General A question for the men of the forum

Welcome to our Community
Wanting to join the rest of our members? Feel free to Sign Up today.
Sign up

BeardOfKnowledge

The Most Consistent Motherfucker You Know
Jul 22, 2015
60,547
56,268
they're not. the say don't go over 50 miles and use light oil. But I was taught to use 'break-in oil' and then switch to heavier oil and go longer...the principle is the same, you're nit-picking.
Okay, so here's who doesn't break in engines. Auto manufacturers, Professional race teams.

Here's who break in engines, some performance shops, none of whom ever have consensus on the "right way" to break in an engine.

p.s. "break in oil" is about as heavy as it gets unless you fill it with gear oil. Usually single grade 30.
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
same principle, IMAO.

1) a few minutes on the stand, ideally with the trans/rear gears connected, running light oil. Makes sure everything is put together right and not coming apart. Drain the oil and check it for parts. :)
2) Put your regular oil in it and slowly move it in the power band. You're checking your valvetrain, mostly, and seating the cam.
3) get it at temp running light for 'some period of time'...high compression V8s was about an hour...then do some vacuum pulls from the middle of your power band to seat the rings.

and then keep your foot out of it for the first couple hundred miles in case you missed something.
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
Okay, so here's who doesn't break in engines. Auto manufacturers, Professional race teams.

Here's who break in engines, some performance shops, none of whom ever have consensus on the "right way" to break in an engine.

p.s. "break in oil" is about as heavy as it gets unless you fill it with gear oil. Usually single grade 30.
not assembly oil. a lighter than normal oil specifically for the period where you're making sure everything is together correctly. You want an oil that will allow shaving and pieces to flow freely so you can find them when you drain it.

manufacturers don't do it because they heat treat the motor as an assembly. Problem solved.
race teams don't do it like that (they just break them in on the stand) because their motors are usually built to be rebuilt.

i haven't build a motor in a while, something changed I'm all ears.
 

BeardOfKnowledge

The Most Consistent Motherfucker You Know
Jul 22, 2015
60,547
56,268
not assembly oil. a lighter than normal oil specifically for the period where your making sure everything is together correctly.
From your article:

We recommend AMSOILD SAE30 Break-In Oil for initial start up and break in.
You want an oil that will allow shaving and pieces to flow freely so you can find them when you drain them.
1) If you have shavings and pieces in your rebuild, you've done something terribly wrong. 2) Encouraging those pieces to move through an engine is the last thing you'd want. If you've got something hung up you want it to stay there, not move into a tighter place a score the inside of your engine even worse.

manufacturers don't do it because they heat treat the motor as an assembly. Problem solved.
Not that I've ever heard of as a common practice. The parts are heat treated as they're built, but are assembled on a line piece by piece and dropped into the vehicle. They don't put it all together and then heat treat it.

race teams don't do it like that (they just break them in on the stand) because their motors are usually built to be rebuilt.
The main reason is that race engines (true high performance engines) have life expectancies in hours. Those engines perform at peak for the duration of their life so they don't want to waste time doing things that don't contribute to performance, but are ultimately detrimental to it.

i haven't build a motor in a while, something changed I'm all ears.
As I said, breaking in engines went away a long time ago and lives on as "accepted wisdom". The next time you rebuild an engine, put it back together, idle it long enough to bleed the coolant and check for leaks. Then close the hood and drive as normal.
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
From your article:





1) If you have shavings and pieces in your rebuild, you've done something terribly wrong. 2) Encouraging those pieces to move through an engine is the last thing you'd want. If you've got something hung up you want it to stay there, not move into a tighter place a score the inside of your engine even worse.



Not that I've ever heard of as a common practice. The parts are heat treated as they're built, but are assembled on a line piece by piece and dropped into the vehicle. They don't put it all together and then heat treat it.



The main reason is that race engines (true high performance engines) have life expectancies in hours. Those engines perform at peak for the duration of their life so they don't want to waste time doing things that don't contribute to performance, but are ultimately detrimental to it.



