Engine break in procedure... (may not be the right area for this thread)

[JustJason]

So I'm curious as to what you all think. I read a few threads about engine break in's, including a guy that just blew up a 3.0L.
When I was in school, my Merctech instructor (merc master mech and factory trainer) said the procedures outlined in the owners manual are not for breaking in an engine, but to actually help aid in boat handeling especially when it comes down to a new boater.

His example was... "Merc knows that there are idiots every single year that go out and buy something they can't afford in the first place, and something off the wall. Like a gofast with twin 502's. In order to keep owners from going out of control before they know how to handle a boat of any size, they print an "engine break in procedure" in the owners manuals in hopes that the owners will follow it, and learn how to control the boat responsibly by NOT turning the key and slamming the shifter to WOT"

So in the classroom a lengthy discussion ensued. Sure the loudmouths said the bearings and the rings needed to "break in".

So the instructor asks us all... What causes an engine to grenade... wether it has 0 hours or 2000 hours. What failure(s) would you have???

The typical answers were shouted out. Spun bearing, siezed piston, rings need to seat etc....

Then we went through as many scenarios as we could 1 by 1.

Spun bearing/siezed bearing -- Oil clearences, Main journals and rod journals. If an engine is properly measured and put together correctly to specifications. And if the correct oil weight is used. Then this should never happen.
The probability of this happening on high hour engines is higher because of the amount of time it sits in between cold starts. It is cold starts that causes journal on bearing wear. Not the actually running of the engine itself as long is it is within specified rpm.
Newer engines have higher oil pressure because the gap is very small. The gap does not double in size in an engine that has 1 hour or 1000 hours magically. Specific conditions will wear the bearing faster, but it has nothing to do with hours. He states that well taken care of 2000+ hour engines will have a gap larger than when it was built, but still withing specifications.

Seized piston --- Well, what specifically causes a piston to sieze?? 2 things will. A hot sieze and a cold sieze.
Hot Siezes - If the engines cooling system was set up properly when the engine was new. And every part of the cooling system is functioning properly with no malfuntions. Then you will never have a hot sieze (which happens during a bad overheat) So what changes between an engine with 0 hours vs a properly maintained one with 2000 hours??? We don't break in water pumps. When ever a water pump, curculating pump, thermostat is repaired/replaced... we do not "re-break in the engine"
Cold siezes happen when a numbskull starts a cold engine and revs the sucker to WOT. (this is not common with 4 stroke engines) Because the piston and the cylinder are not the same material, they do not expand at the same rate. If the piston expands faster than the cylinder walls do then the piston to cylinder wall clearance falls under spec, and the piston siezes. Again this is not common. But if the piston to cylinder wall spec is within spec at the time the engine was built. Then what changes between 0 hours and 2000 hours? Not much. If anything, the 2000hr engine will eventually wear off its cross hatch, but all that does is make the piston to cylinder wall gap larger (which will not sieze a piston) and not smaller (which would sieze a piston)

Ring seating, cross hatching --- Okay... soooo, people say an engine has to "break in" to seat the rings. What does that mean? Specifically?
Rings seating into what? Into the piston? No... the rings do not seat into or wear into the piston. The rings do not wear into the cylinder walls either.
Cross hatching -- Boring a series of small grooves into the cylinder wall. Okay, for you folks that don't know. Cross hatching happens during maching and it machines a specific groove into the cylinder walls. There are many grooves machined tighty together. And as with any groove you have a high spot on the groove, and a low spot.
Now the difference between the high and the low is microscopic. A good cross hatching job will not show up on a dial bore gauge. But when the engine is running, the piston ring is riding on the high part of the groove, over the total cylinder. Engine oil, microscopically, sits in the low parts of the groove. The oil helps lubricate the rings, and helps with the over seal that needs to happen in order to get good compression.
So what are we seating again exactly? The rings don't "conform" to the cylinder wall. So are we conforming the cylinder wall to the rings? Not really. On every engine. Wear and tear, cold starts, extended WOT running, will eventually start to break down the high parts of a cross hatch groove. When it does, there is less room for the oil to hide out in. When there is less room for oil, we get poorer lubrication, and poorer sealing. The 4 properties of oil are to "cool, clean, lubricate, and seal". Less oil in the cross hatch grooves means a loss of all 4 properties.... So then the real question should be... Will I ruin my cross hatch by not following break in procedures... and the answer to that is no. Cross hatch will wear over time. But it is cold starts and hi rpm that causes the most wear... not what you do in the first 20 hours.
Not marine related... but personally i've pulled heads on many a high mile Honda and still saw good cross hatching.

