[goquick]

Here is an interesting site on Engine break in;

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

[Murf'sDad]

I've never been as methodical as this guy in the break-in process but I've never followed the manufacturer's recommendation for break-in driving. Mostly just run it. Never beat on it but make sure the engine is revved regularly, never driven at a steady state and gradually work the blasts up to the red line. I've never had a problem with any engine I've broken it this way whether it was built by me or was a new factory engine.

I've seen guys drive a new engine very cautiously for the first 500 - 1000 miles and then, figuring the engine was broken in, started to flog it unmercifully and had nothing but problems.

There may be something to what this guys is promoting.

Stewart

[BruceWilkie]

Ditto Murfs Dad! Though i may go to redline much sooner I only do it in low gear then back to reasonable for a while. I did have an engine built once that was tight on all the clearances(in limit but tight side). after a 1000 miles of driving I felt it was well broken in. Went to the track and found differently. 4 passes and each significantly(and unpredictably) faster. from very disappointing 13.8 to 13.08 that day no changes! Back the following week same thing only not as drastic. First pass 13.20 broke out with a 12.98 1st round. Car eventually settled in with consistant 12.60's by the end of the year.(which was where it should have been as build goal was mid 12's) No parts were changed and tuneup ended up being same as its very first pass.(not that I didnt try some things that slowed me down) Who knows i may have had the track record for most consistantly inconsistant car! I only won 1 round that year and when called to staging for round two my starter went up in smoke. Yeah I pretty much break in now like I'm regularly going to drive it but in short bursts.

[performerrpm]

i was told breakem in how your gonna drivem if they cant take it when new they definateley cant take it later on when it losens up

[tempest455]

A freind of mine recently built himself another 454 BBC with aluminum rods. This was a completely fresh motor, bored/honed block, rings, bearings etc. I was there when he fired it up. It ran less than 5 min before he was out of the street doing 8,000 RPM burnouts!

If it's built right and on the loose side, it's good to go. Look at the pro NHRA classes.

[HWYSTR455]

Bearings, well, they break in so to speak within the first hour or so of running, right? Maybe a heat cycle or two would be safe.

Rings, back in the day, the ring material was harder, which is one reason breakins were slower. These days, with properly prepared cyl walls and ring materials, I would think a few hours or a couple 100 miles would do it for sure.

So what's left? Piston to wall? Think that's where you see times pick up, mostly due to drag. Cam is taken care of at startup. Valve guides? That's pretty quick I would think.

If I had to generalize, I'd say 500 miles would be enough to where you can feel comfortable flogging a new engine. Several initial oil changes within the first 500 is pretty mandatory, get all the build debris out...

[tempest455]

Also, when runing a roller cam, it does not require any break in. So rings are it like the motor I mentioned above.

[Region Warrior]

We've aways break'm in a 1/4 at a time.

[johnta1]

Or 1/8th mile at a time.

[Ron Landis]

usually a few good hard pulls up and down the rpm range will seat the rings. Best to have a load on the engine...just don't go crazy. An experienced engine builder told me to find a small hill to accellerate up a few times. I had one smoking out of the right bank once and this manuever did the trick in @ ten minutes of run time. Never free-rev an engine in an attempt to seat the rings. Good luck. Ron

[goquick]

I've always gotten them warmed up,, back out, get straight and get it thru the gears! Turn around and get it again. And people ask why I hate the idea of ever living in a town limits

[Larry Navarro]

Ask the guys who operate engine dyno's how they break-in engines.

[Half-Inch Stud]

All my break-ins have been success: Start-it, check it (timing, leaks, idle set) run it hard somewhere. Biggest ordeal is a new FLAT HYD cam and new Rings/CYL walls.

I really like the idea of using known Carb & HEI on such a break-in. New stuff is more grief to adjust. So, I like the idea of new cam AFTER fresh Rings/CYL walls.

[mikeb]

Start it and break in the cam; check for leaks; retorque the heads, and take it straight to the track.

[Region Warrior]

Same as H.I.S.
Have a q-jet and holley carb, intakes, hei and a points distrib.
Like to grab the q-jet(have adapter for square bore) and points distrib whenever someone stops by with problems.
They just cant believe how well they make thier modified engine run