Question for stroker guys

[moponys]

I'm getting my 331 stroker back in about 4 days....

How long does it take to break it in and would it be safe putting it on a dyno after about 300 miles to get it tuned?

I know I should not drive for long distances under load, such as on the freeway. Should I not get on it until 1000 miles are on it?

Thanks

[HotRoddin]

Originally posted by moponys
I'm getting my 331 stroker back in about 4 days....

How long does it take to break it in and would it be safe putting it on a dyno after about 300 miles to get it tuned?

I know I should not drive for long distances under load, such as on the freeway. Should I not get on it until 1000 miles are on it?

Thanks

http://www.mototuneusa.com/break_in_secrets.htm

Do yourself a favor and read this top to bottom. In my opinion as far as engine building goes this my be the most important thing you ever read. I totally agree with it. The engines i've built that were run hard right from the get go were always the ones that sealed the best and lasted the longest. I don't think its a good idea to run the RPM's way up or let the engine overheat or run the engine at a constant speed for long periods, but i do believe what this guy is saying, because i've experienced the same thing.

[moponys]

Thanks for the article...it was very helpful.

Should I then wait to put at least 1000 miles on it prior to putting it on the dyno?

The majority of the break in will probably be on the freeway at varying speeds between 55 and 75 with the first 20 miles being driven kinda hard after the engine has warmed. Does this sound right?

[Scrapla]

Very good reading, the mechanic building my motor says pretty much the same thing he does not understand why people want to "break a motor in" he said just drive it from the get go exactly how your gonna drive it on a day to day basis, just some good food for thought.

[andy669]

Alot of it has to do with cylinder wall finish and the material of the rings. I have run several new engines on the engine dyno, and everytime its the same process: Fire it up and set the timing; Let the engine high idle a little to get some heat in it; Make a short pull to 4-5000 rpm (depending on the max rpm); If everything looks good, make the next pull to peak.

My engine literally went from never being run, to 8000 rpm in about 20 minutes time. Usually after the third or forth pull, depending on the ring material and cylinder wall finish, you can see the engine making more power due to the rings sealing. This is on a race motor though, a street motor might take a little more time.

My advice, is to take only the advice of your engine builder. He knows your engine better than anyone.

Andy

[moponys]

Good advice...

My engine builder specializes in race engines and said it should be fine on the dyno. The one specific thing he said not to do is the long drives at a steady pace, like on the freeway.

[PWR_RYD93]

I always break my engines in HARD. They always have great ring seal and don't use oil.

[jonnyk]

Originally posted by PWR_RYD93
I always break my engines in HARD. They always have great ring seal and don't use oil.

Agreed.
Another thing to think about is heat treating...the harder you run it, the faster/more likely things like pushrod tips, valve tips, cam lobes, etc. will generate enough friction to efffectively heat treat themselves. Of course you want to do this with enough cooling time in between pulls to not damage anything, but I agree with the high load theory early in the engine's life.