Re: can i turn over a packard motor with diesel instead of oil to clean out oil passages?

Posted by Fish'n Jim On 2015/9/22 14:59:43

Easy way isn't always the best way. The whole concept is suspect. Sounds like you're not rebuilding but fixing some valve train damage in the car and suspect it was caused by lack of lubrication. You want to do something so it doesn't reoccur, but aren't sure what.
First, I would think one would clean before attempting repairs, so you could check for damaged components, not after repair?
Second, a proper "rebuild" would require complete disassembly and have all cleaned, trued, checked, etc.
Third, I'm not up on 40s, so gurus chime in, but I thought these were solid not hydraulic lifters.
Fourth,to do any significant cleaning of the passages would require high pressure and flow and you only have at best the oil pump to do it and it's cranking slowly. Proper type flow won't occur at low (turnover) speed. For that reasons, they make a drill adapter down the distributor, where appropriate, to turn over newly rebuilt motors to get the oil flowing properly.
Fifth, you risk more damage by clogging the oil pump and may not get clean blocked passages anyway, no matter what fluid you use at that speed.
Simple fixes. There's always the old run a wire through the passages or blow out with an air gun, if you can get to them. Or take something like Blaster or WD 40 with a nozzle tube and spray to see if it passes through each one.
What plugs the passages is similar to the sludge that settles out in the pan, a combination of metallic fines from wear and thermally degraded oil and additives or "char". These are discrete sub micron particles that became insoluble in the oil and settle out but can stick together. The diesel fuel may soft the carbon deposits but won't touch the metallics. A diesel injector cleaner may be more appropriate but those rely on a warm, not cold, functioning motor. As old school, I prefer to soak parts in kerosene (or carb cleaner), repeat until fluid comes out clean and then inspect/clean manually. There are chlorinated materials that will easily "degrease" this but are not recommended for what you propose as they'll do too good a job and damage the seal/bearings from lack of lube. Mostly they've gone to hot aqueous type block cleaners, detergents and enzymes, now for environmental reasons as well. So to use that requires further tear down and possibly a drying oven.