13 replies to this topic

[bikenutmart]

Hi, Im rebuilding the head on my 998 A+ engine(99H) code and am not sure if i should put seals on all the valve stems, i do have 8 of them, they were only on the inlets on stripdown, but have been told to put them on all the valves by several poeople, is this correct? im sure someone on here will know the answer. Cheers Martin.

[racingbob]

i was told put them on inlets

 

but on the exhaust put them on but take off the little spring thing

 

this was from a top engine builder builds mini 7 engines

[bikenutmart]

Cheers Bob.

[mini=love]

Iv never bothered with exhaust, but if yo have them it cant harm to stick them on

[mm man]

i was told put them on inlets
 
but on the exhaust put them on but take off the little spring thing
 
this was from a top engine builder builds mini 7 engines

Why? Remove the springs

[Gremlin]

Advantages-
Limits oil being burnt

Disadvantages-
Stops valve stems being lubricated against stems
Could increase wear as it does not let the valve go where it wants

[mini-luke]

Even rover couldn't decide if it was a good idea to fit them to exhausts, some came with some without

[grahama]

I think it was standard to fit them to all stems after a certain date,  put them on all mine when I rebuilt.

[Dan]

  They started to be fitted to all of them as emissions laws got tighter.

[mini13]

also use the mpi ones as they take the exhaust temp better.

[bikenutmart]

Wow !!! So many replies, as ive got 8 i may as well use them, Thanks again everyone. Martin.

[mm man]

I have just rebuilt my head (89 mg metro 4 seals from standard ) and fitted all 8 as this seems to be the way forward now a days but just wondering why remove the springs on the exhaust seals ?
I get the reason why to fit the seals but the spring removal only on the exhaust ???

Does any one have any ideas as Bob was told this by a mini race engine builder but he doesn't know the reason why ???

[scott_65_cooper_s]

One disadvantage of leaving them off is that oil can run down when the car is parked, giving the classic ploom of smoke on start up.

[Turbo Phil]

The reason he's  been advised to leave the small spring tensioner off the exhaust valve stem seals is to allow better lubrication of the valve stems by allowing some oil to pass. The exhaust valves run hotter than the inlets & lack of lubrication could cause them to seize. Not so much of an issue on a basic road motor, where the springs can be left on, but on a race engine or Turbo motor it certainly is.
As said the later MPI stem seals are superior.

 

Phil.

Edited by Turbo Phil, 20 May 2013 - 11:04 PM.