Took the cylinder head to work today for a cleanup in the sandblaster and a valve bowl porting job. Using a 1-5/32" drill bit, the cast obstructions in the valve bowl, around the valve seats and cast value guides were bored out down to the valve stem contact area.The cast was "soft" and easy to cut.
I didn't allow enough for deflection of the drill bit and dinged the valve seats a little. The seats were borderline low anyways after a couple of valve jobs. Cutting and installing hardened seats should do the trick.
I though the coolant passages were bunged "some" with calcium,lime and Barrs Leak. The amount of crud was unreal.The engine had been running air cooled rather than water cooled. The fool Amish that had it used it to run cow milking machines for 20-30 minutes twice a day. The engine must have been smoking hot by the time the milking was completed..He must have added cooling water from the cattle water trough plus something nasty to attempt sealing of the coolant seepage from under the head gasket.
Several passages were completely blocked. I've sand blasted and chiseled all I can reach. I guess a soaking in muratic acid is next, too bad those new bronze valve guides are going to get dissolved. The engine shop that had "boiled" the head and installed the bronze liners.Didn't remove the welch plugs from the sides of the head. The exhaust side coolant passage was 100% plugged.
The sand blaster was also pointed down the ports for several minutes from the manifold side. Surprising how much the ports were cleaned,smoothed and fresh cut edges rounded off.
The edges should be blended with a dremel tool around the valve bowls.
I had hoped there would have been some spot to drill and add a weenie little N8 sized glow plug but there is no obvious place in the cylinder head.
The head will have to be planned on the combustion chamber side and the intake,exhaust and coolant port surface.The areas previously exposed to the "coolant" are pitted.
The head pretty much matched the cobbled up combination of parts the fuel system consisted of. Looks like the bottom end will have to come apart for inspection too. Who knows what they may have tinkered together in there.