Are jakes available form my 1985 6v92? If so, where would I look, how much, and who could install them? San Antonio area.
David
If you want to come west of I-25 then Jakes are a good idea. Jakes are so good now that most all the big Diesel engines in trucks come with Jakes as standard equipment. Jake brake was the first thing I had installed on my bus before I even drove it home from Portland, Or. Good Luck, TomC
David,if I remember you have a front mounted turbo is that correct ? if so it is a major job you need to reroute the air intake on the passengers side it's not worth the time and effort on a 6v92 JMO
Quote from: luvrbus on February 02, 2016, 01:24:39 AM
David,if I remember you have a front mounted turbo is that correct ? if so it is a major job you need to reroute the air intake on the passengers side it's not worth the time and effort on a 6v92 JMO
Yikes I didn't want to hear that. Let me take a picture so you can tell me for sure, but I think you are correct.
David
Quote from: TomC on February 01, 2016, 05:25:37 PM
If you want to come west of I-25 then Jakes are a good idea. Jakes are so good now that most all the big Diesel engines in trucks come with Jakes as standard equipment. Jake brake was the first thing I had installed on my bus before I even drove it home from Portland, Or. Good Luck, TomC
I want to take the DW to Washington State and Oregon one day. I will never forget some of the steep grades I encountered when I moved to washington many years ago.
The first thing I said to her was I think we may need to ad some jake brakes, but then again, these buses ran all over the US and I could probably get there using the gears and I would think that having the jakes might remove allot of the worry away?
Here are some pics
David
You are good to go David they will work on your setup
Quote from: luvrbus on February 02, 2016, 01:46:44 PM
You are good to go David they will work on your setup
What would I expect to pay? I'd have to have it done. It's beyond my skill level.
David
Expect to pay around 6 to 8 hrs labor plus the parts by chance do you have the tall valve covers ? somewhere on this board I posted the parts list lol I wouldn't waste the wire for doing a 2 stage Jake
Hey David, what part of the country are you in the Eagle Ford area (south texas) . I found out if you check with the well service companies they seemed to have a 2 stroke cat around as they used those engines for years on the rigs or at least they did out in the west Texas (Odessa) area years ago. Don't have or haven't found anybody up la grange tx. way.
Easiest way to wire is to have an on/off switch with a foot operated switch. Then you don't have to deal with the governor switch. Good Luck, TomC
This is probably how religious battle-lines are drawn, but I am genuinely curious,
Just how useful are jakes, on a 6v92 in particular?
I too had tossed around the idea of having them installed based on some previous posts. But we have that engine and I had a assumed the compression was high enough in the engine, to simply back off of the throttle, drop to a lower gear, and use that natural back-pressure to hold a grade.
Please keep in mind, I haven't driven it in CO type grades (yet), but we did bring it back from CA to MO (along the southern route) and we came across some fairly decent grades. But the real test was in her original stomping grounds of the PO. They lived on a fairly steep and long hill (~10 miles), that reminded me of CO driving; and we had no problem creeping down that hill (several times), in first, and holding the grade well.
We do intend on doing quite some driving around CO, as we spend time exploring that state; among others with similar topography.
I'd like to get thoughts, opinions, and direct experience with and without jakes on that engine and the preception of their usefulness.
Do jakes make it easier? More fuel efficient? Safer? Less strain on the engine?
Or is creeping in first (we actually ended up needing 2nd because first was toooo slow, in our experience) usually sufficient with this engine?
Thanks,
George
Here's another way to think of Jakes:
They let you go faster down the hill than you otherwise could do safely without them.
By safely, I mean without having to use the brakes to control the downhill acceleration so much as to overheat them.
How much faster, depends on the strength you can get out of a given set-up.
How fast do you want to go?
happy coaching!
buswarrior
Diesel engines naturally don't have back pressure. As they are motored over on no-fuel coasting down a hill they fully compress whatever air they take in ( always positive air pressure in a two stroke from the blower so the cylinders always get about fully charged with air) and then they get all the energy that it took to compress the gas back on the down-stroke. Virtually a zero-sum game, energy in is energy out less friction losses. Exhaust brakes, variable geometry turbos, et al all add a restriction that traps the exhausting gas and creates a back pressure, but two strokes don't use those tricks.
