Split Head 6 Valve Guide

[Guest WayBro]

I am rebuilding a 1931 Pontiac Split Head six that broke a couple of tappets from bad gas. A couple of the valves, as you can imagine, are really hard to get out and have pulled the valve guides with them. I am not familiar with replacing once I get the stuck valve out bit assume they are held in place by tapping them back in but not sure how to without damaging or the exact depth?

[Guest]

They would normally be pressed in but I suspect if you were to put the guide in the freezer over night and used a brass drift or a hardwood block you could tap the guide in.  As long as it was lined up with the others it should work.   While  the engine is apart though I would check the valves fro clearance in the guide.  Now is the time to replace the guides if worn rather than after when you discover you are pumping oil out the exhaust.

By the way you can replace the Pontiac adjusters with flat head Chrysler, dodge or Plymouth ones.  I think it is worth the bother as you only need two wrenches and a feeler gauge then to adjust the tappets rather than three wrenches and a feeler gauge.

Edited March 1, 2016 by Guest (see edit history)

[Bud Tierney]

Can't comment on 31, but Motor Manual 35-46 valve guides sez:

when new guides taper .001 to the inch...larger diam to top (allows for expansion)

Fit should be that valve just falls thru guide by its own weight...

If too loose, new guides, straight holes, should be reamed accordingly...

Says to measure from top of guide not yet removed to top of block; install new

to same dimension (no comments re' cooling to shrink, tapping, hammering)

Aware this's useless for you, posted in case your 31 had such kooky matters to watch for......