Engine Break-In
 

OPINIONS:

How many hours does it take to break in a new BBC engine?

LS JR.

An hour on the dyno. Avoid any idle time.

It depends.... if you have chrome rings.... the valves may be worn out before the rings "seat"... it all depends upon what kind of oil you are using... how hard the engine is run... etc etc... but a safe bet in a boat is about thirty plus hours... The big thing you have to worry about with a new engine is getting hot spots on the pistons and scuffing them.... usually within the first few hours of easy running the "high spots" have been shaved off and you can run it a little harder. Change the oil in about 5 to 10 hours the first time... 30 to 35 hrs after that... in cars heat usually destroys the oil first.... in boats it is usually contamination from moisture... if your oil gets up over 200 degrees you will turn the moisture into vapor and the oil will last longer... if your engine oil never gets up close to the boiling point of water it will begin to get contaminated with moisture and look like brown goop.

I prefer to change the oil and filter right after the initial warm-up and while the engine is still warm. Then 10-15 hours as Reed suggests.

I go so crazy scrubbing and cleaning the internals before assembly that I don't have to worry about any debris floating around during initial start-up... I've got the long bore brushes and take my engine stand outside and scrub the block and heads crazy with hot soap and water and then blow them out with compressed air... never had any problems.

My biggest deal is with the cam lube, assuming that a moly-lube is used on flat-tappet cam/lifters. It's not uncommon to have the filter plugged with the lube. That's becoming less frequent because a lot of people are switching to roller lifters. Yeah, I'm a big believer in assembling a clean/clean/clean engine too. Besides, you end up looking everything over very closely several times. It's amazing what you can find.

I've been told that the first hour on the trailer or dyno that you want to run cheap NON detergent oil (Valvoline 265 ??) for proper ring seat; Then a good Dino race oil for 20 hours or so; then move to you favorite synthetic.
I'm sure there are many methods and myths.
Dave;)

I am anal about it and run the motor for the first few hours without the thermostat.

Curious; Why?
I'm concerned about getting enough heat in at break in...:confused:

I take the thermostat out to make sure I get water to the heads right away on the first start up and I have always left it out for the first few hours just to be sure. Less heat, less friction, right?

Just a couple of thoughts. Don't know if they're right or not but one would be;
I would think the heads would get more water with the thermostat in and partially closed. This would force water to the head passages rather than just a free escape path out the the thermo housing. Wouldn't it help also move air pockets out. Yes/No???
The other is I would think you need adequate temp to seat the rings properly.

:confused: :confused:

http://www.mototuneusa.com/break_in_secrets.htm

This is the philosophy I have always used in my cars, snowmobiles and motorcycles. I do not know if it has been the right way, but it has worked. I have not had a failure due to it.

Also I have heard that with a new cam you only want to run the lighter spring for less tension the first break in then swap in the other spring or two once you actually drive it. Maybe this is only relavent on non-roller cams? just my .02

I have heard this with Nascar engines because they use solid flat tappet cams with a lot of spring pressure. The breakin for these cams is critical. With almost any cam used in a boat, this would be unnecessary.

The engines we've been doing around here, like Dyno's, mine, SuperV's, Waterfoul's, only have about 110 pounds on the seat so the spring change isn't necessary. But the cams still need to be broken in properly. That's why we run them on the floor before they go in the boat. Check for oil and coolant leaks, pressures and temperatures, and set the ignition timing. After the break-in run the oil and filter is changed, it's run again, and antifreeze is run through it if it's cold enough to freeze. Spark plugs are removed to get a small amount of oil into the cylinders, turn the engine over by hand, and reinstall the plugs. Then all the openings are taped shut and it's ready to go in the boat.

Rookie, interesting post. Makes some sense and I sure like it better than the conventional break-in.
Problem for me is I always have to break in (at least the cam) on the trailer.

Only a small amount of the oil is "filtered" as the oil flows through the engine and filter... all " full flow" filters... ALL FILTERS.. and engines have an oil bypass because you can't push thick cold oil through a filter matrix that has holes only microns big. If there isn't a bypass for the filter the oil will just exit out the pressure relief valve in the pump.The oil has to bypass most of the time... the filter only flows all the oil at low rpm's and when the oil is very hot... like at idle after the engine is totally warmed up. If there isn't a bypass system for the filter the bearings will be starved for lubrication and will fail quickly... trust me on this one guys... If you remove the built in oil filter bypass on a chev engine... you have to run a filter that has a built in bypass like a fram HP6. Or suffer bearing loss..

Yeah, whatever you say, bucko.

I've blocked my bypasses and will run this summer with none. I am going to run filters with bypass valves. Problem with a boat engine and the bypass in when it opens, the oil not only bypasses the filter, it bypasses the cooler. Therefore, you always have X amount of uncooled, unfiltered oil running through the system. Blocking the bypass, oil will only bypass the filter (via filter bp) and will be forced though the cooler. This way you will run a percentage of unfiltered oil but all oil will alway be cooled. Hope it works!!

BT :cool:

It will work fine, BT.

Thanks CH, I think so too. Lots of others do it with good results.

BT :cool: