2001 gtx 787 RFI Top end rebuild

[wlong1957]

I split the case and there was tons of brass and aluminum filings there. I assume a piece of the pto piston broke off and got in there to destroy the rotary valve gear. I ended up vacuuming out the upper and lower halves. Rinsed with gasoline. And put it back together.

I'll reinstall next weekend. Hopefully it will fire right up

 

[etemplet]

Hmmmm.... I don't think the piston can get into the chamber. On the one I repaired the gear failure was a lubrication issue. Good luck with it !!

 

[etemplet]

This SOB kicked my butt for a lot o hours. This is the RFI running with a destroyed brass gear on the rotary valve. It definitely teased me and confused me as it would run like this. Now I know a WHOLE LOT about Sneaky Rotary Valves. LOL Don't judge me.... after I opened up the Rotary Valve and reset the timing in the dark I spent a lot of time trying to diagnose this problem. Live and learn.

RFI ROTARY VALVE PROBLEMS - VIDEO

 

[wlong1957]

So yours was running like that with a bad .rotary valve gear? At least mine would just sputter and die. But it wore me out as well. The only thing I can think of causing the brass gear failing is perhaps If not a piece of piston then it may have been from one the the sleeves that cracked.

I have the engine all back together. I am planning on reinstalling this weekend. Hopefully it will run.

 

[etemplet]

That was about the 15th time I tried to start it and one of the few times it kept running. If ever your engine blows oil back through the intake that's a good place to start. LOL

 

[burtshaver2021]

Don’t forget to clean out the oil tank and lines well before firing it back up, there could be brass shavings in there

 

[etemplet]

Don’t forget to clean out the oil tank and lines well before firing it back up, there could be brass shavings in there

Yep, there WILL BE shavings in there.

 

[wlong1957]

Thanks for the heads up. I hadn't considered that. I'll drain the tank and clean out the lines before I reinstall.

Also you got me wondering about how I thought that a piece of piston could have gotten inside. I went back and looked at the old cylinder sleeve on the PTO side that lost compression. It looks like a piece of the skirt on the sleeve chipped off. Perhaps that caused the whole failure.

 

[etemplet]

Nothing can get inside the rotary gear reservoir. It is sealed from the rest of the engine.