D 397 fuel pump

I'm looking at a D379 (8-cyl) parts book, assuming the 12-cyl is similar and I don't see the usual injection pump drain that should take care of fuel lekage from the injection pumps so that it doesn't wind up in the pump crankcase. Does you pump have that feature?

Hi team,
the D397 is an older style V12 with 5 3/4" bore 8" stroke and Roots Supercharged--its sister engine is the Naturally Aspirated (NA) D376.
In the same family is the V8 D375 Roots s/c, and the D364 NA.
They have self contained oil systems for the injection pumps that are separate to the Vee valley.
Cannot recall if there are fuel gallery plugs in the pump body with O rings that eventually fail and leak into the pump body and contaminate the oil reservoir.
OM is looking at the D379 V8 later series of 6.25" bore engines that have a skeleton type pump housing that is part of the Vee valley cover and does not have a self contained sump--they are part of the engine oil system.

OM is correct that you need to check any fuel leakage drain off lines from both the injection pump, they take away any fuel leaking past the injection pump plungers and barrels and another one for the leakage past the fuel transfer packing's/seals--it is a bit hard to decipher your description of the "oil lift pump" if I recall the two pumps--oil for the fuel pump lube and fuel transfer pump are piggy backed.
I am not sure if the transfer pump is mounted to the injection pump so, if it is and the drain line fuel can enter the injection pump oil via leaking transfer pump packing's which need to be pressed to expand them to seal properly to the shaft with a special tool---see Fuel Transfer Pump Packing Tamping Tools by Advanced Search, at the top right of this page, for explanation of the tooling and usage.

At The Dealer on many standby installations we also found fuel bypassing the plungers and barrels due to the static head pressure of fuel in overhead gravity fed day tanks, which we recommended should not be used for standby engines, are OK for engines in daily use--if the housing drain line is blocked fuel can get into the injection pump oil sump.

I searched earlier and could not find any literature on this family of engines in my collection--except sales brochures, and it is too long since I saw one of these to recall any more about them.
Hope this helps.
Cheers,
Eddie B.

[quote="edb"]Hi team,
the D397 is an older style V12 with 5 3/4" bore 8" stroke and Roots Supercharged--its sister engine is the Naturally Aspirated (NA) D376.
In the same family is the V8 D375 Roots s/c, and the D364 NA.
They have self contained oil systems for the injection pumps that are separate to the Vee valley.
Cannot recall if there are fuel gallery plugs in the pump body with O rings that eventually fail and leak into the pump body and contaminate the oil reservoir.
OM is looking at the D379 V8 later series of 6.25" bore engines that have a skeleton type pump housing that is part of the Vee valley cover and does not have a self contained sump--they are part of the engine oil system.

OM is correct that you need to check any fuel leakage drain off lines from both the injection pump, they take away any fuel leaking past the injection pump plungers and barrels and another one for the leakage past the fuel transfer packing's/seals--it is a bit hard to decipher your description of the "oil lift pump" if I recall the two pumps--oil for the fuel pump lube and fuel transfer pump are piggy backed.
I am not sure if the transfer pump is mounted to the injection pump so, if it is and the drain line fuel can enter the injection pump oil via leaking transfer pump packing's which need to be pressed to expand them to seal properly to the shaft with a special tool---see Fuel Transfer Pump Packing Tamping Tools by Advanced Search, at the top right of this page, for explanation of the tooling and usage.

At The Dealer on many standby installations we also found fuel bypassing the plungers and barrels due to the static head pressure of fuel in day tanks which we recommend should not be used for standby engines, are OK for engines in daily use--if the housing drain line is blocked fuel can get into the injection pump oil sump.

I searched earlier and could not find any literature on this family of engines in my collection--except sales brochures, and it is too long since I saw one of these to recall any more about them.
Hope this helps.
Cheers,
Eddie B.[/quote]

you are correct,the lift pump piggybacks the oil pump.and there is a plug in each end of the housing at the fuel cavity.there are no drain lines, any fuel internal leakage will eventually run to the sump. The shaft seal between the oil and fuel pumps is supposed to leak at a weep hole between the two.I am going to do some further testing as our dealer does not have the tool to time the pump after replacement.Its good to find some folks who are familiar with this engine,I thought I was alone! Thanks, Bill

I didn't see mention of replacing the injection pump fuel gallery seal/s (O-ring). These can be a problem with other engines, depending on where the leakage migrates.

I didn't see mention of replacing the injection pump fuel gallery seal/s (O-ring). These can be a problem with other engines, depending on where the leakage migrates.

the unit will be locked out of svc. tomorrow.I have plans of doing further diagnostics based on the info I have been given here.I will be sure to update you all on my progress. Thanks

Well closer inspection revealed drain holes in the pump housing to remove any fuel leakage before reaching the sump. That left the transfer pump so i removed it and pressurized the fuel pump half- no bubbles at the oil ports. I am going to put dye in the fuel next week and will let everyone know so maybe the next guy will have more hair left than me after this issue!

I know this is not the same pump but I'm pretty shure yours is a similar configuration.

My money is on that 5F7054 seal as your leak source.

Also that L-2288 plug would be a good candidate to check.

Well old magnet,your money is good the 2288 plug at the governor end had a bad seal. Of course it was necessary to remove the pump housing wich was my last resort but some times we have to do what we dont want. Our local cat dealer has the tool for the timing so we will bring him out for a check. Thanks to all for the help you have been a great resource.