Valves do not need to "break in" or "seat in" either. 30+ years ago the same may not have been said. Because the materials were a lot softer than they are today. Neither to valves springs, or any part of the valve assembly.

So what do you old salts (Don S, Bondo, Rodbolt) have to say? Would you agree or disagree with the instructor?

 

[fishrdan]

Re: Engine break in procedure... (may not be the right area for this thread)

Interesting subject

While I was building my first engine in high school the machinist asked me to bring it over when I was done,,, so he could look it over. I had about an hour on the engine when I showed up and he reached over and flipped the carb WOT.... I mean I was freaking out for the longest 60 seconds of my 17 years when he brought it back down to an idle.

His reply: "Now you don't have to worry about blowing it up"

Disclaimer: I accept no responsibility for people blowing up their engine/outdrive by doing this and advise people NOT to do so.

 

[Bondo]

Re: Engine break in procedure... (may not be the right area for this thread)

So what do you old salts (Don S, Bondo, Rodbolt) have to say? Would you agree or disagree with the instructor?

Ayuh,... I've built Alot more big Diesels than SBCs,...
For Break-in,...
We'll put a Heavy load on the truck,+ Run it, Run it Hard....
Then change the oil after 20hrs... Break-in oil is nothing but Cheap 30W, without detergents or nothing...
If nothing suspicious shows during the oil change,+ Look Over,...
It's called a Sucess,+ everybody goes back to work....

My personal boat motors,...
I run it like I Stole it....
Working the motor, Hard seats things the way they should be....

That's My opinion,... Your results may vary........

 

[Fun Times]

Re: Engine break in procedure... (may not be the right area for this thread)

Jason, I was Just curious if the stern drive it's self came up at all while talking about break in time???

I can kind of see where he is going with all of this, Because you know most of the boat manufacturers do not break in the engines while prop testing all their new style boats Any more, They just hit the throttle right from the start for the most part, The only "break in" time is on the trailer and getting out of the no wake zone. And I my self do not really remember seeing any damage done to a engine, Do to no break in time. But there was one time we had a brand new 502 engine start to knock really loud and sieze up about 4 minutes into our on the trailer break in time of 15 minutes of different rpm settings we where going to do while the boat owner was standing there, And we had to pull a all nighter to get the boat ready so he could go to the river. Then finely at 5:00 am we started the engine up and it siezed up. So I guess they can sieze up at any time, Depending on set up.

Also just in 2008 we had a new 350 mpi engine that did not set up right And the new owner had to put 9 Qt's of engine oil in just to keep it on the full line of the dip stick with in 19 hours before he brought the boat back into us for sevice, And he did not like what mercruiser had to say about the engine may not have broke in yet Because they have seen some engines take as long as 85 hours to brake in and stop using so much oil, So they said keep running it till then, And if it does not stop using oil, Then they will give him a new engine. And I am not joking here. Also he had a few little problems with the boat it's self, So he ended up with a 100% new boat, So he ran the heck out of the old one while waiting for the new one.

 

[a70eliminator]

Re: Engine break in procedure... (may not be the right area for this thread)

Had you ever discussed effects of the major and minor thrust sides of a piston on a cylinder wall in a V-8 engine? Why is a flat top piston directional? Are the loads exerted on a piston even throughout it's travel?

 

[JustJason]

Re: Engine break in procedure... (may not be the right area for this thread)

Jason, I was Just curious if the stern drive it's self came up at all while talking about break in time???

It did. And the question to us all was, "what changes in a sterndrive with 0 hours vs 2000hours". If tapered roller bearings are preloaded correctly from the start, then they will last indefinitely. (as long as they stay properly lubricated) If a bearing flys apart at say 5 hours because the owner decided to WOT the thing, then it is because it was never set correctly in the first place, and putting 50+ hours on it before you decided to WOT the motor would not have changed the same inevitable outcome.
If gear height and backlash are set correctly, same thing. The gears are hardened, they don't break in, and they don't wear out, as long as they stay correctly lubricated.
Same thing with clutch dogs and cone clutches, they do not wear out if your shifting correctly and at the proper RPM. Has nothing to do with the amount of actual hours on them.

