6 replies to this topic

[tricky123]

why are there only 4 valve stem seals in a head gasket set ? . i`m rebuilding a head , should all 8 be replaced ?

[Dan]

Common theory is that you only really need them on inlet valves, as the exhaust valves have pressure behind them rather than depression and so oil doesn't get sucked down the stem. So some gasket sets come with only 4 seals. Fitting all 8 is a good idea IMHO.

[tricky123]

Common theory is that you only really need them on inlet valves, as the exhaust valves have pressure behind them rather than depression and so oil doesn't get sucked down the stem. So some gasket sets come with only 4 seals. Fitting all 8 is a good idea IMHO.

Cheers Dan , thats what i thought , have you any recomendations on head sets. i was going for the minspares one with the AF460 copper head gasket in it.

[samwell]

geniune. I got mine from minispares. Was about £13 which isnt alot for peace of mind.
samwell

[samwell]

also comes with 8valve stem seals

[Guess-Works.com]

fitting all 8 is only a good idea if you have high temperature seals, std rubber seals on exhaust valves is not good as they degrade, harden, split and then end up floating around in your oil, with the potential to get stuck in oil ways...

IMO, there's a reason why there's only 4 and the above it..

and unless you've got a freshly faced block and head, stay away from copper....

998 use a std gasket, 1275 use a BK450.

[tricky123]

fitting all 8 is only a good idea if you have high temperature seals, std rubber seals on exhaust valves is not good as they degrade, harden, split and then end up floating around in your oil, with the potential to get stuck in oil ways...

IMO, there's a reason why there's only 4 and the above it..

and unless you've got a freshly faced block and head, stay away from copper....

998 use a std gasket, 1275 use a BK450.

Thanks for that , i nearly slipped up there . what compositon is the BK450 , do minispares stock it.