Cummins big cam 365 and Cummins C brake.

[Evan]

Maybe this is the best place to post this?Theres a cummins big engine guru here that i cant remember his name.

I'm trying to get more breaking from the big cummins. I'm dropping solenoids or butterflies at 1800-1500 rpm. I've rewired so all solenoids come on all the time the 3 way switch is gone but still losing engine braking at high rpm.

365 has no trouble idling with switch on sounds like only one solenoid is on.

 

At and idle I flip the switch motor just about dies then powers through and idle at about 700rpm chugging right through the brake.

 

I'm not entirely sure how the system even works.

 

Thank for any help.

[dave110]

04mach1. He left. I'd post it down in the other vehicles section.

[NIsaacs]

It is possible you have the wrong lash adjuster, they are sized by your turbo and how much retarding turbo boost you make. Here is a link to the lash adjuster kits depending on your CPL and turbo type. Also, I had to replace my control valves quite often, the hydraulic valve spool.

 

https://www.powerlinecomponents.com/cecparts/cecpg55.htm

[Evan]

I haven't changed anything but the switch. 

To me it sounds like week solenoids or possibly I dont have enough voltage going to them.

 

I really have no clue.

 

Thank for lash tip. Didnt know there was such a thing or that its adjustable 

 

I've personally put about 200k on the truck. Motor was inframed at 837000k trucks at 1.2mill now. Never messed with anything but wiring. All wireing is falling apart 

 

I noticed a few relays marked retard 1 2 and 3. Might be worth changing them just for shits.

[NIsaacs]

I would install a rebuild kit, they come with the 6 control valves. Like I said, they fail regularly. Also, the lash adjustment is important.

[Evan]

Did some looking today.

With ignition on brake switch on it has 12v on all 3 solenoids.

 

With truck running front solenoid has 13v plus middle and rear have 1.9 . Possibly I'm wired wrong grounding out through ignition switch.

 

 

[Evan]

Yesterday she over heated enough it couldn't recover and I shut it down with a load on it. That's worsted case scenario at times it's the bread earner.  And has been for the last few days.

 

I found myself researching low flow coolant systems last night. Wtf . May be a tstat issue but likely is the low flow radiator with 1.2million miles on it..

 

I try to free fridays for repairs and maintenance that almost never works out lol though I guess today it will.

Hopefully back moving material later today or tomorrow have been in contact with Mac's in boise they seem knowledgeable on the low flow coolant systems 

 

I better go get at it. Check tstats out and go from there

 

Good to have cummins here. Truck had two bypass tstats.  

Edited July 19, 2019 by Evan

[Dieselfuture]

Green coolant in big rig, scary. I don't want to start another debate on coolant use what works.

[Evan]

I'm more concerned what tap water does. Anything coming out of the ground is nasty. 

 

I dont know how much coolant the truck holds but I put damn near 10 gallons of straight water in it and it's still turning dark green.. 

 

I'm planning to get a bunch of distilled water and some kinda antifreeze and redo it.

Or buy all premixed  but I don't even think I'll ever get it all drained to start over fresh with no tap water

[dripley]

Been running mine on well water since it was new. 

[Evan]

Got engine brakes working. Bypassed factory wiring. Brakes now all work and braking is tons better.

 

Now need to bring at least throttle switch back in. Clutch switch is nice but I can do without it.

 

Will be soldering connections as I do a test run with throttle switch wires in. Prett sure throttle switch is mounted at the pump. Electrical is not my thing. Truck needs the exhaust redone I'd rather be working g on that. Thinking about putting a short twister muffler on it.. need to buy one 90 and make the 45s to redo the rusted out exhaust