Engine start up and Break in first impressions, and a question
 

Hi everyone,

Started up my 1989 911 3.2 yesterday after a full engine rebuild. Mileage at teardown was 220K and I was getting about 250 miles per quart of oil.

Bored to 3.4, Dougherty Racing DC-15 cams, and Steve Wong 91 Octane chip. Factory exhaust and CAT left in. Car was and will continue to be a daily driver.

Car started and ran smooth from the beginning. The 20 minute camshaft / rocker arm break in at 2200 RPM went fine. Oil drain and new filter, and followed the steps in Wayne's book.

Road break in went smoothly. I know the idea is shift often, and vary RPM's with medium to hard acceleration uphill, engine braking downhill, but honestly not being allowed to go much over 4K and not much less than 2K is pretty tedius and I hope in the spirit of "vary the RPM's constantly". I know there are a lot of opinions on this topic.

Engine runs very smooth, pulls strong, and idles smoother than my old Autothority chip that was in the car when I bought it.

Oil pressure didn't really change much on the high side. Didn't get much over 3.5 bar when fully warmed up before rebuild and same after. I am pretty sure my clearances were where I wanted them to be. On the low side at idle, I have more pressure than I used to. I only have 100 miles on the engine, but it seems like the pressure isn't getting much below 1.5. I'll pay more attention as time goes on. It's HOT here in Western WI this 4th of July weekend. 90+. Oil temps never got much past horizontal on my gauge, which is similar to previous experience pre-rebuild.

One pretty insignificant observation, but I'm really curious about other's experience. When draining oil, I am not seeing ANY metal bits / sparkly stuff. I guess I was expecting to see lots of silver dust. I used Brad Penn Break In 30W oil and it really didn't look much different coming out than going in. Same thing with next batch of oil. No bits on either magnet. I think I had more on the magnets pre-rebuild than now... I assume / hope this is somewhat typical for my particular rebuild configuration.

One other question. If at start up this morning after the full cool down last night I had no smoking, does that suggest my rings are nearly seated? I suppose that's not a good metric. I'll keep track of mileage and oil consumption. Just a curiosity question.

Very excited to get past the 500 and 1000 mile mark so I can get up in to the RPM's where I think the Cam and Chip will develop more power. Right now, things are pretty benign.

This was my first engine rebuild. Lifelong wrench turner, but I've never done an automotive project anything like this. Continued Thank You's to everyone that answered my seemingly endless list of questions, whether they were simple or complex. I'm guessing the questions will continue for a while...

Regards,

Mark

Don' hold back on the revs , Drive it now the way you want it to run .
You need to put the load everywhere on the cylinder walls , the only way to do that is to vary all inputs .
Have fun

Oil pressure gages & senders are not exactly precision instruments. I used to have a little over 4 bar as max pressure with RPM's above 3000, then the sender went flaky, got replaced, and now I have 3.5 bar as my max pressure.

I imagine the metal being worn off during break-in is too fine to be visible as "glitter", and the oil isn't sitting long enough for the magnets to attract much? FWIW, if you mix the black assembly lube with some fresh oil in a glass, it can look quite glittery in sunlight ...

This is exactly correct. There is a lot of experience in the racing world (they don’t baby their rebuilt engines after rebuild), from motorcycles to F1: vary the load constantly and don’t be shy about high RPMs. “Run it like you stole it“, to borrow a phrase. Also, there is some metal in your oil, but you just can’t see it much. Don’t expect big shavings or anything (if you do see that, expect something bad). These engines have pretty tight tolerances between pistons, rings, etc., and the nicasil on the walls helps achieve pretty smooth finishes. The wear occurs in the hone grooves and, once seated, which can occur pretty quickly, you are set. Be sure to keep oil samples from each change and send for analysis to confirm what’s in there. If you aren’t seeing any smoke, whether at idle, load, or coasting (engine braking), you are probably good to go. And give it some revs!
Congratulations on your first rebuild...you should be proud.

Drive it like you stolen it after the 20 minutes of initial running in. Don't hold back throttle or rpm.
That was my method, did a leak down recently that showed 1% or better.

The old saying from the south , Brake it in slow and it's never going to go .

Brake it in fast and you know it's going to last .

Congratulations on your successful build. And as others have said, don't be shy with the revs, just don't keep it up there too long and vary the speed. As far as millions of flakes in a 20 minute run time oil change, I have built many engines of all types and if you are seeing that, something wasn't right. No harm done with the multiple oil changes - other than your wallet. Enjoy!

Congrats Mark, if you run down towards Madison stop in. Would love to see your car and rebuild. Mark from Merrimac WI.

if you remove the oil cap while engine is running and no pressurised air is coming out, your rings are sealed.

Chris
89 3.2

Now that is a useful bit of information.....very logical, but never thought of it before.

Thanks!

Dennis

Hi Guys,

Thanks for all of the feedback.

Chris, that’s an awesome tip on the oil cap!

I’ll be a little more liberal with the revs and throttle, but still respectful of the relative newness of everything.

Mark, I grew up in Madison (go JMM Spartans) and historically have gotten back quite often to see my folks who live on the west side, but with everything going on, trips have been few and far between. I honestly haven’t taken the 911 on a road trip since my trip from Wichita, KS to Minneapolis with my brother (owns a really nice 83 SC) when I bought it roughly 10 years ago. After I get a couple of thousand miles on the engine to build some confidence that it’s not going to blow up, I think I’ll plan a trip... Another brother of ours also has a 964, and we always talked of a family 911 reunion :)

Not looking forward to adjusting the valves. Haven’t ever done it with the engine in the car. Last time I adjusted before the tear down I had the engine out to replace my stretched timing chains. Like many things, just have to be in the right frame of mind and know that a 3 hour project is going to take me 8 the first time. Seems to always be the case with me.

Thanks again,

Mark