Initial startup questions on a rebuilt motor

[RickKlem]

I installed my rebuilt 3.0L into my car this weekend and I’m getting ready to startup it up after a long (9 months) wait.
I have searched the post about brake in procedures and I was wondering how critical it was that I get it running correctly and out on the road to seat the rings. What I mean is, I have read many post that say NEVER start it up and let it idle in the garage for very long. What is very long, I guess I need to start it up, let it idle for a few minutes until it reaches proper op. temp. (?) Checking for oil leaks as it is warming up. And then take it out on the road varying the rpms . Is this Okay?

What if there are issues like the ones Leland and others have faced on the initial startup, i.e., fuel pressure, ignition timing, or popping sounds from the air box, and co setting. If I’m unable to get it running right a way because of any of the above issues does this affect the way the rings will seat or does it have no relevance?

Do I just concentrate on getting it running smooth enough to drive to seat the rings and then worry about setting the timing with a light, and adjusting the CO setting (too rich or too lean) later?

As always thanks for any input on the subject

Rick
1977 911s with a 80 3.0L

[mb911]

Rick

First of all answered your PM.

Second set timing and go out and run it for a 10 minutes or so bring back and check for leaks set idle/co/airbypass etc. Go out and run it for a while longer (10 minutes) bring home and shut it down recheck everything and give it about 200 miles of good treatment but not race car type. Don't baby it . If something is going to go wrong it will within the first 30 seconds or so.

Good story for you
I did the same project as you and while checking things out I replaced the crankcase breather gasket and a few others as only redid the top end along with new rings. When I pulled the nuts off the crankcase breather I left the washers on it. I was then distracted for a moment and then resumed my work. I pulled the breather off and forgot the washers where still on it. Well I could only count 3 after that> I did not know where the other one went. Well this weekend I changed the oil along whith cleaning the sump. Well ther it was untouched the 4th washer WHEW! that could have been bad. Any how double check evrything and come up to Wisconsin so We can compare

Ben
77 911 3.0
75 914-6 2.7

[kstylianos]

Rick,

If you had your rockers refinished or cams reground, the 20 minute 2K idle is essential for proper cam/rocker seating. During this period, you can tweak the timing and CO if needed (make sure to keep idle at 2K). During this time, the rings aren’t really seating. There is not really enough pressure on either side of the rings to seat them thoroughly. What really seats the rings is the WOT at low RPM's. This forces the rings outward into the cylinder wall, same thing with the deceleration down a hill, etc.

If you don't need to do the initial cam break in, I think you can get away with setting the idle, timing, and CO (if really necessary), making sure to keep the RPM's low. Once you are satisfied all is well, go for your ring break in roller coaster ride.

Be sure to check for fuel pressure leaks and build oil pressure before you start her.