Break In Procedure

[Donnie Weaver]

I'm just curious of some of you guys theories on break in procedures after a rebuild? What method do you use and have you tried others that didn't work as well. Ie rings didn't seal worth the crap.

[Gary Wlodarsky]

you'll prolly get 20 different replies.. or everyone is afraid to say how they do it....

Macs,,I use standard oil fuel, 8 oz to one gal alky, run it for a few minutes on the stand just to make sure everything is ok,,,,then 2, 3 10 minute sessions on the track,,,keeping it rich, blubbering,,,, but as clean as possible,,,then accelerate out of corners, but no high RPM...heat up, cool down like this 2-3 times more,,,,then run it like ya stold it..

or many other ways,,but thats what I do when I have TIME to do it....

gw

[Bill Peck]

you'll prolly get 20 different replies..   or everyone is afraid to say how they do it....

Macs,,I use standard oil fuel, 8 oz to one gal alky,  run it for a few minutes on the stand just to make sure everything is ok,,,,then 2, 3  10 minute sessions on the track,,,keeping it rich, blubbering,,,,   but as clean as possible,,,then accelerate out of corners, but no high RPM...heat up, cool down like this 2-3 times more,,,,then run it like ya stold it..

or many other ways,,but thats what I do when I have TIME to do it....

gw

I use standard fuel mix (8 oz. of Klotz per gallon) and it let run at a fast idle with the rear wheels off the ground for a half hour. Then run it easy and blubbering in the first warmup, let it cool down. Second warmup, run it easy for the first half, then lean it out to race setting and stand on it for the second half. Now let's hear from the other 18 guys!

bp

[Chris Sahagian]

Hi; I pretty much do what Gary W. does. Only exceptions are I use 110 leaded race gas,with Klotz super techniplate. On the 8oz. per gallon deal,I add one ounce of Marvel mystery oil,during bench testing only.[A real old timer who passed away told me to do this years ago] Beats me what the mystery oil does?? But have used that recipe for years with great results. Regards;Chris

[ted johnson]

I like what GW says. Remember a lot depends on the ring and cylinder wall material and the piston/wall clearance. Chrome rings take longer to run in. If you can find Hartman Super Sealer rings, they're tool steel and break in fast. Never run chrome rings in a chrome cylinder, but they're O.K. in a Nikasil plated cylinder. I try to run easy for a half hour, with short bursts of speed, then step it on up to full blast. Of course I'm running alky/castor, so sticking potential is minimal. I can remember when the first Saettas imported had about .0025 piston clearance. It took hours to break them in. If you're running 1/16" iron rings, such as in an original Mc10, they only need ten minutes of easy running. TJ

[Donnie Weaver]

I appreciate the replies. It's a mc91 with mcculloch tool steel rings. I'm not sure of the clearances. I just had New rings installed along with new seals. The cylinder was also honed.