James @ M Developments.

iTrader: (2)

Bruny the piston itself won't have caused the gasket to fail. But the type of gasket or thickness of gasket we had to use to prevent the piston hitting the head may well be the weak link. If the compression test shows all good, but it's dumping eater on boost, the head is either lifting on boost or the sealing faces have failed this may be a distorted block face as the head was skimmed so we can eliminate that side. As boost increased so does the cylinder pressure this is why it leaks cylinder pressure into the water jacket on boost

bruny

People keep going about the comp ratio.well looking through msd website on a set up they check Compresion test.so surely msd cam confirm this for me after the car was done.?? I can tell every 1 now its all good

ajamesc

Im not talking about engine out full strip just remove the sump and pull that one rod and piston put the other 3 on tdc and measure there hight do the same with the odd one then get the differance taken off if the rings are still with in tolerance and the shells ok then put it all back in how much power do u have can u not just use a small turbo escort h/gasket once u have sorted the odd piston seems a shame to give up on it everything can be fixed

RS SHAUN

iTrader: (24)

Sounds like a good plan!

DAN400

iTrader: (3)

just what i was about to say, and it wont cost that much to do!

bruny

Yer thats what i was told how to do it but the extra price to do this was just way out of budget for me.

LHD220Turbo

iTrader: (4)

exactly what i would do - you could do all the donkey work yourself. to have a piston machined shouldnt cost more than Ł50 inc vat

bruny

It was the labour what was to much for me to pay.il defintly learn from mistakes.

fiesta23

iTrader: (1)

correct me if im wrong but a compression test is different to a compression ratio ?

wasnt trying to start an argument when i commented before got the wrong end of the stick, just sounded like msd were getting the blame.

bruny

Not sure on power.id say 340-360 with my spec.if i went for the piston to be done it would of been a idea to put new shells in which was way to much for me to pay

James @ M Developments.

iTrader: (2)

Get the spammers out mate. You already have the gasket to go on it, it's just your time if you do it yourself or even part of it. Head off is dead simple, and I will make myself available via phone 24/7 to help if you need it. Don't give up mate!

bruny

Compression pressure test i mean

bruny

Giving me a spanner is like jumping in a pool full or crocodiles.it would turn messy.lol
If it doesnt go i will pay someone to do a whole bottom end rebuild for me

botters

iTrader: (2)

yes compression test and compression ratio are two completley different things, the taller piston will give a different compression ratio on that cylinder but not neccesary a massivley different compression reading on a compression test

carcollector

a engine with 3 same and 1 different piston ?? u taking the piss here ??

u been fooked well before it went to MSD, honestly i wouldnt even have touched ur pile of rubbish knowing above.

if u cant afford a YB rebuild then you probably shouldn't have 1 to start with.

why do people think cosworth YBs are cheap to run ? they are not.

ajamesc

can u not do it yourself its only nuts and bolts any good machine shop can mill a piston crown the only thing that may catch u out is the measuring up all u will need is a sump gasket and a headgasket set once the head is off if you bend to old bolts into a hook screw them back in then use one of the wing to wing engine suports u can then remove the cross member to take the sump off may sound a lot of pissing about but will save alot of money

James @ M Developments.

iTrader: (2)

Get the spammers out mate. You already have the gasket to go on it, it's just your time if you do it yourself or even part of it. Head off is dead simple, and I will make myself available via phone 24/7 to help if you need it. Don't give up mate!

bruny

Wouldnt be long till you get 1.do 1 jeremy clarkson

ajamesc

But if they still look good then they are good lol it is best practice to change them if they are out but if u are on a budget

Chaz888

to pull down a head and find a piston not machined to spec would make me think ho shit what else was missed skimped on !If it was me it puts the last build up in question and the quality of said work just look at it this way your engines ok no big damage done you know the problem and it can be fixed .