But there was one time we had a brand new 502 engine start to knock really loud and sieze up about 4 minutes into our on the trailer break in time of 15 minutes of different rpm settings we where going to do while the boat owner was standing there

Sounds like a crank or rod bearing clearence was not measured correctly from the get go. Shouldn't have anything to do with break in. If you had a knock that wasn't piston slap, more than likely a clearence was to great. A clearence that was to great would not fix itself during break in.

Because they have seen some engines take as long as 85 hours to brake in and stop using so much oil,

True, new engines do sip a bit more oil. Your story certainly sounds exxcessive though. Was the guy running straight 20W in that engine??? Oil consumption on a new engine happens because the cross hatch on the cylinder wall is new, and alot of oil stays in the low points and gets above the rings. As the engine "wears and tears" itself. The high points of the cross hatch will start to wear down, there will be less room for oil to sit, and consumption goes down. But your not going to hurt anything by not following a the break in procedure.

Had you ever discussed effects of the major and minor thrust sides of a piston on a cylinder wall in a V-8 engine?

We did a bit and the best we could not having (instructor included) PHDs in physics, engineering, or metallurgy. During a combustion cycle, gas expands equally in all direction. But because of the angles of the cylinder and piston in any V engine. The outside of the piston (the side that essentially points to the exhaust ports) sees more of a load.

Why is a flat top piston directional?

Because when you actually measure X and Y on a piston (not Z at this point because it doesn't matter how tall a piston is) Most pistons are not round, but elliptical to a degree. Its not much, but its a measurable amount. Because the cylinders and pistons are 2 different materials, and thermally expand at 2 different rates. The pistons will expand to actually be round at their operating temperature. They make the pistons this way to help prevent cold seizing. They are directional also because the skirt, and material supporting the wrist pin is not always as (technical term coming up here) "beefy" on both sides of it. The general idea is to make a piston light as possible, but without giving up its strength. So they take away material where they can, but leave some where they have to, to support the loads on it. My question to you sir... Is what happens when you put a directional piston in backwards and run an engine. What exactly breaks?

Are the loads exerted on a piston even throughout it's travel?

Good god no they are not. But really to answer that question specifically first i'd have to have a degree in engineering which I do not. And I would have to break down a piston to its individual features (the crown, skirt, ringlands, wrist pin supports etc) and talk about the stresses and loads on every part of it during the entire combustion process.
But the question is.... What loads on a piston change on an engine with 0 hours vs 2000 hours? Nothing changes.

It was somebodys WAG that components in the engine needed to temper. So the instructor asked that student to describe the tempering process and what it actually happens, and what it actually does for metal, and how any of it relates to engine. Well that student was laughed out of class.
Unless there circumstances that physically damaged a piston or caused a piston to greatly exceed its operating temprature (preigniton and detonation) a piston could be used over and over indefinitely, through many re-builds. If it measures in spec, then it measures in spec.

Rings, cylinder cross hatch surfaces, plane bearing will all "wear and tear" themselves over the course of the engines life. But it has nothing to do breaking an engine in.

It was described to us like this... 70% of actual wear and tear happens in the highest 10% of the RPM range. So do not run motors at WOT all they time. Sure they will run fine, but keep in mind that the engine will last a lot longer if you run the motor at cruising RPM. 20% of wear happens during cold starts where there is minimal oil lubricating the cylinder walls and plane bearings. And the last 10% of wear happens in everyday running of the motor.
The point of the discussion was, if you took a XYZ brand motor, and it was built correctly and by the book. You could run it even with a moderate to high load indefinitely if you had an uniteruptable cooling supply, if you could change the oil on the fly while it is running, and if you never shut the motor off, let it cool down, then restart it.

 

[Bronc Rider]

Re: Engine break in procedure... (may not be the right area for this thread)

Lots of great info jason.
I'm not a mechanic, so I cant say I have the credentials to give a real opinion on this. What I can say is that auto racing in my area is common. There are several old guys like myself that will run an engine hard right after a rebuild. We use common sense and not go wot with a cold engine for example. Its a touchy subject as many people are the type to only go by the book. They feel you cant go wrong if you follow the manufactures recommendation. Its not really a bad thing to be that way though. Most of the time thats the only way to do things right. As far as engine break in goes, I completely agree with you.

