How can you break an engine in properly on a engine run stand?
Engine Break in
Cameronluster
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Define "break-in".
There is essentially two phases to what folks call "break-in"; the first is "breaking-in the cam and lifters", the second is "seating the rings".
Breaking-in the cam and lifters is needed on flat-tappet engines. Not especially required on roller-tappet engines, but it doesn't hurt. Breaking-in the cam and lifters can be done on an engine "run-stand", or in the vehicle with the trans in neutral. This also allows time to verify ignition timing, check for abnormal noises, leaks, top-off coolant, etc.
Seating the rings CANNOT be done on a run stand, or with the trans in neutral. You'd HAVE to have a dyno, or in the car, trans in gear to provide load. Without load, the rings don't seat properly.
Ericnova72 suggests ten runs in middle gear, followed by ten runs in high gear, with engine braking in between each run. My only comments on that would be that I run the engine up to operating temperature by driving out-of-town on a secondary highway (little or no traffic, little or no likelihood of police/highway patrol), about 20 miles, turn around, disable the kickdown of an auto transmission if practical. Get into HIGH gear, then nail the throttle as hard as possible without tire spin or detonation. Allow revs to get to or above expected "peak torque" RPM, (Peak torque RPM+ load = maximum cylinder pressure) but no higher than 2/3 expected redline. You want heavy throttle but not high RPM. This is why I don't bother with the "ten runs in intermediate gear". When you've met or exceeded peak torque RPM, lift the throttle, coast to as low a speed as will still pull in high gear. This increases manifold vacuum, which pulls oil up the side of the piston to wash away wear particles. Repeat until it stops being fun.
Fairly common for the Butt Dyno to note a performance increase especially during the first few hard pulls.
Do you do this procedure when you buy a new vehicle ? Does anybody ? Do the OEM's recommend that ? That's a 1950's holdover when the norm was, poor metallurgy , sorta close machine work , no understanding of proper cylinder honing & poor quality rings ..
I haven't bought "new" since 1983, Honda CB1100F. Yes, that's exactly what I did. Every "fresh" engine I build gets similar treatment.
I don't know or control what "anybody" does with their new vehicles.
The OEMs are run by lawyers, not engineers. They'd get sued by some *****-for-brains when they got stopped for speeding/reckless driving during the ring-seating phase of the process; especially since anyone with a credit rating can buy 600+ horsepower from major manufacturers. We've all seen videos of doofus drivers wrapping Ferraris and Mustangs and __ around lamp-posts on youtube.com. Moreover, the OEMs want to give appearances that the engines are so well-made that they don't need any "break-in", even if that's obviously not true.
Explain Total Seal giving essentially the same run-it-hard-under-load advice in the video. Process is different on a dyno, but the "cylinder pressure = ring seating" concept is exactly the same.
Further, explain why power tends to improve during the first few pulls if it's not the rings bedding to the cylinder walls via cylinder pressure while under load.
Already do. And enough data to support that belief, based on my own experiences.
I'm guessing you've never worked at a new-car dealership. I have. EVERY new car gets driven during the incoming inspection process, and they get the snot beat out of them. By the time the owner has a chance to "seat the rings" it's probably already been done by the Tech at the dealership. But that didn't stop me from giving it a whirl in '83.
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Not to mention all those 5.7 IROCs I test drove in 1986 and 1987!
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Some people broke them in.
My uncle (he’s 97 now) would order his new truck first of September and arrange to pick it up from the factory in Oshawa. Drove it home 2000 miles To southern Alberta at various speeds. He bought a new one every 5 years. Just a barebones 1/2 ton to serve as his company truck in his construction business. He started in 63 and bought the last one in 88.
There was always a line up to by his old truck.
My uncle (he’s 97 now) would order his new truck first of September and arrange to pick it up from the factory in Oshawa. Drove it home 2000 miles To southern Alberta at various speeds. He bought a new one every 5 years. Just a barebones 1/2 ton to serve as his company truck in his construction business. He started in 63 and bought the last one in 88.
There was always a line up to by his old truck.
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So after the break in process is done and rings are seated. How can you tell if they are fully seated correctly?
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When Leak Down percentages and power go up or the oil consumption goes down.
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What’s a more immediate way to know if they are seated properly ? Like could I check and cylinder walls with a borescope and be able to tell that way?
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Nope.
What I already said is pretty much it.
What are you getting at here? Is there a problem or possible problem your trying to work out?
What I already said is pretty much it.
What are you getting at here? Is there a problem or possible problem your trying to work out?
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Depends a lot on the ring selection, moly really doesn’t need much attention. Chrome needs a lot of attention and adherence to a good procedure, if not they may never provide satisfactory performance but when done right they wear forever. Simple cast iron are also sensitive to the break-in but no matter what are short lived compared to moly or chrome. This needs to be done under load for many hours. Often it is recommended to vary the load so the rings produce an in and out movement within their grooves to keep the groves clean of rubbed off ring and bore material during this period.
