300tdi disco head gasket choice - with skimmed head

[markyb]

hi I m in the process of changing my head and gasket , Ive picked up a skimmed head, old gasket was the 1.5 3 hole type gasket.

in the parts shop they were saying I should go with the 1.6 no holes to allow for the skimmed head.

can any one advise fitting back the orignal (new gasket thickness) or go with the next size up ?

[barmiebrumie]

Just done this job & use a 1.6, no problems so far but have only done 100 mile but all seems fine

John

[markyb]

cheers john, did you go from 1.5 to 1.6 then?

[Thys]

The piston protrusion above the block should dictate the head gasket thickness, there are tables in the manuals specifying the values. After the head has been skimmed, the valve recess clearance must be checked, again it is specified in the manuals, get that recess wrong, and the valve and piston will eventually touch.

[Les Henson]

Head skim doesn't dictate gasket thickness (the burn happens inside the piston crown). Piston protrusion is what tells you how thick the gasket should be, so you should use the same thickness gasket. Valve stand down will be affected by the skim, so you should check that. The stand down may well still be within the limits, and it would have been handy if you had known how much had been skimmed off.

Inlet valve stand down is .81 to 1.09mm.

Exhaust stand down is .86 to 1.14mm

If you have the original pistons in it (and you're sure it hasn't been tinkered with before, then use the same thickness gasket.

Head off a different engine/new item. then check the protrusion.

Check piston protrusion - how to is here:-

http://forums.lr4x4.com/index.php?showtopic=24508

Les.