Valve stem oil seals

[fillpoke]

Could anyone please tell me if I can fit the 'top hat' type oil seals to the valves in my 1098cc cylinder head. The valve guides do not have a groove in them so will the seals remain where they are put? I'm reluctant to use the rubber 'o' ring type seals which were on when I took the head to bits. They just seemed to be sitting in the middle of the valve stem and serving no useful purpose.

[simmitc]

I would get a set of new guides with the groove in and fit the top hat seals. In my experience they dramatically cut oil consumption. As you have the head apart anyway, it's only a few minutes work to fit the new guides, and well worth it.

[fillpoke]

I've no idea how to fit new valve guides - is it a specialist job or can anyone do it?

[GBond]

Valve guides are better left to a specialist with the proper machinery, but if you're rebuilding your engine it's a good thing to have them replaced.

When I rebuilt my engine I used the little o ring seals and they broke so now I have no seals at all; car runs great and doesn't smoke much but if I had to do it again I'd use the 'top hat' type.

[MarkyB]

Valve guide are easy enough to do yourself, they just hammer out with a suitable drift then the new ones hammer in.
You need to use a drift for this as well and make sure they go in to the same depth, maybe using a small block of something the right height to measure against.

[bmcecosse]

You do need that drift...so I suggest you just fit the top hats and they should stay in place - or reasonably near enough to do a job for you. If changing guides - just do one at a time, and a steel rule across the tops of the others 'guides' you for the height... Also new guides may need a slight reaming where the drift has been in contact with the top face...

[philthehill]

I agree with bmc you do need the drift to remove and fit the valve guides.
Here is one which I made and use when removing and replacing valve guides.
The top guide is a standard Minor one and the lower guide is a modified one from a 940 head with tapered shoulder where it protrudes into the inlet valve tract. It also has the 'oil seal retaining grove.
Minor Wksp manual section AA19 gives the physical dimensions of the drift.
When you replace the valve guides do not automatically expect the valve to seat correctly, it may do or it may not. Try a bit of fine grinding paste on the valve seat (engineers blue would be even better) and then fit the valve and turn the valve. When the valve is removed if it has a nice grey seat (or blue) all the way round all is well if not a bit of valve grinding may be required.[frame][/frame][frame][/frame]

[les]

I used a very similar tool but it had the addition of a fixed outer tube over the shown assembly, that stopped the guide at the correct depth when it made contact with the head deck.