How Many Miles Break-In period??
- Thread starter bobpo
- Start date
Gerard
Well-known member
Eh , just my two cents here :breaking in freshly overhouled engine ( new pistons , bearings etc ) should be done gradualy first 500 mi not faster then 25 mi with varying speeds, another 500 mi going not faster then 30 mi again with various speeds. My personal pref is not going any faster then 35 mi for the next 1500 mi . carefully check oil and residue during oil change intervals and watch temperature
Fred K-OR
Well-known member
All kinds of throughts on this. And I am no expert on it-so this is my 1 cent worth. The guy that rebuilt my engine said to take it easy (varing speeds up to 40mph) for first 500 miles. Don't beleive me, this is what I way told. I am sure others on the Barn have better info than I do.
Kohnke Rebabbitting
Well-known member
Right on the money Gerard. It doesn't take long to put on 1500 miles, when you are having Fun. Herm.
Tom Wesenberg
Well-known member
If I was buying a used engine from someone I would hope it was broken in the way Gerard said. Some might think this is babying it a little too much, but this method will certainly be the best and safest for a good running, long lasting engine.
Karl
Well-known member
Have just installed a rebuilt engine . For the first 250 miles I drove under 25 miles per hour and varied the speed constantly. It ran like a dog missing at idle and vibrating badly. The engine builder who did the work suggested that I was babying it and that I should essentially drive it normally except avoiding prolonged running at high revs. He felt that the rings hadn't bedded in and suggested that I imbed these by ocassionally when running at about 25mph open the throttle up fully and take it up to 45 mph then back off the throttle. Seems to be running much better now . It does have inserted bearings which might be relevant. I have a friend who has just restored a Mini Cooper and after a couple of slow runs round the block to exclude leaks he ran the motor in at 70 miles per hour !! He has 2000 miles on it already and it runs like a (fast) swiss watch.
quickchange
Well-known member
I run them up in the revs & drive it like i stole it, If you ***** it around the rings are less likly to bed in. Having said that one also does not lugg the engine, keeps an eye on temp, etc, I understand if you have a new cam it needs work straight up or can wear lobes, Don,t quote me on that but i always lube well & give it some reves,
After having engine rebuilt twice by pros & not happy tore it down myself , checked all, rebalanced again with differant balancer plus a few of my ideas & guess what i think we have fixed the harshness, 145 comp on each cylinder ,
Years ago i hade two engines , a B4 plus V8 both had gental running in, they smoked after 300 miles , so drain good oil, put in straight 30 , took both on 30 mile run , up & down a hill, drove them hard & i mean hard, They stopped smoking & fuming & both engines 25 years later no problems. Hot day in Kiwi land.
After having engine rebuilt twice by pros & not happy tore it down myself , checked all, rebalanced again with differant balancer plus a few of my ideas & guess what i think we have fixed the harshness, 145 comp on each cylinder ,
Years ago i hade two engines , a B4 plus V8 both had gental running in, they smoked after 300 miles , so drain good oil, put in straight 30 , took both on 30 mile run , up & down a hill, drove them hard & i mean hard, They stopped smoking & fuming & both engines 25 years later no problems. Hot day in Kiwi land.
Kevin in NJ
Well-known member
You have some idea when the engine is loosened up when it rocks back when you shut off the ignition.
George Miller
Well-known member
I would go with Gerard. That is how I would do it, with the exception that I always like to run them at a fast idle until they get to operating temp, then shut them down until cool. then do it again 3 or 4 times before I drive them. This might save the rings and bearings. That is the way we did it back in the day at my Dads garage.
Richard in Anaheim CA
Well-known member
I break them in just short of what quickchange does.
Initial startup I immediately rev to 1000 to 1200 rpm. You want that oil splashing everywhere until warmed up then retorque head.
I then drive normal, rev through the gears and decelerate against compression. Repeat often. I drive short distances on the freeway and get off at each off ramp.
After the first tank of gas, I increase the speeds and lengthen the periods of varying the speed.
I use 10W30 or 20W50 and change at about 500 miles. Then it's every 3000 miles. I have a pressurized system and full flow oil filter.
Richard
Anaheim CA
Initial startup I immediately rev to 1000 to 1200 rpm. You want that oil splashing everywhere until warmed up then retorque head.
I then drive normal, rev through the gears and decelerate against compression. Repeat often. I drive short distances on the freeway and get off at each off ramp.
After the first tank of gas, I increase the speeds and lengthen the periods of varying the speed.
I use 10W30 or 20W50 and change at about 500 miles. Then it's every 3000 miles. I have a pressurized system and full flow oil filter.
Richard
Anaheim CA
Bob-A
Well-known member
Years ago when I would break in a new rebuild on my Harley. I would put about 25-35 miles putt'n around the neighbor hood. Then get up on a super highway and break it in like I would normally ride the bike. 55-60 miles an hour, varying the speed up and down at times. After a 1,000 miles I considered the motor broke in and I never had a problem. Again an air cooled motor so there will be differences. I've been told that rings will seat within the first 50 miles or less as long as you do not over rev the motor.
Bob-A
Bob-A
Special Coupe Frank
Well-known member
I have seen this recommendation too, my understanding is that the alternating acceleration and deceleration loading helps seat the rings before the honing-pattern on the bores smooths-out.
60 mph might be a little fast for an A, but the general idea
seems sound.
I have read many older texts that talk about "running-in" a rebuilt babbit-engine on the bench ( from a line shaft ! ), to seat / burnish the bearings before installing in the chassis... I have to wonder if this was with the rods and pistons/rings installed, and if so, did they have trouble getting the rings to seat ?
Tom Wesenberg
Well-known member
I have a small one cylinder REO engine that I overhauled. I bolted it to a wood board with an electric motor. I left the head off and squirted some oil on the cylinder walls, filled the crackcase, and let the electric motor spin the engine at 1,500 RPM for a half hour or so. I then installed the head and mounted the engine in a small car I built. Great running engine and uses no oil.
Pa Joe
Senior Member
I'm glad that this post was brought up because I'm doing the same thing. Just installed a rebuilt engine in my 28 tudor. What I gather from the posts is most agree run it but vary the speed up and down. Don't cruise at a constant speed. Some say run it hard, some say run it easy. I'm going to run it about 30mph for the first 500mi, change the oil then run it close to normal. Hope thats right.
Mike V. Florida
Well-known member
Sounds like what I have done. Just vary the speed, around town driving.