compressions

[katykoo]

Hi, Have replaced a second hand cylinder head to my 82 2.0l Aircooled.
There are no compressions...my mate says its because the gaskets weren't replaced when putting the head back on..discovered from JK that I do not need the large cylinder rings, as they were there to help if engines were to be run on low grade fuel..so JK say just put the cylinder head straight onto the block, and the only gaskets are exhaust and rocker cover...help!

would the gaskets really affect compression and mean that the two cylinders show no compression?

Thanks

[HarryMann]

They meant with new seals, not just straight back on, no-one does that... JK are not a technical resource now are they, they are a parts seller...

But you 'have' re-set the tappet clearances, so that the valves aren't being held open?? Haven't you?

[katykoo]

Where do I get the seals from?. My mate, the mech says he has re-set the tappets..

[camper]

The head gaskets come as part of a complete engine gasket set for a 2ltr cu from gsf carparts cost aprox £50.00.I had this problem gsf dont supply them separate only as with a complete gasket set for the engine.However advice from Aircooled engine rebuilders will tell you that lapping the cylinder to the heads using fine grinding paste to get a good seal is done.

[katykoo]

Ahh JK recomended this fine grinding paste..where can I buy it from and whats it called?

Thanks

[camper]

The paste is the same as used for lapping or grinding in exhaust or inlet valves to cylinder head valve seats.It is supplied as course or fine called valve grinding paste obtained from halfords or other motor parts supplies.

[katykoo]

Thanks! Do you think that the lack of a seal etc is giving the lack of compressions?

[camper]

As adviced by HarryMann check that your valves are not held open.

[VWCamperfan]

Just to join in here...!
My engine is different to yours, I have the 1600 CT engine but I have never used gaskets on it as both faces are a machined fit. Never had any problems and compression it top notch.
The usual culprit when refitting heads is the pushrods. They have to sit in little cups in the centre of the lifters down in the engine block and quite often they slip out and this prevents the valves from closing.
Take of rocker cover and shine a torch down the pushrod tubes. Have a looksie and make sure the pushrods are in the centre of the lifters. If not, loosen the two nuts securing the rockers to the head just enough to reposition the pushrods in the centre of the lifters.

[HarryMann]

If that's the case then the 'mechanic' can't have set the valve clearances

[ghost123uk]

And if your "mechanic" starts messing with grinding paste, then remind him that the slightest trace of it left where it shouldn't be, such as in the bores or combustion chamber area will very quickly do a load of damage !

Good luck, and if unsure, keep asking on here

p.s. = most motor factors sell it.

[Laurie]

It might be a good idea to ask your mechanic HOW he has set the tappets.

1: Has it got the original hydraulic tappets?
2: Has he located the push rods centrally in the hydraulic tappet?
3: Has he understood the difference between sprung and unsprung movement.

Ans:
1: If he has adjusted solid tappets to hydraulic spec. The valves are open.
2: If he hasn't located the push rods and done the above, the valves are open.
3: If he has adjusted all the free play out of the tappet and then given it the 1.5 to 2 turns, the valves are open.

Chances of having no compression due to not grinding the head in is negligible unless the barrel was severely damaged.

The 2 litre heads currently sold often have a second cut in the combustion chamber which eliminates the need for the head seal. Most original heads won't have that cut, and therefore the leaving out of the seal means that the deck height is far too small.So... if thebarrel sealing face on the head is raised by about a millimetre you won't need a seal.

[katykoo]

Thanks guys..will pass on the info to my mechanic friend!!

[katykoo]

Oh..Am thinking that the gasket I mentioned earlier on is the one for the barrel liner.... is this where the suggestion of grinding paste comes in..or should I just get the gasket? I see that JK have the barrel liner gasket, but from 83 onwards?

Thanks

[HarryMann]

Done properly, the grinding paste will just clean up the surfaces nicely... the old way on similar m/cycle stepped heads was to use coarse on the bottom step and fine on the top (I think )