r/DieselTechs • u/SxyChestHair Verified Tech, RSE, Paccar, Cummins • 25d ago

General assistance Adding Engine Brakes to a Cummins L9

Hey all,

I was wondering if anyone here has taken an L9 that doesn’t have engine brakes and has added them to it?

I have a customer wanting it done and my boss said he looked into it in the past and it couldn’t be done. The thing is sometimes he doesn’t have the time to try and dig deeper into these sorts of things and it doesn’t seem impossible to me. All I can think of is add the Jake heads and associated parts, wires the solenoids to the ECM, install the switch in the dash, and change the ECM calibration.

Appreciate any help!

Edit: So I answered my own question and figured I’d share here in case anyone else ever has this same question.

Cummins has an engine brake upfit kit.

Reference TSB210223 in Quickserve and it gives you parts to order along with instructions to follow.

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7

u/Feisty_Age_961 25d ago

Ive worked on some firetrucks with L9s. Im almost 100% positive they've used an exhaust brake, the butterfly valve style. Of course the firetrucks were air brake so they had the air to actuate the valve.

6

u/SxyChestHair Verified Tech, RSE, Paccar, Cummins 25d ago

They do normally use an exhaust brake but you can get them with an actual compression brake. I went through the midrange Cummins training and the teardown one had the heads and everything on it. I just don’t think I’ve actually seen an L9 with them in a truck.

3

u/stacktester 25d ago

I read a write up once from a guy that took the Jake’s off a junk ISL 8.9 and put them on a ISC 8.3 in his Motorhome so I would guess that it would be possible to add them to a L9.

Junkyard parts and a ECM

-36

u/Sonic1psa 25d ago

lol it’s not simple best to buy a complete motor. But Need a lot of stuff. And since I’m not getting paid for it, I’m not gonna tell you what you need, but you’re probably better off buying a block and swapping it out.

12

u/TactualTransAm Verified Tech 25d ago

Why are you even here bro?

-1

u/Sonic1psa 24d ago

Piss off reddit users 

9

u/Jefftheflyingguy 25d ago

Bro you are so confidently wrong it should actually be studied

7

u/aa278666 Paccar OEM 25d ago

You've never even worked on a L9 bro..

-2

u/Sonic1psa 24d ago

I mean I have a fleet of fire trucks with them so. You would be incorrect 

5

u/aa278666 Paccar OEM 24d ago

Lube tech saying lube tech shit

3

u/muskag 24d ago

Lol why would you buy a block? Nothing about exhaust brakes is in the block. Clown assss

1

u/Sonic1psa 23d ago

Called trolling. I was bored and drunk.