CM871 kickin my Butt

[Rawze]

(07-27-2020 )RustyWood Wrote:  Well here I am still waiting, (weeks now) for my Cam Wedges and Crank Pin to get here. According to procedure I must have them in place and they must remain in place before removing Cam Gears to get my Head off.

There's information on backing off the Cam Scissor Gear bolts, I haven't taken outer cap off yet to see if that's what mine are, but there's no explanation as to why this design was used?

Hey Rawze, was this to unload pressures between the Gears ? I'm trying to understand why the heck these truck Cams wouldn't just have straight gears, since you know these so well, maybe you can explain the purpose to Cummins using Scissor Gears ?

I suspect I have the original Balancer, so I think I'll be ordering one of those as well.
Do you recommend replacing the Cam and Crank Position sensors since I have it this far stripped?

Thanks,
Russ

First of all, I don't see any scissor gears. The pic shows you only have straight gears. There is nothing to worry about with that.



NEXT:...


you have the old style cam gear retaining plate. Those were prone to failure and yours should be thrown away once it is removed, and replaced with the flat (newer) style. Otherwise, you are risking a gear train failure.
ref: http://rawze.com/forums/showthread.php?t...9#pid23329

ALSO: it looks like you have removed all the rockers and rocker shafts. There is nothing stopping you from removing the 2 top gears (for the overhead cams) and the cams, and then the head. -- you only need the wedge kit to re-assemble the engine, not to take it apart.

BTW: here is a wedge kit + gear puller... Looks like this one would work just fine: https://amzn.to/2X2HAmE

[Waterloo]

I was looking and straining my eyes... No scissor gear there, and I think Rawze, and I know I would, have told you to replace it with what you currently have on there. I did see the old retaining plate... You are lucky you do not have that scissor gear, mine was ready to blow apart. We replaced it with a solid gear like you have on there, which was around $400! YIKES!

When you go to assemble the cam gears, make sure you use the Green Loc-Tite that Cummins calls for. You apply to the OD of the camshafts surface that contacts the ID of the gears when you go to put this all together. What is it, 609? I know that it is a favorite of bicycle shops, and sometimes can be difficult to find. Rawze found it at https://www.mcmaster.com/loctite/retaining-compounds/ there in Atlanta if you cannot locate any. It is extra protection to prevent cam gear slippage. The small bottle will suffice, as it is not cheap, and once open, you probably never need it again, it drys out quickly.

And best for two of you to remove and install those cams, the edges in that head are sharp, like razor sharp. An extra set of hands will make everything go a lot smoother.

When you go to install the front cover, I went to the hardware store and found two bolts that fit the front structure holes, cut the heads off and used those as guide pins when I had to fix a leak last year in that top cover. Near as I can figure, the plate was slightly warped, enough to cause a tiny leak, which sent oil everywhere under the hood over time. I discovered it using UV Dye for oil from NAPA, only way I could locate where it was coming from.

When I got everything apart, the gasket looked fine, no pinch marks and it was seated in that groove. So, I used some high heat RTV and laid a thin bead all the way around the outside of the gasket itself on the aluminum structure. I installed the two bolts and simply guided the plate back into place, installed bolts and torqued in the sequence recommended by Quickserve. Leak is fixed. I did use anti-seize on those bolts for the structure when I put everything back together. ;-)

Pay attention to this comment! That front structure gasket, when you go to fit it in that groove, it will need to be cut to fit, as it is an inch or two too long... When you trim that, make sure you have a grip on that end, I didn't the first go around in Rawze's driveway, and that piece fell into the front structure and dropped clear into the oil pan. Tip, if you have the oil pan off, install the oil pan when the top end is completed and ready to take oil, after it is all buttoned up. Trust me on that. Oil Pan LAST! If the pan is on, watch that lose piece of gasket, it can get away from you quickly, as it is as thin as a piece of pencil lead and is slippery as a wet noodle, it can and will ruin your day.

I also discovered the gasket at the oil fill neck was old and heat soaked, very brittle, I replaced that too. I still get a bit of oil seeping out from there, but it is manageable, I think I need a new neck to go with that new gasket, as it is plastic and more than likely getting old from time and engine heat and losing it shape.

