Running in?

[911 wide]

I am re building my 964 motor, can any one advise the best way to run in the motor.
How many miles?
When to change oil and filter?

[HawgRyder]

With any newly built engine I run in at varying RPM's for 25 - 35 minutes on the first run...then drop the oil and filter.
This lets me see if there is any crud inside (when I look at the oil).
Then...500 miles...oil and filter again...and look at the oil.
At this time....check head nuts for torque...reset valves...check EVERYTHING!!!
After this...every 3000 -5000 miles...whatever you feel comfortable with.
And the knowledge that each time you checked the oil...no bad stuff in it!
Oil changes are the cheapest form of maintenance you can do for your loved one.
Bob

[E Sully]

Keep under 5,000 rpm for the first 1,000 miles.
Vary engine rpm, don't lug the engine at low rpm. Use engine braking to help seat the rings.

[hcoles]

Originally Posted by 911 wide

I am re building my 964 motor, can any one advise the best way to run in the motor.
How many miles?
When to change oil and filter?

This is well described in the Wayne book.

[911 wide]

Thanks for all of your advice
John

[Ronnie's.930]

Originally Posted by E Sully

Keep under 5,000 rpm for the first 1,000 miles.
Vary engine rpm, don't lug the engine at low rpm. Use engine braking to help seat the rings.

Why would you limit the RPM to below 5K for 1000 miles? In my experience, after three heat cycles it is time to start ringing the engine out on a dyno (or elswhere) . . .

[E Sully]

If you read Wayne's book, 1,000 miles is his recommendation for complete break in before dyno testing.

[Ronnie's.930]

I wonder what his logic is - very different thinking from what I am familiar with . . .

[E Sully]

A scan of my manual's recommendation.

[Walt Fricke]

The counter theory, at least for race motors, is to start it up, do a quick checck for oil or other leaks and things which might have been overlooked, and put it on the track (or dyno) and hammer the piss out of it. Said to seat the rings during the "golden time" when the cylinder surface is still rough enough (not too rough, of course) to do a good job of mating the rings to it. Some motor builders swear that motors run in this way seal better and are always faster than those which are babied.

Me, I can't break in a race motor - I'm not going to pay for dyno time to do anything other than tune it, which requires full power runs, and I'm not going to pay for track time to putz around.

Old VW run-in involved lots of oil changes, but those motors had no oil filter at all.

So, as is often the case, one is left to decide for himself how best to do it.

One would like to believe that Porsche had some engineering studies behind its recommendations, where engines were subjected to various regimes of break-in, and then tested for power output and ring seal and whatnot, and then torn apart to check wear. Cams and rockers sometimes are asserted to wear in to each other to account for slight differences in surface angle, or to self-harden against each other. Not clear to me why these break-in systems would affect that one way or another. Maybe there are engineering papers out there reporting the results of some testing like this?

I am by nature a bit of a skeptic. We are told that the proper way to bleed brakes is to start with the caliper farthest from the master cylinder. Well, since the late 1960s all cars have had tandem MCs, and all Porsches have had the split be front and rear. Which means that what happens to the front circuit doesn't affect the rear, and vice versa. But the advice never changes. And the difference in line lengths for the right and left rears is miniscule, even if the left front (on a LHD car) is a bit shorter then the right. Why would it matter?

Of course, believing things to be so because that is the most convenient has its pitfalls as well.

[lindy 911]

I found that an engine will run it's life like it was run the first five minutes. If you want a fast one...

Start it, time it, check for leaks and pressure and if all OK stomp it.

That's just me of course, your experiences may vary.