6G Celicas Forums

I'm trying to break in my motor as quickly as I can before Saturday or else I won't be able to take my car back to Albuquerque with me for a while.

The shop that rebuilt my motor and my mechanic all told me to do a slow break-in. You've all heard this one: Take it slow for 500 miles, change the oil/filter, take it slow for another 500, change the oil again and you're good to go. No highway, no higher than 55mph, and constant speeds are bad, mmmkay.

But I've been reading online and found a contradictory method that seems to have a lot of evidence against the manufacturer and mechanic recommended slow break in. It's called it's called the MotoMan method (here's the link: http://www.mototuneusa.com/break_in_secrets.htm). This one says that you should start off quick and hard in order to get the rings to seat properly and drive it normally for a little while and you're good to go. The biggest evidence against slow break-in that MotoMan has is that with the slow break-in, the cylinder walls are likely to glaze and the rings will never seat properly, thus causing oil burning and other problems down the road.

What are all of your opinions on this?

I've already started breaking in my motor and I'm 200 miles in. I didn't do it slowly, but I've been driving normally, except no hard acceleration and no constant speeds. I haven't gone on the highway and haven't gone faster than 45-50 mph.

I've had conflicting opinions as well from multiple sources.

It seems the younger mechanics state to always break it in, this including new clutches, and an engine rebuild. Then when I talk to the older crew of mechanics they say go balls to the wall otherwise you are hurting yourself in the long run...

I just don't know =/

I'd say have a combination of both methods with more of a lean towards the conservative break in the shop suggested

I guess its motomans hypothesis versus the entire car industrys method. The point is that the cylinder walls are still rough. Why would you believe that running the rings harder, hotter and faster against a rough surface would be a better idea. Im not trying to be a dick Im just skeptical about anything posted as fact on the internet. Millions of engines have been built the normal way so why second guess that?

I know somebody who's a professional race track driver who follows this method. His tuner does it on the dyno. Whenever they rebuild an engine for a new setup, they put the car on a flatbed and carry it over to the dyno a couple cities away (like an hour and a half drive or so; that car is an MR2 with a 3s-gte tuned by Predator Performance, Inc. in Puerto Rico. You can google that.)

They give it its first start and let it warm up to op. temp. at home to check for leaks and everything, but is never run on the street. Its first runs are done on a dyno using this method (3rd gear pulls with rests in between) and then the oil is changed. He uses AMSOIL break-in oil, because it has no detergents or additives, just pure 10w-40 if I'm not mistaken.

His build consists of 10:1 CR pistons with a fully build engine, 272 cams, titanium springs, retainers, HYDRA Nemesis II, I believe he's using a GT28-sized turbo running around 20~psi... and the engine is broken in boosted, of course.


I'd rather believe success stories than big companies who'd like you to bring the car in for work in the long run. I'm breaking in my engine this way when I build it down the road.


EDIT: The oil is SAE-30. Here's the link: http://www.amsoil.com/storefront/brk.aspx




The idea behind this is that most of the time (in our case it is true) the rings are a softer metal than the cylinder walls, so seating them in softly will wear the rings and not the walls, causing excessive blow-by in the long run. Heat-cycling the engine as suggested by the MotoMan method heats up the cylinder walls, softening them up making it possible for the rings to wear INTO the walls, making a better seal.

This post has been edited by Syaoran: Aug 14, 2012 - 11:00 AM

The thing with the MotoMan theory is that the slow break-in method was good a long time ago when machining left rougher surfaces. But nowadays, machining leaves much smoother surfaces so it's better to do the quicker break-in, or so the method says. I'm just trying to get my motor broken in within the next few days (I just don't think I'll have time, unfortunately. 620 miles of constant 70+ mph... )

ive heard the fist 20,000 miles on the engine is crucial, if you run it hard, it will run like that. thats what my dad said when he bought is 04 mach 1 at least. older mechanics, have rebuilt engines in there cars and ran it to hell and back and had no problems, then again engines were a little different back then. newer mechanics, go by the book, dont't take any short cuts.

Put your car securely on jackstands and blocks with the front wheels suspended, place a box fan in front of the grill, place the transmission in 5th gear, start the vehicle and use the cruise control to hold the engine at various RPMs. I would think 20 minute intervals would suffice, seeing as how the engine is run for 20 minutes during the initial startup to seat the cams and lifters. Gas milage should be well over 100mpgs without any actual load on the engine.

If you are determined to run the engine hard to seat it then good luck. Im sure that at 200 miles it mostly broken in and your just being cautious at this point but you never know.

But that way, there would be no pressure in the cylinders and that's what seats the piston rings. I shouldn't be revving with no load on the engine anyway.

There would be some pressure with the drivetrain in 5th. But of course, the objective would be to slowly and softly break it in at various rpms. Little strain would be ideal with the conventional break-in method. Im meerly presenting you with another option than going out and racing your car to break it in.

I vote put it on jackstands and use the cruise control to put 800 miles (1/2 a tank maybe) on it. Its a for sure way to get you car ready to drive it 11 hours to New Mexico. Im the only person in here giving you critical thinking because Im trying to provide ideas.

Good luck with it however you choose. It probably wont make a huge impact on the life of the engine anyhow.

This post has been edited by Special_Edy: Aug 14, 2012 - 5:22 PM

Just do what the mechanic told you to do and stop reading the internet. There is really not much to it than that, yet people still don't want to do what they are told. You trusted him with the rebuild, so trust him in how he tells you to break it in.





Sounds perfect. Keep doing that.

I'd do what the shop said. I'm sure there's a warranty on the engine, and not doing what they said would void that warranty.

Interesting read: http://en.wikipedia.org/wiki/Break-in_(mechanical_run-in)