Is this a bad idea?
 

Do you think it would be ok to pour a pint of gasolene down the oil fill tube on an 8BA engine after your drain the oil (and before you reinstall the drain plug) so that the gas would help remove sludge that may be in the engine or oil pan?
Then refill with fresh oil.

Here's another idea. Weld a larger nut to your drain plug and label it so it's easy to see what size wrench is needed and easier to remove.

Of course you don't do this on AACA restorations.

Re: Is this a bad idea?
 

I think it would be safer to use Varsol (mineral spirits) as this is not as combustable as gasoline. Even though you are leaving the drain plug out some fuel will likely accumulate in pockets in the engine and any combustion blow-by that could get past the piston rings could ignite that residual fuel and send your engine to the moon!

Re: Is this a bad idea?
 

People usually underestimate the power of exploding gas, use something else. You would probably be better off just leaving the sludge firmly attached to wherever it is until the next time you pull the pan.

Charlie Stephens

Re: Is this a bad idea?
 

THANKS. My gut feeling is that leaving it alone is the most prudent advice. Sometimes what seem like good ideas can literally backfire. I didn't do it.

Re: Is this a bad idea?
 

Trying to use a solvent, gas or other, with the engine in the car is not a good idea. If any of the sludge is dissolved, it will be circulated in the system where it can cause bearing damage. When you remove the intake manifold on an old Ford that has not been apart for a long time, often years, you will find the valve chamber full of "black Jello" sludge to give you an idea of what the rest of the engine looks like. Best to leave the sludge in place until overhaul time.

Re: Is this a bad idea?
 

I doubt you'd find much if any sludge with modern oils anyway unless it's never been apart. Jack E/NJ

Re: Is this a bad idea?
 

“To the moon Alice!

I have used diesel fuel in the past. But you’ll end up changing your oil twice to get rid of the residue.

Re: Is this a bad idea?
 

I agree with leaving it alone. But if you're going to do it, I'd use something like this (there are several brands):


https://i5.walmartimages.com/asr/26a...0&odnBg=ffffff

Re: Is this a bad idea?
 

Don't put anything combustible in the oil. It may ignite. Just drain the oil. Add Marvel Mystery Oil in the oil. Change you oil often. If you have already cleaned out your oil pan when you first obtained your car. Or if you are worried about sediment actually drop the pan and clean it out if you suspect it could really bad. At my first cleaning of My 1933 engine pan I found a 1 inch layer on the bottom of what had the consistency of sand. No solvent would have dissolved that.

Re: Is this a bad idea?
 

First, never use gas for flushing engine or cleaning parts, - ever. A friend set his house on fire cleaning his lawn mower carb in the garage, using gasoline.

Second, an engine with really bad sludge should be pulled apart to clean. Attempting to flush such an engine may cause more harm than good by loosening crud on surfaces that then blocks the screen on the oil pickup, or oil passages.

Third, an engine cleaner flush is helpful to keep things from building up if used early and often, like every 10,000 miles. I use Kerosene. Cheap and effective. Drain the oil down to make room for two quarts of Kerosene in the crankcase. Run the engine at idle until it gets up to normal temp and then for another 5 minutes or so. Let it sit for half an hour and then drain the crank case. Unlike diesel fuel, Kerosene is sufficiently volatile to evaporate remnants out of the fresh oil. After the oil change, run the engine at idle for 15 minutes to drive out the Kerosene.

Third, if you use a good grade of high detergent oil, you will never get significant build up of sludge in the first place.

This u-Tube describes the flush with Kerosene process.

https://www.bing.com/videos/search?q...0798&FORM=VIRE

Re: Is this a bad idea?
 

Once your pan is cleaned, Use Marvel Mystery Oil and change the oil often and you will have minimal sludge.

Re: Is this a bad idea?
 

Thank you all for the helpful info.

Re: Is this a bad idea?
 

Is idea 1 bad? YES. Don't wake the sleeping sludge beast. Teardown. Your idea just sends the sludge on a round-trip through your bearings and galleries.

No problem with idea 2 at AACA. Those judges can't look in that area. V-8 Club judges will be able to look, but really, just one point for that excellent maintenance shortcut!

If you mess with the drain plug I'd try to make it magnetic.

Re: Is this a bad idea?
 

I like the term sleeping sludge. I have an original 1933 old engine and use non detergent oil, because I was worried that if my engine gets too clean, it may start leaking from places where 85 years of particles have sealed cracks and gaskets. If I even rebuild the engine, then I would start using detergent oil.
I remember the tale of a guy that used an extra efficient detergent oil on an old engine and the engine quit. He removed the pan and it was full of large black Doritos looking debris. He had to trash the engine?

Re: Is this a bad idea?
 

Didn't Ford actually recommend adding a pint of kerosene to the crankcase during cold weather operation?

Re: Is this a bad idea?
 

As a common practice, I used to wash out my Y-block with kerosene whenever I changed oil. My dad used to do it on his old Fords. Never hurt anything. Might not have helped either, but I did it for years.

Re: Is this a bad idea?
 

Always change the oil while the engine is at operating temperature ,this will help remove suspended sludge ,never flush an engine with a large quantity of sludge build up, as stated above the crud will plug up the oiling system and burn up the engine. seen it happen.

Re: Is this a bad idea?
 

Some of the old round motored aircraft had a fuel dilution system for winter starting. The very different thing about them is that they are dry sump engines so the fuel is added in a special compartment around the oil pickup in the oil tank. It diluted the oil enough that the engine would get lubrication while starting and warming up. It only pumped a small stream of fuel in there for a minute or so. The fuel will evaporate out after about 20-minutes of operation in the air. The oil tanks can hold anywhere from 5 to 30 gallons depending on the size of the engine.

A car engine has a wet sump and it doesn't fly real well to draw out the fumes from the engine draft tube like an airplane does. A PCV system might do it though.

Re: Is this a bad idea?
 

Drop the pan and clean the sludge. Contrary to the expert opinions gasoline shouldn't be used for anything but driving. Wash parts with something like diesel. It won't catch on fire and explode. I learned this the hard way. Decided to use gasoline for charcoal lighter once. Put the glass jar down and then lite the charcoal. Low and behold the gasoline vapor also caught fire and found it's way to the jar of gasoline about 10 feet away. Gasoline is dangerous. The kerosene treatment is not necessary for today's oil. If you used detergent oil and stay away from non detergent oil you won't get any sludge in the motor. IMHO a kerosene engine flush is a bad idea you would be reducing the motor oils ability to lubricate.

Re: Is this a bad idea?
 

NEVER use gasoline for cleaning anything !!! I have a deceased friend who would tell you the same IF HE COULD... Jim Langley...