Camshaft vs Piston Rings Break In

[JedIEG]

With a ground up build, what do you prioritize for break in: the Cam and lifters (flat tappet) or piston rings? These require totally different and seemingly opposed break in procedures.
Cams 2000-2500 rpm with no load,
Rings full rpm range with higher loads up to100% with no load time minimized.

I was considering pulling a used cam and lifter set to use for ring break in then swap to the new cam and run a separate brake in cycle for it. The other option is to throw the new cam and lifter set in the spare 318 and break it in there with super light springs then install that in the new engine for the ring beak in. If it goes flat in the 318, it would avoid sending metal all through a brand new engine.

 

[nutz]

cam first

 

[middleagecrisis]

You’re overthinking it. Break the cam in first with 20 minutes continuous run time above 2000 RPM. I personally drain the oil after the initial break-in. Make sure all your fluid levels are correct, set your timing and then find a road that you can accelerate in high gear and decelerate with your foot off the gas and low gear to break in the rings. How you should break in a new motor is going to get about as many different opinions as everybody’s favorite oil, but this is how I do it and I’ve never had any problems, other than the normal gremlins that happens when starting a new combination up for the first time.

 

[nutz]

i was told to break the rings in the rpms going to drive it without any wot heavy load running

 

[fishmens67]

With proper cylinder wall finish the rings will break in during camshaft break in.
You only get one shot at successful camshaft break-in.
Rings are set after the first heat cycle.

 

[MopaR&D]

With proper cylinder wall finish the rings will break in during camshaft break in.
You only get one shot at successful camshaft break-in.
Rings are set after the first heat cycle.

Agreed, I did a ground-up 360 build with moly rings. I reused a known good cam and lifters but didn't really worry about breaking in the rings. First run was driving it on the freeway for an hour to get the car back home from where it had been stored, I'd give it half-3/4 throttle every now and then but overall it seemed the rings were broken in by the time I hit the road; never noticed any oil burning out the exhaust at all. I put 25k miles on that engine with no issues until it finally broke a ring land because of a tuning issue (incorrect timing curve, one too many WOT runs with pinging).

Unless the rings are bare cast iron, don't sweat it. Hardly any ring kits are uncoated anymore.

 

[1WildRT]

Nothing sez the camshaft needs to stay at 2000-2500, the rule is keep the RPM's above 2000... If you do break in on a Dyno you can load the engine from 2000 to 5000 a few times & know the rings were loaded and enough to be fully seated while the cam is being broken in....

Beyond that as others have stated, the cam is more critical.... Lots of flat cams, not often you hear of rings not seating....

 

[Dart Frog]

You’re overthinking it. Break the cam in first with 20 minutes continuous run time above 2000 RPM. I personally drain the oil after the initial break-in. Make sure all your fluid levels are correct, set your timing and then find a road that you can accelerate in high gear and decelerate with your foot off the gas and low gear to break in the rings. How you should break in a new motor is going to get about as many different opinions as everybody’s favorite oil, but this is how I do it and I’ve never had any problems, other than the normal gremlins that happens when starting a new combination up for the first time.

About covers it.

 

[MOPAROFFICIAL]

The Rings begin seating upon firing and running the engine through the break-in of the cam. After that I would do a couple part throttle cruising to wot runs and call them seated.

 

[TT5.9mag]

You’re overthinking it. Break the cam in first with 20 minutes continuous run time above 2000 RPM. I personally drain the oil after the initial break-in. Make sure all your fluid levels are correct, set your timing and then find a road that you can accelerate in high gear and decelerate with your foot off the gas and low gear to break in the rings. How you should break in a new motor is going to get about as many different opinions as everybody’s favorite oil, but this is how I do it and I’ve never had any problems, other than the normal gremlins that happens when starting a new combination up for the first time.

This ^^^^
There is no set rpm for flat tappet break in, what you’re trying to do is keep the cam oiled and it gets splash lubrication so you just spin the motor up to keep oil flying around. I like 2500-3000 varried for 30 minutes. Rings I just do a burnout once the cam is in. Seated!

 

[92b]

On the dyno I fire the motor and take it up to 2500 and vary the rpm from 2500 to 3000 with the throttle. I check oil pressure , listen for noises, look for leaks, check exhaust gas tempratures to make sure all cylinders are firing, check timing and put my hand on the valve covers, oil pan and timing cover before they get too hot to check for something rubbing or making contact. Soon as it gets a little temp in it I use around a 100ftlb load to pull it from 3000 down to 2500 then release the load back up to 3000 over and over in a cycle. I do this for about 25 minutes. My dyno has a program for this I just set the load and flip a switch once it gets a little temp in it and the dyno will sweep the rpms with the load. I monitor oil pressure vs oil temprature and watch for leaks during the break in. oil pressure should drop with temperature and stabilize when the temperature does. If pressure continues to drop after the oil temp has stabilized that's usually not good. Also I have a checklist that I go over before I fire the motor.

 

[MOPAROFFICIAL]

On the dyno I fire the motor and take it up to 2500 and vary the rpm from 2500 to 3000 with the throttle. I check oil pressure , listen for noises, look for leaks, check exhaust gas tempratures to make sure all cylinders are firing, check timing and put my hand on the valve covers, oil pan and timing cover before they get too hot to check for something rubbing or making contact. Soon as it gets a little temp in it I use around a 100ftlb load to pull it from 3000 down to 2500 then release the load back up to 3000 over and over in a cycle. I do this for about 25 minutes. My dyno has a program for this I just set the load and flip a switch once it gets a little temp in it and the dyno will sweep the rpms with the load. I monitor oil pressure vs oil temprature and watch for leaks during the break in. oil pressure should drop with temprature and stabilize when the temperature does. If pressure continues to drop after the oil temp has stabilized that's usually not good. Also I have a checklist that I go over before I fire the motor.

That sounds about right.

 

[furrystump]

I don’t worry about the rings. I think most ring seat failures are a result of other issues. Bore geometry/bore surface finish/or excessively rich fuel conditions wash the cylinder walls of oil during initial startup. Camshaft break in is a whole different deal. I run a solid flat tappet cam. I run the EDM lifter and have had zero issues and would continue using them. No real downside I can think of. The most important thing is to make absolutely sure the lifters spin in their bores as you turn the motor over by hand. This is with the valves lashed. If they don’t, fix whatever the issue is, if they are new cam and lifters. Move the lifter to a different bore, look for burrs. If you can’t get them all to spin, I wouldn’t start the motor.