Thread: Breaking Motor In..

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I have only 768 miles on her.. should she still be burning oil?

She's not smoking like last time.. so.. When does the motor usually quit burning?

ya ,give it about 2500 miles.The motor is not yet brokin in.

How do you know its burning oil? Low level,smoke,what?

Low level from time to time. I check it alot. This is my second time to build this motor. The knucklehead that helped work on it put the piston ring gaps in wrong.. so it burned oil. I had to rebuild it and.. I'm stuck in the habit of checking.

Originally Posted by Crowbie

I have only 768 miles on her.. should she still be burning oil?

She's not smoking like last time.. so.. When does the motor usually quit burning?

Did you replace the valve guides,or valve stem seals?
What finish is on the cylinder walls?
What type of rings were installed?

That reminds me ,I could not figure out why I kept burning oil in a engine I had.I pulled the intake a few times ,and check everything else I could think of,except valve stem seals.I used the ones that came in a cam kit.None of them were sealing correctly Just a thought ,might want to check.

Piston ring gaps have minimal effect on oil consumption.

The time to break-in depends on the type of rings used and the type of hone performed. Moly rings take only a few hours to break in. Ductile iron rings should be broken in by the 1000 mile mark. Chrome rings take significantly longer.

I bet you have installed a ring or two.

yup, too many variables on assembly techniques and build procedures to have a hard and fast rule on break in time. Saw a block the other day that was honed with a computer controlled power stroke hone.... looks like the rings will be seated about the same time the cam break in is over.... unbelievably finish on the cylinders!!!!! And I thought the powerstroke hones did a nice job!!!!

Well we took the motor apart.
Pistons came out, new rings, new bearings, new guides, and new seals.

We honed it by hand with a powerdrill and the honing beads and kerosene.
This was done in a machine shop.
Thats about as much as I had a hand in.

The shop guys did the rest, they put the bearings, rings, and pistons.. and the put the entire motor together.

The rings.. I don't know what they are, the machinist chose them.
He said he bought better than stock rings. But they're not something mega-expensive. Just a little bit above OEM standards.

Then they might not seat til around 1000 miles. Do I read your post right, original old pistons went back in, engine wasn't bored?

We bored it a year ago.
Pistons are a year old as well.

Vatted everything.

I'd say give it a thousand miles. If you're concerned or the oil use is excessive, you could do a leak down check on the engine.