Engine Break-In Secrets

W5R

New member
I found this article and just wanted to share it with others, since most seem to believe that breaking an engine in easy is the way to do it. I believe in running an engine in hard from the start, after warming it up of course. This article made alot of sense why you shouldnt break one in easy.

http://www.mototuneusa.com/break_in_secrets.htm
 
That article and philosophy has been around for a long time, but break in methods are as varied as hair styles and you may as well just let each person do as they wish. My belief is if the engine is mechanically fit and properly lubricated it will last no matter how you break it in.
 
All my experience with break-in is with two cycle, so it might be different with four cycle.
I would let the engine idle a little higher than normal, on the dyno. At some point, the idle would jump up quite a few RPM's. I took this to mean that the rings had seated. I would then make three complete full throttle, full range, runs. Comparing the HP curves would show a slight increase from the first run to the second run, but the third run would be about the same as the second run. I took this to mean that the engine was fully broken in. I could be wrong, but it worked for me.

Now if you don't have a dyno, one or two practice sessions should, after breaking in the engine at high idol, be about the same as one or two dyno runs.

As has already been said, do what you like, because this is only what I did. Just for the record, my procedure worked very well.
 
Excluding 2-cycle (per AL above) No body will beat the Break-in theory of the 'true' drag racer...."1st pass, 1000ft; 2nd pass, Stab-it & Steer-it"!! (and 'No', I didn't read the article either) :)
 
Excluding 2-cycle (per AL above) No body will beat the Break-in theory of the 'true' drag racer...."1st pass, 1000ft; 2nd pass, Stab-it & Steer-it"!! (and 'No', I didn't read the article either) :)
When I was drag racing, with a new engine, I would just short shift on the first and second run.
 
dad always said to fire a new engine up and let it run at a high idle until it was nice and hot, then shut er down....next run? crank it up, stab the throttle to the floor....if it's gonna blow, it's gonna blow and you ain't gonna be able to stop it!
 
dad always said to fire a new engine up and let it run at a high idle until it was nice and hot, then shut er down....next run? crank it up, stab the throttle to the floor....if it's gonna blow, it's gonna blow and you ain't gonna be able to stop it!

Thats the same thing my grandfather and uncle taught me, if it s going to break let it happen wide open, at least it will give a show.


The Moto-man break in method has been around a very long time, it was discusses many years ago on an RC forum when compared to the Ron Paris break in method, it took a couple of years but guys finally saw the light that a slow break in done more harm than good.
I know a man that heats his engines with a heat gun and breaks them in under load with an electric motor

A 2cycle, I still believe they should be broke in the same way, but very rich
 
dad always said to fire a new engine up and let it run at a high idle until it was nice and hot, then shut er down....next run? crank it up, stab the throttle to the floor....if it's gonna blow, it's gonna blow and you ain't gonna be able to stop it!

That 'was' old-school flat tappet theory/proceedure and the Roller Cams/lifters re-wrote the book. Either way, I DO NOT agree with 'Un-loaded' full-throttle...(Ouch)! :)
 
Thats the same thing my grandfather and uncle taught me, if it s going to break let it happen wide open, at least it will give a show.


The Moto-man break in method has been around a very long time, it was discusses many years ago on an RC forum when compared to the Ron Paris break in method, it took a couple of years but guys finally saw the light that a slow break in done more harm than good.
I know a man that heats his engines with a heat gun and breaks them in under load with an electric motor

A 2cycle, I still believe they should be broke in the same way, but very rich
Years ago when 'race' motors started life from junk-yard dogs and re-conditions rods, that stuff was common place. Things are a tad different these day's (Good and Bad)! 2-strokes are a bit diff becuz when thay are 'fat' they will never see peak rpm and will only 4-cycle.
 
Thats the same thing my grandfather and uncle taught me, if it s going to break let it happen wide open, at least it will give a show.