 

[Don S]

Re: Engine break in procedure... (may not be the right area for this thread)

Personally, I think the break in is more of a "Knock the newness off the new parts" then change the oil and filter for some clean stuff.
The cross hatch is a perfect example. You can clean and clean on a newly honed bore, to where it is no longer dirty. Then you put a piston with new rings in it and run it and you will be knocking the high spots off the cross hatch until it gets to certain smoothness. This may take 20 hours to happen, I doubt it, but I don't design, test, and examine each part under a microscope. But I figure the big names like GM that builds the engine have done so and give Mercruiser, and Volvo a set of specs for breakin procedure of their engines, since they are the ultimate warrany center for engine failure.
So, would I tell my customers not to follow the breakin procedures outlined by the manufacturer, no.
Would I follow them to the letter myself on MY new engine ...............
Maybe I better not say

 

[Maclin]

Re: Engine break in procedure... (may not be the right area for this thread)

Most of the motorheads I know say basically the same thing..."Break it in the same way you are going to drive it." No break-in past the cam/lifter stage. Change oil and go out and make some noise with it

 

[dr_bowtie]

Re: Engine break in procedure... (may not be the right area for this thread)

the 1st part of your post is but only a small part of the whole big picture...

the break in only covers the "frictional" surfaces...this currently covers piston rings in todays engine...older engines had more frictional surfaces...cam lobes and lifters, rocker arms and pushrod ends...

A hot piston seizure can be more than and over heated coolant system...you can have lower than normal coolant temps and still over heat the cylinder due to high combustion temps...detonation can cause a seizure as well as lack of oil...lack of oil can cause cold and hot siezures...in 0 to 2000 hours it can come from poor maintenance from sludge in the oil rings and not getting oil to the walls...oil gets there the same way it comes off...

The oil ring is constantly saturated...it puts oil on the walls as well as take it off...loosely...mostly due to splash...although newer higher compression engines have squirters...these help oil control as well as help cool the piston...even better oil control is demanded in these situations...

the fact that another poster noted a 502 started knocking and ultimately seized up is NOT a bearing clearance that is too great...this will just continue to knock and just eat itself until it either throws (breaks) the rod or you stop running it...

If the bearing spun that means the clearance was either within spec or too tight to begin with...if it was within spec then I suspect the engine wasnt properly primed...if it was too tight and didnt have sufficient clearance this may have cause the bearing to spin....

the most part you need to understand was there WAS definitely and oil issue...the crank journal touched the bearing long enough to gall it and cause it to turn...there is a reason bearings are made of soft babbit...

once the surfaces have touched each other the damage has been done...

now on another side of the equation....the rings could have caused this...how you ask...they could have been set too tight and once teh engine fired they simply binded in the bore...the force of the piston starting to seize in the bore would put undo force on the main bearings and rod bearing as the crank will still try to turn regardless...this will knock a bearing out pretty fast due to drag...

Now the fact they tore it down and put it back together and it still seized leads me to believe the rings...

most importantly...if you measure ALL the specs and make sure all tolerances are within those specs and engine will NOT seize if it is properly primed and then run with oil pressure within spec as well...rule of thumb is a 10# rise in pressure per 1000rpm...

the reason you seat the rings as is Don posted...you are bringing the wall to a uniform surface...and yes the cross hatch is for oil control...no oil and the cross hatch can go away very quickly...

I have torn down engine with as little as 500 miles and the cross hatch has started to disappear and I have torn down V8 with good maintenance and 300,000 miles and there is still a visible cross hatch...

as far as side loading on pistons...yes there is...this natural and only a slight amount....proof of this is looking at a used piston...as you look at it you will see on the long skirts there is more wear then on the short sides...

why are there long and short sides of pistons...? to help combat side loading..

think about this for a second...as the engine turns and the crank stroke is in a clockwise rotation...the piston travels up and down...as the crank pushes the piston up it is forced to the right side of the wall...think 3o'clock...and as the piston fires to push teh piston down not only does it go down it also pushes down on the left side...think 9o'clock position....

this is aggravated more by the higher the stroke of the crank due to rod angle...this is the same load that throws a rod out the side of a block when it breaks....ever wonder why they never go straight up and straight down...

it sounds like you got the basics down and alot of that is right...as long as all tolerance are within spec and engine wont blow...but remember this..racers do the quick break in that them pop it in the car and run them down the strip full throttle...do they break alot...no

even the nitro cars dont break in the engine...they rebuild then EVERY pass and then full throttle again...

if you want to fully understand engines hang out with those tech guys...you'll learn more than your brain can handle...

my procedure is easy...build it right the 1st time...prime it well and run it...I run them 20-30 minutes and build good heat in the engine...I shut them off and let them completely cool...and then run it like I normally would...

this is on a pre-seasoned engine...new engine do have break in procedures differently because the blocks move as they season...the more heat you put in it the more it moves before it settles...

