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871 mess - CANNONBALL - 10-23-2021
Built a motor for a customer that brought it to me in boxes. They tore it down 2 years ago and let it set open in their shop. It had previously spun a cam bearing. Cut the block, new bearings, pistons, liners, camshafts. Everything went together as well as can be when you go back behind someone else. Truck rolls over gets good oil to the top of the motor. Hooked the fuel back up fires easily. Good oil pressure, get the air out of the fuel system, best this truck as ever sounded and felt. 650K Miles on it. Peterbilt put 3 motors in it all under warranty this is the 6th total rebuild. #4 and 5 were done at pee dee eye so those don't really count. Upon assembly found why they spun a bearing to start with, rocker arm bolt stripped so they just put a standard thread bolt back in the hole. It stripped out also. Got that issue fixed. Drive the truck 10 miles or so runs good. No issues. Then it dies like you cut the fuel off. Plugged into it, 14 PSI fuel pressure. Slap a high pressure fuel pump on it same thing. Thought better start at the top like Carl on sling blade with with the lawn mower being out of gas. Pulled the valve cover barred the motor inj cam isn't moving Valve cam was moving as it should. Pulled the front cover, inj gear bolt was 1/2 out gear was loose on the cam. I know I tightened it to quick serve spec. 100 ft lbs plus a flat and a 1/2. Back it off and repeat. 609 on the gear. Same way I do all of em and have never had one come loose. Got to looking around aluminum shavings around the #1 cylinder. Several long strands. Put the bolt back in the cam. She's locked down. Put a breaker bar on it got it to move but its not right. Get it to come out finally, front 2 bearings are welded on the cam. We ran it with the valve cover off in the shop, everything was oiling as it should.
Now to the fun part--why?-- Aftermarket head and I'm sure the machine shop used aftermarket bearings as they warranted the last spun bearing. Bad combination? I always use a factory head so I don't know about aftermarket quality but the customer provided it. Should've known better.
Now where did the aluminum shavings come from? Bearing coating of some sort?
RE: 871 mess - Nostalgic - 10-23-2021
Ok, I have to ask...
What rocker bolt? Rocker shaft bolt? I assume if that caused the spun rod bearing, all of the cam bearings were toast too?
Injector cam gear is 161 lbs, plus 90 degrees.
Valve cam is 109 lbs.
Quickserve has changed the specs several times on BOTH cam gears recently. I know when I did my valve cam, it was a certain lb, plus degree, and now they've changed it back to a straight lbs torque. But either way, 100 lbs and 1 1/2 flats is not nearly tight enough to hold an injector cam gear.
As for where the aluminum came from... Old style oil pump, oil thermostat housing, someone cross thread an oil filter and eff up the threads or do something goofy with the oil thermostat?
RE: 871 mess - CANNONBALL - 10-23-2021
Rocker shaft bolt yes. Valve cam rocker. Front shaft back bolt. When they brought the motor the head had been warrantied by the machine shop over the 1st spun bearing. I never Personally saw the motor before they tore it down. Machine shop said lack of oil fried the bearing. Loose bolt on the rocker shaft would allow it not to hold oil pressure.
I double checked to make sure I was correct. It’s 100 plus 90 degrees on the injector camshaft with a scissor gear
New oil thermostat, cleaned the cooler out, new oil pump.
RE: 871 mess - Nostalgic - 10-23-2021
Here's an old copy I had saved...
[attachment=8152]
And from today...
[attachment=8153]
Not sure why exactly those specs are changed so much, but it screws with my head when I think I know it, look to make sure, and it's different. Dear Cummins, I don't need any help developing dementia lol.
RE: 871 mess - Rawze - 10-24-2021
(10-23-2021 )Nostalgic Wrote: Here's an old copy I had saved...
And from today...
Not sure why exactly those specs are changed so much, but it screws with my head when I think I know it, look to make sure, and it's different. Dear Cummins, I don't need any help developing dementia lol.
I don't know where you got that top picture but that is NOT what I am showing for my ISX. Even my old manual from 2007 says 160-Ft.Lbs then 90-degrees.. this is what I set all of them to (CM570, CM870, CM871).
(this is from the 2007 ISX service manual) ...
