Engine Break-In

[Sean]

Alrught guys, I found a couple threads here on R3V, but I want to get a new one started. Since we seem to have a good deal of stroker guys here now - what is the BEST way to break in an M20 stroker engine? I personally think that the breakin for our engines are different than the new engines being made today - they're older, and clearances aren't nearly as tight. To the links!



Here are the other threads I found:

http://r3vlimited.com/board/showthread.php?t=43880

http://r3vlimited.com/board/showthread.php?t=52248

Informational Sites found:
Drive it like it's stolen: http://www.mototuneusa.com/break_in_secrets.htm

http://www.enginesonly.com/break-in.html

http://www.aera.org/consumer/engbrkin.pdf

More? Let me know!



So, what's the best way? How do you guys plan on breaking in your strokers, and for those that have made them already, how did you break them in?


Here's what I'm leaning towards:
- Run Castrol GTX Dino oil 10w-40
- Do not start engine until it's ready to be driven - warm it up and bleed the coolant system.
- Drive around for about 5-10 miles, half throttle - goin up half way.
- Change oil after 20 miles
- Refill with Castrol GTX
- After that, do 3/4 throttle up to about 3/4 revs - do about 50 miles
- Then take it full throttle to half revs - do about 150 miles
- Change oil after next 100 miles
- Take it full 3/4 throttle all teh way up - do about 50 miles
- Take it full throttle all the way up - do about 50 miles
- Last change to dino oil after 200 miles
- Change over to Mobil 1 15w50 after the last 100 miles of breakin


I kinda just pulled that out of my ass - so what's the consensus? What should I follow? Drive the piss out of it, or take it easy, and raise the load and use as the miles climb?

I won't be using synthetic off the bat, that's definately for sure. But, outside of oil - how should my new motor be broken in??

[modifiede30]

I wouldn't run synthetic in a newly rebuilt engine until about 10k miles.

[Sean]

I wouldn't run synthetic in a newly rebuilt engine until about 10k miles.

Really? that long? Why is that?

[JRowe]

I think the consensus on engine break in is as follows:

1. Use assembly lube
2. Use conventional oil
3. Start it, fast idle it, and bring it to operating temperature.
4. Drive slowly/smoothly for a few miles, keeping RPM's low.
5. Seat the rings by heavy accelleration and decelleration runs repeatedly.
6. Change oil.
7. Continue accellertion/decel runs.
8. Change oil at 500 miles.
9. Avoid prolonged, consistent rpm's for the first several thousand miles.

That's a thumbnail sketch, but I think it pretty well summarized the overall break in procedure. Of the links posted above, I don't believe they say much to the contrary.

[Sean]

For number 5, should one stay under a given RPM's? (say - don't go above 5 grand or so?)

[SA E30]

Really? that long? Why is that?

Cause ur rings and bearings wont seat properly.

[PiercedE30]

Well, I know my buddy who just built a turbo ls/vtech and the way he is breaking it in is he warmed it up and got it to operating temps and then ran the hell out of it for 20 miles, changed the oil and was done with it.
Now he is putting out over 450 at the wheels.

[NC325iC]

so basically your saying he didnt break it in at all, he just drove the hell out of it

[nando]

as long as you don't keep it up at the redline for extended periods of time, you will be fine. my plan is basically to drive the shit out of it, but break it into the redline slowly and not keep it there for too long until I put some miles on it. if I can get mine running in time I'll be bringing it to an autox next weekend, with probably 100-150 miles on it.

I asked jim @ MM this very question, and basically what he told me is with modern rings, break in doesn't take very long at all if done properly. he typically delivers motors to his customers with less than 100 miles on them, which are broken in enough for track events. he said that long periods of high rpms too early was what basically killed the rings on people's motors that broke them in wrong.

[Sean]

Took it for a spin tonight, despite my leaky slave cylinder (damn thing).

Runs gooooddd.

