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Topic: Adding an engine brake to U320 (Read 1451 times) previous topic - next topic

Adding an engine brake to U320

Is adding an engine brake an option and how much would it cost?
Steven Green
1997 U-320

Re: Adding an engine brake to U320

Reply #1
What year U320? You (should) have a hydraulic transmission retarder.  You want to add a compression release engine brake (Jake brake)?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: Adding an engine brake to U320

Reply #2
Yes, if you are asking that an engine compression brake can be added to a Cummins M engine it can be done. An expensive engine upgrade plus wiring to the front.  Contact your Cummins dealer with your engine serial number.

But, like Chuck, I have to ask WHY?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Adding an engine brake to U320

Reply #3
Once you have a Jake, the question is answered.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Adding an engine brake to U320

Reply #4
Once you have a Jake, the question is answered.

Pierce

Pierce,

I am also a big fan of engine compression brakes-- excellent braking HP without adding heat to the transmission.

BUT, not sure I could rationalize adding it to a coach already fit with at transmission retarder.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Adding an engine brake to U320

Reply #5
Heard that same statement about a retarder,sounds almost like your spending $10 to save $5.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Adding an engine brake to U320

Reply #6
Pierce,

I am also a big fan of engine compression brakes-- excellent braking HP without adding heat to the transmission.

BUT, not sure I could rationalize adding it to a coach already fit with at transmission retarder.
Understand that but if the budget allows, it's great. Not just heat to the retarder but added complexity and maintenance down the road. I just leave the Jake on all the time and don't even think about it. But we live in the mountains. Would have the retarder light on all the time here.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Adding an engine brake to U320

Reply #7
I see alot of signs in towns saying no engine brake allowed,never saw one for a retarder.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Adding an engine brake to U320

Reply #8
I have no experience with an engine compression brake, but I've read that those with exprience with both prefer the Allison retarder. Any comments from those with experience with both?
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Adding an engine brake to U320

Reply #9
Have had "jake" brakes in 3 coaches, two on 2 strokes and one on a Series 60. Compression brakes generally only have 1,2 or 3 stages, unlike the multiple ones on a retarder. Jakes are more dependant on engine speed, but as Pierce says, you can just leave them on all the time and not worry about transmission temps. I made the mistake of putting a resonator on the coach with the series 60, sounded like a machine gun with the jake on.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Adding an engine brake to U320

Reply #10
Quote
Any comments from those with experience with both?

I've had all three (Pac, Compression, Retarder). The retarder is the best but a two or three speed Jake is pretty sweet. Both? Go for it!
jor

Re: Adding an engine brake to U320

Reply #11
The 11 liter m11 engines displacement limits its jake brake abilities somewhat.  My Cummins shops foreman/owner showed  me a jake assembly that was off of a crane trucks engine.  Used parts seem to be about a  CB.  Really had considered it as an adjunct in serious down grades to add another reserve method of braking.

So far enough reserve in up to spec brakes and the retarder barely so I understand the interest. 
"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Adding an engine brake to U320

Reply #12
I'm in the market for a 320 and when I get one I have been thinking about adding  a Jake brake. I drive in the mountains all the time and with the engine brake I don't have to worry about heat. I like the idea of both for the highway and for town the retarder.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Adding an engine brake to U320

Reply #13
Should have said that we had a retarder on one fire truck with a six speed Allison. With almost 10,000 lbs of water and fuel, it was pretty easy to have the warning light turn on when going out of town on campaign fires. Worked slick around town.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Adding an engine brake to U320

Reply #14
I prefer a jake break: I'll jump in and provide my 2 cents on jake brakes - 98% of our fire truck fleet (approx 400 rigs) use a jake brake or a similar engine brake. My own experience of driving fire engines with jakes for 30 years is that they work great, no heat build-up, minimal downtime, and maintenance. While I have less than 4 months driving my FT with a Retarder - I prefer a jake brake.

