What was the proper mileage to put on an engine after rebuild which included new piston rings and valve seals??
Thanks. !!

 

IMO proper break in is 20 minutes with no load at 2500 rpms. Then I would take it easy for the first 500-750 miles then slowly offer more abuse until 1000. When taking long drives, dont sit at any one particular speed for too long. You need the load to be varying. So cruise at 80 then 65 then 75. Something like that. You dont want it to "get used too" one load. Shifting gears will also help. After 1000 miles, do a compression check, and oil change. Take the time to read the plugs and make sure everything is happy. Then GO LIKE HELL.

My def of taking it easy is, allow the car to warm up, dont rev above 4000.

 

I like using non-detergent oil. It promotes good ring seal quicker.

 

LUG the engine in some of the upper gears for a few seconds each day to seat the rings. like shift to third at 25 mph and floor it until it gets to 4 grand. if you baby the engine only it wont seat properly. piston aircraft run at 100% POWER for 5 hours before considered broken in.

 

does everyone agree with this? i'm breaking in a rebuilt motor now, with a blower still on, so i've been realllllllly babying it for about 150 miles now b/c i don't want to dip into the boost. should i just take the belt off or something so i can give it a bit more gas?

 

here's a suggestion. i came across this one. not really sure if this is the right way to do it - any experienced engine builders comment on this guy's methods.
click away http://www.mototuneusa.com/break_in_secrets.htm

HTH

 

Is that mototuneusa.com stuff true it makes sense but is opposite of everything I have ever heard. People have been ez does it breaking in motors for a hundred figgin years ya know.

 

all the engines i have ever built..appx. 25 +...i have recommended not exeeding 4500 rpm .....no synthetic oil...and no long periods of driving at a constant rpm....for at least 1000 miles...and all of my engines get 0-3% leak down.
DO NOT drive in a higher gear at low mph/rpm (bogging)...unless you want to detonate and burn a piston.

 

everyone i've talked to and even a couple engine builders/machine shops say to follow the 1000mile rule just like everyone else is recommending...........follow it and you should be fine.........

 

What about the oil weight to use?

I've heard one person recommend straight 30 weight. I can't remember who is was on the board.

But, the general consensus is to use 5W-30.

Any significance to using non-multiviscosity oil for break-in?

 

i used straight 30 weight oil for my 20min break in and only for about 100 miles then i drained it and put in 10W30............that 30 weight seem pretty thick......starting it up in the cold mornings sounded pretty weird.........

 

DO NOT drive in a higher gear at low mph/rpm (bogging)...unless you want to detonate and burn a piston.


if it detonates when lugging then your timing is set too advanced or your fuel pressure is too low. you have to get the cylinder pressure "up there" to seat the rings or they'll glaze and you'll have too much leakdown. keep it below 4500 rpm though for the first thousand miles..