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Black oil??? on rebuild

673 Views 4 Replies 5 Participants Last post by  camachinist
When I first changed the oil in the 429 after 180 miles the oil was black. then I changed it at 350 miles still black. I figure I could leave this oil in for about 2000 miles. it is not as black when I check it but it still looks black. My oil usage has gone down. but it went through a quart the last 400 miles. When I first changed the oil I went to synthetic. Then read that was not real good to do yet so I changed it at 750 miles.
Is it normal to have such black oil after such a short time?????
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I did. When I rebuilt the Cleveland (new rings and bearings with a hone on the cylinders), I had black oil for awhile. I have about 3k on the rebuild, and I have changed the oil 7 or 8 times. It is finally beginning to clear up. I had to pull the pan for gasket leak, so that probably helped me.
Maybe the snythetic oil is cleaning everything out? I don't know, I use regular oil. But it sounds good /forums/images/icons/smile.gif
Until everything will have some blow well, as use a little oil..should clear up with time
New engine? Goes through a quart in 400 miles?

Talk to whoever built it...something isn't right here...

My personal opinion is to not run synthetic oil in a new engine but hey, I'm an OF..*G* If you have a conversation with the engine builder, you might wish to omit this part, since they might use it against you...but that's a judgement call.

The oil gets black, when an engine is new, because of the assembly lubes getting swept into the pan, along with some contamination until the rings seat. With modern rings and honing techniques, this should happen mostly within the first few hours of use.
Incidently, the oil in my diesels gets black almost immediately after changing....the engines still go their normal 3-5 K (or 50-75 hours) between changes with exemplary service life and consumption rates. Modern oils do a pretty good job of cleaning and suspending I don't go by color too much any more. There are test kits out there for testing what's in the oil (a lot of diesel truck/equip. guys use them, I've read)

Run a warm leakdown test and share the results....leakdowns on a well-built engine, when new, should be under 5%...Personally, my racing engines stabilize in the 1.5-2% range after about an hour or two of use, but that's with gapless rings and precise honing techniques, with torque plates and warm water circulation.

Lastly, how does the engine run? How do the spark plugs look?
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