Jake brakes work fine on a two stroke as long as you don't expect too much. It's a gentle retardation at low speeds and rpm, and works best at high rpm. Mine will slow me down too much on a typical Interstate grade of 4%, keep up just fine on a 6% grade, and I need to tap the brakes a bit on a 10% grade. Anyone from the east coast that knows the grade down I77 from Fancy Gap, I have to cycle the Jake brake on and off to maintain speed. Now, add 15K lbs of coach to my 30K lbs and the story might be very different.
Brian
IMHO, Jakes are well worth the investment.
One-time installation cost, very little maintenance.
Less expensive than two complete brake overhauls, which you WILL be doing if you spend anytime going up and down RockyTop out west.
Coming down the hill, the cooler your brakes, the better.
WB from Reno, NV to Sacramento, CA on I-80, you've got 70 MILES of 4%, 5%, and 6% grades. That's 3rd gear @ 45 mph and on/off the brakes constantly, with them stinking at the rest stop without Jakes. With Jakes, it's 60 mph in 4th and never having to touch the brakes unless traffic requires you to do so. BTDT - fully loaded MC-9s, both with 8V71s and 6V92s (there's only 16 cu.in. difference between the two, really insignificant.)
Additionally, when wired thru the throttle, they come on instantly as soon as you back off, which means they'll actually start slowing the coach before you've got your foot on the service brake and applying it. Could be the difference between a hit and a miss. . .
For me, I consider them a SAFETY item on my coach.
FWIW & HTH. . .
;)
I recently rebuilt my Jakes using the Pacbrake tune-up kit - new oil connector tubes (one of the old ones was completely snapped in two!), new O-rings for the solenoids, new spool valves, then I adjusted them to the recommended 0.064" clearance. Wow, what a difference! They don't have Throw-You-Through-The Windshield deceleration, but they will hold speed down 6% grades in 3rd gear with no problem. In 2nd gear the Half setting is usually enough, but I normally only use them on Full. Jakes won't do much if the transmission is not in lock-up. Curiously, even though there's little difference in cubic inches between a 6V92 and a 8V71, the eight-cylinder engine has more advertised Jake braking power, because my bus is less than 30,000 lbs and has lower gearing than most, its Jakes work well.
John
Low gearing is the key to Jakes on a 2 stroke IMO
Thanks guys for those great answers and explanations!
I understand jakes much better now, and their importance in a diesel; and in a 2-stroke in particular.
So any slow-down I'd been getting thus far, has been predominately the work of the trans. And the engine had little to nothing to do with it. Good to know :)
I suppose jakes are now on "the list".
Aye, the list grows long, LOL.
But I suppose that's one of those fun things you get when you own a bus -an ever increasing list of must'ves, should'ves, and wouldlike'ves ;D
Keep in mine that Jakes on a automatic transmission only work when the transmission is in lockup example the 700 series Allison do not lock up in 1st the 600 series do not lock up in 1 or 2nd gear unless a torque converter lockup has been installed.David's bus has a Voith and I do not know anything about how it works when it comes to lockup
All I know about 2 stage jakes in my 1991 8V92TA with 755CR trans is they work and good. Don't really need the brakes if you watch a head when stopping. Don't have any steep hills around where i live but use them all the time in every day driving.
I'm kind of with Muldoonman. I actually leave the Jakes off for the majority of my highway driving because I try to maximize coasting with throttle off to the greatest extent possible. I flip them on only when a hill requires braking to the extent that I am willing to give up the coast. Where I use them a lot and really appreciate them is in country road driving, to set up my speed going down a little short hill with a corner at the bottom, and in stop and go traffic to keep from getting on and off the throttle/brake dance.
If you have a 60 series then know how good Jakes can be ;D I change the one on my series 60 to a 3 stage the 1st and 2nd stage were just to much, you won't have that problem on a 2 stroke DD
The Jakes feel about the same in my 6V92 as they do in a loaded semi (80000lbs) with DD15. With the HT740, I don't remember using them in 1st gear. In 2nd gear, they are very powerful and will hold us back on any hill. 3rd gear is good for 8% grades, and 4th for 6%. Nice for off ramps. Once down in 2nd at the right speed, I turn them off before the yield sign. As nice as they are, we never had them on buses until the 1980s. We were trained to downshift to a gear low enough to hold us back going down the hill. Yes it was slow...
