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Old 03-05-2021, 11:49 AM   #21
johnneilson
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Default Re: What is Engine 'Break-in'??

Yes, Brent does invoke some interesting conversations.

And while I do agree that technology today, as far as manufacturing is much better, it still has two limitations. The first is the operator of said machinery and tools, have you noticed the machinery is more complex and requires less operator input? But it still relies on an operator. (less crank handles and more switches and knobs)
The other factor are the materials that the parts are made from, at best, 90 year old metallurgy and quality. FWIW, it is pretty good, but a limitation.

I was having dinner with a very wise engineer from Cosworth some years ago and we were discussing materials and coatings. This was the time of ceramic coating everything and moly spray coatings, before cryogenic treatments. "If you have to rely on some sort of surface treatment to make the assembly live, you have the incorrect material in the parts". Since we cannot change the materials we have to make changes to design and accompanying parts, such as pistons, rings and bearings. A change to the oiling system makes a world of difference in the materials and construction.

The process of "break-in" today is a much different process than 80 years ago.

Best, John
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Old 03-05-2021, 11:54 AM   #22
katy
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Default Re: What is Engine 'Break-in'??

Quote:
Originally Posted by Mister Moose View Post
My Model A engine rebuilder instructed me to run for short periods of 10 minutes and then a cool down. The explanation was the rope rear seal would burn if run for too long, that it needed to seat from wear over a longer period of time. If the engine was run too long the rear seal would carbonize from the frictional heat before the seal was worn in.
Last time I looked, Model A engines don't have a "rope rear seal".
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Old 03-05-2021, 12:02 PM   #23
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Default Re: What is Engine 'Break-in'??

Just food for thought- when someone asks for you to challenge their theory, they will find holes in your response just as you find holes in their theory. I've got better ways to spend my time. Both sides already "know" they are right.
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Old 03-05-2021, 01:53 PM   #24
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Default Re: What is Engine 'Break-in'??

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Just food for thought- when someone asks for you to challenge their theory, they will find holes in your response just as you find holes in their theory. I've got better ways to spend my time. Both sides already "know" they are right.

I dunno, many of us respond based on our own experiences under varying situations - different perspectives - the majority of which are no-doubt valid based on particular circumstances. However, if you're already sure you know the answer, why do you ask the question?

The questions and responses are a great way to get to know personality types on this forum!
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Old 03-05-2021, 02:15 PM   #25
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Default Re: What is Engine 'Break-in'??

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Just food for thought- when someone asks for you to challenge their theory, they will find holes in your response just as you find holes in their theory. I've got better ways to spend my time. Both sides already "know" they are right.
Best and most accurate response!

Bill
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Old 03-05-2021, 05:35 PM   #26
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Just food for thought- when someone asks for you to challenge their theory, they will find holes in your response just as you find holes in their theory. I've got better ways to spend my time. Both sides already "know" they are right.

Funny, this is how i learn something new.. through discussion with folks who hold different ideas..
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Old 03-05-2021, 05:36 PM   #27
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Default Re: What is Engine 'Break-in'??

X2 Bill.

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Old 03-05-2021, 06:05 PM   #28
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Default Re: What is Engine 'Break-in'??

I won't respond with my opinion, but I will post a couple interesting reads so folks can formulate their own. Now, if someone from the "break-in isn't necessary camp" could do the same, I think we could have an interesting conversation.

https://www.compcams.com/pub/media/w...chBulletin.pdf

https://help.summitracing.com/app/an...and-lifters%3F

https://www.melling.com/wp-content/u...Rev4-12-07.pdf

https://www.mahle-aftermarket.com/na...procedures.jsp
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Old 03-05-2021, 06:23 PM   #29
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Default Re: What is Engine 'Break-in'??

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Originally Posted by PotvinV8 View Post
I won't respond with my opinion, but I will post a couple interesting reads so folks can formulate their own. Now, if someone from the "break-in isn't necessary camp" could do the same, I think we could have an interesting conversation.

https://www.compcams.com/pub/media/w...chBulletin.pdf

https://help.summitracing.com/app/an...and-lifters%3F

https://www.melling.com/wp-content/u...Rev4-12-07.pdf

https://www.mahle-aftermarket.com/na...procedures.jsp
Good Job! Bill
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Old 03-05-2021, 06:25 PM   #30
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Default Re: What is Engine 'Break-in'??

