Technical Head gasket price

[[email protected]]

Evening all :wave: Today I took my cinq sporting to be checked why it blows white for brief period with loss of power. Garage tested it for 10 mins but couldn't find the cause - told me best to get head re-skimmed? at price of £250+ vat ( told me it would have to go to specialist ) Does this sound about right???
Driving home up a hill I felt it lose a lot a power and found it harder than normal to climb.
Do you guys reckon the problem is still the head. Im in Wiltshire area if anyone knows of a cheaper garage. Cheers Ash

 

[nogin]

think this is probably bout the usual price for a skim and a head gasket change, why did they say it was the head gasket, eg using water, misfiring, low compression on a cylinder. where are you in wiltshire

 

[[email protected]]

Im in Swindon. Cant remember exactly what the chap said but he did mention anti freeze can corrode the seal and leak into areas it shouln't. Had good work from garage before so happy to go with what they say but not sure if price was high. Thanks for help.
(not using water or mis firing)

 

[vandisian]

as far as skimming the head goes ive done it too many times to count for people that have just arrived at the door of the workshop and asked if we could do it. Dont know what the boss charges but its a 30 min job to any skilled toolmaker or miller. I saw someone mention 40 quid to get it done that would make it 80 quid an hour for labour easy money for them. Best trying to find a small sub contract engineering firm but you would be better chancing your arm and going in somewhere there is a nightshift 20 quid nudge and a wink should do it. Depends where in the country you are?

 

[sumplug]

one thing to remember. when torqueing the head down, the figures for the punto 60 should be used. this is why the gaskets tend to go on the sporting.

 

[arc]

30nm and then 90degrees, and then another 90degrees is what i've always done.

 

[Oldschool]

one thing to remember. when torqueing the head down, the figures for the punto 60 should be used. this is why the gaskets tend to go on the sporting.

They are on all 8v FIRE engines with cast iron block the same torque values.

 

[arseofbox]

as far as skimming the head goes ive done it too many times to count for people that have just arrived at the door of the workshop and asked if we could do it. Dont know what the boss charges but its a 30 min job to any skilled toolmaker or miller.

That long ...my local guy charged £15 and took about 10mins...

 

[vandisian]

10 mins is a croc of **** cant have clocked the bloody thing up, never mind clocking it up you couldnt get it on jacks and clamped in 15 mins. the actual skimming bit may take 10 mins or more dependant on machine, cutter capacity and how much needs to come off. A crap job with cause your head to warp and i would guess there is a maximum you can take off a head.

 

[arseofbox]

10 mins is a croc of **** cant have clocked the bloody thing up, never mind clocking it up you couldnt get it on jacks and clamped in 15 mins.

Well maybe you couldnt, but the guy I used had been doing it day in and day out for many many years, so its not implausible.

the actual skimming bit may take 10 mins or more dependant on machine, cutter capacity and how much needs to come off.

Yeah...but whats the most taken off on an average pass..IIRC most milling Ive had experience its in the region of 40 thou / 1mm per pass at absolute most, but the most Ive ever needed taking off a head is less tahn a quarter of that figure. They dont warp that much...

A crap job with cause your head to warp and i would guess there is a maximum you can take off a head.

Agreed...if its too rough cos the cutter/ feed speed ratio or something was wrong, the surface finish is gonna go to pot as the tool may chatter, that would mean the head was no longer flat. But thats something someone that had experience probably wouldnt do, as they would know how to prevent it.

As for maximums...IIRC with the 8v FIRE heads its around 30-50thou / 0.762-1.27mm, from stock, but thats before having to use a race fuel. You could probably go much further with race fuel.

As for the 899cc, I dunno...but I understand a lot of heads have skimming marks on them that indicate the maximums to the machinist, Ive heard the FIRE definately does.

 

[vandisian]

to reiterate not only is it implausable it is impossible. Doesnt matter the guy has done 50000 heads it just cant physically be done in ten minutes. Not my oppinion just a matter of fact. Take it from someone who has 18 years experience in machine shops. You mentioned finish im glad you did, would not matter if you took .004" or 1/2 an inch off, to get a finish thats not like a ploughed park it will go at the same rate. Oh and i mentioned cutter capacity what i should have made clear is cutter diameter. A head is what7-9 inches wide yes!, not many machine shops need nor would stock a cutter that wide its an expensive item. So your looking at 2-3 passes to cut it.
I dont know of any machine shops that cut heads day in day out cant be that many heads need skimming surely.
Sorry i had to add most milling youve done max 1mm was it a toy mill?
The biggest machine ive worked can take upto .7" per cut on Duplex.
(Duplex is a tough stainless approx 23 percent chrome).
And there are bigger machines than that.
Any millers or toolmakers will find your claims laudable and as aluminium alloy is quite brittle the slower feed is required.

I would also like to add that not only have i skimmed many a head i have machined them complete from castings.