I have noticed on Ebay under Jake Brake that there are 3 or 4 advertising Jakes etc for 8v71/8v92. I have the 8v92 with the 6 speed spicer. What is the general opinion of adding this to my 8v92. Is it worth the time and expense ? In a few years I hope to get out to the north west and I now there are many mountain roads with steep grades where a jake may be usefull.
Descend one mountain pass out here without one and you will never ask that question again. ;D
As I mentioned here before, I bought used jakes on e-bay and found out the hard way that getting them rebuilt and correctly installed was anything but a bargain.
Having said that, I will tell you that I love having them, and I don't live in the mountains. They help in most braking situations, and we all know these buses, for the most part, do not stop as quickly as our cars. Jakes help. They also save wear on your brake shoes, etc.
And occasionally when I am descending a mountain pass or serious grade thay bring a huge smile of contentment and feeling of safety.
YMMV.
Mike in GA
I love my Jake brakes because I go through the Rockies every year on I-80. Mine came factory installed on a Series 60.
We use the Jake brakes coming into Salt Lake City on I-80 even though it is prohibited. I remember one year I was driving and the guys in back started yelling about me overheating the brakes because we could smell burning brakes. I told them it wasn't us since I hadn't touched the brakes in more than a minute. We were smelling the brakes from one of the trucks.
Just to give you an idea how important Jake brakes are to truckers, Detroit Diesels DD13, DD15, DD16 all have Jake brakes built into the engine. The Mercedes-Benz versions, OM471, OM472, OM473 have Jakes-as a matter of fact, the first Mercedes-Benz engines to have Jake brakes. Mercedes has had compression brakes before, but mostly use hydraulic retarders or Telma electric drive line retarders. The Cummins ISX15 has Jake brakes built into the engine-ISX12 is an option. The Cummins ISL has Jake Brakes as an option with turbo brakes optional on both the ISL and ISB.
Even if you have all wheel disc brakes that will work when glowing cheery red hot, you'll never want to do that since all that heat will be transmitted to the wheel and most likely will blow out your tire. Hence, coming down a big grade, Jake brake is the way to go. Install them, you'll not be sorry. Good Luck, TomC
Any one know when Greyhound 1st starting using Jakes on their buses,Trailways never had Jake's on their Eagle's Scanzel be careful buying Jake's off E bay
Your bus is a 6 speed you are going to need to down shift for Jakes to be affective anyway just weigh your options if you don't know how to install and rebuild the Jakes by the time you are finished you will be looking at 2 to 3 grand
good luck
This will show how old I am, (getting there), but we never had Jakes in the '70s when I drove for Brewster's. You just downshift to a low enough gear that will hold you back so you don't need to brake much. It is slow down the hills. So, in strictly practical terms, they are not necessary. But they sure are nice to have. You have to decide if the cost is OK for what you get.
JC
I will pretty much echo what has already been said. Jakes are great. I consider them an essential although others will say they get along fine without them. But then again, I consider air conditioning an essential also when people had gotten along without it for thousands upon thousands of years. However, there is a difference between Jakes and air conditioning or even an automatic transmission. Jakes drastically increase breaking power and safety, while those other things merely make like more pleasant (that's not such a bad thing either). How can anyone claim that they would rather have less breaking?
In short, if you get Jakes it will be on your list of the best purchases you have ever made. I would not completely eliminate the possibility of buying them on Ebay as long as the are rebuilt and from a verifiably reputable company. If not that, look to get a set from a trusted source. Mine were rebuilt and installed by Don in Bakersfield. I don't know if he has any more. Luvrbus may also know where to point you to get a set. There may even be some local diesel shop that can help you.
Yes for years and years, both trucks and buses did not have Jake brakes. The old rule of thumb was to go down the grade in the same gear you went up in. But-in this day and age of 80,000lb trucks pulling the Grapevine at 35mph and buses going full tilt at 55mph up the hill, going 20-25mph is just not practical anymore. Hence most new engines put out as much Jake braking as they do power.
I can tell you from experience-on my 8V-71, after Don Fairchild adjusts my Jakes, pulling my car behind, I weigh almost 35,000lbs. Coming down the 6% grade of the Grapevine, I have to switch back and forth between 1 head and both heads on the Jake to keep from slowing down to much. When properly adjusted, Jake Brakes are VERY effective on both 71 and 92 series engines. Good Luck, TomC
Jakes are affective on a 2 stroke with gearing and oil pressure sure you have good Jakes with your bus TomC it probably has 4:00 or lower rear gears it is a huge difference than buses with the 3:33 rear gears
Unless you program a World Transmission to due other the Jakes will not engage in 5th or 6th OD
I for one would not consider a Bus Conversion that did NOT have a Jake. Would also reject out of hand a Bus Conversion that COULD NOT have a Jake Brake installed and used. I feel that they are now just another SAFETY device. Plus the fun factor is still a great positive issue.
