Engine Breakin-What's your opinion

[Stackett]

A mechanic told me that after I rebuild my engine it doesn't matter about giving it time to break in. He stated that new cars don't have a break in period and that if you don't have everything torqued to the correct specs, it won't matter if you it wait 100 miles or 3,000 miles to let her go full speed. Let me know what you think. Before I get finished with rebuilding close to a $10,000 engine that I can't replace without saving up for another couple of years; I want to know what fellow Pelicanites think about the subject.

[jtratza]

i just had my engine rebuilt. Builder said there wasn't a breakin period but to not hold it at a high rpm for too long. Also said to come back at 30000 miles to adjust the valves.

[Rot 911]

Originally posted by jtratza
i just had my engine rebuilt. Builder said there wasn't a breakin period but to not hold it at a high rpm for too long. Also said to come back at 30000 miles to adjust the valves.

Thirty thousand miles?????????????? Even on a well broken in engine the recommend valve adjust is every 15 thousand miles.

Yes there is a break in for a 911 engine. When you first start it you want to run it for twenty minutes at 2000 rpms. Then drain the oil and change the filter. Then drive it for 500 miles alternating rpms, never exceeding 4000 rpms. Try to go down hills allowing the engine to brake while going down hill. After you get 500 miles on the engine again change the oil and filter, check the torque on the head studs and adjust the valves.

[flipper]

Originally posted by Kurt V
Yes there is a break in for a 911 engine. When you first start it you want to run it for twenty minutes at 2000 rpms. Then drain the oil and change the filter. Then drive it for 500 miles alternating rpms, never exceeding 4000 rpms. Try to go down hills allowing the engine to brake while going down hill. After you get 500 miles on the engine again change the oil and filter, check the torque on the head studs and adjust the valves.

I second that.

[JeremyD]

Originally posted by Kurt V
Thirty thousand miles?????????????? Even on a well broken in engine the recommend valve adjust is every 15 thousand miles.

Yes there is a break in for a 911 engine. When you first start it you want to run it for twenty minutes at 2000 rpms. Then drain the oil and change the filter. Then drive it for 500 miles alternating rpms, never exceeding 4000 rpms. Try to go down hills allowing the engine to brake while going down hill. After you get 500 miles on the engine again change the oil and filter, check the torque on the head studs and adjust the valves.

Down shift to brake the engine - 2000 rpms is high enough to oil the cams on the inital run in- the rest of the 500 miles should be at constantly changing rpms. No cruise control. wait until the engine temp gets to the first bar before you exceed 3000 rpms. Make sure that you have hard acceleration and hard deceleration (using the engine) More improtant during the first 500 miles.

Out of the first 500 miles probably the first 100 is THE most important to do this.

[Rick Lee]

Look at the oil that comes out after the first 20 minutes and tell me no break-in is necessary. That's nuts. You would not want all those metal shavings flowing through your engine for thousands of miles. When I did mine, we follwed Wayne's book's directions to the letter. When I adjusted the valves after 1000 miles, there had definitely been some movement AND two head studs needed to be retorqued.

[Superman]

Originally posted by Rick Lee
Look at the oil that comes out after the first 20 minutes and tell me no break-in is necessary. That's nuts. You would not want all those metal shavings flowing through your engine for thousands of miles. When I did mine, we follwed Wayne's book's directions to the letter. When I adjusted the valves after 1000 miles, there had definitely been some movement AND two head studs needed to be retorqued.

The "no break-in procedure" advice is lunacy. Change the oil very soon after its first operation. There are metal bits in there. Accelerate and decelerate HARD. Retorque head nuts frequently until they stop changing. Same with valve adjustments.

Did you put a thin (very very very thin) film of oil on the cylinder walls?

[Stackett]

I haven't started building my engine. I plan on starting just after Christmas. I'm going to start stripping the car next week so I can have it painted while I'm working on the engine.

I just wonder why there is no break in period on new cars? I understand what everybody is saying about changing the oil after the first 100 miles and so on, I just wanted to know if anybody had any documentation about the procedures Wayne states in his book and what other builders have done.

I can't afford not to. $40 for an oil change compared to $10,000 for another rebuild? I think this needs to be a Visa commercial.

