Breaking in a track-only motor

mikequig · 01-01-2003, 02:46 PM

What do you think?

I'm ready to finish up my top end rebuild which includes new P/C's. Since this 3.0 Euro will only see the track, how hard should I go at first? We all want longevity but I don't have the luxury of putting 500 gentle miles on this one.

Thanks,

Mike

'75 911- F class PCA

cstreit · cstreit's Garage

Mike,

I'm in the same boat... My plan is to plate and insure the car for a few weeks...

However, if you don't have that luxury:

From what I understand the most critical time in the break-in is the first 20 minutes or so anyway... The theory is to do a few runs of increasing RPM and load to help seat the rings. See http://www.mototuneusa.com/break_in_secrets.htm

THis you can probably do in the first practice session.

What I want to know is this:

The CAM break in says to let the engine run for 20 minutes at 2000 RPM, but the ring break in would not occur properly if you did this. How do you reconcile both?

TimT · 01-01-2003, 03:55 PM

Hmmm

The engine I have in my car now got broken in on the track. Yes I thought I could restrain myself from redlining the engine and be content to stay offline and let the traffic by. NOT!!!! In the second or third session I was pushing the engine to the limit....subsequent compression and leak down tests show no ills..

just makes me think well assembled engines have an advantage

Randy W · Randy W's Garage

Chris, I was there when my mechanic broke in my rebuilt 3.2. It idled for about 10 minutes, then revs were raised to 2,000 for a few minutes, then increased 500 rpm at a time for a few minutes over a total of about 20 minutes, topping out at about 4,000 rpm. A couple of blips thru this range then a change of oil (still dino oil). Then some dyno work where it was run pretty hard. Then we changed oil again (still dino). Then I seated the rings by accelerating in 3rd and 4th gear on the freeway and using the engine's compression to slow down. Then a couple of full on autocrosses, then a change to synthetic. I think that you should be able to replicate this at a couple of DE days, Mike.