I still have the very first engine I built myself in high school..a 283cu in small block chevy with a 280 duration and 495 lift cam...10:1 peanut motor..this thing is still a stock bore stock bottom end and has seen a hard life...

runs 12 seconds in the 1/4 all day long and has seen a large amount of street life...and it has seen more time above 8,000rpm than below it...and it has logged almost 200,000 miles in 20 years and it still runs very strong today sitting in my 86 Monte...

 

[JustJason]

Re: Engine break in procedure... (may not be the right area for this thread)

A hot piston seizure can be more than and over heated coolant system...you can have lower than normal coolant temps and still over heat the cylinder due to high combustion temps...detonation can cause a seizure as well as lack of oil...lack of oil can cause cold and hot siezures...in 0 to 2000 hours it can come from poor maintenance from sludge in the oil rings and not getting oil to the walls...oil gets there the same way it comes off...

I agree with you there... But the thread was more about what changes during the manufactorers actual engine break in procedure/process. And not every possible way a piston can sieze. In a brand new engine you shouldn't have to worry about detonation, pre-ignition, and the oil pump not working.

the fact that another poster noted a 502 started knocking and ultimately seized up is NOT a bearing clearance that is too great...this will just continue to knock and just eat itself until it either throws (breaks) the rod or you stop running it...

Actually what I said was...

Sounds like a crank or rod bearing clearence was not measured correctly from the get go. Shouldn't have anything to do with break in. If you had a knock that wasn't piston slap, more than likely a clearence was to great.

What I meant by that was you need to isoloate the knock and rule out piston slap first. If your getting piston slap on a new motor then somebody didn't fit a piston correctly. We all know that just because you can fit a piston with rings down a cylinder doesn't mean that it is NOT to big, and fitted correctly.
And after you isolate the knock, and rule in or rule out piston slap, you move on the the crank and rod bearings. I reread Boat Tecks post, and I guess i missed it the first time where he wrote the engine siezed twice. And that sounds like sticking piston to me. Gets hot and sticks, gets cold and free's up.

I will disagree with you and say that yes knock can happen if a bearing clearence is to big (or somebody forgot to put in 1/2 a plane bearing, or the whole dang thing) If it is knocking because of a clearence issue... then your losing oil pressure everywhere else downstream of issue. If you lose to much oil pressure than kaboom... something is gonna weld. Either way, again this thread is about engine break ins. A mis-fitted piston, or a mis-fitted bearing has nothing to do with breaking an engine in correctly. Your going to have an issue if you follow the manual to a T or running it like you stole it... It just will not matter.

 

[a70eliminator]

Re: Engine break in procedure... (may not be the right area for this thread)

what happens when you put a directional piston in backwards and run an engine.
I've got first hand experience on a Ford 351W of the 70's, I took one apart that was assembled with some of the pistons upside down. With the oil pan off, I could see the rods installed 12345678 right down the crank rather than in their perspective bores, resulting in several backwards pistons. it was in a van that I bought, supposedly with a freshly rebuilt engine, It ran good but always had weird knock to it that eventually got to where I couldn't stand it anymore (ran for about 1 month 100 miles per day).
The backwards pistons showed severe scuffing of the skirts along with some cracking and breakage, #1 and #8 were correct and the piston and bores looked great, the rest was scrap it was a cryin shame.
Put a cobrajet piston in backwards and kiss it goodby the first revolution.

 

[Apollo75]

Re: Engine break in procedure... (may not be the right area for this thread)

what happens when you put a directional piston in backwards and run an engine.
I've got first hand experience on a Ford 351W of the 70's, I took one apart that was assembled with some of the pistons upside down. With the oil pan off, I could see the rods installed 12345678 right down the crank rather than in their perspective bores, resulting in several backwards pistons. it was in a van that I bought, supposedly with a freshly rebuilt engine, It ran good but always had weird knock to it that eventually got to where I couldn't stand it anymore (ran for about 1 month 100 miles per day).
The backwards pistons showed severe scuffing of the skirts along with some cracking and breakage, #1 and #8 were correct and the piston and bores looked great, the rest was scrap it was a cryin shame.
Put a cobrajet piston in backwards and kiss it goodby the first revolution.