Granted, if I have to rebuild, it won't cost the full amount, but I plan on this car lasting me the rest of my life. Hopefully without rebuilding it ever again. That's easy for me to say since I'm only 40 and don't plan on this being a daily driver.

Do the magnets on the sump plate help with the metal shavings? Of couse I'm sure they help, but I'm just curious how much they help and how many shavings actually show up after 100/1,000/3,000 miles.

[JeremyD]

Shine a light on the oil that come out after the initial 20 minutes at 2000 rpms. looks like a tiny galaxy in there.

And Superman is right - EVERYBODY that I sought advice from said the same thing - drive the car HARD for the first 500 miles.

I followed Wayne's book to the T - 20 minutes at 2000 rpms - change oil - Drive the car around the block for x minutes - change the oil - drive the car for 500 miles - retorque and adjust valves, change the ouil.

[Rick Lee]

New cars DO have break-in periods. When I toured the Porsche factory, I saw the giant room where they break in the new engines for something like 4 hrs. of continous running. They also drive the piss out of those cars around the factory grounds before loading them up.

[jpnovak]

After the initial run-in for cams, change oil. Then let her rip. Just make sure the engine and oil are at proper temperature before doing so.


You want high cylinder pressures to help the rings seat on the cylinder walls. The only way to get these pressures is high load - both accel and decel. Good read here.
http://www.mototuneusa.com/break_in_secrets.htm

[jtratza]

Make that 3,000 miles. Next time I'll type with the bifocals on.

[David]

It seems like people are getting away from the hold it below a certain RPM rule, because the rings may not seat without more RPM. My plan is to run my rebuilt engine at 2000 RPM for 15 or 20 minutes to break in the cams. Check for oil leaks. Change the oil with more dino oil. Drive it a few times up to temperature for a total of an hour or two. Check for leaks, retorque the heads, and check the valves. Change the oil with more dino oil. Take it to the dyno, tune the ECU, and let er rip.

[Rick Lee]

What are symptoms of rings failing to seat properly and how long does it take for this to show up? My rebuild has about 4k miles and 9 track days on it. I'm starting to use oil again, but no leaks and no smoke at all.

[ckissick]

Rick Lee answered a question I've always had. My father sold Porsches from 1955 to about 1973 and he said, of course the engines didn't smoke when they were started. And there were no special break-in instructions. If the car smoked for the first 1000 miles, and you told the customer to change oil, etc., (the usual break-in advice you hear today), they would have sold a lot fewer cars.

I go by the advice on this thread. In fact, I have an engine with about 2000 miles on it, so I just went through it. I always wondered how Porsche did it back in the day.

[VaSteve]

Originally posted by Rick Lee
New cars DO have break-in periods. When I toured the Porsche factory, I saw the giant room where they break in the new engines for something like 4 hrs. of continous running. They also drive the piss out of those cars around the factory grounds before loading them up.

Wasn't it a beautiful site? Every 15 min a brand new Porsche did a redline launch out the factory gates for 40 miles of flogging in the countryside. Brings a tear to my eyes thinking about it.

[air-cool-me]

i want that guys job...

[Rick Lee]

Geeze, those guys are scary. You really have to watch where you're going when walking around the factory grounds. Luckily,those cars are usually heard before they're seen. Rest assured, the new cars get spanked like a newborn baby.

[sammyg2]

Several different things need to get "broken in" and the proper way to do that is in conflict:

1) Bearings need to see light to moderate load and lower speeds at first, just in case there is a tight spot. That way they might be able to wear in and "scab over" instead of burn. Of course if they are installed just right it doesn't matter.
2) piston rings like to see hard load and varying speeds alternating between load and vacuum to seat quickly and properly, so that means run it like you stole it but don't stay at any rpm for extended periods. I say they are either broke in right or not within 100 miles anyway, but that's just my opinion.
3) cams: ordinarily the rule of thumb is 20 minutes at 2000 -2500 rpm, but that is more for the lifters and not cams so it doesn't apply to 911 engines at all.

My break in procedure is to try and stay off boost, at least until the oil gets warm

[Wayne 962]

There are big differences between a rebuilt engine and a new engine. New engines are perfect, with all in-spec tolerances right from the factory. Rebuilt engines almost always reuse parts, which are not new. Thus, the procedures are different for break-in.

-Wayne