Rebuilt 3B startup

[PressOn]

My 3B (81 BJ42) rebuild is almost complete. (New head, pistons, sleeves, crankshaft, etc.). I'll be starting it up next week and was wondering if anyone has any suggestions for the break in?

A diesel mechanic told me to run it like I stole it. I know that's not how gassers typically do it so thought I'd run it by the forum. My current plan is to take it on a 1000 mile trip. No freeways allowed.

Any thoughts appreciated.

Thanks,

 

[cruiser_guy]

I'm not sure I'd go on a 1000 mile trip with a newly rebuilt engine. I'd go easy on the engine and give a few quick oil changes.

 

[Radd Cruisers]

Broke in a couple 3bs, 2hs, hit it hard for short stins like a couple seconds or a minute then back off.

Set the rings in, they are hard and take a fair bit of heat and abuse to set in.

I once had a 2h rebuilt, it sounded terriable after the rebuildk, it just plain sounded like metalic hammrs?

My buddy around the corner is a GM mechanic who specialized in diesels.

He had me load up my Boaler trailer climb a unreal grade with carboard in front fo the rad, two times, after that the engine pured like a kitten.

He informed to load it up for about 50 seconds then unload and ride it for ten then load it again. Did this a few times and it set in nicely.

Rob

 

[roscoFJ73]

Sometimes newly rebuilt engines run warmer than usual. I would wait until that period has passed before a 1000 mile trip.
Engines are supposed to driven at various rpm during the running in phase

 

[PressOn]

Thanks for the input guys. I'll hold off on the long trip until I get some shorter run times in and after a quick oil change.

Rob.... your story is similar to the mechanics description of driving hard initially. Interesting.

Jeff

 

[crushers]

best to drive it around the city for a while, you are to vary the rpms when breaking in an engine. do not be scared to drive it. watch the oil pressure and water temp...

 

[brownbear]

I was always taught with new engines such as aircraft piston engines, that the oil needed to get full of metal to break the engine in. Like lapping compund, much less tho. That is why we used regular mineral oil. No synthetic till it was broken in. I think doing the oil change at 1000 kms first or so would be fine. Maybe even more. We would change the oil after I think 25 hrs. So think of driving 25 hrs at 100 kms an hour... 2500 kms. But 1000 should be good.

The oil IMOP needs some metal in it to break in the engine. So if you keep doing too quick of oil changes you just prolong the break in period.

Now the metal I am talking about cannot be seen. And its jist a theory.

 

[crushers]

exactly, i run the cheapest oil for the first fire up, run it for a hour or so then change it out for another cheap oil change including filter and then after a 1000 km change it again with some decent dino oil for the next 5000...

 

[phatwheels]

How soon do you wanna give it full load? As soon as its up to temp or give it a couple miles? Just put 'er to the floor? Just pulled the 2H and its getting completely rebuilt.