I do not really understand the post's intent --- break-in procedure ? or just getting opinions

Consider this little piece of information ---> piston pin offset.

This article is not all there is too it just explained better than most.

"The piston and its half of the connecting rod stops twice per crankshaft revolution, even though the crankshaft continues to turn. This means the piston and top of the rod also start back up twice. This stopping and starting imposes stresses on all three of the parts, stresses that increase with crankshaft rpm. To reduce these loads, the piston is mounted to the connecting rod slightly offset. This causes the piston to reach top dead center at a different time than the connecting rod, effectively spreading the shock loading over a greater number of crankshaft degrees. In short, the real reason for piston pin offset is that it softens reciprocal loading, permitting lighter more power-efficient parts to be used, and the engines to be capable of higher rpm. "

Full article : http://www.motorcycleproject.com/motorcycle/text/cows-offset.html

So, installing a piston with the offset 180-degrees backwards causes more issues than are initially apparent.

Another forum that discusses this : http://forums.autosport.com/index.php?showtopic=94768

OFM

 

[dr_bowtie]

Re: Engine break in procedure... (may not be the right area for this thread)

I will disagree with you and say that yes knock can happen if a bearing clearence is to big (or somebody forgot to put in 1/2 a plane bearing, or the whole dang thing) If it is knocking because of a clearence issue... then your losing oil pressure everywhere else downstream of issue. If you lose to much oil pressure than kaboom... something is gonna weld. Either way, again this thread is about engine break ins. A mis-fitted piston, or a mis-fitted bearing has nothing to do with breaking an engine in correctly. Your going to have an issue if you follow the manual to a T or running it like you stole it... It just will not matter.

I didnt mean to get you to think a bearing clearance to great will not knock...it will...what I merely tried to imply is that it may not cause a bearing to spin resulting in a seizure...

a spin will result in a knock but a knock wont always result in a spin....

but I do agree like I said if all clearances are set then all will be fine...ignition problems like detonation can be an issue if the engine comes without the distributor...you never know how someone put in the distributor and runs it before checking the timing...

 

[Fun Times]

Re: Engine break in procedure... (may not be the right area for this thread)

Sorry if it was confusing, It only siezed up one time, And now that I think back about it, The rod put a small hole out the side of the block within 4 minutes on the port side of the boat. And yes we primed the oil, But Thinking back about it we had trouble getting it to prime up while on the engine stand, It just took longer it seemed like then what we where used to. hummm. Timing was already set. Like always jason good info, Thank's

 

[Mischief Managed]

Re: Engine break in procedure... (may not be the right area for this thread)

Fascinating subject. Thanks for all the interesting posts.

I have owned a few Kawasaki motorcycles. They always come with a sticker on the gauge cluster that says "do not exceed 4000 RPM for the first 600 miles". The owners manual also goes into detail about break-in. Well, in the Kawasaki factory in Nebraska, they apparently take every brand new bike at the end of the assembly line and run it ot the redline in each gear on a chassis dyno. So much for gentle break in...

I break-in new engines in with a few cyles of WOT accleration followed by closed throttle deceleration after the engines are fully warmed up. So far, so good...

 

[Don S]

Re: Engine break in procedure... (may not be the right area for this thread)

One other thing to consider.
A marine engine doesn't have the same duty cycle as an automotive or even a race engine.
How may automotive or race engines could run up hill in low gear for hours on end at 3500 to 4000 rpm (or higher) year after year.

 

[Bifflefan]

Re: Engine break in procedure... (may not be the right area for this thread)

How may automotive or race engines could run up hill in low gear for hours on end at 3500 to 4000 rpm (or higher) year after year.

I think my Dad walked everywhere up hill (with no shoes) for his whole life...

I do want to add, I am not a fan of ripping on a cold engine. They need some time to warm up and let everything size up and come up to temp.

You bring up alot of interesting discussion in this post and I wish i was in the class to hear them. It sounds like you have a very good instructor and it would be wise to listen to all he says.
I had an auto shop teacher in high school that was the best teacher i had. He never answered a question with an answer, rather he asked you questions that would lead you to the asnwer you were looking for. Taught me alot.

 

[JustJason]

Re: Engine break in procedure... (may not be the right area for this thread)

The class was years ago. I was just thinking about it earlier. I think about the people here that "rebuilt" their engine and it blows up in a few hours time. They start asking about how to baby the new motor in so parts can "break in". When its really they didn't measure something correctly (or not at all) along the way