I find myself having to really match engine speed, trans selection, brake pedal force, and retarder temps on my FT when descending hills to find a comfortable braking speed and the trans can quickly go from 198* to 250* in less than 30 seconds of hard retarder application - making me have to worry about too many inputs and variables to not damage my trans and also be safe. Which lead to distractions when driving.

But I will admit that when my DW drives our FT - I think that the simplicity of having the retarder switch turned on offers greater safety for her not having to fiddle with the jake - but then again she is not doing the mountain driving.

This is only my own opinion based on personal experience.


Re: Adding an engine brake to U320

Reply #15
The disk brakes are somewhat cold blooded especially if the coach has not been driven recently.  Rotors I think get surface rust on them.  Need to be warmed up and deglazed before they can be relied upon if really needed.

Hence the factories wider adoption of the retarder versus only the 6v92 U300's originally.

Especially as the D2 seems to slowly lose pressure from oil buildup in the valving, at least in my case.

Adjusting the D2 to the max of 130/110 gives much stronger braking.  Lessening the need for the retarders input.

The brakes  obviously have a certain limit of heat absorption as does the retarder.

As Wolfe mentions downshifting the engine/trans increases the natural ability of a four stroke engine to hold back any vehicle.

Helps.  Mixing the retardation and the brakes and keeping the revs up maximizes their abilities.

Driving hard like I am used to doing and living where everywhere out of our area involves hills I tend to be probably closer to the coaches limits.

Trained a lot of customers of the coaches actual limits versus they got concerned(panicked) if the temp gauge moved off its nominal minimum position.

The jake addition I put  on similar displacement marquis with 3176 cats made the coach a true up and down interstate grades at 65 at 37,000 pound combined with both heels in front on the drivers seat.

2,4 or 6 cylinder jake panel on the left drivers wall(which was hollow to allow this placement) allowed the driver to control their downhill speed. 

The 8,3 can have an exhaust brake if the engine has the correct valve springs which I think all the Foretravels have oem.

Which actually worked fairly well if you kept up the motors revs.

Rocky Mountains and high loads and increased speed users might consider the m11 jake option.  I have.

The cat marquis had an optional after delivery customer preference software update available that allowed the jake to work with cruise control.

Like my 97's retarder.  Works with the cruise.  Marvelous.

If I added a jake it would have to be able to operate separately from the retarder and work on cruise control.

If possible....

Pipe dreams so far but the idea is there
"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Adding an engine brake to U320

Reply #16
Is this discussion confusing 'engine compression braking' and 'exhaust braking'?

'Jake'obs Company makes both types and both could be called 'engine Jake brakes' 

Cities sometimes outlaw engine compression Jake brakes because of the brap brap sound from compressed air being released at the top of the compression stroke..  I don't think cities outlaw exhaust Jake brakes.

How an engine brake works | Jacobs Vehicle Systems

Exhaust Brakes | Jacobs Vehicle Systems

The original question was one of the above vs 'transmission braking'


Re: Adding an engine brake to U320

Reply #17
An engine brake also known as a Jake break pops a valve open before top dead center on the compression stroke to eliminate the rebound of the compresson created. Where as an exhaust brake works like a potato shoved up the tailpipe. Exhaust brakes are not as efficient as a Jake brake but are cheaper to build and install and don't add excessive noise.
 The question was adding an engine brake to a U320 which would have the retarder already installed.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Adding an engine brake to U320

Reply #18
An engine brake also known as a Jake break pops a valve open before top dead center on the compression stroke to eliminate the rebound of the compresson created. Where as an exhaust brake works like a potato shoved up the tailpipe. Exhaust brakes are not as efficient as a Jake brake but are cheaper to build and install and don't add excessive noise.
 The question was adding an engine brake to a U320 which would have the retarder already installed.

