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View Full Version : Fresh 12A - What is the proper break in?



Shannon1530
09-17-2007, 11:49 AM
When I bought my 1st gen, it came with a rebuilt/refreshed 12a motor with 0 hours. What is the best way to break in this motor? I would assume that showing up for school next year with a motor with 0 hours, and runing it on the track is not the smartest thing to do. I am interested in doing some Solo II events before then in the car as a shakedown, but I would think you would want some hours on the motor before this as well. Any and all advice is appreciated.

Speed Raycer
09-17-2007, 01:18 PM
IIRC, a fresh build with fresh bearings needs ~600 miles @ below 4k before it's properly broken in (do not take those numbers as gospel)

If the cars not street legal, you might want to look for open track days or HPDE's in your area just to get some low RPM track miles... or a very large parking lot on a Sunday :D

This is when it would be good to have a registered street car that's the same as your race car

lateapex911
09-17-2007, 06:19 PM
Mazdaspeed has the break in requiremetns on their sie in the info section.

The satae of Maine might be able to issue you a registration for you to use on the car.

C. Ludwig
09-19-2007, 03:31 AM
Run it at a high idle for about a half hour in the shop. Check for leaks. Change the oil. Hit the dyno and wail on it. There is nothing in the bearings that needs to wear in. If your bearings are wearing you have problems. You should be able to pull an engine apart after a season or more use and not see noticeable bearing wear. We've also noticed no difference in combustion chamber sealing with extended breakins versus short. On used housings compression may continue to come up as the seals continue to wear in but running the engine hard from the start does not seem to make a difference one way or another in ultimate numbers.

kbailey
10-21-2007, 09:32 PM
For my rebuild I had new stationary gears and bearings, new housings and seals, but the old rotor bearings. The shop (Kearney Racing) had me do the fast idle break-in for several hours ( I think they wanted 6 hours total). We then took it to a test and tune day and broke it in by gradually increasing rpm and applied power. Total break-in was about 5 hours of varying speed fast idle, and then 1.5 hours of track time.

I know of one guy that ran his in a street car for 1,000 miles to break it in, and another that throw one in at the track and broke it in during qualifying. Both motors lasted fine.

Warning- non-expert opinion follows: If you can break it in right I'd do it. If not then I would do the fast idle thing per the Mazdaspeed instructions, then take it easy in the beginning of school.

tom_sprecher
10-22-2007, 09:16 AM
Bring to the ARRC and I think I can line up someone who could find the time to run it all weekend. It should be broke by then. ;)