As I said, breaking in engines went away a long time ago and lives on as "accepted wisdom". The next time you rebuild an engine, put it back together, idle it long enough to bleed the coolant and check for leaks. Then close the hood and drive as normal.
the heat treating is after machining on blanks. That's why you don't have break in new car engines.
if you're shedding a piece of metal, you want it in the crankcase. But like I said, it's basically just running it at idle and making sure everything is together right.

and pro race engines are not hot rod or hobby engines. so you have two examples that aren't at all like the situation we're discussing (rebuilt motor that you want to last forever)...so I don't know exactly why you keep pointing to irrelevant examples...
 

BeardOfKnowledge

The Most Consistent Motherfucker You Know
Jul 22, 2015
60,547
56,268
the heat treating is after machining on blanks.
I know, all parts going into an engine are heat treated. When I rebuild an engine at work it also doesn't get broken in.

and pro race engines are not hot rod or hobby engines. so you have two examples that aren't at all like the situation we're discussing (rebuilt motor that you want to last forever)...so I don't know exactly why you keep pointing to irrelevant examples.
A hot rod or hobby engine doesn't have the expectations put on it that a typical passenger car enigne, or an actual race engine does. Hobby/hot rod engines are things that weekend warriors overthink because they're playing mechanic and want it to be a bigger deal than it actually is.
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
I know, all parts going into an engine are heat treated. When I rebuild an engine at work it also doesn't get broken in.



A hot rod or hobby engine doesn't have the expectations put on it that a typical passenger car enigne, or an actual race engine does. Hobby/hot rod engines are things that weekend warriors overthink because they're playing mechanic and want it to be a bigger deal than it actually is.
you're not rebuilding my engine, so it doesn't really matter.
What engines do you rebuild at work?
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
Generally, no.
AFAIK, the whole reason you 'break in' a motor is to seat the rings.
If you're not boring or honing the cylinder walls, I wouldn't break in an engine either.

real race engines have specially hardened or sleeved cylinder walls...Nickaseal or Kevlar sleeves were pretty common, back when.
But those are usually pro racers running super-skinny rings on short pistons with long rods.
 

BeardOfKnowledge

The Most Consistent Motherfucker You Know
Jul 22, 2015
60,547
56,268
AFAIK, the whole reason you 'break in' a motor is to seat the rings.
If you're not boring or honing the cylinder walls, I wouldn't break in an engine either.
I say generally because if the original cross hatching isn't worn off (it almost never is) there's not really a need to do it. The act of doing it will over bore the cylinder to a minimal degree which in theory would actually impede the function of rings, but I digress.
 

ThatOneDude

Commander in @Chief, Dick Army
First 100
Jan 14, 2015
35,390
34,272
I say generally because if the original cross hatching isn't worn off (it almost never is) there's not really a need to do it. The act of doing it will over bore the cylinder to a minimal degree which in theory would actually impede the function of rings, but I digress.
I love watching a true professional and a layperson argue about things the professional does professionally.
 

Filthy

Iowa Wrestling Champion
Jun 28, 2016
27,507
29,834
I say generally because if the original cross hatching isn't worn off (it almost never is) there's not really a need to do it. The act of doing it will over bore the cylinder to a minimal degree which in theory would actually impede the function of rings, but I digress.
you can always ball hone it and put in new rings, gapping appropriately, but I digress.

but if you're not boring and honing, you're not 'rebuilding' an engine. you're just replacing parts.
Engine break-in process is for seating rings as part of a rebuild. Unless something has changed, but it doesn't sound like it.
 

BeardOfKnowledge

The Most Consistent Motherfucker You Know
Jul 22, 2015
60,547
56,268
you can always ball hone it and put in new rings, gapping appropriately, but I digress.

but if you're not boring and honing, you're not 'rebuilding' an engine. you're just replacing parts.
Engine break-in process is for seating rings as part of a rebuild. Unless something has changed, but it doesn't sound like it.
I've never before met someone who would not consider replacing every component in an engine block as rebuilding.
 

ThatOneDude

Commander in @Chief, Dick Army
First 100
Jan 14, 2015
35,390
34,272
I've never before met someone who would not consider replacing every component in an engine block as rebuilding.
He tries so hard to be right.


An Engine Rebuild is defined as a process where the finished product is “as new”, inside and out. All parts that have “wear” on them get replaced with new items. This includes valves, pistons, bearings, seals, O-Rings, rubber or plastic parts, and gaskets. All other engine components are inspected and measured to ensure that they are in serviceable condition and to factory specifications. Items that do not pass inspection get replaced.