Looking for break-in advice on the L-6 Motors

[spawpoet]

Well, we are finally almost done with our re-cage, and almost all the parts are back on the car. Hopefully this weekend we will be running the new motor for the first time. I was just wondering how you guys break-in your rebuilt L-6 motors for the track? Does it need to run under a load a fair amount before we hit the racetrack at PBIR next weekend, or do we just need to run it for a half hour to get a rough tune, and set the rings (deves) a bit? Also how easy should we take it on the motor the first couple of weekends? And lastly do you do anything special breaking in a new clutch (NAPA) for the track on the Z's?

[joeg]

Endless debates on proper break-ins. I just start it a few times after cam break-in to check and make certain there are no leaks of any kind (nut and bolt it) and go racing.

Hard running is what a motor likes...but not abusive hard running.

[Tristan Smith]

Chris,

I have always been told that after about 6 - 8 laps racing at 10/10th, the motors are "broken in". The the thing I am always told is to make sure you are going up and down through the rev range, as opposed to "cruising" at a constant speed.

[Ron Earp]

What all these guys said. I get the motor running in my garage and make sure it doesn't leak etc. Then on track the first few laps I take it easy gradually increasing max RPMs. After a few laps like that I let it have it. Haven't had a problem yet.

Never worried about any clutches. Put them in and go racing.

[spawpoet]

Thank you gentlemen. One last question. Do you change your break-in oil after the initial run-in to set the tune/check for leaks, or do you change the break-in oil AFTER the motor's first hard run?

[joeg]

I change it right after break-in (remove all the moly paste lube, etc). I then put in a good non-synthetic Racing Oil--like a valvoline or a Kendal for the first race weekend.

Thereafter, change to synthetics or oil of your choice.

[spawpoet]

I change it right after break-in (remove all the moly paste lube, etc). I then put in a good non-synthetic Racing Oil--like a valvoline or a Kendal for the first race weekend.

Thereafter, change to synthetics or oil of your choice.

Perfect. We are using the Brad Penn break-in oil, then will run their 30w racing oil thereafter. It's supposed to be good for our antiques. Thank you again for your advice.

[Tristan Smith]

Again, all good advice above. I was told by my motor builder, "Digger" Don Dixon, to use Rotella Diesel oil for the initial break in weekend, changing after the first session on track, and again at the end of the weekend to the oil of your choice (in my case synthetic). The Rotella still has a lot of the anti friction additives such as zinc that are no longer allowed in conventional oils.

[BruceG]

Perfect. We are using the Brad Penn break-in oil, then will run their 30w racing oil thereafter. It's supposed to be good for our antiques. Thank you again for your advice.

Right on, Chris! Brad Penn is the old ,original Kendall Formula before they sold to Pensoil and discontinued the brand. It's the only Pennsylvania crude, still green in color and loaded with ZDDP(ZINC,etc). Must be great for aircooled engines(Formula VEE),too.

[spawpoet]

Again, all good advice above. I was told by my motor builder, "Digger" Don Dixon, to use Rotella Diesel oil for the initial break in weekend, changing after the first session on track, and again at the end of the weekend to the oil of your choice (in my case synthetic). The Rotella still has a lot of the anti friction additives such as zinc that are no longer allowed in conventional oils.


Until we found the Brad Penn oil we were looking at running the Rotella even after break-in. Modern oils just aren't as friendly with older motors that need the zinc and other goodies left out of newer oils. We had wear issues relating to oiling on a consistent basis with Datsun Roadsters (my uncles). Couldn't keep oil temps down, but didn't have a problem keeping water temps down. We "think" at least some of the problems were with the oil itself, as the motors never got an oil with the zinc etc. in it.

[MMiskoe]

Best quote I heard about motor break in was from a guy who did dyno work for Busch North teams:

Warm it up, shut it down, let it cool. Re-torque stuff. Warm it up, check for leaks. Slam it. No point spending any extra time on a motor that is going to break. Break it as soon as possible so you can move on to the next one.