The Moto-man break in method has been around a very long time, it was discusses many years ago on an RC forum when compared to the Ron Paris break in method, it took a couple of years but guys finally saw the light that a slow break in done more harm than good.
I know a man that heats his engines with a heat gun and breaks them in under load with an electric motor

A 2cycle, I still believe they should be broke in the same way, but very rich

I would think you guys uave the same family as me. Heat em up once. Then punish her was always my fathers philosophy. BUT you guys are forgetting one very important step. She needs a lil tiny sip of bud heavy before the first breath of life haha. Ahhh childhood memories lol. But i gota say im gona carry on that tradition cuz every motor we built ran like an ape. Shhh dont tell anyone our secrets haha
 
I would think you guys uave the same family as me. Heat em up once. Then punish her was always my fathers philosophy. BUT you guys are forgetting one very important step. She needs a lil tiny sip of bud heavy before the first breath of life haha. Ahhh childhood memories lol. But i gota say im gona carry on that tradition cuz every motor we built ran like an ape. Shhh dont tell anyone our secrets haha
Alass...that 'sip' of bud now comes from a 'blue' bottle....:)
 
Let me ask a question; how many of you have a compression test gauge?
Try all of your methods, test the compression pressure, then tell me which one is best!
A good stock Yamaha should show about 160 PS I. A good reed or rotary, should show about 210 PSI.
If anybody has tested the stock clone or Briggs let me know.
 
Let me ask a question; how many of you have a compression test gauge?
Try all of your methods, test the compression pressure, then tell me which one is best!
A good stock Yamaha should show about 160 PS I. A good reed or rotary, should show about 210 PSI.
If anybody has tested the stock clone or Briggs let me know.
I'd be happy 2help AL, but I have never been confident/consistant nor convinced that the #'s I have drawn were reliable. Example being that the 'highest' i've seen on a Yamaha KT100 was 125psi, fresh off the track in the winners circle!

As you'll recall....my 'Holly Grail' is "Leak-Down" :)
 
Let me ask a question; how many of you have a compression test gauge?
Try all of your methods, test the compression pressure, then tell me which one is best!
A good stock Yamaha should show about 160 PS I. A good reed or rotary, should show about 210 PSI.
If anybody has tested the stock clone or Briggs let me know.
You cant just check the compression that easly, they have a compression release on the cam. You have to spin the engine fast enough, or get a false reading. (and they vary in height from one to another). My modified builds have 235lbs and up. (spinning with a starter)
 
I'd be happy 2help AL, but I have never been confident/consistant nor convinced that the #'s I have drawn were reliable. Example being that the 'highest' i've seen on a Yamaha KT100 was 125psi, fresh off the track in the winners circle!

As you'll recall....my 'Holly Grail' is "Leak-Down" :)
And I believe, " leak-down" on a two cycle is a total waste of time. There are many camps you can belong to and I belong to the one that says compression is the "Holy Grail".
 
And I believe, " leak-down" on a two cycle is a total waste of time. There are many camps you can belong to and I belong to the one that says compression is the "Holy Grail".
We Agree Al! A leak-down can/will identify where the problem lye's and the 'condition' of the a 4-cycle engine weither it's (1) or (12) cylinders. L/D on a 2-cycle can 'only' monitor the ring seal, where as (I feel) on a single cylinder 2-cyl go-kart engine....all I need too do is 'attempt' to turn the engine by hand and know weither it's 'ok' or not! Hey...ur camp'n in Texas and (unfortunitely) i'm camp'n in Caliexico!
 
Years ago when 'race' motors started life from junk-yard dogs and re-conditions rods, that stuff was common place. Things are a tad different these day's (Good and Bad)! 2-strokes are a bit diff becuz when thay are 'fat' they will never see peak rpm and will only 4-cycle.

Trust me, my grandfather(Alvis Hatfield, the man who raised me) and uncle where multiple time track champions at Flat Rock speedway, there was no re-conditioned rods in any of there motors, nor was the motors junk yard dog's, at 15 I ran modified street, an engine built by me, being in the pits and on the fender from birth, its amazing what you can learn, from concrete I went dirt mod street where I won rookie of the year, the next season went latemodel racing, i continued to wrench the whole time, and all of those engines we're broke in just as they were meant to run.
An oval engine was built to run wide open for hundreds of laps, not 4 or 5 seconds and cut it off

A 2 smoker run fat isnt just because it hinders rpm's, it also flushes the eninge of metal shavings
 
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