Flat tapped cams are very sensitive to initial break in but unlike rings don’t need crankshaft loading. They need a lot of initial protective lubrication like Isky Rev Lube and ZDDP additive in the oil then run at 2 to 3 thousand RPM for a steady 20 to 30 minutes. The moly provides initial wear protection, the ZDDP forms a chemical bond with the rubbing surfaces that is for long term protection. The high RPMs is to get enough oil throw off from the crank to insure the cam and lifters are well lubricated on their interface surfaces. Keeping the oil clean of initial wear particles is important. The two high wear points for engine parts is at the beginning and end of their life cycles. So refreshing the oil with proper additives several times in the first 500 to 1000 miles of street life is of utmost importance to long engine life.
Moly is a great initial lube product but the filter takes it out pretty quickly, plugging the filter which puts the oil system into filter bypass thus delivering grungy oil to the engine, so at least changing the filter is important but doing it and oil is the best answer. ZDDP is a consumable product it is both forming an EP layer on the lobes and lifter contact faces but also work is to neutralize acid formation in the oil. In the case of forming an EP layer this is something that heat and pressure form but is transitory there always needs to be enough ZDDP in reserve to replace the formed buffer as detergents, acids, and simply the passage of time degrades this micro-thin layer. So it constantly need to be renewed. The inter-granular reaction on the cam lobes and lifters is also subject to excessive amounts of this stuff in the oil. When the concentration exceeds about 1800ppm the desirable characteristic of EP film formation begins to go in reverse, so more of a “good thing“ is not a good answer.
Roller cams are not so sensitive break-in. Keeping them well oiled at assembly is plenty sufficient.
As you should see from this the needs of ring break-in and that of a flat tappet cam are different. However, the needs of the cam must come first.
Bogie
Flat tapped cams are very sensitive to initial break in but unlike rings don’t need crankshaft loading. They need a lot of initial protective lubrication like Isky Rev Lube and ZDDP additive in the oil then run at 2 to 3 thousand RPM for a steady 20 to 30 minutes. The moly provides initial wear protection, the ZDDP forms a chemical bond with the rubbing surfaces that is for long term protection. The high RPMs is to get enough oil throw off from the crank to insure the cam and lifters are well lubricated on their interface surfaces. Keeping the oil clean of initial wear particles is important. The two high wear points for engine parts is at the beginning and end of their life cycles. So refreshing the oil with proper additives several times in the first 500 to 1000 miles of street life is of utmost importance to long engine life.
Moly is a great initial lube product but the filter takes it out pretty quickly, plugging the filter which puts the oil system into filter bypass thus delivering grungy oil to the engine, so at least changing the filter is important but doing it and oil is the best answer. ZDDP is a consumable product it is both forming an EP layer on the lobes and lifter contact faces but also work is to neutralize acid formation in the oil. In the case of forming an EP layer this is something that heat and pressure form but is transitory there always needs to be enough ZDDP in reserve to replace the formed buffer as detergents, acids, and simply the passage of time degrades this micro-thin layer. So it constantly need to be renewed. The inter-granular reaction on the cam lobes and lifters is also subject to excessive amounts of this stuff in the oil. When the concentration exceeds about 1800ppm the desirable characteristic of EP film formation begins to go in reverse, so more of a “good thing“ is not a good answer.
Roller cams are not so sensitive break-in. Keeping them well oiled at assembly is plenty sufficient.
As you should see from this the needs of ring break-in and that of a flat tappet cam are different. However, the needs of the cam must come first.
Bogie
Piling on with an additional question...
I've read that when trying to seal new rings you want to get the motor primed so that it starts on the first or second revolution. Why is that? I mean I've spun the motor dozens of times by hand when installing the rods/pistons. And then another dozen or so times when setting initial valve lash.
I've read that when trying to seal new rings you want to get the motor primed so that it starts on the first or second revolution. Why is that? I mean I've spun the motor dozens of times by hand when installing the rods/pistons. And then another dozen or so times when setting initial valve lash.
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I think you might have misunderstood the reason....it isn't quick fire-up for ring seating reasons...this is for flat tappet cam break-in reasons.
Prolonged cranking on the starter, either to prime the oil system, get timing right, or have a mechanical fule pump fill the fuel bowl on the carb,... is a bad for the new flat tappet cam. It only gets oil from splash oiling bled from around the lifter and from thrown off oil from the spinning crankshaft, so the entire time you spend cranking on the starter all you are doing is wiping assembly lube off the lobes.
If you've got a roller cam, the requirement to get it fired up with minimal cranking no longer exists.
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