Later valve guide oil seal

[Ufudu]

Hi I am in the process of changing the valve guide oil seal from the ordinary 'O' ring to the cap type on my 948cc.

On replacing the existing guides with the new ones with groves that accommodate the cap type seals do I have to compensate for the seal thickness on top and decrease the height shown in the manual as 19/32"?[frame][/frame]

[bmcecosse]

No!

[Ufudu]

Excellent!

Many thanks BMC.

[JOWETTJAVELIN]

Just bung them on, later Austin Mini type, but remove the tiny spring circles from them before fitting.

Fit to inlet valves only.

[bmcecosse]

Huh?? You must keep the spring retainers if supplied - not all types have these.. !! The seals are of course intended for use with later guides with a groove.....

[Ufudu]

Thanks,

I have the guides from minispares.com with 2 grooves, & the seals from EMS have the retainer springs, so I will not remove them.

[JOWETTJAVELIN]

I've found that the seals stay put regardless of whether the springs are present or not, but as they can easily become dislodged and possibly fall into the engine, I always remove them myself.

[puffin]

Just seen your advise regarding valve seals. I have similar problem. My valves are not the type for the small O ring seals, but the guides do not have groves to hold the later cap type seals. Will the seals stay on my guides or will I have to replace guides?

[daveyl]

I have bought a set of the 'minispares' valve (bullet-nosed) guides in the past. Yes they do have two grooves at the top for the 'top-hat' seal fitment. Don't know why there are two grooves though.
They are also much longer than the standard. So, they look like they need to be shortened. Perhaps, they are universal and also fit in the 1275 head.
For the next head I'm fitting, I purchased a set from ESM which are the standard size but unfortunately don't come with a groove. So, I was just going to fit the top-hat seals anyway. Has anyone tried it successfully?

[bmcecosse]

They will stay in place well enough to do the job - even if they 'ride up' slightly. But WITH groove is better - and keep the springs! As mentioned in another thread - you do need a proper stepped drift to put the new guides in without damaging them - and then check if they need to be reamed to clear any damage at the top edge.