[1911a1]

If all goes well tomorrow I will fire up my rebuilt stroked 455. It has a roller cam so I’m under the impression you don’t run that type of cam as many RPMs as you do a flat tappet.

Thanks for the help!

[steve25]

What has given you that impression as you say?

[1911a1]

Originally Posted by steve25

What has given you that impression as you say?

An internet guru! HaHa

I meant to call Butler and ask them but I got sidetracked.

That’s why I’m asking here.

The fellow on the internet just suggested you call the cam manufacturer.

[1911a1]

I’m going to try and contact comp cams.

[steve25]

In general a well set up hydro roller ( enough spring pressure ) cam with the same specs as a flat tappet hydro will make a tad more top end power and this would give you the option of spinning up to higher rev range.

[b-man]

During flat tappet cam break in you generally want to keep the engine at 2000 rpm or a bit above for the first 20 minutes to keep the cam and lifters splash oiled from the spinning rotating assembly below. Avoid idling the engine during that first 20 minutes, this is crucial to avoid flattening a cam lobe.

A roller cam doesn’t need this but some splash oiling of the new roller lifters with a faster idle speed can’t be a bad thing. A faster idle speed than stock after initial break in is usually recommended for any type of higher lift performance cam flat or roller to enhance cam and lifter oiling.

[Verdoro 68]

I used the traditional flat tappet break in method when I fired mine up. Like b-man said, I figured it couldn't hurt to get the oil splashing and circulating.

[1911a1]

comp said just run it around a 1000 and maybe up to 2500 a little but no real specified break in rpm on a roller cam. Which is what my impression has been.

It’s just that I’m getting anxious because I’ve never assembled an entire engine before.

[1911a1]

Thanks those sound like very valid advice!

[lust4speed]

I prefer to keep the RPM range at 2,000 RPM which is a little lower than the general range quoted. If you aren't getting enough splash at 2,000 then 2,200 won't help.

Like Bart said, idling can be the death of a new engine. While a roller cam isn't quite so dependent on splash oiling, the cylinder walls still are. I suggest to new engine owners that for at least the first thousand miles to shift to neutral at a stop light and rev the engine up a little waiting for the light to change.

[Schurkey]

Roller cam? Idle speed is way less important than loading the rings against the cylinder walls.

Put that thing on the highway. Put it in high gear--disable the auto trans kickdown if applicable. Stand on the gas from 30 mph to ~70 mph, depending somewhat on gearing. When you get to highway speed, release the gas pedal, coast back to 30 with the throttle shut. High vacuum brings oil up to wash-away the wear particles. Then stand on the gas again. You want as much cylinder pressure as possible WITHOUT DETONATION. Repeat until it stops being fun.

You do not need high rpm. You need cylinder pressure. Anything over 3500--4000 rpm is wasted.

[steve25]

As posted above with a roller there’s nothing to break in valvetrain wise as long as everything is oiled up well during assembly.
This means all the normal stuff plus the timing chain and the valve springs themselves which a lot of folks seem to miss!

Cylinder walls should only be lubed up with a film of ATF and the same goes for the rings .
Cheap insurance is to also use Total seals ring break in powder on the walls.

Be sure to over fill your oil pan by one Qt and make that a light weight oil.

Now let’s thing about this in a logical way and to counter what some have posted.

If you have not got the parts pre-oiled well and you have not spun the pump enough to see oil getting to the top of the motor , then why the heck would you fire it over and bring up to 2000 rpm or more?

If you have done everything right right in a roller Camed motor then the only thing to break in might be the rings depending on the wall finish.

4 to 5 full throttle runs up to peak rev’s thru the gears is all it should take to bed the rings in .

If the cylinder walls where final finished off with a plateo bottle brush hone then ring break in will take place in no more then about 1/2 hour of normal driving if the rpm’s are a tad above 2000 .

[mgarblik]

Engine RPM is certainly not as critical to break-in with a roller cam as a flat tappet cam. Running above idle, especially cold and during warm up allows for the high oil pressure which is appreciated by the new bearings and the top of the engine during break-in. There is nothing good about idling during warm-up. The extra splash above 1500 RPM's helps cylinder walls and other splash lubed parts as well. One thing not mentioned is getting the engine to start and run just as quickly as possible for the first time. Have the timing as close as possible for a quick start. Make sure the battery is 100% charged. I pre-fill the carburetor bowl or cycle the key several times before cranking if fuel injected. This is most critical with a flat tappet cam but important in general. I absolutely don't want the engine to have prolonged cranking and a bunch of drama getting it started or keeping it running. Over 15 seconds of cranking time is too long. That doesn't sound long but is really is.
Shurkey makes a good point in his post about cylinder pressure and breaking in the rings. Not much cylinder pressure at idle, that's why we don't recommend it. As soon as the engine is running good and the timing checked, and leaks checked, get the car out on the road and make it "work". That doesn't mean abuse it. But run as Shurkey describes, up and down through the lower/mid RPM range and even cruise for 5-10 minutes at a time. I like a minimum of 25% load on the engine for 1/2 hour or so. At that point, it is mostly broken in. That's the way we do it on the dyno. Then we change oil and cut the filter open for inspection. Good luck and have some fun.

[78w72]

Most of whats mentioned is a good practice but for a roller cam there is no break in required, set the idle speed a little higher like 1200-1500 after initial start up and check for leaks etc. Most rebuilt engines done right will have assembly lube on all critical parts and priming the pump before fire gets oil to the top end enough to fire the engine, oil psi is there almost instantly so can go to any given rpm right away, just like for a FT cam break in.

But all the special steps arent usually needed for engines with modern rebuild steps like the right final hone/finish of the cylinder walls, most types of rings with proper wall finish will seat very fast without doing the old process of a bunch of under load driving then decelerate with high vac... nothing wrong with that procedure but its not really required... new cars with roller motors even high power ones like vettes, stangs & challengers etc dont tell you to do all that, just drive the cars a little gentle the first 500 or 1000 miles then do a oil change when they recommend. Were the older FT cam engines even broken in with all the steps guys take for rebuilds? Think Ive read they were just sent out with a short list of how to drive the first X amount of miles... or did they do a 25 minute cam break ins at 2000+ rpms then drive them under load/decelerate for every single engine/car ?

On my recent 500+ hp stroker 467 with OF roller cam, I didnt do any special break in related to the cam and wasnt told do so by the engine builder or comp or SD who supplied the cam. Pretty sure the builder said the rings will break in/seat after a short time on the dyno or the first partial load run, or like 10 minutes of driving. So nothing wrong with doing any of the above, heck do a FT cam break in on the roller cam if it makes you feel better, but it should be fine doing basic start up things for a new motor like verifying leaks and getting timing set, then drive it for a few short trips and do a oil/filter change looking for any signs of problems in the oil or filter.