Your crankshaft damper, if it is original, I would replace now when everything is apart. The viscous fluid in them hardens over time and will start giving you vibrations in the motor as it has lost its mojo... Cummins recommends replacing at 500,000 miles. They need to be painted too when installed, or no warranty from Cummins. I think they are still running around $650 nib. I would stick with Cummins on this part, OEM.

[RustyWood]

(07-28-2020 )Waterloo Wrote:  Pay attention to this comment! That front structure gasket, when you go to fit it in that groove, it will need to be cut to fit, as it is an inch or two too long... When you trim that, make sure you have a grip on that end, I didn't the first go around in Rawze's driveway, and that piece fell into the front structure and dropped clear into the oil pan. Tip, if you have the oil pan off, install the oil pan when the top end is completed and ready to take oil, after it is all buttoned up. Trust me on that. Oil Pan LAST! If the pan is on, watch that lose piece of gasket, it can get away from you quickly, as it is as thin as a piece of pencil lead and is slippery as a wet noodle, it can and will ruin your day.

Thank you guys for your input. I was wondering about that cut to fit gasket, I imagined I was going to coat it a bit with RTV to get it to stay in place as I install it. The all-threads for guides are a good idea ( I do that for aligning a body back to a frame), but one thing I ran into was, I began removing the front main bracket to accessories (alternator & A/C compressor) but got to the last bolt in front above the balancer and it stripped the head before it would break loose. (Damn !) So I was still able to remove the gear cover and it's metal clamp strip together slipping them out, I figured that's why I'll need some RTV to hold the gasket in place as I worry about exactly what you said Waterloo of the gasket dropping down into the engine, which also brings to mind probably disable me using any all-threads guides for the cover.

Thanks for telling me to replace that outer cap cover over injector cam gear, I didn't know they go bad. Seems like a simple steel cap but I since I haven't removed it yet to have a look at it's thickness, I imagine it must be thin enough they must get fractures and crack huh?

The procedures from Quickserve are very limited in explanation, but I did get Loctite 609, just waiting for wedges and I think my kit (which I just found their shipment is delayed again) comes with a few different wedges with different markings? So I was waiting to test which wedges fit in before I removed cams so I know which to use for re-install, best I'm understanding the procedure and saw the warning to not remove gears without the wedges and crank pinned, yet looking at it, it seems the wedges would disallow the cam's to slide out, it doesn't seem like I'd want them in place. I have rotated the engine to the insert pin location with the cams (flats) to the outer lip of the head so they should be positioned right, but for removal it just doesn't seem like you'd want them against the cam's flats as the bearing surfaces need to pass by when sliding out.

Dang, at the rate this is going it will be September before I can get to Rawze's in Georgia, but I bet the weather would be cooler, yet my plates for my truck are also due in Sept. I often wonder with this damn pandemic BS, and folks are shooting at truckers now, God is doing everything to hold me back from hitting the road. I've only ran 1 week so far in 2020 I've had so much bad luck this year.
Thanks guys !

[Rawze]

(07-28-2020 )RustyWood Wrote:  ...
The procedures from Quickserve are very limited in explanation, but I did get Loctite 609, just waiting for
..

watch the series... here is the part i talk about face gears and loctite 609

[Nostalgic]

(07-28-2020 )Waterloo Wrote:  And best for two of you to remove and install those cams, the edges in that head are sharp, like razor sharp. An extra set of hands will make everything go a lot smoother.

As long as you use Permatex Slick Lube for assembly, the blood kinda just blends in haha.

[Nostalgic]

(07-28-2020 )RustyWood Wrote:  Thanks for telling me to replace that outer cap cover over injector cam gear, I didn't know they go bad. Seems like a simple steel cap but I since I haven't removed it yet to have a look at it's thickness, I imagine it must be thin enough they must get fractures and crack huh?

The one you have has a taper on the outside. If I remember right, it was made with powdered metal which is pressed together and cured. They were prone to fracturing due to the stress they're under, and the way they're made there's no signs of cracking before they fail - they just do. The new ones are flat, kind of like a big washer, and made from solid steel. New style are reusable as long as there is no visible damage to them.