[attachment=8154]
RE: 871 mess - Rawze - 10-24-2021
(10-23-2021 )CANNONBALL Wrote: ... I know I tightened it to quick serve spec. 100 ft lbs plus a flat and a 1/2. Back it off and repeat. 609 on the gear.
...
that is not to quick-serve / service manual specs... you need to correct how you do it.
============
AS FAR AS the spun bearing .. I have seen this a lot actually ... It could be blamed on aftermarket components... OR... the more common issue that I have seen.. is that a lot of shops who are not extremely careful with its install ... will accidentally bump that front bearing during cam install .. or bump the third (or fourth) bearing in ... while installing the cam and it.. it then spins later on and no one can figure out what went wrong. -- Not saying your shop did this, but since it has a spun bearing, you need to really be looking closely on how those cams are being installed by who did the work at your shop. All it takes is a mechanic to gently bump into that front bearing (or 4th bearing) while installing that heavy injector cam, and a spun bearing is going the be what the result is. - Not knowing any better, as a truck owner who's seen this mistake many times ... and not knowing anything about how it was installed, I would conclude that this is most likely what happened if someone were to ask me.
It could also be that the oil hole was not aligned and no one inspected the head properly before installing it .. and it ran dry, or there was a dry-start (due to not enough assembly lube on the bearing) condition and it spun that way.
I talk about these same cam install issues in this cam install video here on my rebuild series...
and I talk about inspecting the head and oil passages, etc.. here in this video...
not knowing the situation, no one can say for sure what happened.. only that all precautions must always be followed as to not set yourself up for such a situation... and to avoid using any after-maggot crap or re-worked crap.. because most of the time, a shop is going to be blamed (just like how I described above) and not the workmanship of some unknown quality head. this leave the shop with a bad taste in its mouth, a pi##$sed off customer, and everyone pays the orice for trying to take that shortcut of "used", "After-market", and other things that actually save no money but only lead to grief in the end.
--- NEVER EVER EVER EVER USE AN AFTER-MARKET OR RE-WORKED HEAD ON AN ISX ... IT IS A VERY BAD CHOICE AND SHOULD NEVER BE DONE.. AND IF YOUR CUSTOMER SAYS HE WANTS TO DO THIS.. REFUSE THEM AND RUN THEM OUT OF YOUR SHOP... PLAIN AND SIMPLE AS YOUR SHOPS NAME AND REPUTATION IS ULTIMATELY ON THE BAD END OF THE BLAME GAME IF ANYTHING GOES WRONG!.
RE: 871 mess - Nostalgic - 10-24-2021
(10-24-2021 )Rawze Wrote: I don't know where you got that top picture but that is NOT right at all for ISX. Maybe a smaller engine, who knows ... Even my old manual from 2007 says 160-Ft.Lbs then 90-degrees.. this is what I set all of them to (CM570, CM870, CM871).
(this is from the 2007 ISX service manual) ...
I got it straight off of quickserve service with my ESN. I'll save the pages to PDF and print them out to use in the shop so I'm not fingerprinting up my ipad.
Top one has a end of page date of Mar-2020 and I saved it from quickserve in July 2020. The 160/90degree one from today has a end of page date of June 2006.
I have the full procedure in PDF of each, so no clue as to why or how.
RE: 871 mess - tree98 - 10-24-2021
Using an aftermarket head is a big no no. Maybe they used aluminum for the cam bearings???
RE: 871 mess - CANNONBALL - 10-24-2021
Attached is what quick serve says off the ESN. Cam and bearings are always coated with way more lubriplate than needed when sliding in cams. Always take it gentle and don’t force it. If it doesn’t slide together something is wrong. This one slid in. Oil holes were all lined up. Double checked them all. Did it all myself so I know how it went in. No issues during assembly. Cam turned it by hand just like the valve camshaft. Always try to bar the motor after every part installs to Make sure there isn’t any drag or anymore resistance. Cheap insurance I guess. That’s how mad dad always built them just always stuck with me.
I cant place blame on anyone but myself for using the head knowing what issues it had in the past. I’m not mad about it. Customer has been a good one over the years. He understood the risk and I wasn’t warranting anything that wasn’t Cummins brand.