Break-in procedure tips?
 

I've been studying various write-ups on this topic. Wayne's book suggest 20 minutes at 2000 rpms to break-in the cams and then changing the oil before going on a first drive. But, I think that some would argue that this doesn't help seat the rings. The need there is accel/decel to prssurize both sides of the ring to seat them.

Should I maybe start it up, run it in the driveway for a few minutes checking for leaks, etc, and then take her for the first 20 minute drive to get the rings seated?

Let's start some dialog on this...

Run it hard, not red line but 5ish, don't baby it for Gods sake. dialog started:

Ed,

As far as "breaking in the cams" goes, the amount of valve spring pressure is pretty much a constant so you can get the same effect, starting the process of wearing the cam lobes and rocker faces against one another, whether the engine is at idle or at redline. (Obviously if you are floating the valves you're outside the envelope of break-in operation) So I wouldn't run the engine at idle for any length of time to facilitate that.

I would warm the engine up by gently driving to a country road without much traffic. Then drive it like an NYC cab driver: full throttle in 2nd or 3rd gear to 5K, lift for a second, stand on brakes. Full throttle, stand on brakes. You want to achieve high cylinder pressures and plenty of vacuum on the overrun. Obviously personal safety and regard for Law and Order take precedence over the ideal break-in but you get my drift.

I think we're on the same page on the drive portion, I guess you're confirming that maybe the 20 minute "high idle" isn't needed. I'm not leaning to a short run in the driveway on the first start to check that all is well and to yell yeeha and grin from a job well done. Then, it's off for a drive.

One note though, shouldn't one allow the engine to do the braking to get the full effect of the vacuum?

Ed, engine braking would be better, I was thinking more along the lines that with stock 915 III-NT-23/29 and IV-QQ-26/26, a 7:31 and 24.2" tire, you'd be doing a cool 64 and 81 mph at 5,000 rpm. Then again you DO live in Texas, it's not like it's FDR drive or something.

http://www.mototuneusa.com/break_in_secrets.htm
http://www.aircooled.net/gnrlsite/resource/articles/engnbrkn.htm

"Drive Friendly, the Texas Way" Dolph Briscoe, former governor of Texas and on all the signs welcoming you to Texas.

I've got the perfect rd for you, FM 782 from Henderson going north through a lignite mine. Great road, long curves, and you can see ahead for miles!

I've been wondering about this too. I'm doing a 2.7 rebuild right now, but the cams and rockers looked fine, so I'm reinstalling them as-is. Rockers were bagged according to position, so I will have all the rockers back in the pre-rebuild positions. No break-in required - so I've been thinking I'll just skip the 20-minute deal and hit the road. Thoughts?

Charles, thanks for the links.

I'm still kind of confused, however, as there is a lot of conflcting info out there. In fact those two links are about 180 degrees apart.

I've got new cams, rockers and rings. If you do the 20 minute high idle for the cams and rockers, that seems to be not as good for the rings, as there is no load on the engine.

If I start it, check for leaks, and drive it with the accel/decel mode under 5K for 20 miles or so to get the rings seated quickly, do I do disservice to the cams/rockers?

I wonder if anyone has ever torn down their freshly rebuild engine and documented the condition, rebuilt it, started it, driven it a different way, torn it down again, documented it, etc etc. point being, start it, let it warm up, check for leaks, listen to it, then drive it at different speeds, break it in at different speeds, then take a trip. IMHO

Ed,

Great job on the rebuild. Hope to see you at the track in the Spring.

I agree with the drive it hard group. I think I would use the "high-idle" method only to look for leaks and verify timing. This is not really needed with a Motronic car. So, as long as you have no leaks, take it for an easy drive until it warms up and then build as much cylinder pressure as you can. Foot to the floor to an rpm point above your peak torque value (around 5K for a 3.2) and then snap closed throttle. Rinse and repeat for as long as the road allows.

Closed throttle decel down a hill is supposed to work really well.

