Engine break in best practices

[jayro]

Hi all,
I am in the process of putting my 3.2 back together to drop it in my '94 mtx. I was wondering what is recommended as the best break in procedure after a rebuild? Anything special to do or avoid with these engines? I searched, but couldnt find anything specific. Thanks

Jeremy

 

[TimboSHO]

If you used new rings, there is usually a break in procedure listed for them (I can't exactly remember what it was for mine, it's been a few years). If you had any block or head work done it would be good to change the oil frequently for the first few thousand miles (like every 500 or so). Otherwise, just beat on it! Some say the harder you drive it to break it in, the more of a freak the motor becomes. Good luck!

Hi all,
I am in the process of putting my 3.2 back together to drop it in my '94 mtx. I was wondering what is recommended as the best break in procedure after a rebuild? Anything special to do or avoid with these engines? I searched, but couldnt find anything specific. Thanks

Jeremy

 

[gmail]

44 psi boost

 

[Ishodu]

For what its worth, when I put my rebuild in last fall I had it break in the cams at 2k for 20min. (Not required if you haven't done cams) after the 20 mins it was out the road for full load and de cell runs. Best to seat the rings with high loads and high vacs to seat the rings.

 

[yamahaSHO]

My favorite: http://www.mototuneusa.com/break_in_secrets.htm

 

[Lorenr]

Engine Breakin

YamahaSHO your "My Favorite" is something I learned from a guy that knew a lot about motors back in the mid "eighties". Even then, on our race motors, we tried very hard to have round cylinder bores and a very fine cross hatch on those same bores. We used quality rings, but "break in" was at most a minute or two.

Today, most new engines have very round cylinder bores and 1.2 mm rings. I'd guess they are all broken in, in about a minute.

Pre-**** your motor and immediately run it to 3000 rpm. in another minute it will be broken in.

By the way, the Japanese engineering gave the SHO motors quality round cylinder bores. The cast iron block is also a big advantage.

 

[yamahaSHO]

Round or not, you need pressure behind those rings as the tension they offer alone is not enough.

 

[jayro]

Thanks all. I will read the break in procedure on the new rings. So it basically is rev it to about 3k for 20 minutes. After that I should "drive it like I stole it" while changing the oil every 500 miles for the first few thousand.

For some reason I was thinking that you were supposed to avoid high rpms ect for the first couple thousand miles. Your way sounds like alot more fun. So hitting a road course or autox while breaking it in should be a good thing as long as I change the oil?

 

[frosho]

FYI, an easy way to raise the idle for an extended length of time like that is to prop the throttle open with business/credit cards. Use them as shims behind the throttle plate stop screw. It's much easier and more consistent than trying to use your foot.

 

[AREA 91]

I use feeler guages.

 

[jayro]

FYI, an easy way to raise the idle for an extended length of time like that is to prop the throttle open with business/credit cards. Use them as shims behind the throttle plate stop screw. It's much easier and more consistent than trying to use your foot.

Thanks for the pointer. I used some folded up cardboard when I was breaking in my cams.

 

[jayro]

My favorite: http://www.mototuneusa.com/break_in_secrets.htm

Very interesting reading. I will have to read up on my clutch break in to make sure I can do both correctly at the same time.

 

[yamahaSHO]

Once the clutch is engaged, you can rip on it all you want (you're likely not making enough power to make it slip when already engaged).

 

[jayro]

Once the clutch is engaged, you can rip on it all you want (you're likely not making enough power to make it slip when already engaged).

Thats what I figured, just wanted to double check on it. With the clutch u just dont want to slip/overheat it during break in. Get the heads back in about a week, then its assembly time.

 

[gmail]

i agree with the link... and do the cool down steps also , basicly run it like the dyno run he described.

also i was joking earlier about the 44psi.. granted if you plan to boost it you could do a good break in with low boost to help seat the rings properly

 

[jayro]

also i was joking earlier about the 44psi.. granted if you plan to boost it you could do a good break in with low boost to help seat the rings properly

Yeah, I caught that. Boost would be nice, but I dont see it happening for a while atleast. Maybe a zex kith though.

 

[gmail]

yeah follow that link and you should be good... just remember AFTER you seat the rings drive it nice and let it cool all the way down first few hundred miles and it will treat you good for a long time.

i would change the oil after first 20 mins of idle (cam break in) or if you drive it after the first session then after that 500 miles then so on and so on till you get it broke in.

just remember how much crap could have got in your engine from building it

 

[jayro]

i would change the oil after first 20 mins of idle (cam break in) or if you drive it after the first session then after that 500 miles then so on and so on till you get it broke in.

I will probably drive it to get it up to operating temp faster and then break in the rings. I wouldnt think that I would need to do the cams agian, since I broke them in when I intalled them last winter....or do you need to do this everytime you have them out of the heads? From reading the article I was under the impression that after you seat the rings (and change the oil ect) the engine is pretty much broken in and ready to go. Are you saying that I should drive it nice for a certain period of time after doing the break in procedure? I will definatly be changing the oil after the first 20 minute drive and then at 500 miles and probably 1000 miles.

 

[gmail]

if they are broke in do not worry about them as the break in is for the fresh cut on the cams to get all the rough edges off etc..

as for the engine being broke in so early yes and no... that is to seat the rings and wear them in but you will still need to be easy after that for a little bit just to make sure its all good... id say first 1000-2000 miles, if its good after that just run it.

this is just a precaution to know your engine is in good health to monitor its make sure you dont get any funny noises etc.

if you got high quality rings like chromoly you will have a much longer wear in time.
i hear they can take up to 5k miles

 

[Eric VerValin]

I broke mine in on the street. I think I read that same article back in the day too... I remember firing it up, and immediately took it out to the road nice and easy then put her in second and let her have it, then third and did the same... then I let it ease itself back down...

I did that for a while until she was warm, 10-15 min or so then when I got close to the house I ran it a little further into the red.. (wasnt too worried with the udps on there)..

I had some guy tell me once it was nice and hot to do that.. .run it a little past where you would normally run it, because once the pistons and rods are as hot as they are going to get they stretch a little and you want to make sure they get seated all the way to the top of the cyl. Reason being... if you don't do that on break in, and then miss a shift or something later... there could be a little 'ledge' on there that could chew into your rings, then cause them to leak after that..

Just what I heard.. and how I did mine. After that first time it ran, I changed my oil, ran it again thru a heat cycle, changed it again. Was nice to it for 1000 miles or so, swapped to synthetics at that point, and normal intervals... car hasn't leaked or acted funny in 20,000 miles... 30 mpg on the highway...

Sounds like your oil change plan.. lol