It seemed to be misfiring at first - but after driving around for 8 miles, it seems to have gotten smoother. I did around 1 mile or so of driving around the neighborhood (staying below 2 grand, and literally crawling) - then taking it for a 7 mile round trip where I went into 2nd and 3rd, and went from 2 grand to 3 grand, and let off over and over again Towards the last couple miles, I took it to 3500 instead of just 3 grand - and it wasn't there long - there, then hit the brakes softly to slow down.

So, am I doin good thus far?

I can feel the torque at a little under half throttle (which is what I did the above in) - it's awesome! It seems to run absolutely great! No stuttering or anything! :D

Pretty damn exciting! Can't wait to get my car back together tomorrow and seriously take it for a drive. So, no more than half throttle, and no higher than 3500 for at least 10-15 miles, right? Then slowly take it to 4 grand...etc etc. That's what I'm thinking anyway.

[Sean]

Well, I added another 60 miles to the car last night, after an oil change.

I've pretty much just been giving the car enough gas to put load on the rings (so between 1/4 and 1/2 throttle). I take it up to anywhere between 3500 and 4000. Then I let off, back down to 2 grand, and do it again.

Are the rings probably broken in now? Should I start revving higher than 4000, close to redline, now? What's the best way to get the bearings broken in? Should I get close to flooring now?


Car has been running smoother and smoother. Oil pressure has been good, haven't noticed any issues with it dieing off or anything. Light stayed on a bit long the other night - but it was off instantly...so I didn't think much of it.

It pulls so good at a half throttle! Can't wait to open it up!

[nando]

I think you should drive it harder now. I would do WOT up to 4500rpm, then decellerate quickly, then repeat in 200rpm increments until you get to the redline. you're being a bit overcautious on the oil changes, but I suppose it can't really hurt. you should go for the next 500 miles on this oil change, and then resume normal intervals (3k miles or whatever).

[Sean]

I think you should drive it harder now. I would do WOT up to 4500rpm, then decellerate quickly, then repeat in 200rpm increments until you get to the redline. you're being a bit overcautious on the oil changes, but I suppose it can't really hurt. you should go for the next 500 miles on this oil change, and then resume normal intervals (3k miles or whatever).

Can't argue with that! hehe I'd love to take it WOT! :D

Think tonight will be an awesome evening!!!

[Sean]

Well, I did just that.

I'm now at a little over 190 miles on my new engine, and the damn thing PULLLS like a MOTHER!

God damn, the thing doesn't stop pulling! it's got power thru the WHOLE powerband! It's AWESOME!

Before, I'd sit there, and get bored, waiting to shift. Now it's like, whooa whooooa whoooooooooooooaaaaa LOL


I took the car on many different treks thru the mountains, mostly in 3rd and 2nd, revving from 2 grand, up to between 4500 and 6000. At first, I did increments like you said - after that, I just did it randomly. Most of the time, I'd hit where I wanted to go, and add a little braking to help slow the engine down faster. I was probably not up high for any longer than 30 seconds - and no longer than 5-10 seconds when nearing 6grand.

I hit 6 grand probably...4-5 times today, once I think I went a bit over. It was STILL pulling!


My friends told me I did the wrong thing - they were like, NOOO YOURE NOT SUPPOSED TO DO THAT! I'm just like...ok, well...that's not what my research showed. I mean, I can't baby teh engine the ENTIRE time. it NEEDS to be DRIVEN to be broken in. SOOO...that's what I did today.

It's a blast. The engine is amazing!

Still a couple tiny coolant leaks somewhere - but I'm thinking I'll track those down, and my car should be golden.



So - I did the right thing, right? From here on out, do I just drive it, and make sure not to stay at a certain RPM for a long time (such as longer than a minute?)

[nando]

like I said, just don't stay at the redline for a minute or something. jim said most people who ruin their rings on a new motor try to top it out too soon, which means long periods of high rpms (6,000+) and the new rings don't like it. I've known lots of people who break their engines in by running them hard from the get go.