First starts and long idles

[MB750]

This topic is something I'd like to share with the forum. It's a rule I follow, based on logic and the experience of other engine builders I've ran across in my travels.

During a Harley build, there was a "rule" that once you first get it running you always shut it down after 60 seconds. Maybe a few blips of the throttle, but kill it after a minute. After it's completely cool (a day later) do that again but let it run for two minutes, then kill it. Again, let it completely cool, then do the same sequence for 3 minutes, then cool down. After those cycles you're free to take it out but go easy with lots of throttle variation and engine braking for 50 miles.

Those are called Heat Cycles, and there's a really good reason they are recommended. Lemme explain...

When your engine is fresh (assuming brand new, never run, not even broken in at the builders dyno) you have a round bore with a round piston and ring pack. The problem is they're not perfectly round in relation to each other. As perfectly round as it's measured, there's some egg-shape going on, even if it's microscopically. There will be some points around the bore where there's more contact between the rough cylinder wall and the ring.

Those places are subject to something called "microwelding". Here's a really good article on it: https://www.enginebuildermag.com/2019/03/what-is-microwelding/

Long story short, improper or hasty break-ins create hot spots around the high contact areas of cylinder wall and piston/ring mating surfaces and can melt things at a microscopic level, causing blowby and power losses.

I know a lot of us buy engines that are dyno tested or factory run. Regardless, I baby all new engines specifically for this reason.

[MB750]

And here's a good video from Mahle on it:

https://www.youtube.com/watch?v=BG3FjZ49fjA


https://www.youtube.com/watch?v=BG3FjZ49fjA

[Jeff Kleiner]

I'm pretty sure that Ford, GM and all the others don't spend 3 days letting their engines "heat cycle" :rolleyes:

Jeff

[Ted G]

I always thought you should break in an engine like a race car.... Drive it hard but don't let it get too hot. Change the break in oil very early (100 miles) with more break in oil, then again at 500 miles with the the oil your plan on using.

Ted

[rich grsc]

The most ridicules thing I've heard in a long time. No engine manufacturer in world does anything like that

[J R Jones]

I did development for Harley in the seventies/eighties when the EVO replaced the Shovelhead. The EPA was a major influence because durability was challenged by the (20K mile) test cycle. That and noise drove the EVO development. Harley was well aware that their cylinder, piston and ring expertise was lacking, and valve guides were also problematic. Air cooling and the meager oil system contributed to poor durability. Hot test at the end of the engine line was very basic, start, run to hot and ship. If it broke, there was a hospital area for repair. Buying expertise, Harley enlisted Mahl to do the cylinder, piston, ring design. They brought experience and computer simulation to the table. The critical parts have to heat and grow together. The results can not be over stated. Regardless, when production was launched, low bidder Karl Schmidt became the supplier. That kind of loyalty drives development guys insane.
In my Ford racing experience it was not the top end that was problematic, it was the bottom end and oiling that ruined our days.
jim

[MB750]

I know manufacturers don't do this. They also don't care what happens to your engine after 36,000 miles.

Y'all do what ya want, I like the proof behind this so I'll do it. I like my new engines to run as best as possible. I'm not in a hurry to get on the road anyway.

[narly1]

I did a lot of research into break-in proceedure when I was getting ready to run my rebuilt by me 302 for the first time.

The main takeaways for me were to a) use an oil made for the purpose and b) not spend a lot of time running the engine lightly loaded. On the second point it was suggested to do load and unload cycles to get the piston rings and cylinder wall surfaces micro machined to each other.

Earl

[MB750]

I did a lot of research into break-in proceedure when I was getting ready to run my rebuilt by me 302 for the first time.

The main takeaways for me were to a) use an oil made for the purpose and b) not spend a lot of time running the engine lightly loaded. On the second point it was suggested to do load and unload cycles to get the piston rings and cylinder wall surfaces micro machined to each other.

Earl

Kudos for building your own engine, it will probably give you thousands of trouble-free miles.

[narly1]

Kudos for building your own engine, it will probably give you thousands of trouble-free miles.

