Starting a new build and I plan on re-using a cam, lifters, pushrods, timing chain/gears, rocker assemblies, and crank from my last build. These parts only have 10K on them since new/rebuilt (rocker assemblies).

Properly broke in the the old build with the above parts - 2,500 - 3,000 RPM for the first 30 min, break in oil, ZZDP, flush right away, 2nd oil change at 250 miles.... All the parts I plan on re-using were new, original LR except cam (Crower) and crank (-10) and they all look great.

The new build block has a fresh set of top hat liners, pistons/rings, crank/rod/cam bearings.

What’s the best way to properly seat new rings and break in new bearings?

Thanks,

 

I believe varied-speed and rpm's are your friend for the first 500 miles

 

Conventional motor oil, no synthetic for first 500, diesel 15w40. Nothing else required. Since your re-using cam no need to do the high speed varied rpm on startup.

 

Thanks! Wouldn’t use anything other than Rotella 15-40.

 

Make sure your machine shop finishes the cylinder walls with the right grit hone to match your piston ring material. If they're iron rings, not terribly picky.

In my experience, most guys seem to prefer the "break it in by running it hard" method. Puts more pressure on the rings against the cylinder walls to seat them in quick. Your machine shop may have a recommendation of their own on this.

 

I agree with Alex in running it hard. Many years ago I worked in an Aircraft engine (piston) overhaul shop. To break in an engine we ran it at various speeds, building up to a fairly long period of time at wide open throttle. I realize that due to differences in material and application, aircraft and automotive aren’t directly comparable, but I wouldn’t baby an engine I was trying to break in.

 

Thanks for all the responses.

One more Q. What's everybody's opinion on running a new timing chain on gears w 10K?

Genuine LR gears and chain new 10K ago. Amazing how lose the chain gets with just 10K.

 

Chains break in some too. How much slack are we talking about?

I've run new chain on old gears many times. Not an issue.