While I have never rebuilt an engine, I have often thought of the same topic as you mention Brent and what comes to mind foremost is not that the technology isnt available today- to build a motor and not have to break it in. What my concern is - is that every builder has different methods- some truer then others and I believe, therein lies the problem.
One fella goes to one hospital for treatment and is supposedly getting the best treatment avail and dies- over some miner infraction. Another fella goes to a diff hospital for the exact same thing and gets another 20 years. Less about the knowledge available then those practicing the knowledge.
Does every shop rebuild an engine the same? no
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Old 03-05-2021, 09:40 PM   #31
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Default Re: What is Engine 'Break-in'??

Content also aircraft engines have half wedge rings. Cylinder pressure forces the rings against the cylinder walls. High power settings are required for the first few hours.
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Old 03-06-2021, 03:03 AM   #32
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Default Re: What is Engine 'Break-in'??

Of the four articles melling has it right in my opinion,the use of diesel grade engine oils is spot on..Mahle, makes superior engine parts has the fire up and rev up to hold at 1500 rpm advice..Ive spent the last forty years working in,and running mechanic shops..ive never seen a mechanic do that proceedure..we ran it warm,checked for leaks,test drove tuned changed the oil and shipped it was the routine in the gas powered fleets I've been around.
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Old 03-06-2021, 09:53 AM   #33
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Default Re: What is Engine 'Break-in'??

Brent,
Specifically: Why raise and lower the engine rpm when breaking in? If done rapidly, from a high rpm by totally closing off the carb., it will draw oil into the rings and promote lubrication of the upper cylinder wall and rings thus reducing the heat being generated between these components.
I follow this practice.

All the rest? I basically agree with what you are saying.

I do have another purpose for running the long-blocks I build longer, as I am verifying them to be leak free well past normal driving loads by using a water brake/Dyno to load them. Doing this, I know when the customer picks them up that all is proper.
The customers also like the dyno report.

As to my driving and operating instructions when asked how to break it in: I tell them "Don't lug the engine" and repeat it two more times during the subsequent questions as we are loading the engine. Often, the last thing I say to them as they are departing is "Don't lug that engine!" rather than goodbye and we then both laugh. That's it!
Good Day!

BTW: I think Henry lied. I am seeing about 2 hp short on every engine I build that has close to stock bore, cam and original head. (Yes, I have had the Dyno calibrated.)

Last edited by Dave in MN; 03-06-2021 at 04:16 PM.
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Old 03-06-2021, 10:00 AM   #34
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Default Re: What is Engine 'Break-in'??

Starting in the late 70’s we would put a brand new Diesel engine in the test cell and warm it up. When the water and oil was warm it went to full power, up to 400 hp loaded by the dyno and depending on engine model. The engine was instrumented with a blow by pressure gage in the crankcase vent which had a calibrated oriface. We monitored that pressure. You could see the crankcase pressure (blow by) drop within less than a minute as the rings seated. The whole test routine took less than 20 minutes. This brief run in was the result of cylinder sleeve machining and coatings as well as coated piston rings that didn’t need “breaking in”.

In 200O I put new cylinders on my Lycoming airplane engine. Running at 75% power I was monitoring the the cylinder head temps. After about 3 hours I saw the all 4 cylinder head temps start dropping within minutes of each other. They stabilized 20 degrees lower after about 5 minutes.
Fast forward to 2018; new cylinders again. Same routine, 75%+ power. This time the initial cylinder head temps were lower after the initial climb out, about 5 minutes. Again improved machining tolerances and coated piston rings instead of bare chrome rings on steel cylinders.
Some of these coatings are manganese phosphate. You can Google piston ring and cylinder coatings see a wide variety of processes that have virtually eliminated the need for break in.

Last edited by GPierce; 03-06-2021 at 12:50 PM.
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Old 03-06-2021, 10:28 AM   #35
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Default Re: What is Engine 'Break-in'??

Quote:
Originally Posted by Dave in MN View Post
BTW: I think Henry lied. I am seeing about 2 hp short on every engine I build that has close to stock bore, cam and original head. (Yes, I have had the Dyno calibrated.)
Henry was a clever marketer. Maybe he just rounded up. ;-)


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Old 03-06-2021, 10:34 AM   #36
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Smile Re: What is Engine 'Break-in'??

Duplicate

Last edited by GPierce; 03-06-2021 at 10:44 AM.
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Old 03-06-2021, 10:43 AM   #37
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Default Re: What is Engine 'Break-in'??