It better, it cost me enough as compared to buying a crate or pallet engine. But I learned a ton and ticked one off of the bucket list. I'm finding that it shakes a bit much for my tastes, the plan is to get back at it while my frame is out for powder coating.

Earl

[mikeinatlanta]

I know manufacturers don't do this. They also don't care what happens to your engine after 36,000 miles.

Y'all do what ya want, I like the proof behind this so I'll do it. I like my new engines to run as best as possible. I'm not in a hurry to get on the road anyway.

Give up. Seriously. This is the modern age were number of youtube likes/views/subscribers, or volume of misinformation equals credibility. This is the age where font size is equal, logic irrelevant, and learning almost non-existent, while repeating incorrect in sufficient volume equals correct. Confirmation bias and cognitive dissonance rule. People want to believe that what they do is best, and finding affirmation via social media is more important than opening up one's brain to real understanding.

I've made similar mistakes around here and quickly learned that any information that might make somebody feel bad about the shoddy workmanship in their build is unwanted information. I still get sucked in from time to time, but I'm slowly getting better. I wish I was better at following my own advice.

[rich grsc]

Now Mike, I know you & I have had our differences of opinions in the past, but please, DON"T confuse people with logic and intelligence. ;)

[narly1]

Give up. Seriously. This is the modern age were number of youtube likes/views/subscribers, or volume of misinformation equals credibility. This is the age where font size is equal, logic irrelevant, and learning almost non-existent, while repeating incorrect in sufficient volume equals correct. Confirmation bias and cognitive dissonance rule. People want to believe that what they do is best, and finding affirmation via social media is more important than opening up one's brain to real understanding.

I experienced a lot of this during the process of building my engine. The ability to apply critical thinking to the spectrum of answers that you get in response to a question is everything.

I'd be happy to explain my technique to anybody bored enough to listen LOL.

Earl

[flyboyjy]

SO I read the article attached. It makes specific references to having raised top ring positions and it also cites the pistons being used are for uses where turbos, superchargers and nitrous are being used to make big horsepower. In all my years of building and rebuilding diesel and gas burning engines I have never seen this happen. In a quick check on Summit Racings website getting pistons like this is a special order. So personally I would not worry on this.

[mikeinatlanta]

Fixed my profile name for you guys.

While the times we live in certainly have an influence, around here I largely blame the culture resulting from the "kid gloves" policy. One certainly doesn't want to be hostile to inexperienced builders, and we certainly don't want to discourage them, however, that inexperienced new member often becomes an experienced builder giving out horribly bad advice with something learned from the last uninformed builder. If you call it out for what it is, all the other ill-informed builders jump in and the bad advice wins on volume.

What is not allowed is an in-depth discussion where the true merits of any particular subject can be discussed. Proper break-in being one of the better case-in-point subjects. Rather discussing the merits of whether heat cycles are beneficial for contact surface polish or do anything to prevent micro weld, we end up tolerating comments saying that a motor should be broken in how you intend to run it. In a forum that promotes technical discussion, such displays of ignorance would quickly be ridiculed into silence.

Maybe we should have a "Technical" section where it's allowed to call out stupid advice for what it is? A place where we could honestly discuss things like:
Use of Home Depot and Autozone quality wiring terminals vs "real" terminals
Use of Home Depot fittings (especially compression) fittings on brakes and high pressure fuel systems vs "real fittings" (hoses too)
Cheap flaring tools and resulting issues (especially the much praised Eastwood)
How certain types of RTV silicone react to aluminum and why others don't.
Anything Wilwood brakes
Chemistry, risks, applications of different composite materials
What really happens when any mechanical device is "broken in"
Blind fasters in non-blind locations
Use of a proportioning valve in the FRONT brake
The list goes on.

[narly1]

The list goes on.

You can add these if you still have any fight left in you LOL.

Piston ring end gap.
Bearing clearances
Oil: viscosity, pressure
Oil pumps: high pressure, high flow, or stock?

Earl

[mikeinatlanta]

You can add these if you still have any fight left in you LOL.