Believe Jacobs Brake Technology filed for a patent on the engine compression brake, to be called a "Jake brake" to differentiate it from the Jacobs exhaust brake. As you say, big difference between "jake brake" and "exhaust brake" even though both are made by Jacobs.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Adding an engine brake to U320

Reply #19
When people ask me how I like our exhaust brake, I tell them "It's not a retarder, and it's not a Jake, but it's better than nothing!"

We've crossed the Rockies 3 times pulling 4000 pounds of towd, and lived to tell about it.

4th gear at 45-50 mph (about 2400 rpm) is the sweet spot for descending a steep grade with our exhaust brake.  :thumbsup:
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: Adding an engine brake to U320

Reply #20
Jacobs invented the Jake Brake many years ago but installed on Detroits and Cummins starting in 1961. Jacobs Vehicle Systems now produces the Jake Brake as well is using their name for an advantage in marketing the exhaust brake that restricts the exhaust system rather than utilizing the compression stroke and then releasing the compressed air near the top of the compression stroke.
https://www.youtube.com/watch?v=HkfjCJClWVA

Our U300 does not make a lot of noise but if we had a resonator on it, it would probably wake the dead. Modern Jake Brakes in the latest trucks do not make any additional noise. Ours just makes the Emmy winning 2 cycle noise if you open the driver's window in a tunnel.

I have to agree with Pibutler in that with the Jake switched on, there is nothing to fiddle with, in fact, I don't notice that it's on. In the taller gears on Interstate downgrades, it keeps the speed about perfect and when the smaller highways are steeper, I just drop a gear and use both the normal engine braking at higher RPM and the Jake as the higher the RPM is, the better it works.

Heading down to Lake Tahoe over Donner Pass on I-80, I shift down to third (four speed) and only have to use the service brakes perhaps three times for just several seconds on the way down. Jacobs did his first trial on what is now I-50 at Lake Tahoe.

Anything that will aid the service brakes to allow a safe grade decent is great but Jakes are my favorite of the bunch.

Pierce


Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Adding an engine brake to U320

Reply #21
Thanks everyone for your help. I am sorry for not getting back to you so late but I was having a hard time getting on the forum due to username and password. Issue. Any pointers for a newbie driving in the mountains with a retarder?
Steven Green
1997 U-320

Re: Adding an engine brake to U320

Reply #22
Thanks everyone for your help. I am sorry for not getting back to you so late but I was having a hard time getting on the forum due to username and password. Issue. Any pointers for a newbie driving in the mountains with a retarder?
Be conservative and treat the retarder as a secondary/supplemental aid to the service brakes. Overuse can cause the transmission fluid to overheat and a warning light to come on. Shift the transmission to lower gears to descend grades. The Interstates are not usually that steep but the mountain two lane roads can be steep and with cars behind, you may feel pressure to go faster. Use turnouts and let traffic go past. After a few downgrades, you will feel more confident.

Go easy on retarder operation in the rain and especially snow. Once the rear end comes loose on a downhill, it may not be possible to catch it.

I frequently drove a fire truck with 10,000 lbs of water and diesel. It had drum brakes and the retarder was a welcome addition. We had a six speed Allison so used the transmission and retarder as much as possible to keep the speed down but I did have the big yellow retarder light come on several times when we were in a hurry.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Adding an engine brake to U320

Reply #23
We push 7% downhills often: I figure my intended speed before the grade and let the six speed gear down them hit the Pac Brake and toggle on/off as needed. Only have to use the main brakes for pokie RVs w/toads or semis. Works perfect!  ^.^d  Brett moved the shifting console and mounted the Pac Brake switch below. My hand reaches it without taking my eyes off the road!
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
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Re: Adding an engine brake to U320

Reply #24
When this link first started up I was in the process of buying a U320 and thought a Jake would be nice. Now that I have a U320 I am
looking for a good used Jake so I can install it in the spring. I love the retarder but on the long grades I would have to slow down
and with the Jake I wouldn't, as it won't over heat.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport