Engine break in

[Northvale PA]

Bringing my TO-20 Continental engine home just rebuilt. I know
its been discussed 100 times. What is the right break in
procedure? Thanks.

 

[J.Wondergem]

Work it if you can.

 

[Bruce(OR)]

Which is great for a roller cam, maybe not too good for a flat tappet cam.
YMMV.
Hopefully the oil pump got filled with vaseline or other. Cavitation can be a problem.
Me? Fire it of asap, no extended cranking. As soon as the oil comes up and no leaks, run the engine on
straight 30W and vary the RPM from 800 to 1300 +/- for 25 minutes. Up, down, up, down. . .
If the manifold turns cherry red, your timing is whack. Shut it down and reset the timing. Then repeat this
again.
Up/down for 25 minutes to seat the cam and the tappets. Shut it off and change the oil and filter.
I went to a 15/40 diesel grade right out of the box.
Cam is lubed with splash oil. Steady RPM might not supply the cam with enough oil on the lobes to properly
seat the tappets. As I said,
YMMV.

 

[LarryMaine]

Just a thought, when I rebuilt my own engine, everything was a tad tighter than it was before. One thing I noticed was that I could not get the standing idle as low as it used to be, it would stall out if I tried. Eventually things got smoother and I could get it to idle at a lower rpm. Just a thought, if on start up you have a similar issue, dont worry about it.

 

[wore out]

(quoted from post at 20:18:12 07/29/23) Just a thought, when I rebuilt my own engine, everything was a tad tighter than it was before. One thing I noticed was that I could not get the standing idle as low as it used to be, it would stall out if I tried. Eventually things got smoother and I could get it to idle at a lower rpm. Just a thought, if on start up you have a similar issue, dont worry about it.

You don't WANT to idle a rebuilt engine at low RPM's.

It takes some RPM's to sling oil around for camshaft and cylinder wall lube, and during the break in period this is ESPECIALLY important.

Get it broke in, then try to win the ''how low will it idle'' contest, if you MUST.

 

[Bruce(OR)]

So how long is the break in period and for how long?
Any specific rpm?
What kind of oil?

 

[Ericp351]

1- Re Read Bruce, above. 2- Have engine ready- timing, fuel, water, bathroom break, et certera so you can keep her going ang watch it. 3- After you run it OK and up to temp, re check and work her gently for a bit (5-15 hrs) before progressively adding to full load. Bog her down after 1 hr spinning a 5 foot brush hog in chest high weeds and you have wasted a rebuild.

 

[Bruce(OR)]

This is getting to be fun.

 

[Bruce(OR)]

Work it how hard and at what point?
Fire it off and stuff it in a tractor pull?
That ought'a work it.

 

[rustred]

do u know what break in means?its not so much as the crank and cam rolling around. it is referring to the piston and rings. what you want is so that the rings expand into the cylinders on the power stroke. so idling rouns is not good. you basically work the engine like a person would do , just dont overload it that it is chugging and ready to stall in a hard pull. vary the rpm and load also for the first bit. on the power stroke the rings are forced into the sleeve and u get them wearing in a matched set. use the oil you would normally use. years ago we used to use mineral oil in rebuilt engines , and come to think of it i dont even know why. so normal operation with out pulling its guts out for the first few hrs. pistons grow with heat, and in a new engine clearances are tight.

 

[marloweg]

i have rebuilt a lot of engines and run them like i stole them when we raced stock cars we had no dino so we just put them in and hit the track believe it or not never had one blow up did a lot of Perkins and Case engines and others only had one that was bad and that was due to bad parts .

just make sure you change the oil and filter after 25 HR. or sooner

 

[Bruce(OR)]

You talkin' to me?
*
Dis' is fun.
*
I dunno nuttin'
I 'specially don't know nutting due to oncoming old age,
failing memory, eyesight, hearing and whatever else comes along.
Breaking in enginz.
Done that once or twice.
I like it where you break it in and it goes kaflooey cuz the machine shop missed something.
Or better yet, the torque values were not met during assembly.
How about the nut that fell into the manifold and find a new hole in the piston or maybe just a bent valve.
i dunno nuttin'
And I am an expert at that.
Occasionally though, i do get lucky.
That way I don't have to repeat it.
Nowadays I just work on my own junk.

 

[Bruce(OR)]

No worries on longevity with one of those. But I suspect this machine might need to do more than a few laps around the field. If your race engine has been built since the 70's it should also be running a roller cam in it also. Another reason that breaking in the cam was not needed with those engines.

 

[Mad Farmer]

(quoted from post at 14:36:45 07/29/23) Bringing my TO-20 Continental engine home just rebuilt. I know
its been discussed 100 times. What is the right break in
procedure? Thanks.

Anybody use GM EOS as an assembly lube and for break in?

I use to rebuild SBCs and the Chevy Power Book suggested to use that for breakin/assembly. These were both flat and hyd lifter engines.

I would run the engines w/straight 30W at varying RPMs under light load for several hours then change the oil and filter.

I also have a distributor with the drive gear and advance mech removed. I brazed a 3/8" to the top of the shaft and could prime the whole engine using a drill.

This post was edited by Mad Farmer on 08/01/2023 at 08:14 am.