Piston ring end gap.
Bearing clearances
Oil: viscosity, pressure
Oil pumps: high pressure, high flow, or stock?

Earl

OMG, you said oil on an internet forum!!!

[MB750]

Give up. Seriously. This is the modern age were number of youtube likes/views/subscribers, or volume of misinformation equals credibility. This is the age where font size is equal, logic irrelevant, and learning almost non-existent, while repeating incorrect in sufficient volume equals correct. Confirmation bias and cognitive dissonance rule. People want to believe that what they do is best, and finding affirmation via social media is more important than opening up one's brain to real understanding.

I've made similar mistakes around here and quickly learned that any information that might make somebody feel bad about the shoddy workmanship in their build is unwanted information. I still get sucked in from time to time, but I'm slowly getting better. I wish I was better at following my own advice.

Oh I hear you, LOUD and clear. It's as if I asked some of the old farts here to abide by the mask mandate.

Going forward, I know what works for me, and from now on I'll just keep it to myself.

[narly1]

Going forward, I know what works for me, and from now on I'll just keep it to myself.

There's something to be said for "If it aint broke don't fix it" and I think that we all follow this to a varying degree.

But that being said I think there's always room to take a look a time tested method to try to understand why it works in the first place.

Earl

[Jeff Kleiner]

Can we all start calling you "The Godfather" around here? This is amazing, exactly what will work. Thank you.

Godfather, old fart whatever you like...

;)

Jeff

[J R Jones]

There is an inconsistency here in the OP and the attached reference links. To further muddle the discussion it has gone tangent with "I said", "he said" and maybe indignation.
I responded to the OP which expressed concern that the break in procedure is intended to match the ring diameter to the bore diameter. Harley had exactly that problem with the Shovelheads not just because of rings, but because the piston shape was not correct through the warm-up cycle. A questionable solution was "loose" is better than "stuck".

Mahl resolved that problem in the Evolution engine through complex piston cross section(s) and cylinder liner, cylinder cross section, and stud retention. NOW:
Micro welding as defined in the attached links, is metal exchange between the sides of the rings and the sides of the ring grooves. Not ring to cylinder. This condition is similar to rings stuck in the piston due to carbon accumulation.
Break in is about wearing the rings and cylinders to be synergistic. My concern with brief running periods is oil starvation. Time is required to get everything wet with oil, especially the ring grooves.
jim

[MB750]

Jim

I only referenced Harleys because that's where I first heard about this. Ron at Axtell did an article about it, regarding power loss on a Twin Cam. He fixed it with a fresh hone using torque plates and new rings. I was just curious if that microwelding business applied to water cooled auto engines, which apparently it can regardless of what old farts want to believe. And you're right, it's ring-to-piston related, and leads to reduced compression due to blowby. My only reference to the cylinder wall was to illustrate how the imperfect contact between a fresh bore and new ring can lead to excess heat until the ring gets filed down by the fresh bore. That first fire up of an engine when all those moons are aligned and the oil hasn't accumulated in the ring pack is my point, even though actual damage may only happen in one in a thousand engines. and even then someone might not even notice it or care.

I just wanted to do everything I possibly could to make sure my engine was solid and performed the best it could, that's all. I never thought it would lead to such polarizing opinions from the forum. You'd think I proposed putting a Hemi into my Cobra.

[J R Jones]

A buddy here in WI bought a vintage Shelby GT350 race car from CA. It had been idle more than a year after the Pebble Beach Historic races. When it arrived here it started once and died. After weeks of troubleshooting I got involved with a compression and leak down evaluation. Compression was blowing by the rings.
The float bowls were marked with fat jet sizes which lead me to speculate that it had been raced on an alcohol based fuel. That washed the cylinders clean and the CA (salt water) atmosphere rusted them. The ring lands were packed with rust.
So with short run times and ethanol fuel content, I would consider fogging oil in the cylinders. The engine builder gets the last word on these details.
jim

[bobl]

