Z500 fuel in oil

[Micah1]

I just finished replacing a piston, bearings and oil pump. (replaced piston due to blowby caused by a crack between ring lands) I have filled the engine with oil to the correct level. After running for 30-45 minutes the oil level has increased and is thinner causing oil pressure to drop. This may have been what caused the piston/bearing failure. I changed the oil and filled to the correct level and it happened again. Has anyone else had this issue? I'm thinking maybe a gasket or O-ring inside the injection pump is leaking fuel into the oil. Outside of that it seems to run great. No smoke. I loosened the injector lines while it was running and both cylinders seem to balance out.
Thanks

 

[North Idaho Wolfman]

Yes you need the injection pump rebuilt, you also might want to check the lift pump, rarely they will leak fuel into the engine.

 

[Micah1]

Is there a rebuild kit available or do I have to take to a diesel shop?

 

[Mudball]

Is there a rebuild kit available or do I have to take to a diesel shop?

I believe there is a rebuild kit available for most however considering the tools and tight tolerances I needed to follow I took mine to a diesel engine shop.
The new rebuild stopped my fuel from getting into oil and havent had any trouble since. (knock on wood)
Im not sure if your injector pump is like mine but you might already know to take extra care of the spacer shims under the pump when/if you remove it.
Document letters and numbers on the pump.
Im not saying that your not capable of rebuilding the pump but if I remember correctly it can be quite a pain.
Sorry not much help for now.
Good luck.

 

[Micah1]

Thanks North Idaho Wolfman and Mudball. There are several diesel injection shops in Charlotte, NC where I work. I'll check with them on rebuilding it.

 

[Micah1]

I got the pump back today from the shop. Also had the injectors serviced too. It runs like a top now. I run it hard for a good 20 minutes and there is no sign of fuel in the oil. However there is an oil leak at the injection pump now. Do you use sealer between the shims? I wasn't sure because the shims affect the timing I was thinking sealer would add to the thickness of the shims. The manual I have doesn't specify.

 

[North Idaho Wolfman]

Try snugging the pump down and give it a little time to seat.
If it doesn't, you're, right using sealer will mess with the timing, you can pull the shims and put a very light coat of spray paint on them to get them to seal.

 

[Micah1]

Thanks Wolfman. I'll give that a shot.