BC3 cam & follower issue

[Hallback]

CPL is 891 I believe.

 

[Truck Shop]

To me if the overheads were adjusted wrong it should have run like a sack full a$$ holes.
I think that cam was possibly bad when inframed.

Truck Shop

 

[Hallback]

It ran like a Cat with a turpentine'd ass!
Really pulled well, I bet you are right TS.

 

[Truck Shop]

891 is a III and the only cpl in the 800 series, Does that pump still have the seal on the plunger cover on the back? If it's a$$ is turpentine'd I'm willing to bet it's got
a #5 or #7 button and shimmed for rpm beings it's a logger. Stock button would be a #32 or #37 IIRC which would put it at 35 to 40 % over fueled and that's
strictly a guess. No load from standing idle cracking the throttle hard a 30% over fueled big cam will sound like a PC Cat, really rattles.

Some years ago a logger that use to haul on the west side now and then would come in to the shop I worked at in Eburg and have us put his Hot Rod pump on
so he could run with the bunch on the west side.

Truck Shop

 

[petepilot]

To me if the overheads were adjusted wrong it should have run like a sack full a$$ holes.
I think that cam was possibly bad when inframed.

Truck Shop

a sack full of a$$holes lol never heard that one before

 

[Tenwheeler]

To me if the overheads were adjusted wrong it should have run like a sack full a$$ holes.
I think that cam was possibly bad when inframed.

Truck Shop

The ones I saw done like that did not run well enough to leave the shop. They readjusted them, replaced push tubes and such. They left running fine but damage could have already been done. Regardless of the cause bad is bad.
We used to just replace the bad rollers and always replaced the lock pins also.

 

[RZucker]

Confession: I bent a bunch of pushtubes once on an old smallbore 335. Turned out somebody replaced the accessory drive without timing it.

 

[Hallback]

I really hope I get it sorted out this next week here as it needs to just go into retirement as a hobby truck.

 

[StanRUS]

Hallback,
Later OEM Cummins BC3s use crowned camshaft lobes and rollers. If you purchase recon Cummins lower boxes; use a pressurized engine oil source to flush out any assembly crap before installing on the engine. Pressurized oil source: Clean weed sprayer type pumped to 15psi. Fab a flat metal plate held on by 2 bolts-nuts, lower box gasket and drill-tap 1/8" PT hole to allow oil to enter the boxes lube oil orifice. Manually work the rockers and rollers for 10 minutes per lower rocker box. Use a clean catch pan and paint gun filter to determine if particles are flushed out. MAYBE Cummins recon parts have improved, I don't trust them.

Truck Shop / RZucker,
Did you guys ever see Custom Stainless exhaust manifolds for Cummins Small Cams; featured exhaust port stainless steel stuffers to raise flow rates (velocity and cfm)? Installed on Safeway's fleet early 80s to increase fuel mileage. Soon after Cummins came out with small exhaust port heads.

Preluber and Lower Rocker Box Plate (with Cat **** stains)

 

[Truck Shop]

Don't remember any stainless, I've been in been in just about every III cpl there is and I don't remember any crowned lobes on rollers or cams. Picture please.

Truck Shop

 

[StanRUS]

Don't remember any stainless

Not surprising; reflecting a bit (old memory), Stainless aftermarket ‘pulsed exhaust manifolds’ were available prior to introduction of Cummins Big II / 1979. The manifolds were developed by Calif off-road racing airflow expert, his name ? My memory won’t cooperate. Probably not over 150 stainless manifolds produced, expensive to fabricate using round 309 stainless tubing, 6 pipes into cast stainless center section that looks like Cummins cast iron pulsed manifold. All about retaining heat energy; i.e. higher exhaust gas velocity to spin up turbo quicker.

I've been in been in just about every III cpl there is and I don't remember any crowned lobes on rollers or cams. Picture please.

