stellite valves and seats

Got the little f-head 4 apart. Lookslikethe engine puked because the aluminum casting on the oil pickup tube had a great big hole in it somehow, thus not sucking up any oil. THAT I understand and I can fix. What I DONT understand is my valve train. The head is a different shade of blue paint than the block. This tells me that either one of them {or both} have been worked over at some time.BUT--- How can I tell if I have the hardened valves and seats for unleaded gas or not? Rockwell hardness testing? The valves and seats look real good. I dont think I will do anything except seals. I dont want to take the chance of not being unleaded compatible,tho. Does anyone know how I can tell? thanks in advance. MR. HANEY

 

Re: stellite valvesand seats

The valves are not what is unleaded compatible its the seats in the head or block in your case.The exhaust valve needs to have a hardened valve seat fitted in the block, it looks like a steel ring pressed into the block under the valve. The intakes doesn't matter. My understanding is that all F-heads in jeeps were painted black from the factory so your motor has at least been painted at one point or another.

 

OK that makes sense. How do I tell if they are the hardened ones or not?

 

Standard seats are just machined into the iron of the block. The hardened seats are pressed in, so they will probably be visible around the outer edge of the valve as a slightly different colored metal.