drjr56

Ok guys..Proper way to break in a roller cammed 455 .060 with 10.3 pistons, roller rockers,and aluminium heads...really need to do this right.

ah64pilot

From what I understand the roller cams don't need a break in. Mark might want to verify that but as far as I know break in is usually just for the flat tappet cams...

For the engine itself you just want to allow it to warm up properly and then do some light load pulls on it to help seat the rings...Then start making power pulls, as the rings seat better you'll see the power come up.

Do you have a access to a dyno or are you doing this in the car?

L69

Roller cams dont need breakin.

drjr56

I knew about the cam I'm concered about making sure the rings seat.Some say run it the way your gonna drive,other say keep it below 3000 for a while,but don't let it just sit and idle for long,but rather vary the speeds.The motor was run for 20 minutes out of the car at between 2000 and 2500 rpms right after assembly by the builder.The rings seat in the first how many miles?? ah64pilot did yours get broke in on a dyno? I appreciate your opinions fellows. Cutlassefi...what do you say..and thanks you.

ihengineer76

What I have done in the past is run the car for 500 miles with keeping the RPMs below 4000 and then change the oil. Then run it how you want and change the oil in another 1000 miles. I like to do this just to clear out the small filings, etc. that come with breaking in. After that, normal oil changes and run it like you stole it. Have fun with the new motor!

drjr56

That's what I've been doing,but have also let it idle until it gets to about 140,and that takes 5 minutes maybe because of the restrictor instead of a thermostat.Think I'm gonna drop the oil a little sooner...ah64pilot, L69,etihengineer76, thanks for the input..I just can't afford to screw this up!! Anyone elses thoughts on this,I know opinions vary on this topic.

ah64pilot

Yes, mine was broken in on the dyno. 10 min. at 2,000 rpm for the cam (mech. flat tappet) and then a couple of low load pulls to seat the rings a little. Then we started making full on pulls with it.

You need a load on the engine to seat the rings. You can do it over time with a light load or you can do it rather quickly with a moderate load...there are some theories that say if you do it quickly the rings will seat higher in the cylinder making your compression higher etc, IDK...who really knows. I just know it's worked for me.

My convertible just got broken in a couple of weeks ago...we did 20 min. at 2,000 rpm and then made a few laps around the block. Then it got driven 190 miles to Austin, and along the way we did some full throttle pulls on it...you could feel the rings coming in, it got faster and faster.

In all, it's your engine, do what you feel is safe.

drjr56

I'm not putting out your numbers hp/torque,but my car does feel pretty strong,and I'm running it pretty much like you explained...guess I'm doing it right.Thanks again ah64pilot.Your cars are awesome dude....nice job.

ah64pilot

Thanks man! I think you will be fine

I always say break it in hard and it'll run hard...until it blows up, and they all blow up LOL! J/k!

Bill in NC

This is just my opinion, and how I handle my engines. With the crap gasoline and oil we buy today, chances are our older engine designs won't get another 200,000 on a rebuild/overhaul........so why break it in like you're going to get that??
This is all I do.
Whatever break-in procedure the camshaft company recommends with their recommended lubricants/additives because they will stand behind their product in the event of a lobe/lifter failure during camshaft break-in.
Cool down.
A heat cycle while checking fluids or for leaks.
Cool down.
One more heat cycle, set final timing, clean up the tools etc.
Cool down.
Check fluids, check for leaks and GO!

ihengineer76

I don't like to think of it as blowing up. Its a very scientific and systematic process of finding weak parts. This being said by a guy that used to rebuild snowmobile engines on a weekly basis.

ah64pilot

Haha! Alright, I'll give you that!

Intragration

What I've heard was similar to what AH64 is saying, that by fairly quickly getting to some mild power runs, followed by letting it coast to a lower speed, that you're somehow causing a full range of motion, versus just driving it gingerly for a set length of miles. The only engine I've ever had rebuilt was broken in on a dyno and had hours of idling and dyno pulls, so I don't know there's a difference.