Way back before the dawn of time in 1970, I drove a school bus part time for the Kern High School District out of Bakersfield CA. My daily run was up and down the Ridge Route. The ride was a 1963 Crown Supercoach 10 wheeler school bus with a 220 Cummins, the infamous Fuller RTO910 10 speed Roadranger, (installed years later) and....the single stage Jake Brake.
Never had to touch the service brakes coming down the Ridge Route. Get the Fuller in the correct gear and the School Bus would just float down the grade. Very much a safety device and the kids in the back of the bus loved it when it engaged.....seemed the noise was multiplied by the second muffler. Very fun. Long ago and far away. HB of CJ (old coot)
Jake's were never available for the 71 series till 1963 six years after the introduction of the 8v71 in fact nothing had Jake's till 1961
It make one wonder how the poor drivers ever ran the west coast and Canada without Jakes, they are ok but not a necessity you cannot live without. For the GM gurus did GM ever offer Jakes I have installed several sets on GM's and the 4104 with 6L71 is the only GM I never had to alter the back deck I even had to do it on a 4905
I have plenty of Jakes around here ::) If Jakes make one fell more safe then I don't have a problem with it myself. I do think you guys over rate Jakes on a 2 stroke because they will not give the same breaking hp as the engine produces like a 4 stroke will
good luck
I have jakes on my 6v92, but they don't work for some reason? They click but don't work? Anyways I came down some mountains coming back from phoenix on hiway 50 coming thru Colorado or New Mexico and just used the engine without any problems other than the angry people behind me ::)
Love love love our Jakes.
They had begun to work intermittently for us - tracked the problem down to the spring that pulls the throttle cable back to idle. Added a bit more return pressure, and they are back to making even the biggest grades a piece of cake.
- Chris
I think jake brake is nice, but over-rated the way some tell the story. I have jake brakes but they didn't work for the first two years I drove the bus. I never missed them, I merrily flipped the switch on, went down the hill and carried on with life - because I knew they were there and I had no idea they didn't work... I thought I was using them the whole time. So I swapped engines, found out they were so screwed up they had no chance of working , fixed them up and installed them on the new engine and hey presto, I had jake brakes. Just the thing for those 8% and 9% grades in Quebec and New Brunswick on my way to Nova Scotia. So I test them out on the drive here, and at the end of the day I left them off for 90% of the highway hills. I just coasted down the hills in top gear, let the bus roll out the speed, tapped the brakes once or twice maybe, or toggled the jakes on for a minute or two. Where I did use them a lot was in stop and go traffic - on the gas, off the gas, speed up, slow down. There they worked a treat - but that's hardly life or death.
Brian
I was talking the Don Fairchild yesterday. He said that he has some Jake sets and some high valve covers. There are possibly even NOS sets.
Ok guys unless you have a torque converter lock up valve and switch which I don't recommend Jakes do you no good when the transmission drops out of lockup and free wheels then most Jakes disengage around 900 rpm on a 2 stroke because of low oil pressure Drive alt 89 from Cottonwood AZ to Prescott Valley AZ and tell me about Jakes
good luck
Excellent additional information luvrbus and thank you. For Jake Brakes to work properly, lots of times other equally important additions and adjustments MUST be included....such as fiddling with that pesky lock up clutch on Bus Conversions with automatic transmissions. I have learned from this excellent forum that gadgets are available for Allision automatics that keep the lock up clutch engaged practically down to just above idle speed...even in first gear. Very cool.
My old Crown Supercoach 10 wheeler did NOT have that cut off switch that turned off the Jake at a low RPM. When the Jake was turned on and the schoolie was waiting at one of those seemingly endless Bakersfield red traffic lights in neutral with the clutch out, I had to give the throttle a little bit of foot to keep the engine RPM at around 700 RPM. If I did not do so and did not just turn off the Jake, the engine would INSTANTLY "Jake" and stop. No big deal...one just had to get used to it.
Made it nice going kinda slow in about 7-8th gear or sosss with the engine turning about 800-1000 RPM. The school bus just maintained the slow floating road speed going down hill. The school bus route then ran about 5 miles West of Frazier Park....I have no idea where it goes today.....if at all. Pine Mountain did not exist back then. Anyhow, "Jakes" years ago certainly had their place safely hauling school kids. I could come off the "Ridge" and make my first brake application and the brakes would stone cold "squeek". HB of CJ
Hi Guys, I am about to re-power our Scenic with an 8V92 DDEC II and HT748 with retarder. BK mentioned the retarder offered greater breaking force than Jakes, and some of the research I have done supports that for the 2 strokes. I haven't seen much discussion on the forum on retarders, what are peoples opinions of retarders, vs Jakes.
