The Stovebolt Site Forums The Shop Area Engine Shop Good news.... it runs!

Before pulling the engine from the truck (Chevy 3100) and tearing it down I decided I'd better see if the engine would run. No gas tank, no radiator but plenty of Marvel oil and hand turning to insure all felt smooth. Sure enough, after some special set up on fuel and battery I punched the starter pedal. After some coaxing, it fired up and ran great. So I completed the teardown. The cabs off the frame and the engine is sitting by its lonesome. I'm getting ahead of myself, but the question arose that with this old of an engine what is the best oil to use? My b-i-l, a retired farmer, said he would just use plain 30 weight.

What is your advice on cleaning up the inside of the engine and then what oil would you use? It sat for a long time and the oil is really thick and black.

Thanks for your valued advice.

30 weight is probably fine out there where it's hot all the time.

I prefer 15w-40 or 20w-50 on most of my old "worn in" engines here in Atlanta.

This method is pretty popular on this site and my dad worked at a Howard Johnson's garage in the 1950s/60s that did this type of engine flush.

To clean the engine, add 2qt of diesel fuel to the oil in the crankcase and let the engine idle in the garage at 1500-2000 rpm for 30 minutes.

Don't drive the truck while the diesel fuel is de-gunking your engine.

Drain the oil and diesel mixture out add fresh oil and filter.

I would take the oil pan,side cover and valve cover off to inspect and clean since you will have it out of the truck .if it runs good then maybe worth using and finding another stovebolt to rebuild for a back up .

My dad was a motor mechanic on PT boats during WWIII. He said they drained the oil and filled with kerosene and ran the engine until oil pressure dropped and then shut it down, Then, drain the kerosene and fill with oil. Run for 10 minutes and drain the oil again. Fill once again and run 10 minutes and drain again. Fill once again and run and do the next engine. There were three Packard V12 Marine engines in each boat. Beginning of war each had 1200 HP and 1500 HP at end of war under normal conditions. 1800HP under emergency use. (Over revving) That was the procedure for his squadron in the Mediterranean. I thought this would be interesting to a bunch of gearheads.

From internet:
During World War II, the Packard 4M-2500 V12 engines powering US PT boats required meticulous maintenance, often involving flushing with solvent to remove sludge from the oil pan, followed by specific oiling procedures. The Packard V12 engine system typically required roughly 18 to 20 gallons of oil to fill the entire engine and oil tank system, not merely quarts.
WW2 PT Boat Oil Change Procedure (Packard 4M-2500)
Engineers on PT boats, often using a small portable Romec electric pump, followed these steps to manage the oil system:
San Francisco Maritime National Park Association
San Francisco Maritime National Park Association
Drain the System: Old oil was drained from the engine pan and the external oil tank.
Clean Filters: Gas and oil filters were cleaned periodically.
Flush with Solvent/Kerosene: To clean the "mud" (sludge) out of the oil pan, it was common practice to flush the engine with a cleaning solvent (such as kerosene or specialized cleaner).
Run and Drain Again: The engine would be run briefly to circulate the flushing agent, followed by a second, thorough draining of all tanks and the oil pan to ensure all contaminants were removed.
Refill: The system was refilled with fresh, heavy-duty marine engine oil.
San Francisco Maritime National Park Association
San Francisco Maritime National Park Association
+1
Oil Capacity (Packard V12)
The Packard 4M-2500 engines used a dry-sump oil system, meaning the oil was stored in a separate tank, not just the engine oil pan.
Total System Capacity: While specific figures varied slightly by boat builder (Elco, Higgins), the entire system generally held roughly 18-20 gallons (approx. 72-80 quarts) of oil.
Engine & Tank: The 2500 cubic-inch V12 required high-volume, high-quality oil to manage high loads, with regular checks crucial due to their sensitive nature to poor maintenance.

Otto, I will try your method after I do Kevinski's inspection he mentions doing. 1955 1 Series that is very interesting info you provided.

I thank you all for your valued advice.

Yes, I 'd do the same thing. Looking inside makes sense. Your engine may not be badly gunked up at all.

Before pulling the sheet metal and wasting a lot of time scrubbing, do a power wash first. Fill the crankcase with 30 weight bottom-shelf house brand oil from Walmart or your favorite parts store, add about 3 quarts of kerosene or Diesel fuel, and run the engine for about 20 minutes at a fast idle- - - - -1500 RPM or so. The crankshaft and connecting rods splashing down into the overfilled oil pan will work like the agitator in a washing machine, and do a much better job of dislodging sludge than any amount of brush work. Drain the oil and filter housing while it's still warm.
Jerry

We used to do the kerosene thing at the service station where I worked as a teenager. Note, I said "service station" and not "gas station." I think we actually over-did it

Some more great information. Just printed it off to take out and put into action. Thanks, guys.