Cummins camshafts with crowned lobes; you cannot see crowning with naked eye, crown ½ degree or less across lobes parallel to cam center line. OEM effort to reduce lobe failures after introduction of PTD-TopStop-DFF injectors, pneumatic variable timing, step timing; emissions regulations beginnings. Maybe Pumpguy has Service Bulletins, I trash canned all of that subscription literature and engine advertising brochures.

Spam, couple photos of 1962 DIY proto-type rear cam bearing removal tool. Bitch digging out rear cam bearing while in-framing without pulling trans, bellhousing.

 

[petepilot]

Not surprising; reflecting a bit (old memory), Stainless aftermarket ‘pulsed exhaust manifolds’ were available prior to introduction of Cummins Big II / 1979. The manifolds were developed by Calif off-road racing airflow expert, his name ? My memory won’t cooperate. Probably not over 150 stainless manifolds produced, expensive to fabricate using round 309 stainless tubing, 6 pipes into cast stainless center section that looks like Cummins cast iron pulsed manifold. All about retaining heat energy; i.e. higher exhaust gas velocity to spin up turbo quicker.



Cummins camshafts with crowned lobes; you cannot see crowning with naked eye, crown ½ degree or less across lobes parallel to cam center line. OEM effort to reduce lobe failures after introduction of PTD-TopStop-DFF injectors, pneumatic variable timing, step timing; emissions regulations beginnings. Maybe Pumpguy has Service Bulletins, I trash canned all of that subscription literature and engine advertising brochures.

Spam, couple photos of 1962 DIY proto-type rear cam bearing removal tool. Bitch digging out rear cam bearing while in-framing without pulling trans, bellhousing.
View attachment 189117

you brought up 2 things i thought everybody had forgotten custom cal sc manifold and cam bearing tool still have one of those not diy though. custom stainless manifold i had on a400 magnum diy project. i got little over 435 out of a sc that stayed together for a162k miles that i ran it. sold the truck and then lost any further contact with the buyer so don`t know how long it lasted after

 

[Truck Shop]

Cam bearing tool I have, But never saw a stainless exhaust manifold but not surprised either if only 150 made. And the crowned cam, I dug through several of my books and
manuals and found info about it but it also never really changed the wear or longevity. The cam replacement is the same for all big cams except some IV's because of lobe lift
plus those use different pistons/valve reliefs. Actually it was a silly idea because it put more wear in one area of the cam lobe, probably thought it allowed more oil on the lobe.

Truck Shop

 

[Hallback]

Keep going guys, I'm drinking in all of this information and knowledge!

 

[Shimmy1]

Sad thing is, no matter how much we'd like to learn about all of this, guys like T/S, RZ, and Stan have forgotten more than we could ever possibly learn. Agree completely with the fact it's awesome reading these threads though. Thanks guys for sharing your stories.

 

[RZucker]

Sad thing is, no matter how much we'd like to learn about all of this, guys like T/S, RZ, and Stan have forgotten more than we could ever possibly learn. Agree completely with the fact it's awesome reading these threads though. Thanks guys for sharing your stories.

Don't give me too much credit... I still learn new stuff every day. It does hide some of the old stuff though.

 

[John C.]

I bet you say that to all the young mechanics

 

[RZucker]

I bet you say that to all the young mechanics

Actually I do, showing them a touch of humility seems to stop that "I know everything" attitude. Worst guy I ever dealt with was halfway through a 2 year course at the local community college, totally wasted his tuition and had zero mechanical aptitude. But he could tell the other guys he was smarter than me because he was "Educated", too bad his education didn't teach him how to adjust a clutch or how to find problems in trailer wiring.

 

[Truck Shop]

Yeah will every time someone notices a red spot or bump on my bald head they say looks like you bumped your head. I always reply {those are knowledge knots from the last job}.
Everyday I learn something just about as soon as I get out of bed.

Truck Shop

 

[John C.]

My moto, "if you aren't getting better, you are getting worse."