[Waterloo]

The string gasket, I used anti-seize on it, just a light coating all the way around, and it stuck right in the slot. I would not use RTV on the actual gasket itself, but on the outer edge of the structure, towards the outside of the motor. And use the guide pins, anti-seize the gasket, set in place, cut the gasket, run a small bead of RTV around the outer edge of the gasket on the aluminum structure, not the gasket, but the structure, screw in the two guide pins on the top of the structure, set plate on them and work into place. That bracket on the left lower side of the motor is a bitch, but doable. Much easier to do with everything apart, trust me on that.

On that stripped out bolt, I would get a Heli-Coil kit, sounds like you have time. Use a sharp drill bit, BUT, file down the end so that the drill bit does not grab into the aluminum. The two tangs or teeth, I'm not a drill bit expert, you want the end of the drill bit rounded off so that it does not grab into the soft aluminum when you start the hole, so that it is not sucked into the hole, which will more than likely throw everything off and ruin the hole for the Heli-Coil.

I believe this is the kit you will need to use... https://www.amazon.com/gp/product/B0002S...UTF8&psc=1

You will need a 13/32 inch drill...

[RustyWood]

Hey Guys, I'm back working on it, I'm tellin ya if I didn't have bad luck, I'd have no luck at all. I ripped my palm open on a nail slipping on a boat dock, and they Lost my Order for the Cam Wedges/Crank Pin/ & Cam Gear Removal Tools, which finally got here Friday, then my Shop Air Compressor crapped out and I had to order parts to rebuild it, all the while when I have to run out for each thing I run across I don't have as I've only had 1/2" drive tools (car workin level) and never needed 3/4" drive until working on this beast and snapping enough 3/4 to 1/2" adapters, so there's lots of running out and time burnt trying to find tools.

Anyhoo, here are some interesting things I've found and I'll need Rawze's feedback here.
Have you guys ever seen the Seal Plate to the ECM Mount Cooling Plate have an internal Burst like this ? It's all in a sealed contained area, but what the hell could have caused this a backfire at some point ?



Then, as suspected, #3 cylinder did loose the valve face, looks like 3 sides let go, I'm glad I didn't trust driving this thing across country to Rawze's place, I think that last lip edge would have let go and taken out another $4k Turbo.

#3 Cylinder does have a bit of scarring, no clear cracking, but I can feel a slight edge running my finger down through so yeah, I'm still not too crazy about throwing the new head on and would rather put a new sleeve in, but I don't have those tools or know how to do the machine work and shimming Rawze has told me about and will teach me.

Another Question, on 1 more thing I have seen. It looks like this engine has had a valve smack on the piston on #1 you can see, there are a few others but not this bad, so this was my thought. The 6 degree wedge fit nice and flat on the Injector Cam Flat with Crank Pinned, but it wouldn't seat on the valve Cam, but the 7 degree goes all the way down seated, BUT as it touches the lower part, there was about a 1mm to 1-1/2 mm gap to be flush with the 7 degree wedge at the top of the flat surface? Should the 6 degree's fit on both sides? and is this slight turn of the valve cam what caused valve contact do you think ??


I'm making my order list to run to Kenworth, there are many things I think I'm going to replace besides all the needed stuff, the balancer, gaskets, the cam position sensor and since the mesh on the wire loom of my Jake Harness has been disintegrating I may replace that.

I can't get a photo of the slight edge I feel it doesn't really show up.

[RustyWood]

A bit more studying my procedures and learning more. OK I should have the 4 degree wedge on the Injector Cam, and the 6 on the Valve Cam, Since 6 didn't fit proper to Valve Cam I think I clearly I had a cam slip, breaking my valve, and there wasn't much old Loctite 609 on the Valve Cam to scrap off, at this point with #3 sleeve not looking too good, I really don't want to just throw a new head on to turn around and just pull off again, especially since the Head Gasket is $292. Bucks and I'd be damned worried to drop a Liner or cause more damage trying to drive across country. I'm going to do a full rebuild, it's the only thing that makes sense, but I'd sure like an experts help doing the Liners, that dang tool is like $2450. by itself, plus I need Liner Installer/Remover Tool, and maybe get that sled Dial Indicator, All this and I'm at those videos with more to watch, so study them and the procedures about the Liner Deck Height and counter boring cutting and study on all this good, it sucks I'm also by myself with no help with the big stuff like installing the head, and I have to use chains, I don't have that head holding lift bracket.