As has been mentioned, a simple way to wire them is with a momentary switch on the floor for your left foot. Pacbrake sells a nice one. So the power goes through a on/off switch on the dash, then to the floor, then directly to the Jakes. So when you need the Jakes, you rest your foot on the switch. I have driven buses set up this way and it works quite well. My Pete dump truck is also that way.
JC
Clifford's correct. I have a Voith. It is in lockup in 2-4th. It has a retarder, but I'm beginning to have ECU problems with the retarder brakes only. If I don't use the retarder, I have 3 ECU's that can get me home. However, we have done a lot of mountain driving and I used the retarder extensively. Not sure how to do it without it. The Voith service guy has been very helpful with me troubleshooting my issues. He is the last guy left that was there when my bus was running with Houston Metro. When he is gone there is no one left. (Kind of like Norris retiring :-\)
If ECU repairs are available it will probably be in the $2k plus range. Jakes would be a less expensive choice and I believe less wear and tear on the tranny.
Clifford, I don't know if I have tall covers. I can measure. What measurement am I looking for?
David
Quote from: David Anderson on February 04, 2016, 10:12:09 AM
Clifford, I don't know if I have tall covers. I can measure. What measurement am I looking for?
David -Pretty simple, actually. Do you have stamped steel valve covers about 2.5" high, or cast aluminum covers about 4" high?
HTH. . .
;)
I just gave away a set of 92 Jakes for $500 that had EVERYTHING FOR AN 8V92 TA. If you wanted them or a 6V92TA you just needed the correct valve covers.
Fast idle was included with hi and low switch at the dash.
Sorry David.
--Geoff
Jakes work very well on my 8V-71 (Don Fairchild adjusted them). My V730 will lockup in 1st gear if you pull the gearshift lever down to first and keep your foot at least an inch up from flooring the gas pedal. Very nice for slow driving in the mountains. Good Luck, TomC
Here is a pic of my cover. I had to turn myself into a pretzel to get this pic :o
You will need valve covers those are the low model
Quote from: luvrbus on February 05, 2016, 11:35:06 AM
You will need valve covers those are the low model
What do you think those might run? $$$
I wouldn't pay over a 100 bucks for a set,lol you are always late David I gave a RJ a set to replace his leaky stamp steel covers,I'll check around for you I can probably come up with a set I have plenty for a 8V
There was a set of Jakes on Ebay advertised for a 6V92.
Quote from: luvrbus on February 05, 2016, 02:00:43 PM
I wouldn't pay over a 100 bucks for a set,lol you are always late David I gave a RJ a set to replace his leaky stamp steel covers,I'll check around for you I can probably come up with a set I have plenty for a 8V
That's ok. I've got lots of time. I'm here to learn. I don't think I could do this myself. I'd have to find a shop to install this and tune it correctly. I could do the wiring from dash to rear and all that. I've searched a bit online as to how to install, but haven't found enough to attack this all by myself.
From what's been posted here, seems like it could be done for less than $2k which is cheaper than a Voith ECU rebuild :o
David
The going price for 92/71 Jake aluminium valve covers is $50 apiece.
--Geoff
There is a person on Ebay in Texas that advertises 8V92 jake take offs from military 8V92's complete for $499 with free shipping and valve covers $150 extra. Maybe he does a package deal. If I could find someone on the east coast fairly local to install them I would probably buy a set for my 8V92.
www.govliquidation.com (http://www.govliquidation.com) just had a large lot of brand new valve covers in Ohio that went to bid.
Quote from: scanzel on February 08, 2016, 01:34:48 AM
If I could find someone on the east coast fairly local to install them I would probably buy a set for my 8V92.
Steve -
Mark Davia (Onelapper) might be able to help you, he's in CT. Of course, there's always Luke & his crew at US Coach in NJ, too.
FWIW & HTH. . .
;)