New Engine Break In Procedure

[justtorchit]

Not jeep related but still a good tech discussion


So im getting ready to start up a fresh engine and im tossed up betwwen some of the start up procedures. i have read Everything from steady idle for 20 minutes to beating the everyliving hell out of it for 500 miles.
I understand the purpose of the break in is to seat the rings and get everything to wear properly.

What are some of your break in techniques and reasons for doing so?

[Crazy Reid]

I have heard across the board for what to do to a new engine. Back in the day I think it used to matter. With stable gaskets, piston rings, lubricants... I dont think it really matters anymore.

People who say to run it hard, mostly have the thought process that you want to find the weak points early so you can just tear it down again versus finding out later in the middle of the ngiht in a rainstorm, when you really need to be somewhere.

When I rebuilt the 1.9 for my Vangon I just let it idle for a bit so I could check for leaks and strange noises etc and then took it for a lazy drive around. I suggest having someone close by when you first drive it so you arent stranded if something breaks (darn 02 sensor wires ). I did 600+ highway miles straight on my van after only putting about 50 around town miles. I wouldnt suggest doing that but break in periods for newer engines is a lot less than they used to be. Put some easy miles on and if everyhitng is good, stop worrying about it.

Does this mean your Subaru is running?

[ct67_72]

Depends on the type of engine. With a OHV engine you want it to be at high idle to get more splash oil to the cam. With OHC cam engines it doesnt matter as much.
At the race shop I worked for we had an inhouse machine shop and engine assembly room.
We would run the engines high idle for 20 minutes. change the oil and run on the dyno, (or you could just drive around,) normal running. no super heavy loads, but load is good to seat the rings. You want to load it coasting too, (downshift and let the engine slow you down). With street engines we would change the oil again after 125 miles. Then 500.
The first oil change after the high idle run in would always come out looking like metallic paint. This is why you want to change it pretty quick.
After the 500 miles you can just pretty much drive it normal.

[justtorchit]

Depends on the type of engine. With a OHV engine you want it to be at high idle to get more splash oil to the cam. With OHC cam engines it doesnt matter as much.
At the race shop I worked for we had an inhouse machine shop and engine assembly room.
We would run the engines high idle for 20 minutes. change the oil and run on the dyno, (or you could just drive around,) normal running. no super heavy loads, but load is good to seat the rings. You want to load it coasting too, (downshift and let the engine slow you down). With street engines we would change the oil again after 125 miles. Then 500.
The first oil change after the high idle run in would always come out looking like metallic paint. This is why you want to change it pretty quick.
After the 500 miles you can just pretty much drive it normal.

Thanks, this is what i was thinking.
Its a subaru engine, so OHC.
when you say high idle... is that like 2k - 2.5k rpms?
im pretty much scared shitless about the start up of this thing.
the part that worries me is like you said... the metallic paint after the first 20 minutes. i was worrried 20 minutes might be to long considering that oil will be pumping through the turbo also. (dont want to fry that)

im thinking starting it up and to a quick check for leaks. (3-5 mins)
then hold it to 2000 rpm (12-15 mins)
cool down at idle (3-5 mins)
change the oil/filter (shit myself when i see rustoleum ultra mettalic pissing out)

take it down the road and stick to back roads (100 miles)
stick to second and third gear going up and down hills (moderate accel/deccell)
change oil

run it normal for 500 miles (no heavy loads)
change oil

good to go?

[justtorchit]

I have heard across the board for what to do to a new engine. Back in the day I think it used to matter. With stable gaskets, piston rings, lubricants... I dont think it really matters anymore.

People who say to run it hard, mostly have the thought process that you want to find the weak points early so you can just tear it down again versus finding out later in the middle of the ngiht in a rainstorm, when you really need to be somewhere.

When I rebuilt the 1.9 for my Vangon I just let it idle for a bit so I could check for leaks and strange noises etc and then took it for a lazy drive around. I suggest having someone close by when you first drive it so you arent stranded if something breaks (darn 02 sensor wires ). I did 600+ highway miles straight on my van after only putting about 50 around town miles. I wouldnt suggest doing that but break in periods for newer engines is a lot less than they used to be. Put some easy miles on and if everyhitng is good, stop worrying about it.

Does this mean your Subaru is running?

almost

[ct67_72]

Ah, yeah we built subaru engines too, actually primarily for a while. We had a 3 axis cnc that machined the blocks for sleeves, and we sleeved them in house.
Anyway, you want to drain it hot to suspend all the particles. start it, check it for leaks, run it up to 2000rpm or so. Doesnt have to be crazy as oil will be getting every where anyway, run it 20 minutes at high idle ( assuming you spend a few minutes checking for leaks) then shut it off and immediately drain the oil. It WILL look scary lol. Dont worry, as long as the next one is better and the 500mi change is pretty clean its normal.
This is how we broke in our shop car with a GT42R, so Im sure its safe for yours.