E: Engine Cylinder head valve guide oil drainage

[Cyborg]

I’m working on a pair of cylinder heads of unknown history. One head has channels (on both intake and exhaust) milled into the bottom leading up to the rocker bearing bores as well as material machined away (to form a trench) from the side to encourage oil to flow into the channel. The trench on the intake is on the rearward side of the bore and the trench on the exhaust is on the forward side. The other head, bottom photo only has the machining done to the intake side. They are both front heads. I also have a NOS head that just has the machining done on the intake side. It was done at the factory before the the guide was installed. Does anyone know for sure what the last batch of heads looked like? Did the factory eventually put the drainage on both intake and exhaust? Front head as well as rear?

 

[vibrac]

I often hear about these channels its not something I have ever done in the last 40 years of racing, I don't think I have ever had an early head and I fit lower oil seals I never seem to have suffered any ill effects so forgive my ignorance but what is the advantage?

 

[roy the mechanic]

O K, both are "front" heads. When fitted they will both be at different attitudes, so the drainage will be different front and rear.

 

[oexing]

You grab each cylinder head , hold it in the position like on your engine and see, if the oil in this position has a chance to drain from around the guide towards the pushrod shroud. In case it looks like having to run up the hill you get the Dremel and burr and mill a groove for channelling the oil into the tunnel for draining it safely. No matter what was done at the factory before . . . .

Vic

no oil seal in guide, knife edge chamfer instead, channel left side: