Break in procedure for rebuilt 5.9?

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MileHighDart

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So with the 5.9 swap finally done on my Dart and it’s time to start driving it. Is there anything special I need to do to break it in? Obviously it’s roller cam so don’t need to worry about, but just wondering more about getting the rings to seat and all that.
The rebuild was a basic, hone and ring it, new bearings, cam, gaskets.

Just take it easy for a few hundred miles or ?
 
MileHighDart said:
So with the 5.9 swap finally done on my Dart and it’s time to start driving it. Is there anything special I need to do to break it in? Obviously it’s roller cam so don’t need to worry about, but just wondering more about getting the rings to seat and all that.
The rebuild was a basic, hone and ring it, new bearings, cam, gaskets.

Just take it easy for a few hundred miles or ?
Click to expand...
Probably not a bad idea. There will be many suggestions I am sure.
 
One school of thought is that if you drive it easy till it's broke in then jump on it later it could cause problems where the rings normally ride in the bores.
At higher RPM's the rods stretch a little and the rings travel beyond that broke in bore.

Another is that it should be broke in the way it's going to be driven.

I don't fully agree with either, but like to run em fairly easy with some short jump on it's here and there.
 
If its fresh, pre-oil it. No driving at a sustained RPM for log periods of time, just fluctuate the RPM from time to time and rev it up. Honestly with a roller cam and moly rings very little but it never hurts.
 
Prime the oil, break it in, revving up and down slowly around 2500 rpm, checking for leaks etc.
Drive it like you intend to drive it.
If you are going to run it hard most of the time, run it hard.
 
I'm getting a 408 storker built by IMM Engines. Brian said he is going to break it in on the dyno. I don't know his exact procedure but I'm inclined to think he is going to "let it rip" after everything checks out.
I've been wondering same question myself.

I've seen numerous vids including the one IMM Engines has in which they build the engine, put it on a dyno, and run the snot out of it. So I guess the correct answer would be ... run it hard.
 
Last edited:
mullinax95 said:
I'm getting a 408 storker built by IMM Engines. Brian said he is going to break it in on the dyno. I don't know his exact procedure but I'm inclined to think he is going to "let it rip" after everything checks out.
I've been wondering same question myself.

I've seen numerous vids including the one IMM Engines has in which they build the engine, put it on a dyno, and run the snot out of it. So I guess the correct answer would be ... run it hard.
Click to expand...
Well let's see what brian has to say!
 
A couple revs to 3-4k should seat the moly rings then just drive it. No one breaks in a race engine by taking it easy for 500 miles and neither should you.
 
MileHighDart said:
So with the 5.9 swap finally done on my Dart and it’s time to start driving it. Is there anything special I need to do to break it in? Obviously it’s roller cam so don’t need to worry about, but just wondering more about getting the rings to seat and all that.
The rebuild was a basic, hone and ring it, new bearings, cam, gaskets.

Just take it easy for a few hundred miles or ?
Click to expand...

I use conventional oil with a Jomar 100% no-bypass oil filter. Run it and vary the rpm through one full heat cycle. Once it's cooled down fully, snug up all fasteners, check for any leaks and then take it for a good drive. Warm it up fully under light load, and then load the engine under full throttle up and down through the rev range a couple dozen times. Check all fasteners when cool, drive it some more and change the oil at about 50 miles to more conventional oil with new Jomar. Switch over to synthetic oil with a new Jomar once you are sure the rings are fully seated, which should have happened in the first heat cycle. Check and snug bolts regularly.
 
Well, I decided to take the advice of
MrJLR, "Just drive it like you stole it"
Krooser -"No one breaks in a race engine by taking it easy for 500 miles and neither should you."
and
JBC426, - "then load the engine under full throttle up and down through the rev range a couple dozen times".

I was a little worried yesterday, cause when I did get on it maybe half throttle it stared dumping blue smoke out the back. I did have it running, up to temp a couple times in the garage, just idleing and revving a bit. Was afraid I'd already seated the rings.

But after trying the advice of the gentlemen listed above, the smoking went away after the first couple full throttle runs. And I have to say, Holy S**T! This car freakin' hauls ***, ran perfect all through the rpm range, and pulls really hard. Almost glad I didn't have the money for an aftermarket cam and heads, cause this is plenty of power for me.

Very happy with my 5.9 swap right now!
 
I will tell you my break in story. I purchased a new dodge truck in 2000 in June. The day the Hayman fire broke out. I was sitting at the dealership looking at the smoke. So the next day I needed to evacuate my horses and helped out others as well. With less than 100 miles on the Odo, I was pulling over the max GVWR for that truck for quite a number of miles. Below was September of last year same truck.

IMG_0471.JPG.jpg
 
Roller cam engine? Start it up, drive it and enjoy. Rinse and repeat.
 
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