break in procedure - new bearings, rings and cam

[lateracer]

In a few weeks I'll finally be finished with my b25 motor rebuild and will be ready to install and run. It's taking a while b/c it's a nights and weekends project.

When it fires, this motor will have new rings on a fresh cylinder de-glaze (not honed, cylinders were in spec) with new bearings and a new billet cam - not regrind. The head has been rebuilt with new seals, gaskets, eccentrics, etc. Old rockers and springs though - magnafluxed and shot peened. In short, a total rebuild with a new cam.

I've been reading up on how my break in procedure should go, but I'm starting to read myself in circles and almost everything I come across is in reference to a sport bike or an american muscle motor.

It looks like the "don't baby the motor" approach seems to have some credibility these days and camshaft break in seems to basically be along the lines of "keep the motor running between 2K and 3K rpm for the motor's initial 20 to 30 minutes"

So here are my initial thoughts for a break in with 30wt dino oil. Thoughts/opinions/feedback welcome.

1. Start the motor and keep revs between 2 and 3k for about 5 minutes (initial warm up) while listening for grenade-like noises, looking for leaks, loose bolts, etc. Driveway only.
   During this time I'll also be using a chunk of something or other as a throttle block to keep the tps open enough to establish a 2K rev floor.
   
   
2. After motor has cooled to ambient temp - maybe an hour - check/top off fluids. Drain about a quart or so of oil out of the pan to look for signs of destruction. Dump a quart of fresh oil in the valve cover, fire it up again, put the throttle block back in. This time, hit the roads after warm up. Twenty to thirty minutes of 50-75% throttle bursts up to about 70mph with strong deceleration as well. It'll be weird with the 2K rev floor, but it's for cam break in.
   
   
3. Motor cool off, oil and coolant check. Oil and filter change. Freeway driving (no throttle block) with short acceleration and deceleration bursts working up to 100% throttle. Two to three hours, about 100 miles. Repeat drive once more after cool off/lunch. Roughly 200 miles total.
   
   
4. Oil and coolant check. Oil and filter change. Check/Adjust valves with cold motor. Two to three hundred miles of frequent heavy on/heavy off driving with progressively longer pulls.
   
   
5. Oil and filter change. Valve adjustment. Done!

[jlevie]

My break in procedure for a race motor is:

1) Prime the oil system by spinning the oil pump with an electric drill through where a distributor would mount.

2) Start the engine and allow it to reach normal operating temperature. Bleed the cooling system as the engine warms up.

3) Once at normal temperature hold the engine at 2500rpm for 20 minutes. Watch oil pressure and temp during the run.

Change the oil & filter and you are good to go. After you've put 300-500 miles on the engine, change oil and filter again and adjust the valves.

[nando]

be careful with a new cam break in. it should come with some instructions if it's aftermarket. with the schrick you couldn't let the RPMs drop below ~2500 for a 20-30 minutes. if you do this wrong the lobes could wear out quick.

[Sirotto]

My break in procedure for a race motor is:

1) Prime the oil system by spinning the oil pump with an electric drill through where a distributor would mount.

2) Start the engine and allow it to reach normal operating temperature. Bleed the cooling system as the engine warms up.

3) Once at normal temperature hold the engine at 2500rpm for 20 minutes. Watch oil pressure and temp during the run.

Change the oil & filter and you are good to go. After you've put 300-500 miles on the engine, change oil and filter again and adjust the valves.

All makes sense except the priming procedure. Would you explain a little more on that.

[jlevie]

On the left side of the engine, near the front, is a cap covering the hole where a mechanical distributor would mount. If you remove that cap and fish out the oil pump drive gear you expose (and free up) the oil pump drive shaft. Spinning that shaft will an electric drill will run the oil pump. I use a 6mm 1/4" drive socket welded to a piece of rod for this. I'll spin the oil pump a bit longer than it takes to have pressure register on gage connected to where the oil pressure switch would mount.

Even though one has lubricated all parts when assembling the engine, the oil galleries, filter, etc., are all dry. Priming the oil system ensures that all bearing surfaces are lubricated for the first start.

Even if the engine is going in a street car and won't have an oil pressure gage, I always attach a gage for the first start and break-in so I can see what oil pressure is doing.

[lateracer]

Went with the Jlevie/Nando combo approach because the cam needed a break in too. So far, things are good.
http://www.youtube.com/watch?v=_XaOOHn2kso

[felix]

be careful with a new cam break in. it should come with some instructions if it's aftermarket. with the schrick you couldn't let the RPMs drop below ~2500 for a 20-30 minutes. if you do this wrong the lobes could wear out quick.

Any idea what the science is behind running the engine at that speed for so long? Oil flow?

[jlevie]

I think the speed was chosen to be high enough to ensure good oil pressure/flow and low enough to avoid loss of oil film as parts seat.

[lateracer]

Yeah, as I understand it the higher oil pressure at that rpm is necessary.

I peaked into the oil filler cap during the break in to see the spray bar over the cam. At that speed/pressure it's pushing a lot of oil and it's flying all over the place.

Like jlevie said, the idea is to keep an oil film on the lobes. After having my face up close and personal with this motor for too long, I'm also hoping that the oversized rocker eccentrics I have are made of a softer material than the cam. Replacing those is much cheaper and easier than replacing a cam.

[nando]

rocker eccentrics don't touch the cam, they touch the valve stems.

use oil with a good amount of ZDDP (like Mobil 1 15w50) and the cam will last a long time

[lateracer]

Hah! Too much time inhaling uncatalyzed fumes last night!

Had I not somehow turned the image backward in my head, I would have said the rocker arm surface...

Thanks for the recommendation. I'm on the lookout for a good oil to stick with and have been a fan of Mobil 1 for a while. This is the first new(ish) motor I've ever had, so I'd like to pick something good, reasonably affordable, available at a regular parts store (impossible for me to buy JUST oil when I go to a speed shop) and stick with it. Does all Mobil 1 15/50 come with high zdp or is there a different one that includes an additive?

[nando]

I don't think there is any other kind of M1 15w50, high viscosity oils are a bit of a niche market.

plus you can't really beat $21 for 5 quarts at wal*mart..

[buguhrich]

I thought you are supposed to use a non-synthetic oil for breaking in a motor?

And you can buy zdp additives at most auto parts stores.

[lateracer]

I thought you are supposed to use a non-synthetic oil for breaking in a motor?

And you can buy zdp additives at most auto parts stores.

As I understand it, the shearing friction is too low for proper ring seating with some synthetics, so I went with some break in oil and then regular 15/40 or something close to that. After about 100 miles of road testing it's on its third oil change. I'm running dino oil for an open track day in two weeks and then changing to synthetic for a two day event after that. Planning to stay with it after that.

[akinswonder]

Is this the same break in procedure for a turbo motor?