VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 1931 Engine Main Bearing Oil Pocket Sludge

The car I'm restoring ('31 Phaeton) came to me as an abandoned incomplete restoration. The engine had been rebuilt (in 1972!) but never started. Just to be sure it's OK, I've pulled all the accesses and learned a few things:
-- Good News: It was in fact bored, crank turned, new pistons and rings, rod bearings tight, nice valve job, crankcase and pan are clean, etc.
-- Bad news: No rocker arm wicks, one rocker arm shaft in upside down, vibration damper damaged, freeze plugs never removed, rear end of water jacket packed with rust as usual. All fixed.
-- Worse news: The oil galleries above the main bearings are about 3/4" deep in sludge. The engine was obviously never boiled out or really deeply cleaned.

I have the engine on an engine stand upside down. Rather than completely disassemble it, I propose to proceed as follows:
-- Wipe galleries as clean as possible with clean lint-free rags and dowels, popsicle sticks, fingers, etc.
-- Spray each gallery heavily with aerosol brake cleaner to wash all the sludge and oil free (and necessarily, into the main part of the crankcase and underside of the pistons.
-- Wipe up all the residue from the brake cleaner operation, reassemble the engine, fill with oil and prelube using an electric drill to turn the oil pump for 15-20 minutes to clear the residue out of the pockets before attempting a start.

Any thoughts?

All the Best, Chip

That seems to be a great plan to me.

Maybe pack rags into the cylinder bores and piston bottoms to catch most of the debris.

Thanks guys!

Chip

Back when I was in high school and working at a filling station (late 40s) I would hear of guys de-sludging their engines by running coal oil in them at idle. I do not recommend that but would think that after you are through hand cleaning, you could put a gallon of kerosene in the crankcase and run the oil pump with a drill as you suggested to purge the main oil passages of residual debris and sludge and then prelube it with oil and drill.

Thanks Mike -- that makes sense. Just have to be sure to get rid of the residual kerosene from the pockets and galleries before refilling with oil. That's doable.

All the Best, Chip

Back in the 50's the old timers ( in my neighborhood) used to mix kerosene with the oil to flush the sludge. Not sure of the mix but I believe it was 50/50 with 10 wt. oil. They would run the engine just until the temp came up then drain and flush once again with 10 wt.

That is a good way to loosen chunks of sludge and plug-up oil lines and sceen.

i'd disassemble the engine then have it cleaned at an auto machine shop. mike

Chip,
I think your plan makes sense. While it may not be 100% effective, it's probably going to be good enough. You'll probably know whether you have any issues if you change the "motor" oil after about 5-10 hours of running.

This is predicated on your comment that the gunk in the galleries is relatively soft and that you proceed the way that you said (cloths, etc) in your first posting. I'd have no trouble doing that. The oil pump filter screen is pretty darn effective in a '31.

I have heard that running the engine for a short time (10 minutes or so) with diesel instead of oil will clean the engine out. Diesel being a light oil without the abrasives there is less risk of damage.
I am generally in a short time frame when oil changing so have not tried it myself.
Tony

I agree Gene IF the engine has been neglected. I think when done on a regular basis (annually) it should not happen. The person I knew that did it was the "greaser" for an Oldsmobile dealership and did his sons car every fall. He used the drain oil to coat the underneath and applied wax to the exterior but did not buff until Spring. His sons car did not rust out like most in northern N.H. and looked great in the Spring after cleaning. It was a black 52 Chevy coupe. The oddest part though is that he never drove or owned a car.