Breaking in a rebuilt engine.

[riotwarrior]

Here are the details on rebuild.
Bored out .030, new pistons, new rings, new bearings,(rod, main, cam), and line bored & rotating assembly was/is balanced.
Heads have already been rebuilt, new valves, guides, seats, milled, new valve seals.

NOW THIS IS MY OPINION/PRACTICE

Ok so essentially a remaned engine. Based on this the potential for contaminants in the engine is quite high, small machining particles and so forth I tend to take a different route on things.

One practice is some good loades short bursts of power under load, up hill, and down hill preferably, getting RPM's varying as others have mentioned.

The KEY, is that I'll only do this for a short run then drop oil and filter and change again, that is unless you have a bypass with Uber fine filtration, such as down to 1 Micron.

If no bybass, then drop oil/filter and replace, this helps to quickly get any contaminates out ASAP. I can hear naysayers but this is ME...

Then run 1500 miles max do it again, but now you run hard, and always vary RPM never letting idle, no drive through coffee. This engine needs to work and rest work and rest, not setting at one RPM for long, start with ton of weight for few hundred miles watch temps/pressure and increase load over time.

At 1500 miles drop oil/filter and then good to run to 3K still working hard.

As we don't use a flat tappet solid/hyd cam the initial break in can be extended to 150 miles instead of 20 minutes.

AGAIN THIS IS JUST ME!!!!!

Another couple questions along the "break-in" thought.

Machine shop guys said do this for about 100-150 miles???? Thoughts on that..???

I have to replace 2 of the wrist pin bushings, had a spot on both that was broken or "notched" out.(post pics later)
I'm in a spot where I could pull the 6 piston/rods out and replace them all...????
Outside of using a "mic" on em any way of knowing if they are bad..???

I'm just not clear on what you are saying or not saying here so no comment

JM2CW

Al

 

[Brad S.]

Thanks Al good info.
The wrist pin bushing I could boil down to this, do most people replace em or not???

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[riotwarrior]

Thanks Al good info.
The wrist pin bushing I could boil down to this, do most people replace em or not???

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You are welcome it's about getting contaminants out ASAP and NEW engines are high in friction so thus the need to clean clean clean..

Those look not good that chip would be cause for me to be concerned at least.

Get 8 new pin bushings and have them installed and sized properly to new pins/pistons accordingly. Don't forget to leave enough in budget for a balance!

JM2CW

 

[Brad S.]

Well you touched another question.
Its already been balanced, but would adding new bushings throw off that balance???
I'll ask the machine shop guys.

 

[riotwarrior]

Well you touched another question.
Its already been balanced, but would adding new bushings throw off that balance???
I'll ask the machine shop guys.

So marginally it's not worth worrying about, new ones sized to the new pins will be so close to old ones not funny....

JM2CW

but what do I know...if turning 20,000 RPM like F1 engine, ya maybe then!

 

[Brad S.]

I think your right Al, but think I'll still call the machine shop.

 

[typ4]

balance will not be affected more than a gram or so. if they tell you otherwise they just want money.

 

[Andertusa]

I think your right Al, but think I'll still call the machine shop.

Some my say the machine shop is only interested in your money, but I gotta disagree with them.... it's YOUR engine, it's about whatever you're comfortable running/allowing, to me, I'm in more of the 'hi-perf diesel camp, so I'd balance them just for the piece of mind, but that would be MY engine. You gotta do whatever you feel comfortable with for/on/with your engine, most might disagree and give you their opinions, and you're asking for that, but this is your beast.

How are you planning on using this thing, what as the overall plan for the truck, these things will determine what you are doing with this engine, if you're gonna be driving the beast like you stole it, and drifting it, then by all means balance it again, if not, my thoughts are no, but this is YOUR engine, never let anyone-else's opinion stop you from doing whatever you want to your project.

 

[icanfixall]

Those chips missing from the bushings sure looks bad. But in reality its not a bad thing really. Very little of the actual load carrying part of the bushing is gone. See the rod chamfer. That area will carry no load. It looks good to have all that area a bushing but its not bad enough for me to repair. Now I post this because I am not seeing any other places that look suspect. And why did the machine shop not replace and mill the bushings to fit...

 

[trackspeeder]

fire it up and let it idle long enough to verify no fluid leaks and no strange noises. after that, find the heaviest trailer you can hook onto, then drive it like you just stole it. it's that simple.

X2 I always break them in this way.

 

[dsltech83]

X2 I always break them in this way.

Yep, drive it like you stole it just don't get it hot.