@jamesinc & @Samman88 - JFYI for completeness, here are Richard's other two pages on the head.
Note the combustion chamber work.
Note the combustion chamber work.
530/531 head porting and polishing
My machinist cuts the seats and throats the port at the same time.jamesinc;c-147265 wroteAlso wondering what the correct order of operations should be. I would think, because there's risk of damaging the valve seats, the best thing would be to port the head first, then have it machined for the larger valves.
I can't see an immediate gain from touching the short side radius, but a flow bench would be the only real way to say, yes to leaving the split around the guide on the 531, fuel flow is as important as air.
The short side radius is an area to concentrate on as the casting is very rough and uneven.
A 531 doesn’t need much porting inside the ports other than a thorough clean up and smooth transitions. The regular 530 has smooth ports but so basic compared to 531.
The combustion chamber can be improved. What I noticed is the hardened valve inserts can sit proud of the chamber so levelling these is a task worth doing.
James, I can loan you the equipment required (includes a tall glass burettte with fine ) to CC the combustion chambers. Would prefer to give a lesson on setup use and bleeding air out of chamber etc.
With alloy heads, when you find one, you really need to take it to a head shop to test the alloy is hard enough. A soft head in the middle from overheating is a no go even though it might look right. It just won’t torque up right and keep stable against the head gasket etc.
A 531 doesn’t need much porting inside the ports other than a thorough clean up and smooth transitions. The regular 530 has smooth ports but so basic compared to 531.
The combustion chamber can be improved. What I noticed is the hardened valve inserts can sit proud of the chamber so levelling these is a task worth doing.
James, I can loan you the equipment required (includes a tall glass burettte with fine ) to CC the combustion chambers. Would prefer to give a lesson on setup use and bleeding air out of chamber etc.
With alloy heads, when you find one, you really need to take it to a head shop to test the alloy is hard enough. A soft head in the middle from overheating is a no go even though it might look right. It just won’t torque up right and keep stable against the head gasket etc.