BRAMMER

iTrader: (23)

I dont think at all people are blaming the piston for the hg problem its just not ideal. the gasket went because the block wasn't flat, its the main preparation when fitting m/l gasket that's the problem like you knoe, simple fix and lesson learnt

ajamesc

The h/gasket went because it was to thick by the sounds of it as they must have checked to see if it was warped with a straight edge he may as well just use a small turbo escort one with his power level once he has sorted the piston out

bruny

Thats what am saying brammer.i wasnt told that the block would need a skim for the head gasket.if i new i would of defintly got the block done

Miller 3

iTrader: (4)

Just because it has good compression across all four cylinders dont count for squat, its when its on boost the damage gets done as the head will lift a tad and this boost pressure will find its way past the round sealing rings on the H/G and in to the water ways hence pushing the water out of your header tank. Once you get this little issue sorted it will cope with that power you are after with EASE for a long time if maintained well.

If you was close id be round there now stripping it down to help you out.

carcollector

u were told to have the bottom end done, yet you decided not to. at the same time u say u dont have skills for spanners and dont understand engines, on what basis was your decision made then ?

surely on budget and nothing else.

so go do one cheapskate

James @ M Developments.

iTrader: (2)

An engine build wasn't sn option you told me your budget and it would have gone way over that. All work was done with your go ahead to make the best of a bad situation,

The piston wasn't different lol, just hadn't been machined to reduce protrusion like the rest

bruny

No i was giving 2 options to go for.if it was going to be a issue i should of only been giving 1 option and i would have gone for that
So please go and play with the traffic

c20tbo

iTrader: (1)

Fella,

Yes the headgasket has blown for reasons, as MSD stated the thickness - the power running using such a thick gasket, no block skim.

But this is all because of the dodgy piston.

No dodgy piston = No silly thick gaskets = Perfect running car.

James @ M Developments.

iTrader: (2)

Brunt you were given the option of piston out for machining my original contact with you over this issue said that was what was needed, but there was the option of trying a thick gasket,. It hasn't worked, it's no big deal, it hasn't really cost much, it needs now what it did to start with when we found the issue.

bruny

Yes i understand mate.its perfect running before.if i was to put the group a hg on ot will be back running 100 percent again.but people thinking am having a go and blaming some 1 where as i am not.msd did a great job on the car but if i was just more clued up more about cosworths i would with out thinking of had the block done but i was told it should be ok.so me been me went along with it.you win some you lose some

bruny

Yes i was mate.id admit that.but at the time i never thought it would cause hg failure only valve to piston damage.

James @ M Developments.

iTrader: (2)

But it's no big deal mate, these things happen, I think in your position I'd have done the same and gave it a try, but it didn't work, so there's only one option left now

Chaz888

lol dude think a blowing HG is way better than option two !!!

STUCOS

iTrader: (8)

Once the head was off,surley to drop sump,remove piston,get piston machined and refit piston,would of only added another Ł250 max on top of job.and as for ppl saying he isnt blaming any body,thats how his op comes across,and in all fairness this should never have been aired on here,but kept between msd and bruny,

cheeRS stu

Eigdoog

I have just been reading all this and if i was you ill give it ago myself! I dont have a clue about engines but im slowly taking mine apart and restoring it!

Mind you i hope to take it to msd when im done for a check over lol even though its 232 miles away. (i hear there good lol)

Got any pictures of your car mate? be nice to see what we are talking about!

bruny

If the car doesnt sell for what i want for it i will no dout pay for a rebuild of the bottom end.the car surely deserves it as its a mint shell and motor

fiestamad

it will just be easyier for you to take the piston out and get it machined and so on build it back up put the other gasket on and see what happens there as james at msd said he will be on the other end of the line to help you if you get stuck it will save you a load of money on labour and you will have a bit of knowledge if u decided to got for new piston or do the rings as you will know how to strip the bottem end your self

rsdan2evn

What more could u ask for from someone.

On a different note, why would the pistons be odd in the first place?

Eigdoog

Be a shame to sell it after all this now. Give it ago, im sure someone will come round and give a hand (sure i read that someone will come).

bruny

Number 4 piston is sat a fannys hair tad higher than the others.all the same pistons Vo