Thread: break in on a rebuilt

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The engine rebuilder used break in oil in my fe390 short block. I have put 143 miles on the engine so far. How many more miles do I need to put on it before I change it for valvoline 10-30. Thanks Larry

at least 500 miles.

thats for your reply hotrodstud. Larry

Two schools of thought on that subject. Some (like me) feel you should drain it right after the initial cam break in run. Others feel it is ok to go some longer period of time, like 500 miles, whatever. I don't know if one answer is better, and even the boat engine makers say the first oil change should come at 20 hours use. (that is the industry I worked in so it is my point of reference)

My thinking is that from the rebuild lots of metal shavings are floating around in the oil and the sooner you can get them out the better. I guess the oil filter should catch most of them, but I worry anyway. My philosophy has always been "oil is the cheapest thing you will ever put in your engine, so change it a lot."

Like I said, this might be overkill, but it can't hurt.

Don

I'm in the latter group. When we run them on the dyno we usually toss the initial oil fill before shipping the engine. I refill with the same break-in type oil - just clean. You need cylinder pressure to break in the rings - don't be afraid to hit the throttle a few times

should I change the oil to the break in again and a new filter again I have about 175 miles on it now. Thank you. Larry Don

I would change to whatever oil you plan on running normally, but add something like Comp Cams break in lube to it for the next few changes, especially if you are running a flat tappet cam.

I have heard that engines like to have the same oil used over their lifetime, although I don't know if that is fact or myth.

Don

Break it in the same as you plan on driving it. To me that means, leaving some nice burnouts out of the garage! haha. As for oil, was the motor dynoed? if so, then it would have been broken in there and should not need further break in.

There is something to that philosophy of breaking it in like you intend on driving it. I knew a kid whose Dad owned a Pontiac dealership. Every other year he got a brand new car of his choice. One year a 63 Grand Prix 421 tripower, two years later a 65 GTO tripower (that was actually a 421, not a 389) Anyway, he was out racing the night he picked them up and always had the fastest car around, and attributed it to breaking them in hard.

Don

Funny you should have a story like that Don and I don't want to highjack this thread but I have experienced that sort of thing personally. I once worked for the Fiat, Lancia, Lada motor Vehicle dealer in one of our fair cities and with the elderly car groomer we were sent up to Dunedin to take delivery of two brand new top of the line Fiats. Now I can't remember how many miles between the two cities but it used to take 3 to 3.5 hours drive at about 60 mph. Well to cut a long story short, we, the groomer and I, left Dunedin together but once I got on the motorway (freeway) I put the the go pedal down and ran that baby in at an average of 130kmph (80+ mph) all the way home. That same car was sold to a manager of the local Freezing Company who also drove it hard. The car that the groomer drove sedately was on sold to a retired farmer that drove it conservatively and had all types of trouble mechanically where as the one I drove purred throughout it's life. Something that has always stayed in my mind.

Drive it like you stole it from the gitgo. If it breaks, you didn't put it together properly. Agree with Don, oil is cheap. Change it at every opportunity.

Watched a story on discovery about Audi A8?(their HiPo car) the engine after cam break in was run at 5-6000RPM contiuously for like 10 minutes and then up to redline and back to 6000 RPM for another two minutes. Everyone of the motors is run like this then put in the car with fresh oil.

Was a story that Holden in Australia ran all V8 motors on the dyno for 2 minutes at 4 to 5500 RPM to test the motor before putting into the cars.

I have driven all my cars hard from new after proper warm up never had any issues, even when the LS1's (chevy) were first introduced in Holdens in Aus, and there were oil issues and motor failures.

So drive it how you should drive a V8 is my opinion