Main and Rod Bearings CM870

[Andre_The_Giant]

Hey guys I'm changing my mains and rods in my driveway and I'm just about done, but had a question. A few Main cap bolts wouldn't tighten the full 180 degrees, two are at 165ish and one 150ish. Is this acceptable? i put a newer sanp on 1" impart gun on them that apparently has 1800 ftlbs of toque and they wont go anymore. to the point the bolt heads are starting to get beat up a bit so i stopped. Should i borrow a friends torque multiplier and keep tightening? Or try new bolts?
If i remove one old bolt and install a new one will this compromise the anarobic sealant?

Also for oil priming, Cummins says to prime oil in through port #5 and to build 10-20 psi, would that be on the dash gauge? Is that the best way? looks like I'm gonna have to buy an electric pump. Also anyone know the best fitting to use/ connect to? I think it’s m14x1.5

Thanks in advanced for all the videos and Q&A/s everyone, i probably wouldn't of had the courage to tackle this job if it wasn't for you guys =)

[Rawze]

I have always gotten the bolts to go to 180 on the main caps. I use a 3/4" air-cat with a single heavy-duty 15/26" (because its slightly tighter than a 24-mm) deep impact socket 6-points only (no extensions or adapters) with about 180-PSI on the air compressor.

The socket is face-ground nice and flat on its end each time its used, to grind out the wear from the last time it was abused by that much torque. The bolt is marked + socket itself is marked so that I can see the rotation.

The bolt itself is dampened with tiny bit of ultra-slick on the bottom side of the head and threads also slightly dampened with engine oil (but not soaked in it), so that it does not bind or gall.

- It could be that your torque wrench is not accurate and that you over-torqued the bolts initially?. Something seems off in your statement about how tight they really are ... because they are usually about the 485-520 ft.lbs range or so by the time they get to 180-deg. Granted that is a lot of torque, but not really much more than a set of lug-nuts on the truck would be.

Just for reference ... my 3/4" air-cat advertises it is 1600-ft.lbs.. but it struggles (and will not quite make it) to get them all the way to 90-degrees unless I bump the air compressor to above 175-180 PSI + use a 1/2" line with NO QUICK-CONNECTS between the tank and the gun. Then it will get them there.

- SO much for the advertised 1,600+ ft.lbs eh?... but that is typical advertising for ya.
I have this one: https://amzn.to/3H2fLRV

I use truck glad-hands on the gun instead of quick-connects to prevent air-line restrictions... and even if the hose is really long (more than about 30 feet), then it will get weak.

so .. it could also be your air-line setup. - Long hoses and ANY quick-connects .. even a single 1/2" quick-connects in the line will cause far less torque.. even in that 1" gun that you mentioned there. i see a lot of shops with quick-connects at the wall pipe ... + another one at the gun sometimes ... and then wonder why they can't get things as tight as they should be when verifying with a torque-wrench.

======================

About the pre-lube...

I use an electric oil pump. I remove the check-valve at port #2 in that pic you posted and yes.. I turn key on and watch gauge in the dash for about 20 psi or so. - I have pan draining into a clean pail to recirculate the oil several times thru. Oil pump has an inline oil filter on it to keep the oil clean (because I use port#2 to get good flow and this bypasses the engine oil filter) .. and pump runs and circulates the oil several times thru .. all while someone bars the engine over by hand during the pre-lube phase.

- We watch the top-end for proper oil flow (valve cover off), and when it starts oiling really good in the top-end and there is about 15-20 psi on the oil gauge + feels good by hand turning the engine .. then we start buttoning it all up + re-install the updated check valve at port#2 .. fill the engine with the oil, and then crank engine with fuel/timing solenoids (or injector harness on common rails) unplugged so that if will not fire up .. until we see a few psi on the oil gauge in the dash just from cranking it.

After that, we finish priming the fuel system and start the engine for the first time.


When I build an ISX with someone here at the house, I get all the air out of the fuel/oil systems which takes about 10 mins or so of low rpm idle,. feathering it, etc.. , I make damn sure there is no air left in the oil/fuel system and that its all good pressures, no leaks, etc.etc. --> Once we are satisfied that everything is right with it ... I then slam the accel pedal all the way to the floor, let it rev all the way,.. then back it off only very so slightly so the rpm is only about 5-10 or so rpm less than its governed max. I leave it there, not moving the fuel pedal at all (big wrench in hand, between fuel pedal and the floor to help keep me from moving the pedal again) - for about 8 - 10 minutes solid. Me also though, being very cautious about it, listening and feeling for anything that might not be 100% perfect, and checking for anything that might be causing any buildup of internal resistance. Scares the hell out of the truck owner. lol

While holding the rpm by hand at a just a hare under its max, not moving the fuel pedal at all, ... if the engine starts slowing down at all then I know there is excess friction in it, and that it needs to be shut down because something is wrong internally. -- If it holds steady just under max rpm (just shy of the speed governor) without moving the pedal at all, then there is nothing to fear.

