Posted by John W S son of John S [173.245.54.36] on Monday, April 04, 2016 at 13:13:32 :
In Reply to: question about sludge in oil pan posted by junkyardog [108.162.219.180] on Sunday, April 03, 2016 at 14:18:08 :
The flat head engines are inefficient and that is something we can not do much about. This also means a certain amount of sludge will form no matter what we do to stop it.
I do think it is worth while to change all the oil out of the engine. This includes the sludge and junk that forms on the bottom of the pan. It will form again anyway, so why not remove it, and any harmful particulate that may be trapped in it?
Now, lets say I drop the oil pan, clean it, and refill with detergent oil. The sludge layer will begin to build up, just as before. The next time I change my oil there is sludge in the pan. If I do not clean it out somehow, the new junk will mix with the fresh detergent oil. The oil is going to do what it is designed to do, and that is trap particulate and carry it away. The idea is to have the junk caught in the oil filter before it can do any damage. The problem is that the filters on the flat heads only filter a portion of the oil. This leaves the rest to pass through the engine unfiltered.
Knowing how the filtration systems work on the flat heads, I think non-detergent oil is a good choice. Non-detergent oil will still carry the dirt away, but not hold it suspended, allowing any dirt or particles to fall to the bottom of the oil pan. The settling of the dirt acts as another "filter" for the oil. I do not see any real advantage to keeping sludge in the pan. Modifying the drain seems like the answer to removing it, and likely what I will do when I get to the engine for my project.
Just my thoughts and ramblings during lunch,
John S
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