The Stovebolt Site Forums The Shop Area Engine Shop 250 IL 6 is it broken in yet?

New rebuilt motor. I had the old head serviced & now have 500 miles on it. I used the 30 wt break in oil & just changed it & filter.
It has been using a little oil as well as shoots some smoke when I first crank it or rev it up.
Maybe the rings are not seated? Maybe the head was not serviced correctly?
Is there anything I can do to to ID a problem or just drive it some more?
Thanks

Can you define what "using a little oil" means? How much is a little?

Yes, 500 hundred miles & used maybe 2 or 3 quarts.

Define "break in". Perfect Circle piston ring company used to recommend 10 full throttle accelerations from 30 to 50 MPH in high gear to seat the rings, but that assumes a proper cylinder prep and assembly was done. Most oil use after a rebuild can be traced to improper cylinder prep- - - -excessive taper, glazed cylinder walls, and/or incorrect honing or cleanup of the cylinders during block prep. Using 30 weight (maybe "non detergent") oil for "break-in" went out of favor at least 50 years ago. There are at least a dozen ways to mess up a "rebuild" with improper assembly, block prep, or other errors. Loose intake valve guides are usually the cause of a smoky startup- - - -oil drains down the valve stems and puddles on the back of the valves overnight, then it gets burned the next time the engine is started.
Jerry

I bought the motor rebuilt with a head on it. I replaced that head with the one I had in the old motor. I had it serviced at a machine shop local.

I used 30 wt break in oil with zinc. No zinc now after oil change. I don’t want to pull the head just to have it checked.
So you suggest doing the wind out thing first? It has a low rear end so I use a tachometer more so than the speedometer. Rarely drive over 50 mph or 3500 rpm.

It smokes when I rev the motor initially too so I don’t know if that relates to valve guides?

Do like Jerry said. Get it up to temp, get it out on a safe road. Give it several wide open throttle accels as Jerry stated, I was taught to do full closed throttle decels as well.

Is this a typo? Because *one* quart in 500 miles is a whole lot.

2-3 quarts in that timeframe is actively failing engine range.

It sounds like your "rebuild" was done with a couple of rattle cans of cheap paint. Was the seller's name P.T. Barnum?
Jerry

Glenn said, "So you suggest doing the wind out thing first?"

For the record, Jerry wasn't suggesting a lot of rpm, you want to be in high gear (whatever that is, 3 or 4th or 5th) doing 30 mph, put the accelerator on the floor, let off when you're going 50 mph, let it coast down to 30 and repeat. I've done almost the same or 50 years, it works even with chrome rings and a hand scuff on the cylinders. My variation is to do 30 to 40 a couple times, then 30 to 50, last 30 to 60. When accelerating the rings are loaded and creating heat and friction with the cylinders, wearing in. When decelerating (no brakes) engine compression working to slow you back to 30 mph, oil is cooling the pistons/rings.

Good Luck,

RonR