Break in Oil

[pflaming]

New rings are in, rods are torqued, head is on to be torqued on Thurday. Goal is to get it running again on Friday. What oil is recommended for start-up and how long to keep it.

Finally, once the engine is running again, then what are the next three / four critical steps on a 'rebuilt' engine?

[grey beard]

Hi Paul,

Sounds like you've been busy. I like to put a large speaker magnet inside the bottom of my oil pans - helps keep any metal floating around in one place.

Once she'se running, I like to keep the engine at a medium idle for thirty minutes, to get the oil pan hot to the touch, then shut it down and while it's still hot, retoruqe the head bolts in the proper order - from the center out in a spiral motion. I also retighten the manifold bolts - couldn't torque them because they can only be reached with a wrench.

If you can still gfet to it, it would be good to revheck the valve adjustment as well, after it is up to true operating temperature. Since I rebuilt my own engine in the frame - block was not removed - I ran mine about 100 miles, then dropped the oil and filter for clean stuff. It was pretty dark already.

As for oil type, everyone has their own ideas. I use Shell 20W50, and am very pleased with it. My own engine now has 1500 miles and is ready for oil change number two. Oil's cheap, and this is one easy way to help keep it clean inside. I[m now faced with pulling the radiator to find what's leaking at the front - likely the timing cover seal on the crank pulley. Some fun . . . \

Good Luck

[Frank Elder]

I too would be interested in the rpms and length of time to properly break in one of our flatties, do you keep a steady rate or run the throttle up and down for a certain amount of time?

[Young Ed]

The flathead guru that does Dad and my engines says non detergent straight 30w for the first 500 miles. Then change to whatever you wanna run.

[desoto1939]

Since the engine is new I would get some redline Engine Breakin oil. Add this to the oil then run the engine. This helps get the lobes and tappets covered with a protective coating.

Check with any good engine builder to see what they recommend.

rich Hartung

[Plymouthy Adams]

if you running new cam and lifters hopefully you assembled with a cam lobe lube, I prefer to use Molybedylum disulfide paste myself...ensure the engine is ready to do a substained run..break the cam in for approximately 30 minutes at 2000 rpm or so..I do recommend you read up on this from the Crane Cam website..they have the best site for all things cam in general.

The flathead is not super critical in this area as the spring pressures or not great like lots of high lift race cams..but it can make the difference between broke-in and broke-down.

I not so long ago saw a brand new oil pump lock up on a flathead and shear the oil pump gear..thankfully it did not ruin the cam...this pump ws properly lubed, installed, primed and operated for about 20 seconds before locking up..have not heard back from the company as to the WHY..as it was the smoking gun I found in troubleshooting the cause after the effect I did not open the pump to inspect the rotors..it was returned to the shop that built the engine for the man..sure hope there is not a bad source of pumps hitting the market..

[austinsailor]

For the first couple hundred miles you want to make numerous slowdowns and speedups, pulling hard on the motor, nearly lugging it, to seat the rings.

If you read old car owner's manuals, they'll all tell you to "vary" the speed for X miles. That is the purpose. Just changing speed really doesn't help much unless you are pulling fairly hard as you speed up.

The only other suggestion I have is to use oil with high zinc content. I knowthis will be controversial. But I say it anyway. I keep a drum of Rotella 30 of the old formula for this, but there are additives.

[Mike@DRH]

Take all the oils that people have mentioned so far, write them on a sheet of paper, tape that sheet of paper to the wall, stand back about 20 feet and throw a dart.

As long as you are using a "brand name" oil it's kinda hard to go wrong.

The overall durability and performance of your engine is more related to how often you do your maintanace than what type of oil you use.

Mike

[MBF]

I'll jump in an add my 2 cents. I'd run a good detergent oil with a zinc additive for just long enough to get a few miles on it, and then dump the oil and filter to get rid of the assembly lube that was used along with any particulates that are in the oil. And then replace the oil and zinc additive. That's what the machinist wanted done with my /6. The next oil change was due at 1000 miles, and then go to regular oilchange intervals. Good luck-it sure is a good feeling to know that its done and to hear it run. GB's idea of the magnet is a good one too. If you can't find a speaker mag-one from an auto trans will work too. Mike