Classic/Antique Car Repair: valve guide lubrication, grease cups, valve cage

Question
QUESTION: Brad:

Thanks for being a resource.

I'm rebuilding a 1915 Buick 4 cylinder engine.  It has the exposed valves - as did all valve in head Buicks of this era.

The question is just how do the valve guides and valve stems get lubricated?  All the valve train is exposed and the only lubrication is for the rocker arms themselves.  This "lubrication" comes from the driver stopping the engine and turning 4 grease cups!

I'm concerned about the valves sticking as there is no obvious source of lubrication.  I've driven the car for over 30 years with no issues, but with new modern guides and valves, what clearances should I be running and how in the world did Buick lubricate these things?

Your advice and thoughts on this would be appreciated.


ANSWER: Wow did this one send back into the dark ages. Well, if memory serves me correct the valve guides were bronze and a very porus bronze like a johnson bronze that would hold small amounts of lubricant like a sponge. I would replace the valve guides with a johnson bronze. Remember that that old engine turns very low RPM and is also a cooler running engine than modern stuff.
Brad

---------- FOLLOW-UP ----------

QUESTION: Brad:

The stock Buick guides are not easily renewable in that they are part of the valve cage, which is cast iron, and not pressed in.

Our machinist did install a steel guide in one valve cage as a test.  That worked well which means we can put modern press in guides in the stock cast iron valve cages.

We know we could install bronze guides but because of the lack of upper lubrication in this exposed valve engine, we are concerned that a really soft guide running a steel valve might wear quickly.

What clearance would you run in these guides?  We're thinking .003" to .004".

Thanks,

Mike

Answer
The clearance numbers that you quote sounds about right. But steel on steel might be a problem. cast iron is porus and will hold lubrication. It is just a thought but the lubricant that we use on disc brake slides appears weather resistant and heat resistant. Perhaps assembling them with this lubricant will work.
Brad