Who makes a Jacobs-type engine brake for the 250 Cummins?

I want that BIG truck sound (and the extra braking would sure be nice too!)

Does anyone make a REAL Jacobs style engine brake?

(not an exhaust brake, although if I can't find a Jake brake I may do an exhaust brake...)

RE: Who makes a Jacobs-type engine brake for the 250 Cummins

I think a Jake brake is electronic and it's really part of the heads or is it the exhaust manifold, I'm not sure but I don't think you can buy one and just add it to your engine. Somebody please correct me if I'm wrong (I probably am). If it this post sounds mean, sorry no disrespect was meant.

RE: Who makes a Jacobs-type engine brake for the 250 Cummins

Jacobs offers several different products, but the original "Jake brake" is a product that opens the exhaust valve early to release the compression energy. It mounts on the heads, under the valve covers. You can buy one and add it to any engine that Jacobs provides a unit for, but I don't believe they have this type of unit for the NHC-250.

RE: Who makes a Jacobs-type engine brake for the 250 Cummins

The exhaust brake will not give you the "big truck" sound. It produces a intense hissing sound and is about half as effective as the Jacobs, low cost though. Other driveline retarders, electric or hydraulic are very effective but quiet.

looked at putting Jake's on mine when i do the re-power. for me it wont matter that the hood wont fit (the Jake's wont clear the hood) cause i will need to modify that anyway for the turbo cross tube.

I have a jake brake on my M813A1 that the Canadian army had put on all of there 5 tons it works great and has that rumble of a big truck when you use it. I am not sure of the model number of it but I could see if I can find out any info on it. It is an exhaust brake so you can turn it off with a flick of the switch. The pods that sit on the heads sit a little to high for the hood to close all the way so the Army cut a little hole in the hood and built a box around the first pod but it doesn't look that bad I have some pics of it I will try to post here

Pictures would be great! Thanks!

These are the pods mounted on the heads they do sit a little higher than without.

If you look at the pic of the truck on top of the hood by the front is a nose bump so the hood would close around the front pod all it is is a hole cut in the hood and a metal box fabed up and riveted to the hood. The brake has a 3position switch in the cab 1, is more or less off it applies a little braking but you don't really notice it or hear it 2, you really notice it and feel it slow the truck down 3, sounds like a train is coming out your stack and you better have your seat belt on or your going to bump your head on the windshield I can get some better pics this weekend if you like.

What would happen if you installed the brake on just the back two heads? I think someone else made this comment awhile back. It looks like the hood scoop is only needed for the front valve cover. Total braking would then be like #2 on the switch?

Steamy: Did the Hiab crane come installed on this truck from the Canadian Army? Any idea what model and stats? Would love to do this to the new truck using the dropside body we got. Any idea on the pump sizing? Pump on the M812A1 is 20 gpm at 2-2500 psi.
Thanks, nice truck

Love the pics with the crane! Cranes come in VERY handy!!

The HIAB looks like my 1975 Model 765, but I don't see the outriggers. The operating levers are also inverted.
Yeah, I'd be curious about the crane stats too.

The crane is a 1976 Hiab model 550/3 5ton crane it came from the army this way it was used in a armored regt. as to where the out riggers are they never put them on I don't know why? but my friend had lifted a Sherman tank turret from the ground and placed it on a flat deck truck with no problem it hardly leaned over at all so it will lift without the out riggers. I was told the army changed the spring pack in the rear to make up for the lack of the out riggers. As for only putting on the two pod's on the rear the hood would close properly with out modding it as for how you would hook it up ??? but I don't see why it would not work you just would not have full braking as you would with all 3 not a big deal unless your in the mountains with a full load on or just like waking up the neighborhood at 2AM

Steamynachos said:

The crane is a 1976 Hiab model 550/3 5ton crane it came from the army this way it was used in a armored regt. as to where the out riggers are they never put them on I don't know why? but my friend had lifted a Sherman tank turret from the ground and placed it on a flat deck truck with no problem it hardly leaned over at all so it will lift without the out riggers. I was told the army changed the spring pack in the rear to make up for the lack of the out riggers.

Click to expand...

Thanks for the info, Steamy.

Well, mine is classified as an 8-ton crane and causes the truck to lean badly just swiveling it around when extended without a load. Then again yours is a 5-ton truck and that may make a difference.
Anybody know how much a Sherman tank turret weighs?

Wonder if they installed wrecker springs - with the solid steel beam?

Yes, you can put just 2 sets of brakes on just the rear 2 heads. Go to the following link and type in your CPL and it will tell you if there are brakes available.If you have an automatic, you will need a converter lock-up sender.
http://www.jakebrake.com/products/hd.php

Anyone know where I can find my CPL? What does CPL stand for, by the way?

Oh, Steamynachos, thanks a lot for the pics. nice to know it can be done. If you could determine the brand and number that would be great. Appreciate the trouble.

dma251 said:

Anyone know where I can find my CPL? What does CPL stand for, by the way?

Click to expand...

CPL=Control Parts List. It should be on the engine tag. It determines what cam, IP, etc... your engine has. I have seen a few CPL's listed in GL auctions for NHC-250's and could not find those CPL's in the list on Jacobs' site, hence my earlier statement about not thinking they offered one. However, the pics prove there is definitely one available.

The jakes work well,had the other type also but not as effective. When switch is on , just let up on gas pedal and it activates it.