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Brent,

BTW: I think Henry lied. I am seeing about 2 hp short on every engine I build that has close to stock bore, cam and original head. (Yes, I have had the Dyno calibrated.)
You have to correct the dyno reading for temperature, barometric pressure and MARKETING. 😀
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Old 03-06-2021, 11:24 AM   #38
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Default Re: What is Engine 'Break-in'??

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You have to correct the dyno reading for temperature, barometric pressure and MARKETING.




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Old 03-06-2021, 12:59 PM   #39
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Default Re: What is Engine 'Break-in'??

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Brent,
Specifically: Why raise and lower the engine rpm when breaking in?

If done rapidly, from a high rpm by totally closing off the carb., it will draw oil into the rings and promote lubrication of the upper cylinder wall and rings thus reducing the heat being generated between these components.
I follow this practice.



I do have another purpose for running the long-blocks I build longer, as I am verifying them to be leak free well past normal driving loads by using a water brake/Dyno to load them.

As others have attested to above, I do like thought provocation as it does make me think of better ways of doing things.

Dave, I do like your thinking regarding snapping the throttle closed to induce oil movement however I am unsure if it will work that way. Work with me to establish how this works. If the piston is at TDC, the oil that is on the cylinder walls is typically below the bottom oil ring as slinging it around is always under that control ring. If a quality job of boring & honing has been done, the two oil rings should be the first to seal (i.e.: re-shape themselves) to the wall's cylindrical shape simply because of their thickness. Next I would want to figure the volumetric capacity of the bore & chamber at TDC and compare it to the capacity of the manifold draw tube, both sides of the upper tube section, and the port size of both the cylinder and the opposite port to see how much piston movement would be required to create enough vacuum to draw that oil past the oil rings. In other words, my initial thoughts would be that the amount of vacuum draw from the piston moving downward will first be used to pull the air/fuel mixture out of the manifold & ports prior to it creating enough vacuum to draw past the piston rings. Since volumetric efficiency numbers are low on a L-head anyway, I would think the oil would not be sucked by the new rings. Adding to this, one would need to consider the oil rings are already scraping some oil away from the walls as the piston is moving downward which would be less oil to draw anyway. What am I missing??

I guess my thinking is that the only oil that would reach the top rings is what oil is held in the cross-hash pattern on the walls since this would be below the surface of the compression rings and the oil rings. Do you think if compression ring lubrication is a concern, then maybe adding some upper end lube such as Marvel Mystery oil or 2-cycle oil to the gas would be a better option when you are doing the initial start.

One other thing for us all to consider is why do we hone the cylinders and put the cross-hash into the freshly bored cylinder?? In reality, if we could bore the cylinder to a truly perfect diameter, and install a piston with rings that exactly matched the shape of that perfect bore, we wouldn't need to hone. So in other words, the worse the shape of the bore, then the more the rings will need to be cut to meet that bore shape.


Now with that said, an engine rebuilder can put too much/deep of a cross-hash into the walls during the machining process. When this occurs, the mechanical honing away of the piston's ring's metal continues unnecessarily and shortens the life expectancy of that ring. It also causes premature wear on the piston. So how much does this premature ring wear shorten the engine's life? Good question but I am thinking that 15%-25% of the life shortened is believable. I wish Pete Samuelson, Bill Stipe, or Dudley Moordigan would jump in with their opinions on this topic.


Dave, is your running of the engine really a 'break-in' or just running it to verify there are not any leaks and put enough heat in it so you can retighten the head nuts??
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Old 03-06-2021, 01:37 PM   #40
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Default Re: What is Engine 'Break-in'??

I want to address a small item on engine rebuilding that I have noticed. When putting my own engine back together (the block had a crack stitched), I used new tappets. I noticed that an original tappet I had was machined with a central hole up from the face of the tappet, on center, which matched a cross drilled hole. I can only conclude this was meant to lubricate the tappet bore in the block. The reproduction tappets I bought and see that the vendors sell, do NOT have this feature.
When I had my 8N tractor rebuilt many years ago, the shop I used drilled the side of the tappet bosses with a small hole to introduce lubrication to this area. Same idea, different method. I can understand how Model A tappet bores can become out of shape especially if modern tappets without lube holes are used. The only way to get lube in this area is the oil fog that may circulate in the valve chamber, which may work OK, but I don't believe that was what was intended in the original design. Do modern builders bore and re-bush the tappet bores? I would think most do not, but I cannot be sure. Does anyone have a Ford detail of the original solid tappet showing if it were drilled?
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