Thanks, Dave
They work good Dave just install a transmission temp gauge and keep the temp under 300+ degrees you will like it they are reliable
Thanks Clifford, I will definitely have trans and engine temp gauges.
Dave
Somebody once told me or I read some where that a Jake dumps about 30% of the absorbed energy out the exhaust pipe as extra heat and the other 70% goes back into the engine cooling system...great for maintaining a decent engine coolant temperature while "Jakeing" (sp?) down a steep hill. And ...a very small percentage gets converted directly into a cool sound indeed. Just me. The engine cooling system is designed for this with no problem. In fact it likes it.
Please think it through. My old 743 inch 4 stroke 220 Cummins was probably absorbing at least 220 hp through the single stage Jake Brake. It could and did maintain a 33,000 pound 10 wheeler School Bus with sometimes 60 kids going down a 6% grade right at 25 mph without touching the service brakes. A automatic tranny retarder absorbs --converts equal or sometimes greater heat energy...but it has to dump it all back into a marginal TRANSMISSION OIL COOLER system.
The tranny oil cooling system MAY NOT be designed for it. Thus all the required or recommended extra tranny oil coolers. Even then you may not have enough capacity. A short story. Several years ago a un mentioned Type One fire engine, (pumper) came down the Ridge Route at 75 MPH with the tranny retarder set in the max retard position. The august Fire Engineer, (the driver) did not touch the service brakes. He did know any better. $30,000+ damage.
Had the grade been steeper or if he had been going faster, the entire fire engine may have gone up in smoke. Rumour had it the "chip" indicated over 400 degrees F oil temp? Anyhow, they had to tow it back to the shops. The Engineer got off scott free because of...well...use your imagination. My point is he did know better by training and profession. He didn't care. He did not even look at the tranny temp gage or hear the audible alarms....if any. The average Bus Conversion owner?
Maybe, maybe not. My greater point here is that sometimes bad things happen. You can melt an auto tranny with the retarder even if you do know better. Kinda hard to do so with a Jake. I for one think a Telsa type electronical (new word) drive line retarder with heat grid may be a better way to go...you do not have to open up the diesel engine to install the Jake. Also the Telsa type retarders are silent..no small thing now a days. We all must maintain the political correctness.
My read only. I love this Bus Conversion Forum. HB of CJ (old coot) :)
Om my B500 transmission the tranny temp is almost always within a degree or two of the coolant temp. I have an oil to water cooler.
All depends where the sender is located on a B500 mounted on the sump it will read 20 degrees cooler that the converter out temp the converter is where the heat is
The Allison's with a retarder do fine up 330 degrees then start watching they can stand 350 degrees intermittent without any problems
So what does a 5 speed Allison non DDEc old school transmission with an external retarder cost ?.....will it fit an Eagle 05/8v71n.
Or an internal retarder....will it fit ?
Can you put one in any transmission ? at what cost / and last where would you buy it...as in where is the best deal....Mexico ?
They got lots'a steep grades in Mexico...and crappier roads....and more kamikaze drivers...:)...something's keeping those guys alive...
I have a Jake.
The retarders I have used on the H3s quickly cause a lot of heat if used beyond 3rd stage.
I was amazed at how high the transmission temp quickly got. The temp must be closely monitored.
Having said all that, we never had a problem with them, even though we had several not very alert drivers.
I believe damage to the trans may occur if routinely operated above 270 degrees. I learned that from Bob Ware.
Some of you may know him.
Bob Ware the ultimate Allison guru have you talked to Bob lately Joe I have tried calling but never can reach him since he retired,the 700 series won't heat as fast as a B500R the cooler on the back of the B500R is real small
I have an L10 and it is too tall with jakes so I use a retarder in the trans. I upgraded the trans cooler according to my service shop. I have in and out temp on the cooler and a pump that will cool it down if I need to. So on the down hills I turn on the retarder and watch the cooler temp. Turn on the pump for extra cooling if necessary.
It was not set up that way at first BUT a couple of trips over Tennessee Pass in CO and the long down hill into Denver it seemed like a good idea.
As previously mentioned it works fine without but is MUCH more relaxing driving with a retarder (I'm guessing the same for jakes)
HTH
Melbo
I agree with luvrbus. I think they are nice to have but you can live without them. I have been up and down grades and over mountain passes that many bus owners will never, ever take their bus on. I have Jakes and I have intentionally not used them at times to see the difference. I found that without them I have to go slower and be more conscientious of my driving. Probably not a bad thing.
