engine break in

[pick]

love this site. but.... search feature SUCKS. I'm sure this has been covered time & again. Ready to start driving a fresh rebuild insert engine. suggestions, please. how many miles per hour for how long? rpm range? I have always taken it easy for first miles and varied the speed etc. but, have never "broken in" a model A. all comments/suggestions appreciated. Thanks!

[Bob C]

I put in "Engine Break In" and found these in the first three pages.
https://www.fordbarn.com/forum/showth...t=engine+break
https://www.fordbarn.com/forum/showth...t=engine+break
https://www.fordbarn.com/forum/showth...t=engine+break
https://www.fordbarn.com/forum/showth...t=engine+break

[1931 flamingo]

What did your engine builder recommend???
Paul in CT

[Dave in MN]

Originally Posted by 1931 flamingo

What did your engine builder recommend???
Paul in CT

Paul is right on. I'll take his question or maybe it was a suggestion and expand on it. If you expect support with any possible problems during or after break-in, you should follow the break-in instructions of your engine builder or machinist.
Good Day!
Dave in MN

[Ray With]

A properly assy. car motor can be run up with a load at hiway speeds without problems. The main thing is look at the engine temp and oil pressure. You dont want to over heat a new motor. I always ran mine at 50 mph then went to 60 and actually rotated the speeds. I use file fit rings so I can controll the sealing and always proper clearance.The oil we have today is better (use a good lube with zinc or add stp) if your running a flat tappet cam.

[PC/SR]

Sponsored Links (Register now to hide all advertisements)

Drive it until it is warm. Then find a flat road and accelerate to about 50-55, the pressure expands the rings, and decellerate to 20, the vacuum sucks oil to the rings and valves. Do this 5-6 times. Let it cool and check head torque. Then just drive it but for the first few hundred miles do accelerate-decelerate within your normal driving speed-45 to55 and back sort of thing. Its sloppy driving, but you get the pressure/oil cycle. Change oil at 500 miles. By 1000 to 1500 miles things will have fitted in and it will run really well.

[Bruce]

Insert engines present a new challenge ... but I believe the old standard of giving a newly babbited engine 500 slow, break-in miles. The old rule was to keep the car speed under 35 mph. Wonderful metalurigical things happen to the new journals during that time. And then, at the prescribed 500th mile, ZOOM, everything is slicked in and burnished and the engine performance improves markedly. I have experienced the break-in threshhold on a couple rebuilds.
I also have a "new" rod that proves the point hanging on my garage wall. Its new journal babbit siezed and got all screwed up within the first 20 miles. Lots of smoke escaped from the engine to let me know something was wrong. I got to tear the engine down and practice fitting rods while lying on my back with oil dripping in my eyes.
So I would advise against the "fast break in fast car" start up. I'd also advise against performinag an "italian tuneup" on any 80 year old engine.
Easy does it.

[AL in NY]

Bruce, what's an Italian tune-up?

[pick]

Thanks for all of your words. The engine builder is me under the tutelage of a super experienced machinist/engine builder who is a club member / freind. I just wanted to get as much imput as possible since I've never done a complete rebuild on an "A" engine (lots of stovebolt experience). Thanks

[Bruce]

Originally Posted by AL in NY

Bruce, what's an Italian tune-up?

Al,
When I was growing up, an italian (note lower case) tuneup was the easy way to "knock the cobs out." Usually it was performed from the relative comfort of the driver's seat and required a straight stretch of township highway. You can do it today -- just a effectively (?) -- as then.
Just stick the shifter in low gear (auto or manual) and floor the accelerator. Let the engine roar! Then, when the roar flattens out, take your foot off the accelerator and let the engine wind back down. Do this several times.
In theory, any power-robbing carbon buildup will be blown out the tailpipes.
I can't attest to the effectiveness of the proceedure. I always took my foot off the accelerator too soon -- maybe because I bought my own cars with hard-earned cash. And I don't know why it was called an italian tuneup ... unless it had to do with mobsters and getaway cars.