Is it safe?

I would like to drain the old oil from my super a and replace it w/ diesel fuel to just crank it over a few times and try to clean it up some. Any opinions?

what i do is i will pour diesel through it but not crank it over. i dont want to get diesel in the oil gallerys and brgs.due to the fact of improper lubrication. after thats drained out i put in some cheap oil or something thats been sitting around. then run it for an hr. or so and drain that out. then change oil filter and put in the good oil.

I'd say rustred has a much safer plan there, but I have done what you're talking about [have done, not necessarily recommending! ] - actually a bit crazier yet:

left the spark plugs out and drug it 100ft accross the yard really slow while in high gear to get just enough RPM for to circulate the mixture (some ratio of diesel and oil). It didn't blow up, but maybe I got lucky! After that, you definitely want to do the same with some cheap oil and drain that right away too so you don't leave the bearings dry. That was one I'd broke loose after soaking in diesel and still had diesel all the way through the manifold and cylinders too.

What is yet un-noted though - did this have non-detergent? I've always been of the opinion [though no proof] that if you haven't run detergent oil before - then clean it up or switch to detergent - things can get loose and/or leaky.

Never tried it, but [after seeing a bunch of ATF uses around here] I have to wonder if you're going modern oil to modern oil, if ATF wouldn't be a good rinse? If so, I'd still flush that with some cheap motor oil too though, before putting in good stuff changing the filter and starting the tractor.

The crud is in the oil pan, valve train, and inside the block. You can remove the pan, valve cover and head and clean those up, plus the carbon stuck to the pistons. What you want to do will do little if any good, and may even loosen stuff up enough to cause real problems.

Change oil and filter using cheap oil and mix in a bottle of seafoam or anytype of engine flush fluid. Run the engine and get her nice and warm (maybe 30 min to an hour run time). Always monitor your oil pressure during this time. I then drain the oil while it's hot and drop the pan, cleaning the oil pump pickup screen and pan real good. Reinstall pan, another cheap oil/filter along with seafoam or engine flush change, run another hour. Dump oil while hot and replace oil and filter with the good stuff. You can also run a quart of ATF Fluid instead of seafoam or engine flush fluid with your oil to help clean things out. It should be noted if you already have sludge in the bottom of your oil pan dump the pan and clean it good before you start the listed procedure.

You do just as much damage to the engine dragging it across the yard with no oil in it as you do running it with no oil in it. The parts are still spinning without lubrication.

Prove it. Get two old Briggs engines and dump the oil. Spin one with an electric compressor motor, and run the other at full throttle. They'll both sieze at about the same time.

Back in the 70's I worked on drilling rigs. We mostly had 4 to 6 Detroit Diesels (8V74 up to 12V92TA) but sometimes Caterpiller motors. It was standard procedure during oil changes to fill the crankcase up with diesel and run the motor for a few seconds, then drain and fill with motor oil. Those motors were run hard, probably about 20+ hours per day on average. Some days they ran full throttle all day except for being idled back a few minutes every hour or so when we made a pipe connection, and a brief shut-down to check the oil level every 12 hours at crew change. With what I know now, I wouldn't do this at all. However, it didn't seem to hurt them.

Couple of things in their favor... Those old Detroit diesels were built like tanks, and diesel fuel back then was actually "oily" and had some lubricating qualities to it.

I'd drain about 2 quarts of oil, and add the diesel and run at idle for 10 minutes.

Gordo

(quoted from post at 08:20:02 10/14/08) I would like to drain the old oil from my super a and replace it w/ diesel fuel to just crank it over a few times and try to clean it up some. Any opinions?

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Run a 50:50 mix of diesel fuel and motor oil, and don't get carried away with the rpms. Run about 20 minutes and drain for a long time.....
mike

Isn't Marvel Mystery Oil cheaper than diesel these days?