The decel is very important and should not be overlooked. High vacuum creates pressure on the other side of the rings and sucks oil up into the cylinders. All I have been doing for 400 miles is this type of driving.

On my motor we ran it at a high idle while we screwed around with the computer setting base timing and injector pulse. Then on the dyno it went for 3 sessions of accel and loaded decel.

I changed the oil/filter after about 20 mins of total run time, again at about 125 miles, again at 300 miles and am doing it right now before it heads back to the dyno for the full power tuning.

You should feel the motor get stronger (sepecailly the engine braking while deccelerating) as you put the miles on during the first drive.

Keep an eye on temp as well. Don't take it much above 3k until you have some oil temp and do not let it get too hot. Also, do not lug the motor (not that you should with a broken in motor anyways) but DO NOT lug one with new cams/rockers.

Cheers

Thanks gents. I think I'll start it for the leak check and then drive it to round out the first 20 minutes, then back home to change the oil.

I started to put the engine back in today (I'd dropped it without the trans) and cannot find enough front-back room to get it back in.:mad: To clear the spindle with the TO bearing and the mount studs requires the engine to be too far back into the rear body sheetmetal.

I'm thinking about taking the fan pulley off to buy that small bit of room, but I should probably just cut my losses and drop the transaxle, and mate it outside the car, and put it back in as normal. I thought having the car on the lift would make this all feasible, but the clearance is a big snag.

grab some c/v joint gaskets if you do drop the t/a

If I did not replace the cams or rockers does that mean I don't need to bother with the 20 minutes of idle time? Mine all were in perfect condition and everything measured in spec. Am I to understand the 20 minute idle is specifically for the cam/rocker arm interface to set up? I put everything back exactly where it came from so that should not be an issue in my case. Am I missing anything?

better safe than sorry... I feel that any and all engines that have invasive procedures, should be re-broken in to some degree... again, better safe than sorry...
just my 2 cents worth not asked for
Good Luck and report back how it all works out!
Bob

The "high idle" is SOP for break-ins on any 4-stroke, not just Porsches. The intention is to insure that plenty of oil is splashing around to lube the came lobes and lifters as they wear into a mated state. In the "old days" people would often start a new engine, set the idle, and let it run for an hour to gently break it in. That was fine for everything but the cams which were lubed mostly by splash and could suffer during this critical period if not well oiled.
regards,
Phil

The 20 minutes also helps to make sure the engine is up to operating speed. I'm about to startup a new 996 engine tomorrow. I will let it run for less time because this is a water-cooled engine, and will warm up to operating temp a lot quicker. I would keep with the 20 minute or so warm-up / wear-in period...

-Wayne

Here are some good tips on break in:

http://www.mototuneusa.com/break_in_secrets.htm
http://www.aircooled.net/gnrlsite/resource/articles/engnbrkn.htm

We successfully broke in the new 2.9 engine for my wife's Boxster using Brad Penn 30wt break-in with no issues. I'd have to say on this fresh engine, the first drain was the cleanest oil I've ever seen out of a fresh engine.

I was leaning towards doing the 20 minute in the garage anyway since it would allow me to keep an eye out for fuel or oil leaks or any other issues that might crop up. I'm running out of excuses to put it back in and fire it up...I'm just going to have to bite the bullet and go for it. There's no way in hell I'd have even considered doing this without Wayne's book.

I only read and try to draw conclusions. I've read about break in for, what, 30 years? The camshaft manufacturers have their own agenda and it's always been the 20 minute deal. At less than high idle, you have too low of oil pressure.

Why would this be bad for the rings? Do the 20 minute routine for the cams and then do the accelerate/decelerate for the rings. They won't wear the cylinders smooth in 20 minutes the way I see it.

I feel ya man. Went through the same thing last year. I was hesitant when it finally came time to turn that key.

No worries, it will work out fine.

