hell yeah I'd be interested if you think it could be done. but from most guys here they think it's damn near impossible. I'm nowhere near a master mechanic so I can't say either way.

all you need to make is spacer that will go under valve covers and you will be set.like everybody said it may be a lot of money ,but definitly not imposible.i work for MACK dealership and have rebuild and installed many engine brakes.it is relativly simple design. the way mack has it they made jake housing that bolts right on top rocker shaft with longer bolts (this is one of few designs they have)

it would take a lot of precision machining if one had access to one and do it in spare time but would definitly be different:tttt:

does anyone know the tolerance between the valve and the piston at top dead center on the 12v 5.9? i need to know how far i can open these valves so that i dont end up with a grenaded engine that i just got done rebuilding. it is in a freightliner and i tow alot of weight with it, so i definately need something to slow me down other than the service brakes.

i still think your gonna shake your shit apart if you install these on a 5.9 but hey maybe ill be wrong...

let him do it, then when it rattles apart the engine again we can go :ha::lol88::gj::photo:

What is the reasoning for this comment? The Jake Brakes just sit on top of the rocker boxes and utilize oil pressure and an electric signal to operate. You might want to replace the pushrods and the valve springs like we already know. But as for the rest of the engine, I'm sure it could handle it.

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The 5.9 cummins stock block and internals can take 750-800hp but can't take an exhaust brake? You're kidding me right? Have you ever had one apart and inspected it?

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I have a friend who is a machinist and this is what he was thinking of too. We also had an idea of tapping the oil galley via the rocker pedestal to operate the system just like the regular Jakes. We were going to do some research with gauges and tap a set and see what kind of pressure drop might take place with something like this to ensure we wouldn't create starvation of oil to to the upper end. It might be expensive, but someone needs to do it.

it is not going to cause oil starvation simply because oil wont flow thru it unless engine brake is aplied and is going to be under pressure all the time.even with engine brake on you still have tight clearences that it will not affect anything.
i also agree with you on durability of engine block and whole engine for that matter.after all engine brake only holds ex valve open,makes a lot of noise but wont hurt anything for sure

:pca1::c::pals::yeah: well one of you guys needs to hurry up and figure it out LOL, I WANT ONE BAD!!!!!!! Call me crazy, but I think I'd spend a couple grand on that b4 I would spend that kinda money on compound turbos.

you ever held the actuator down on an engine brake while the engine is running on lets say a N-14, with jsut one exhaust valve open at idle the thing shakes like crazy and that n-14 block is alot stouter and bigger then the 5.9, so no i dont think it will hold up, maybe for 25,000 miles yes but most of the guys that would utilize this would be haulers that would put 10x times that maybe more on there truck and it would rattle apart IMHO...someone prove me wrong i would love to see it done...

for all the more that these trucks tow, i know some people tow alot of weight, an exhaust brake would be fine and an engine brake would be over kill...it probably wouldnt even sound that good unless you had 20 K lbs behind it anyhow, i know the big Cummins expecially the ISX's sound like crap with no weight behind them...but like i said before somebody prove me wrong and run a set for 100k miles and then i will say im wrong:pca1:

i just need to know if anyone has any idea how far i can hold the exhaust valves open to have safe clearence between the valves and pistons. maybe .030 in. ? i drive a 97 peterbilt with the c12 CAT everyday at 105,500 lbs and no that motor doesnt shake like crazy as long as the jake deactivates by 900 rpm. only shakes at low rpms.