Running in (Break in) rebuilt motor

[Merv]

I have read what I can find on the processes of running in a fully re-built motor (as against top-end-only re-builds).

There are some variations on the process and most point to the fact that the replacement parts these days (e.g., Nikasil and JE pistons) have finer tolerances and require a different approach from those recommended by Porsche 'back in the day'.

For example: http://www.early911sregistry.org/for...ighlight=Break

and: http://www.mototuneusa.com/break_in_secrets.htm
and of course Chap 6 of Wayne's book.

Common elements of the 'advice' given seem to be the importance of the first 20 minutes and 20 miles/40kms, the use of dino oil and changing oil and filter regularly, finding a long hill and going up and down that, and checking valve clearances and head torquing within the first 500-1000kms.

I know that this process can be over-thought, but would be most interested in any experience or advice that others have had on this important issue.

Thanks,

Merv

[Fishcop]

I've done a couple of engines without drama... You're right, it all happens (or doesn't) in the first 20 minutes.

The first 20 minutes are at 2000rpm - this is to initially bed the cams and other metal-metal surfaces. Drain oil and refresh. CHANGE OIL FILTER. Then I do 200km gently, it can be around town and importantly it's NOT at constant throttle. Check engine (I use an infra red thermometer to check head temps and to confirm gauge readings). Drive another 300-500km with a little more throttle application and find some gentle inclines and declines. Drop the oil. CHANGE OIL FILTER. Set head studs again, do valves. Start driving a bit more "real world", but not red-line, up the 1000k mark. Go over the car again - may change oil... check and see if it's still a little "sparkly" - if it is change the oil and the filter.

From 1000k if it's all running nice - drive it! Change oil every 6 months regardless of mileage, filter every second change.

I'll be cheating with my 68 engine and running it up on Promotive's engine dyno which has a porsche specific program Michael has written. Engine is run in by the computer on a load cell attached to the flywheel. Any issues are identified instantly and the computer will shut the engine down and report.

[Cairns888]

This will be a very interesting topic Merv. I am keen to know as well from a mechanical point of view. Looking forward to some answers on this one.

[Cairns888]

And that was a good answer John!

[Merv]

Thanks John. I believe that Don also may have a dyno and I might ask if he would use that as well.

The first '200 kms gently' will be on the road back to the Sunshine Coast, avoiding the city traffic using Campbell's tunnels, and lots of speed/revs variation. Time of day could be relevant as well I guess. Will need to keep an eye on gauge temps and will take the infrared thermometer as well. Good suggestion John.

[klasikcis]

Slightly different my last Datsun 2000 engine was rebuilt with lightweight rods and ceramic coated pistons and a corresponding weight reduction off the crank and then a lightened flywheel. It was run in on the dyno hard from the start oils filters everything changed then progressively taken up to 7000rpm. Bolted into the car new oils then driven hard from day 1.
Nev

[CamBiscuit]

When the 2.3 engine was built Mark Poole also ran it in on the dyno.

Good to spank it hard from that point on…..although it took me a few hundred keys to get brave enough to take it close to 8,000rpm ;-)

[Cairns888]

Brave referring to wallet damage I would expect Cam!

Maybe a midnight tunnel mission Merv! Stick on a few GoPro's and a dreadlock wig and make a arty video clip.
Oh that's been done (more than once)

That way you don't get stuck in traffic and idle all the way home. Low rpm, low oil pressure.

See you at the Hill Climb if not before. My car is in pieces so lots to do this week.

Jim

[9er]

My Carrera engine was run in on the Dyno.
It is standard procedure for Mark Poole Motorsport, as John suggests the engine can be put under load, quite specifically.

[Merv]

Will call and see if I can arrange that today thanks Chris. Yes Jim, city stop start is not a good idea but also constant highway isn't either. I might have to curb my enthusiasm and get Don to do the first 100-200 kms.

[Merv]

Don's view is to run the motor in initially in the shop and then 30ks on the road with variations of speed/RPM/load, which he will do. Then it is good to go with the normal provisos about oil change at 500kms. No head stud tightening as he has done this progressively 3 times already over 3 days of re-assembly. I am a compulsive oil changer so it will get a few more with close inspection!

[Paul Ford]

I've done a couple of engines without drama... You're right, it all happens (or doesn't) in the first 20 minutes.

The first 20 minutes are at 2000rpm - this is to initially bed the cams and other metal-metal surfaces. Drain oil and refresh. CHANGE OIL FILTER. Then I do 200km gently, it can be around town and importantly it's NOT at constant throttle. Check engine (I use an infra red thermometer to check head temps and to confirm gauge readings). Drive another 300-500km with a little more throttle application and find some gentle inclines and declines. Drop the oil. CHANGE OIL FILTER. Set head studs again, do valves. Start driving a bit more "real world", but not red-line, up the 1000k mark. Go over the car again - may change oil... check and see if it's still a little "sparkly" - if it is change the oil and the filter.

From 1000k if it's all running nice - drive it! Change oil every 6 months regardless of mileage, filter every second change.

I'll be cheating with my 68 engine and running it up on Promotive's engine dyno which has a porsche specific program Michael has written. Engine is run in by the computer on a load cell attached to the flywheel. Any issues are identified instantly and the computer will shut the engine down and report.

Your car might be finished by the time he gets my engine done.

[Fishcop]

Your car might be finished by the time he gets my engine done.

Nup. Need a cage mod done... Won't take my car until yours is done