asked the question in case too much had been taken off or if this was the umpteenth skim it'd had. If you're having trouble getting a good seal on it and you're sure it's flat, then it's possible that it's had too much removed.

There's only so much metal you can remove. Some engines have very tight tolerances - I recall hearing that there was so little excess metal in a Rover K series head (forget which variant or capacity) that they were, effectively, unskimmable. Once warped, the head was scrap and suitable only for doorstop/paperweight duties, etc...

 

[Fl@pper]

they make headsaver gaskets now for those

payen do em i think

 

[cordobabrendy]

carl reinz (iirc thats their name) gaskets from gsf are pretty good if you need to replace.

 

[nodrog]

iv now got the new headgasket, sealent and headbolts, gona put it togeather today...thanks for the help

 

[nodrog]

done, its all sealed.no leaks. how long should i run it in for and whats the highest i can rev it to? iv been told 100miles, no more than 4000rpm(70mph in 5th)

 

[Al]

i'm sure people are going to have a go at me about this but everytime i've rebuilt an engine i've taken it round the block a few times until fully warmed up, then checked for leaks etc and then put it on the dyno.

Lot's of tuners that i've spoke to do this to.

Unless you've changed all of the internal parts there's no point running it in at all.

I've never had any problems with any engine i've 'run in' this way.

 

[nodrog]

ive asked around a few local garages, some say because iv got new valves, valve springs and caps, tappets and camshaft, i should treat it like new, and others say it makes no difference, solong as its properly tuned.

the tuning is done by the book, and all the dyno companys i know of are closed until the new year. im just taking it steady for now...