After that, I drive the piss out of it around the neighborhood for a bit, then straight to somewhere to change the oil again a second time after about 30 miles or so of horsing around with it. then ., Back home, then re-run the valve adjustment a second time after it cools back down.

That is how I do it anyways,,. call me crazy .. but I do everything by hand + use a damn torque wrench on everything.. and am super-anal about every single part, gasket, component, screw, etc.. on how it goes together. I leave nothing to question or chance. If something is going to fail, I want it to show up right now, and not 3 days or 3 weeks from now.

I also re-use the old engine oil that came out of the engine initially (before the tear-down) when priming it, unless something is wrong with that oil. That or I use some really cheap-o farm tractor oil. Remember .. Its going to get contaminated with assembly lube, spray residues, and all kinds of bad stuffs .. so it needs to be dumped in about 30 miles or so. There is no sense in putting brand new, ex$$pensive quality oil into the engine if it is simply getting dumped an hour or 2 after it is put in. Saving the old engine oil (and keeping it clean) if it is still in good shape is perfect for this unless it got contaminated.

[Andre_The_Giant]

Thank you Rawze! I’m going to get some new bolts this morning and try again, I know my impact gun is exceeding 500+ ftlb because when I use it on my lug nuts my 3/4” torque wrench confirms. If New bolts don't go the full 180 degrees I’m guessing my 1/2” torque wrench is wrong for initial 110 ftlb or threads in the block damaged? I’ll let you know how things go at them end of today.

As for priming, so I take the oil check valve out/ leave port 2 open and pump in from port 5??? Any chance you have a link to what kinda pump I’ll need? The old links on old posts aren’t working. I’ll get one ordered up today, an also ordered some fittings for port 5. if I can’t find an inline filter I’ll just keep pumping cheap new oil. As much as I hate to waste, this is my only truck and it being down is costing me money, hopefully I can find a pump tonight

[Signature620]

What lube are you putting under the bolt heads? I’ve tried engine oil, lubriplate and red truck grease. The grease gives best results for me while torque-turning with a 3/4” gun.

As for pre-lubing, there’s no single way it has to be done. Most people don’t bother doing it at all. At my shop I have a hose made up to go from my air drum pump to port #5 in your picture. I throw the filter on dry and put 50L through that port. The engine has oil pressure straight away when we fire it up. It’s more about priming all the passages than pushing a heap of pressure through the system.

[Rawze]

This is the pump that I use...
https://amzn.to/3S3mAsI

[Andre_The_Giant]

Thank you. I pull the worst one down this morning and found this! ill admit I used engine oil under the heads like Cummins says and it got burred. Lesson learned. I bought some new bolts today, Scotchbrite'd the cap lightly and bolted it back up with Lubriplate this time. At first it tightened up the same 140 degrees but I kept impacting and impacting and it eventually went the full 180! I also got all the others to go the full 180! I just needed to impact them more, with 1” gun and when the compressor was at full 150psi. Most of the turns came from the initial pull of the trigger so I think I may have a flow restriction issue in my compressor lines somewhere even tho its all 1/2” hose & couplers. I think the real culprit tho was oil under bolt heads not good enough lubrication. I was able to get them all to 180 degrees, thank you guys much for the help!

The only thing left to do is prime it with oil. I just ordered that pump you linked, Tyvm. I got m14x1.5 fitting today, do you think i could get away with using a hand pale pump into the port5 (while my dad bars the engine over?) Or should i wait for the amazon electric? another day or two off isnt the end of the world. I didnt realize you pumped in thru port 2, Ty for that info. ill go first thing in the morning to buy a fitting for that port. i like your idea of leaving the oil pan open to pump the oil thru multiple times. Is your inline oil filter the one that comes with the amazon pump or different?

[Andre_The_Giant]

How do u guys think these look? they only measured about .001 under the new ones but look like crap. 32k hours, 650k miles vocational dump truck

[tree98]

Kinda look like debris went through them.

[Signature620]

I’d call them good-looking bearings at 32,000hrs. I wouldn’t put them back in but the wear on them is perfectly acceptable for the work they’ve done.