I've been building performance engines of various nature and manufacture for over 15 years now. My break-in procedure has always been that of to pre-pressurize and bleed the oil system, and allow a full and complete warm up period of the motor at a moderate idle(1000rpms or so), leak and temp checks, inspect sub systems, etc. Typically this will take up that 15-20 minute initial run period at which point I shut it down and drop filter/inspect the oil and ad fresh lubricant and filter.

The next step I do is to follow the ring manufactures specified initial ring break in procedure for that exact make of ring being used in the engine. 99% of the time....the ring manufactures will tell you to run it hard. Hastings for example, will tell you to run the engine/vehicle at speed from roughly 30-60mph in a 1:1 gear ratio at WOT, then decelerate in gear to pull vacuum. Do that 10 times for an intial ring break in.

We're not bouncing off the rev limiter of hitting fuel cut, nor are we lugging the engine which puts excessive side loads on the rings/pistons. Porsche break ins I'll typically swing them out to sub 6K during the break in for reference. Some Audi and BMW race motors that'll be 8K rpms. It's all subjective and solely based on the motor in question and build specs of THAT motor.

After that initial run I then drop and filter the oil again. The motor is then run hard on a dyno for further break in and power readings, or put right into use in spirited/track driving fashion.

Rings need compression/vacuum to seat fully and properly. For gas ported pistons using low tension ringsIT'S AN ABSOLUTE MUST.....NO QUESTIONS ASKED RUN IT HARD. Babying the motor is not going to help it any for certain.

Vacuum decel is super important too, so don't just clutch the car and coast to a stop during the initial WOT pulls (dyno, street, or track, doesn't matter). Vacuum decel aid in the rings' ability to deglaze the cylinders. New engines have a good amount of blowby and the walls can glazed very easily due to the fuel/oil contamination on the cylinder walls. Glaze prevents proper ring break in.


This is how I do it. "Simple" as that :)

Spot on Adam!

Adam, I wonder if you could expand on how you "pre-pressurize" the oil system. I've been giving myself a headache trying to come up with some "kluge" to do this very same thing but nothing is coming to mind. Does this require some sort of special equipment only a race shop might have?
TIA

Theoretically, I guess you could use an accusump, fill it, close the valve, and pressurize it to pre-oil the engine if you used a manual valve.

Buck:

I kept my coil wire off and my fuel pump relay out and cranked her over for several seconds. I think a couple of shots of 15 seconds on the starter will get you what you need. It is amazing how quickly you can hit good oil pressure under just the starter motor.

Usually we do that with the plugs left out and pack the oil pump with vasoline during assembly to help build pressure faster.

It's interesting to note that doing this we never were able to build enough pressure with my m96 engine for the oil pressure light to go out. We ended up having to fire it up for a split second, then shut down. After a few cycles, the oil light went out, then we let it run.

It's nothing super special, but is a tool that I made here for this procedure. I took an old old pressure sender and made a screw in adapter out of it. Using an electric pump and a rather simple hose/regulator I can force feed oil into the motor through the pressure port(turbo feed line port on case for example). I have a clean SS tank that I fill with ~ 2 gallons or so of fresh oil. Hook up the pump system, pull the bottom case drain plugs and/or sump cover, and run the pump(put big catch pan underneath.

Usually back feeds at about 20-30psi pending oil viscosity, but it purges the entire system of air. I'll then drain the case and do a proper oil fill up and crank the motor. I'll typically build solid oil pressure withing 5-10 seconds of cranking the engine. Then I fire it up.

I made the system specifically for hydraulic lifter type motors as it purges the valve train of air almost instantly but I just keep making more adapters from various fittings/spare parts to suit any engine I break in here :)

The pump I use is an old Tilton diff fluid pump that I cleaned and rebuilt, but any good 12v pump that can handle petroleum will work just fine. The stainless tank is just an old water based type fire extingushier. Works perfect for what it does!

Cool... Adam, can you show a picture of the adapter~pcs you fabbed up to make the connections to the tensioner.
Thanks, bob

Yeah I'll dig it out today and take a picture for you guys.