Proper breakin procedure for new bearings

[SaintC]

Hi Doc,

I will be starting up the engine with new rod and main bearings in a day or two. My question is about proper breakin procedure.

I had read the following, and want your input....

Never use plain oil for bearing assembly.

You want as much moly assembly lube as you can get packed in there. As well as fresh oil and filter (not synthetic)

Prime the oil system with a screwdriver to the oil pump, through the distributor.

Start it up and let it reach normal temp. Then turn up the idle to 1800 to 2000 rpms for 20-40 minutes before driving it.

Change oil and filter after 500 miles.

I respect your expertise, and would love your input.

Thanks, Doc

[ 12-14-2003, 02:26 PM: Message edited by: SaintC ]

[CleviteKid]

The bearings don't need a break-in per se, but you do need to take the steps you have listed to protect them. Even better than the screwdriver thru the oil pump drive is a proper fitting shaft on the end of your electric drill. Spin it up until you hve good oil flow, and even some pressure on your gauge.

Dr. Lee :cool:

[SaintC]

That is exactly what I was going to do. I have not removed the distributor yet to see how long I need to make it, but having had the oil pump out, I saw exactly what the mating end needs to be like in order to make good contact.

Clockwise direction, I believe.

What do you think about heating up the stp, and mixing it in with the oil PRIOR to putting the oil in the engine? That way the first oil that hits the bearings already has the good stuff mixed in. Is it worth the extra effort...meaning, would it make any difference?

Thanks.

[Bobbie Martin]

Dr. Lee,
A couple of questions on this topic. I have read from some pretty well known engine builders that the only place to use moly lube is on the cam and the face of the lifters (and maybe the main/rod/head nuts). They suggested you should only use lube or STP on the bearings. One more, do you recommend spinning up the engine with a drill if it has flat tappet lifters? I always thought you needed to get it to 2000 RPM ASAP for proper break in.

[SaintC]

I think it may be a personal preference thing. I, too, have talked with chevy engine builders, and they swear by the stuff.

In my case, I am dealing with a scored crank that is within spec, and I want to squeeze as many miles out of it as possible before doing a complete rebuild.

I bought some Sta-Lube Assembly Lube. It has moly and graphite, and states plainly that it can be used on cranks as well as cams.

We shall see how my engine performs very shortly....but would you really know if there was a difference without tearing the whole thing apart a couple of times, trying different assembly and breakin procedures?

For years, I was told to use stp as an assembly lube. Thought I would try the moly this time.

[CleviteKid]

Actually any assembly lube will work for bearings, but you must use the approved moly disulfide prelube on the cam and lifters. 50-50 engine oil and STP is a good bearing assembly lube for bearings and pistons and piston rings, but not for the camshaft.

The spinning with a drill is JUST for the oil pump. When you pull out the oil pump drive, it is disconnected from the camshaft, and ONLY the oil pump turns, not the camshaft or anything else.

And of course you are correct, start the engine and bring it right up to a high idle - 1500 to 2000 rpm to build oil pressure and flow RIGHT AWAY.

Dr. Lee :cool:

[Bobbie Martin]

Spinning just the oil pump makes sense now. I'm so use to Mini (A Series) engines where the oil pump runs off the end of the cam - so you can't turn one without the other. You don't know how long 45 seconds can be until you start one of those for the first time. Even priming all the oil galleries, it takes forever to get oil from the pickup way down in the gearbox!

[grape]

in our race car junk we don't do the 2000 rpm deal unless it is truley a flat tappet cam......If it has rollers just drive it.