4bt cunnins

[minn firewood cutter]

i have a 85 230A timberjack with a 4bt cummins. Problem is fuel is getting in engine oil. injector pump is rebuilt injectors are rebuilt and the fuel transfer pump is new. Any ideas/ Thanks

[moodnacreek]

Had a C series do this due to dirty injectors from burning dirty fuel. I know you said your injectors are rebuilt but things can happen. In checking the temperature of each exhaust port [ the manifold] you find really hot one, that cylinder may be getting too much fuel and it will get by the rings. Should this be the case try burning sea foam by putting it in the filters.

[kiko]

Sounds like you have covered the three places the fuel and oil cross.  I would venture to say it is the shaft seal on the pump.  If the return fuel line is blocked it would push that seal out. It may have a hydraulic pump below the injection pump or just a cover if not. Remove pump or plate and pressurise the fuel supply with supply pump and if the seal is out you can see the fuel running down.  I try to never assume a new part is good.

[charles mann]

could also be an o ring on an injector or the as said, end seal of the injector pump. may even have a cracked injector housing

[mike_belben]

Doesnt that have a cam driven plunger to pump the transfer pump? If it had a bad seal it'd dump into crankcase too i think..  ?

[logging pete]

the cam driven pump has a weep hole in the bottom, if it is not plugged it will be an oily mess on the block if the diaphragm is shot. Common enough to carry a spare pump.

[mike_belben]

Well..  I guess id pull the return line banjo bolt and verify that the overflow valve ("ofv" on most dodge forums) hasnt rusted shut.  If it has the galley pressure would want out.. Into the crankcase.