When do I get my new built motor tuned? (in reference to breaking in my built motor)

I'd appreciate one of the shop guys chiming in too please =) <3

 

just get it broken in on a load based dyno, its a controlled environment and can be done in a few hours... just what i would do

 

Cosworth break in instructions were 500 miles using dino 10w40, keeping revs below 4k not running constant speeds. 15w50 synthetic after that, we already had a baseline tune in place before. Did a check up on the tune at 1k miles. Been running perfecto.

 

There are alot of different opinions on this subject. Some say break it in 500-1000 mi., some say break it in 200 mi., some say break it in on the dyno, and some say break it in by driving it "like you stole it." Although I spent a significant amount of time researching the subject, I never found a solid answer....

It is my understanding that the most important reason for breaking in a motor is to ensure that the rings get seated properly. On my last build (before I overreved it so as to peg the tachometer - probably north of 12,000 rpm, thereby destroying two rod bearings), I broke it in gently for about 500-600 mi. My pistons, rings and cylinders were in perfect condition when we dissasembled the motor. Thus, in my humble opinion, I had a good break-in.

Both JetPilot and myself had our new short blocks balanced and assembled by South Florida Crank and Machine in Lake Worth. According to JetPilot, the owner, Larry, suggested a 200 mi. break in.

Now, one significant caveat. Larry builds alot of race engines for professional race teams, and he is meticulous as h*ll, so his advice may be applicable to his motor builds, but not necessarily others. Thus, I think the safest advice is to ask the person who built your motor what is best on their builds. They should know better than anyone else.

Although I have not always agreed with your conclusions based on your past experience, I think it would be in your best interest to get an AFR plot at the various boost levels you will be running. Also, remember that running a little rich at peak torque can add a nice safety margin, so long as it is not so rich to wash the cylinders. It is my understanding that AFRs below about 8 will cause this to occur.

As for my build, we try to keep the AFRs at around 14.5 for out of boost (vacuum) cruising, but down around 11 in boost (obviously with a smooth transition). At high boost and peak torque, we even dropped the AFR to 10-10.5 or there abouts to add a comfortable safety margin.

Best of luck with your build. Again, ask your engine builder about the break-in period. If you built it yourself or your engine builder does not offer meaningful advice, I personally would go the 500-1000 mi. route, but this is just my opinion.

One last thought. When I first got my G35 in 2003, I leased it, but I bought it outright before the lease expired. Because it was leased when I first got it, I didn't care about the break in. I constantly pushed the living daylights out if it, hitting the rev limiter at full throttle multiple times on a daily basis for years. In other words, I drove it like I stole it. When I sent the short block back in as a core after I got my new short block, it had 42,000 mi. on it. They said the rings were seated well, and the pistons, rings and cylinders all were in great shape. Now, this was a factory motor, so my experience may not necessarily translate to a custom built short block.

 

Jtram who built the motor And who is doing the tuning?

 

I broke my 3.8L GTM motor in by doing 1000 easy miles with no boost. I changed the oil at 500, 1000 and 1500 miles with non synthetic 10w30 valvoline then switched to synthetic 0w 40 mobil 1 at 2000 miles.

 

I did "granny" driving for the first 200mi. Then stayed under 4k rpm until I hit 500mi. After that it was normal for another 300mi all with no boost. No problems so far and mine is daily driven.

 

I would suggest asking your builder as Terry stated. They will know what works with there builds.

 

My good friend and mechanic in wellington is doing the build apex.
He didn't really have a good answer for a break-in. I submit that there really isn't a right answer (except the motorcycle community seems to have it down)

And as my next thread will show- I will be getting a tune from japtrix.
And now that I have someone experienced and reliable to go to for those kinds of questions- I'll get Roger Case's 2cents.