Just to add to this discussion, here’s the general process I use to break in my engines on the dyno. I first fire the engine with no coolant and no load. I’ll run it for a couple of minutes to make sure all the pieces stay inside, connections are good and no oil leaks. I then let it cool while I get the cooling hooked up. Next I’ll run it with no load varying the rpm until the temps are stabilized, set the timing and check for leaks and malfunctions. If all is well I’ll put a light load on it and step it through rpm up to around 3000 rpm, then repeat with a bit more load and rpm. Then shut it off, check everything and let it cool down. Now we stabilize the temps and start making WOT pulls up to 4000 RPM and increasing each pull by about 500 rpm until we get a full sweep. At this point it should be pretty well broken in. This process changes accordingly with flat tappet cams, abradable coated pistons, etc. I’ve done hundreds of engines and can’t say I’ve ever had a problem with break in using this procedure. But yep, I’ve blown a few up on the dyno.

Bob

[CraigS]

MB750 don't let it bother you. I enjoy very technical threads. I don't always agree w/ everything that is posted but I am allowed to ignore what I don't think is correct. This is similar to back in the day when I bought books on popular hi perf subjects. If I learned one new thing from a book, then I felt that the $ and the time was justified. In a recent thread on brake bias adjusting you made a point to me that one of my thoughts and worries was incorrect. I am happy to be corrected because I learned something. Keep up the good work and worthwhile threads.

[MB750]

MB750 don't let it bother you. I enjoy very technical threads. I don't always agree w/ everything that is posted but I am allowed to ignore what I don't think is correct. This is similar to back in the day when I bought books on popular hi perf subjects. If I learned one new thing from a book, then I felt that the $ and the time was justified. In a recent thread on brake bias adjusting you made a point to me that one of my thoughts and worries was incorrect. I am happy to be corrected because I learned something. Keep up the good work and worthwhile threads.

Thanks Craig. I love learning new things, and I come from the belief that nobody knows everything, so when I learn something new I like to share it with people who have interests related to that subject matter. Even if that new information borders on philosophy rather than science, it's still interesting and new and I'd like to share it. Sometimes I lose sight that some people are so staunch in their belief system that my words are taken as an undermining effort to those beliefs and become offended.

Oh well, that's the internet I guess. Closed minds and open mouths. :rolleyes:

[narly1]

Even if that new information borders on philosophy rather than science

All that means is that the information presented is at the time only a hypothesis and that either the technology hasn't caught up to it yet or the scientific analysis hasn't been done yet, in order to prove or disprove it.

Earl

[Railroad]

Aren't some of the crate engines run in with an electric drive motor, no ignition or fuel?
Seems I read that and it might have been related to the Coyote Ford Perf engines.

[narly1]

Aren't some of the crate engines run in with an electric drive motor, no ignition or fuel

Newly assembled engines at a big-3 plant close to me are rotated over in a test cell that monitors the torque required to do so against angle of rotation. A properly assembled engine yields a characteristic curve that proves that the rotating assembly, valvetrain, etc. are all working properly.

I know this because I've seen the test cells and have sold new torque transducers for use in them.

Earl

[CraigS]

Newly assembled engines at a big-3 plant close to me are rotated over in a test cell that monitors the torque required to do so against angle of rotation. A properly assembled engine yields a characteristic curve that proves that the rotating assembly, valvetrain, etc. are all working properly.

I know this because I've seen the test cells and have sold new torque transducers for use in them.

Earl

Now this is some new info that I never would have thought. I always assumed the just installed them and fired them counting on expertise gained over 1000s of builds.

[narly1]

Now this is some new info that I never would have thought. I always assumed the just installed them and fired them counting on expertise gained over 1000s of builds.

Here's a link on the subject for ya: https://www.sciemetric.com/blog/engine-cold-testing

Earl

[AROCK]

I have been building and racing big horse power engines for 50 years, example, a 1800 horsepower 632ci bb , build it install in car and take it to the track and make 10 quarter mile passes shifting at 7000 rpms and never had an engine fail. If you are using good quality parts your engine will live a long life.
I found the key to my builds was to set the engine up tight and at every oil change cut the filter open and read the oil for metal particles. You cannot build a quality engine with junk and expect it to last.