Zu_langsam

My buddy and I have built an E30 race car over the last few months. We managed to accomplish everything on the car before its first big race except an engine overhaul. So the car went to a driving school, comp school, 2 practice sessions and qualifying on its 300k mile engine that has never been opened up!! Then the enduro started, we made it through about 200 of the 300 miles before braking a rocker arm. I couldnt complain, I was very impressed that the engine held up for the 600 track miles that it had seen in 2 weeks. So now we have to do a rebuild, thats fine except for one thing. Typicaly after a rebuild it is best to put a good number of miles on the engine during a break in period to seat the rings, etc. But this is the first time that I have had to deal with breaking in an engine on a non-street legal car. I know that this isnt a BMW forum but you guys can't expect me to get any decent info from them can you So i'm back here at old reliable for some good ideas on how to get this motor broken in within a month without being able to drive it around. Thanks!

Chris Prack

Chassis dyno. Load it up and run it. Three or four hours on it at varying speeds/rpm should be enough. That's what I am doing with a car tomorrow.

Good luck.

Zu_langsam

Yeah I did think of that, but damn I hate to think of the cost of 4 hours of dyno time. It may be the way to go though. Thanks

Ski

Is this a pure race car or is it registered or streetable? If registered, drive it for a 500-750 miles watching the vacuum.

Most dyno shops offer better rates for a 1/2 or all day sessions. The shop that I use is $140 for 4 pulls(calibration run, then 3 pulls - $20/pull after that). $300 for 1/2 day, $500 for all day, Mustang dyno.

Jeff Lamb

Take a read through this:

http://www.mototuneusa.com/break_in_secrets.htm

The article contains a procedure that makes a lot of sense to me, however, it is not the typical "be gentle on it for 500 to 1,000 miles" approach that we are so used to hearing.

Jeff

DAR951

Then of course there's the "Bon-Ami" technique...

Once saw a major engine builder dump a cup of kitchen cleanser down the intake of a brand new chevy F5000 race motor that was pumping oil like crazy into the puke tank, 'cause the rings wouldn't seat... granted this was 10 minutes before the start with no time left to change to the second back-up motor... Worked well enough to finish with maybe a quart or two left...

However, probably not exactly what you're looking for

Zu_langsam

Hmm, Dar I don't know about that But yeah this is a non street legal car so we are not going to take the risk of driving it around. If a 1/2 day or dyno time is only 300 dollars or so that will be the way to go, I'll call around today.

Sach951

For Bimmer forums check out roadfly...

http://www.roadfly.com/bmw/forums

I frequent the E30 forums They archives are full of excellent info.

The racing guys on there speak thus: Drive it like you intend to drive it from day one. THus if you shall be racing, run it hard from day one as described above in the engine tuning secrets guide.

Best Wishes,
Sach