I've got the bottom end of my 541 together and the heads are due to arrive this week. The top end should fall together rather quickly.
Once it's all buttoned up the plan is to break it in on the dyno. I'd much rather deal with any issues outside the car since stabbing the engine in the Imperial is far more difficult than my other cars.

This build has a mild hydraulic roller (235/241) and is destined to get EFI. I plan on discussing the dyno needs with the machine operator when I set up the appointment.

Should we do a cam break in type of run to heat cycle the springs? If so, would that be hard on the ceramic TTI headers? My collector extensions have O2 bungs.
I planned on running a carb and intake to make the dyno time easier. I'm not concerned about power changes with the later EFI installation. I'm open to using the dyno's carb if that's what they prefer.

Other than having the motor ready to fire and not splatter oil or scatter parts what do I need to consider?

I can speak to headers. My headers that I had planned on running in the cuda would not work on the dyno because they hit the chassis or frame of the dyno so, I had to use a garbage set of fenderwells I had. It's worth asking you dyno shop before going.

Always do the run in with a old junk set of headers. My machinist won't even use the customers headers on the dyno until the engine has had the cam broke in, of if it's a roller cam until they have a made a few pulls.

It all depends on the shop. The shop I work with has the dyno cell setup for EFI and they prefer to fire engines with EFI when they can since the EFI system works better than most customer carbs. Customer EFI can be tricky to use, especially if the customer doesn't know anything about it. We always use dyno headers since they fit and work. Trying to use the customer headers is usually a pain. But every shop is different and some shops might not have Mopar headers.

Pro Tip: My dyno guy didnt have any Mopar headers, so I gave him a few sets I had laying around. Made his life easier for his Mopar customers and made me a welcome client that gets a few extra hours "off the clock".

I have done it both ways, but if i were you i would use the dyno headers with the EFI until after the break in and the tune is close, then switch to your own headers. If the dyno is setup for EFI, I think it's easier then doing a carb.


Joe

I used the dyno shops headers, as mine were just recoated. I figured better safe than sorry.

Slightly off topic but Total Seal discourages running new engines, with new rings, without a load.

Actually it’s not, being a roller it doesn’t need cam break in. As for heat cycle for the valve springs, never ever had issues without doing so.

Rings generally need load to break in. Never heard of any exceptions to that.

If you have a flat tappet cam and new rings/hone job, basically a new motor, it would seem
that ring break-in has different requirements than cam break-in.

So what would actually be the best method for initial running of a new motor ?

On a dyno under a load would be ideal for the engine, but if its not a max performance deal you just do what you can. The dyno can at least do the cam break in under a load?

In this situation I'm interested in knowing what kind of numbers it puts out. If it'll tease 650 lb/ft and tickle 570 I'd giggle like a school girl. However, seeing that this is a cruiser instead of a competition engine the numbers aren't critical.

This engine has been another one of my science experiments and I'm really interested in seeing what it does.

I can tell you what we do and why, the rings need both load and a high vacuum, load to seat against the wall and achieve oil control and the vacuum is to rotate the ring on the piston. A flat tappet camshaft needs oil, lots of oil and needs to spin in the lifter bore.
If you show up with a new engine and a flat tappet camshaft with duel spring the inner spring will be removed. After spinning the oil pump/engine to make sure the engine has oil pressure, we start it and quickly get the timing close (usually less then a min) then bring the engine to 2000 rpm and apply a load of around 25-30 HP, then the engine is cycled up to 3000 rpm and back down to 2000 every 30 seconds with out changing throttle position. this causes a high load and then a high vacuum condition after 20 mins shut it down and put the springs back in it. Then begin to tune it.

Joe

First I’ve heard that vacuum makes the rings rotate. I know the angle of the crosshatch affects how fast or slow the rings spin, so I just figured the hone made them spin also. Interesting for sure.