I started another thread
about my rebuild of a B&S opposed twin horizontal engine (model 422437), but wanted to start this new thread because I'm now on a second 422437 engine and wanted to separate out the two.
History: acquired a free 917 CM 18HP GT that died in the field on the PO. The tractor is in great shape and I was hoping for a simple fix. No luck on that as the engine (Engine #1) had thrown a piston rod and the shrapnel took out the casted valve guide. Pulled it apart and scrapped the block, so I now have lots of parts. Enter Engine #2, also a B&S 422437, I pulled off a junked GT but that tested out with 75/90 compression.
Engine #2 Rebuild: Got the second engine running with some fresh oil and starter fluid, ran it a bit to wake it up (been sitting for two years) and then tested compression on cooled engine at 95/115. Pulled the heads to inspect valve seats and cylinder, with mixed results. Not much carbon, but one cylinder wall is pretty pitted, but the other side is clean. I've not gotten to the valve seats yet, but on first inspection they look decent, though one valve stem is also pitted. I'm probably looking at doing the valves and re-ringing this engine.
1) Considering the pitting in the one cylinder, is a rebuild worth the time and money? I'm guessing it's going to require a bore job, meaning new pistons and more $$. Possible to do just a hone and ring job? I know, I should probably spec the cylinders, but I don't have that tool.
Have a machine shop do the boreing, $70-100
2) Engine 1 had a tri-circuit strator with a single lead and 10A AC that gets split into 5A DC- for lights and 5A DC+ for charging, but engine 2 has a dual circuit strator with two leads with 5A AC for lights and 3A DC for charging. What is the best way to proceed?
Swap the stator for the correct one to use on the machine that the engine is going in.
3) Can I use the valves from engine 1 for the valve job in engine 2. I still need to spec the valves and seats, but it would be good to know how interchangeable the valves are. I know one valve stem on engine 2 is pretty worn. I'd obviously reseat the valves, regardless of where they came from.
NO, these valves can only be adjusted by grinding the valve stems. You need to mark them as to which cylander they came out of.
Thanks for any guidance.