Engine Break-in New method

[ScottKelly911]

I thought this was a very interesting article and the theory behind it makes a lot of sense. I'm curious if anyone has tried this on a P-car and what mechanics think about it. http://www.mototuneusa.com/break_in_secrets.htm

[david914]

Not sure I would tout that as a "new method" as that's been the break-in method of choice for some for as long as people have been building cars. My personal feeling is that it makes sense, but it's psychologically hard to take a motor that you've spent good money and time rebuilding and go out and flog the cr@p out of it right away!

[RoninLB]

I was nervous about breaking in new rings on these engines.

I constantly "rocked" the car by flooring it till 4k then completely off the pedal in a 20mph range. I never used 5th till 1k miles.
I used non-detergent 30w
I've posted before how tight my rings turned out.
but it made me nutty to do this for the 500mi that I used for break-in.

[tsuter]

With the HD EFI twincam motorcycles, we get at least 10 miles on the dyno tuning the ECM tables with a custom build 95, 103, 107 incher before the customer ever leaves the shop. So it has seen 6200RPM many times.
The only thing we tell'em not to do is ride at highway speeds for several hours in the first 500 miles.
Something about sustained high temperature being worse vs several heat up cool downs.

[chrisp]

Not ever having broken in a motor before I tried to read all I could (wayne, my mechanic, and mototuneusa.com). Two weeks ago I reinstalled my motor and here's my log since:

1.) 20 min at 2,000 RPM with 5w-30
2.) Change oil to 1/2 10w-40, 1/2 10w-30 (cause that's what I had)
3.) 10 miles on and off throttle, never getting the motor below 2,000 even at stop signs/intersections
4.) Motor sat for one week while I was away
5.) 35 miles to my mechanic. 75% local/25% highway. Again mostly on and off throttle. One 3/4 mile long downhill stretch with engine braking holding RPM at about 4,000 RPM
6.) Set timing, set CO, set idle at 1,000RPM at shop.
7.) 140 miles from CT to RI. Mostly back roads. Avoided the highway except for about 40 miles. Again mostly on and off throttle. Several hard accelerations up through the gears and several downhill stretches with extended engine braking.
8.) 4 one way trips to and from work; 28 miles total (full cool down in between each leg)
9.) 40 mile drive with the wife (she hates the 2in/2out Dansk w/SSI's by the way)
10.) 30 miles round trip to get pre-tech inspection
11.) soon to change oil to full 10w-40
12.) some additional local driving next week
13.) 2-day Drivers ed coming up next weekend.

I'll let you know how it turns out when I hit 500+ miles. So far with around 300 miles on the clock it has used 3/4 of a quart of oil.

I have alusil cylinders which were honed using the correct felt pad process. Pistons were re ringed. I am hoping this turns into an Alusil success sotry that I can post later.

[Rot 911]

Originally posted by chrisp
I'll let you know how it turns out when I hit 500+ miles. So far with around 300 miles on the clock it has used 3/4 of a quart of oil. I have alusil cylinders which were honed using the correct felt pad process. Pistons were re ringed. I am hoping this turns into an Alusil success sotry that I can post later.

3/4 quart in 300 miles doesn't sound good. Is this typical for alusil cylinders? I just finished up my first 500 miles on my 3.2 (with Nikasil cylinder). From my dipstick reading, it didn't use any oil in 500 miles.

[chrisp]

Not sure what it means yet. I am going off of Wayne's book (which I cannot recall details) but I remember it saying something to the effect that it will consume higher amounts of oil until about 1500 miles when it's fully broken in an should settle to be within the Porsche spec of no more than 1 quart every 1000miles (or was that 1000km?).

Since you asked about alusils...they have a bad rap on this board because there have been cases where the rings don't seat well. From my understanding Nikasils are practically 100% reliable after a rebuild whereas the Alusils are less reliable to some extent.

[Glenn from Denv]

I know it's a race motor but my RSR has just recently been re-installed in the car...new rods, new pistons, rings, replated cylinders...basically split the case and re-did everything. I warmed it up for 20 minutes at 2K or so upon initial start up.

The next week end (last weekend in fact), I ran 3 20 minute track sessions. During the first one, I was short shifting at about 5K. Some of the other guys on track pointed out that I had some smoke coming out of the tailpipes (which I chalked up to the rings not bedding in yet). No one said anything about smoke during the second session (which I ran at a max 6K rpm). At some point during the 3rd session, I threw caution to the wind and let the motor scream. No smoke, not too many drips. I figure that means that the rings are sealing nicely.

I'm racing in Vegas next weekend.

[Thack]

The idea about several heat up and cool down sessions has merit. You often get blow-by on a re-ringed cylinder as witnessed by oil going the other way into the combustion chamber. Combustion blow-by gets past the rings and heats up the piston skirt. You don't want to heat up the piston too much or it will grow and possibly seize or gall from being too tight in the cylinder. A water cooled cylinder is probably more dangerous considering it has cooling water to keep it from heating up and expanding while the aluminum piston has a greater expansion rate.
So at first keep the piston cool and only run for short periods until the rings seat.

Mike

[SteveF_911]

I rebuilt my engine 2 years back, new bearings, P&C valves the hole lot new. I ran the engine in driving it to a historic race meeting.

Warmed the engine up and them checked for leaks etc. Then off to the race meeting. Drove the car 160 miles to the event through some hilly areas. Then did a 2 day historic race meeting.

I just kept the load up to the engine much as mentioned in the article.

After 2 years the engine is making good power and uses no oil what-so-ever. Looks like the rings have bedded in fine.