Reply to Old Magnet:
This is the stuff you need.....also need to get yourself some manuals😊 😊
R4Pat - Here's the specs on every valve seat for nearly every Cat built up until March 1953.
Also listed is the dimensions and P/No's of the valve seat inserts for Cat engines. The D2 5U is fitted with the D311 engine.
Valve seat specs - Page 1 ..
http://img144.imageshack.us/img144/6356/valveseats1gv5.jpg
Valve seat specs - Page 2 ..
http://img144.imageshack.us/img144/5364/valveseats2gh7.jpg
Valve seat inserts ..
http://img144.imageshack.us/img144/3368/valveseatinsertses6.jpg
Valve seats and valve faces are usually cut with around 3/4 to 1 degree "interference" fit, to ensure a well-defined contact point at the interface of the valve and seat.
You can also cut seats with multiple angle faces (typically 15°, 45° and 75°ðŸ˜‰ to assist in gas flow. This is usually used when gas flows are high, as in racing engines, and is not so commonly used in Cat engines.
Some of the racing people cut up to 8 face angles to improve gas flow. You can improve gas flow substantially, even in a low performance engine, by ensuring you don't leave a sharp edge at the edge of the seat cut.
You'll need carbide cutters or stones for Cat seats, they are Stellite, and can't be cut with the old-style cutters that are used on cast iron seats. Some cutters will cut three angles at once. The seat depth is critical. The seats must be cut back until all seat imperfections are removed, and clean, original metal shows clearly.
The seat contact area is checked with machinists dye, to ensure a perfect seal. The seat contact point is also critical, and must be neither too high, nor too low.
Mike Mahler should be able to add more info here .. or you can do a Google search using "valve seat cutting" or "reconditioning valve seats", to glean further information. You may also wish to pick up an engine reconditioning book that has useful valve seat reconditioning advice in it. Remember to check every specification, and every moving, wearing surface, to get best results. Regards, Ron.