coscast head info

[basscrazy]

right if i change the head may as well go all out


but they seem to come with 100k + on the coscast heads


how long exactly do these last ???? do they never ever go porus or do they eventually just a lot longer lasting then gm etc any info mega appreiciated

[Benn]

they can and will,theres just less chance...cause of the better casting,

[basscrazy]

so really a 100k one is quite likley to go porus then?

[Jamie_F]

theres less chance of it going porous than a normal KS head, but you can get KS heads with 150k plus and not go, its luck of the draw really.

[basscrazy]

why not just go gm then? can get 70k ones for 70 quid or coscat 100k for 300 huge difference....

[Benn]

cause people think there amasing...hence why i sold mine for 200sheets,

[Jamie_F]

coscast adds 50hp dont you know

[basscrazy]

ok so are basic gm ones way to go then?

[Benn]

coscast adds 50hp dont you know

thats why they sell better...

ok so are basic gm ones way to go then?

al the same..just wack a head on and go...

[basscrazy]

will just get one of those then sodd paying extra nearley 3 hundred quid

[Tathan]

Doesn't really matter how many miles a head has on it. It's a lump of metal. Unless it's been ran out of oil, has det damage, or has been skimmed to buggery, it'll be ok. Just don't tighten a KS down using 90deg lol.

Condition is far more important than mileage. You could have a low mileage that hasn't been serviced, headgasket has gone 12 times and is pitted, or you could have a 200k head that's serviced, cared for, never had a HG.

[draper]

personnaly id get a GM 1 and do the oil gallery modification

prevention is better than repair

[Benn]

personnaly id get a GM 1 and do the oil gallery modification

prevention is better than repair

lol just fit the gm head drive it till it gos then fix it...

[Brian_S]

mmm, there are some differences and some reasons why the coscast gets more money than a GM.

The porousity of a std GM head doesn't really matter tbh, it's an easy fix.

The Coscast head is cast from a better grade of aluminium, and has different valve seats and guides.

Go to swindon race engines and they won't do you a head that isn't coscast... and that includes you supplying the head, they won't work on a std GM head.

For example, increase the valve size +1mm and the GM head needs new seats allround, the coscast doesn't. Incidently, swindon's top head increases valve size 2mm all round.

[Tathan]

Is it the material used or just the casting?

It's much more homogenous and free from porosity (as in proper porosity, gas inclusion) than the KS heads, due to the magic Coscasting.

[Adam]

theres less chance of it going porous than a normal KS head, but you can get KS heads with 150k plus and not go, its luck of the draw really.

like my gm head which had 156 tho on and never went

[Rick Draper]

Also iirc the misconception is the head goes porus, it does not it cracks as garys old pic's of the cut up head showed.

[Brian_S]

Also iirc the misconception is the head goes porus, it does not it cracks as garys old pic's of the cut up head showed.

porous simply means that the oil gallery is no longer fully sealed against the water gallery and thats it; it means no more. How the head gets porous doesn't really matter. The GM head goes porous because of a weak spot in the casting, and the coscast head doesn't.

Mr. Keen, It is supposely a different grade of ali. The main point is that it is nicer to machine/port than the GM head.

[wayne451]

So a Coscast doesn't need anything to go 1mm oversize?

[Gaz86]

heres some info for you mofos
courtesy of scooblers
http://orsas.com/CarStuff/cav/

[wazpaz]

good site there GBE86