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Clifford,
I have a home number for Bob. It worked last time I used it. Call and I'll give it to you.
Really doesn't matter what rear end ratio your bus has-that's what the transmission is for to gear down to whatever speed you feel comfortable. On my V730, if you pull it down to 1st, you can get torque converter lockup. This was very helpful when I crossed from 395 over 89 then over 4 to Angels Camp (don't recommend it in a bus-in a car would be great). Was in 1st gear the whole time.
World transmissions can be programmed in almost limitless ways. Jake can work in any gear. You can also get automatic gear down shift when the Jake is activated-all the way down to 2nd if you like. The World transmission will also lockup in 1st gear if you push the button down to 1st for slow going in the mountains. Good Luck, TomC
Very true about the WT I have a 60 series you can throw a basket through the side caused by Jakes and some off wall programing on a B500
Quote from: luvrbus on April 13, 2014, 07:15:59 AM
They work good Dave just install a transmission temp gauge and keep the temp under 300+ degrees you will like it they are reliable
How difficult/expensive is adding a retarder to a Allison 6 speed / series 60? In general, don't need exact costs.
Does your Series 60 have a flat valve cover or a high domed valve cover. Many of the early buses that used Series 60's didn't have room for the Jakes, so they were ordered without and there is no room to install them. Then some of the buses did start to install Jakes on the front 4 cylinders only and still have no room for the rear 2 cylinder Jakes.
If you install Jakes on a Series 60 with an Allison World, there is either a programming you have to turn on, or the transmission will get the signal from the engine the retarder is activated. Have to hook up the reader to find out. Good Luck, TomC
Adding a retarder to the World B500 or the 4000 series is not that big of a deal the retarder and cooler just replaces the rear cover. The retarder on a World does not change the length of the transmission like it did on the 700 series the WT will require a special yoke for the retarder. The World uses what is called a module and I have no idea what the module would cost you the programing is cheap. The module for the World just adds 40 lbs in weight were as on the 700 series it was close to 200 lbs and 8 inches in length ?
good luck
Quote from: luvrbus on April 14, 2014, 12:34:12 PM
Adding a retarder to the World B500 or the 4000 series is not that big of a deal the retarder and cooler just replaces the rear cover. The retarder on a World does not change the length of the transmission like it did on the 700 series the WT will require a special yoke for the retarder. The World uses what is called a module and I have no idea what the module would cost you the programing is cheap. The module for the World just adds 40 lbs in weight were as on the 700 series it was close to 200 lbs and 8 inches in length ?
good luck
Interesting, any idea what the cost might be on a 4000? I do have Jakes, probably overkill but what the heck.
I know with Freightliner, if you have a transmission retarder, the Jake Brake is deactivated-in another words, you shouldn't have both. I know some ran with Cat brake savers and jakes-but that was back in the day when Cat Jakes were not very effective. Now, Series 60's are very effective and with single drive, probably would get wheel skidding using both at the same time. Good Luck, TomC
Thanks to both of you Clifford and TomC, appreciate the info.
Steve - Our bus came with Jake's installed. Before our bus I have had zero experience with driving any heavy equipment.
Our bus has a 6v-92T with a 740 auto trans.
When at the high end of 4th gear...65-70 the Jake's don't make much difference. They help but not a whole lot. If I get down to the lower end of 4th gear 55-60 the Jake's can hold that speed on a 5% grade. If its a little steeper then you have to occasionally apply brakes to keep the speed.
I love them. They add additional braking power and there have been many hills that would have toasted my brakes (mostly because of my lack of experience) if I had not had the Jake's. They also cool the engine. On hot days at the top of a long climb I've seen my temp gauge go up to 195 and as soon as I crest and apply the Jake's it quickly drops back down to 180. Without applying the Jake's the temps seem to hover on the high end and are slower to come back down.
If I had a bus without them....especially a manual transmission it would be hard pill to swallow to spend what it costs to buy, install and correctly configure the brakes. Once you had them in though...I don't think you'd regret it but I do think you'd always be trying to assure yourself you made the right choice in spending the money.
Lastly - your bus sounds bada$$ with the Jake's on. Nothing more fun for the kids than hitting the Jake's when you are cruising through a tunnel.
-Sean
Fulltiming somewhere in the USA
1984 Eagle 10S
www.herdofturtles.org (http://www.herdofturtles.org)
Jakes don't cool a engine Sean they will raise the temperature it's the coasting under no fuel load and the rpm of the fan that lowers the temps.My X Eagle (8V92) the temps would drop faster without the Jakes strange yours drops faster with the Jakes engaged first time I ever heard of that
Jake does say expect a 10 degree increase in temp with prolong use the 4 stroke are worse with temps rising with the Jakes fwiw