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Author Topic: Jake Brakes on an 8V92  (Read 1819 times)
scanzel
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« on: February 06, 2014, 10:54:12 AM »

Would having Jake brakes installed on an 8V92 be worth the cost ? I have the 8V92 with the Spicer 6 speed standard. I have seen some at a government surplus site that are either rebuilt or new and want to possible bid on them but need some more info from the experts out there. What other items would be needed for them to work ? If doable what should I expect on cost for a complete working install ?
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Steve Canzellarini
Berlin, CT
1989 Prevost XL
TomC
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« Reply #1 on: February 06, 2014, 12:08:34 PM »

You'll have to either get the tall valve covers, or the spacers to use your existing valve covers-the tall valve covers work better-less leaks. Just a matter of mounting, wiring them. I can tell you that properly adjusted jake brakes on a 8V-92 is effective enough to hold an 80,000lbs load going down a 6% grade at 28mph without service brakes. I did that for years on the Grapevine hauling 80,000lb loads of beer and beverages. The key is getting someone like Don Fairchild to adjust them tight enough to be effective. Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
akroyaleagle
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« Reply #2 on: February 06, 2014, 12:28:03 PM »

As Tom said. You would need the tall valve covers.

Probably need to rework the air horn also to clear the tall covers.

Used is iffy.  Plan to have them rebuilt.

They will work great.

You will find folks that can install them a lot closer to you than Bakersfield.

Try to get them set to 55 thousands. 60 will work, but not as well. 65, in my opinion is too loose.

Clifford might have a set he would let go. He had a buffer switch a little bit ago also. If he does, you will not go wrong there. He might also know where the tall covers are.
If he doesn't, let us know. there are other places. Sometimes on ebay.

Good Luck,
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Joe Laird
'78 Eagle
Huron, South Dakota
akroyaleagle
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« Reply #3 on: February 06, 2014, 12:39:48 PM »

Here's a reputable dealer closer to you.

http://bernhardbus.com/JAKEBRAKE.html

Here's another, Tell Don I recommended him.

http://hdd.mrwebsites.ca/pdfs/431_Nisku%20Heavy%20Truck.pdf
« Last Edit: February 06, 2014, 12:47:11 PM by akroyaleagle » Logged

Joe Laird
'78 Eagle
Huron, South Dakota
RJ
Former Giant Greenbrier Owner
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« Reply #4 on: February 06, 2014, 02:46:35 PM »

Would having Jake brakes installed on an 8V92 be worth the cost?

Steve -

Cliff's Notes version of the Reader's Digest version of an answer to your question:

YES!!!

FWIW & HTH. . .

 Wink
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RJ Long
PD4106-2784 No More
Fresno CA
wg4t50
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« Reply #5 on: February 06, 2014, 05:15:41 PM »

Work best at a higher RPM like 2100 or so
Dave M
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luvrbus
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« Reply #6 on: February 06, 2014, 05:44:28 PM »

If that is a DDEC engine in you 89 Prevost it's not worth the price,even with a mechanical engine you are going to have 1 to 2 days in labor, if you buy a set be sure to get all the parts the 500 dollar sets can turn into money in a hurry fwiw
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Lin
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« Reply #7 on: February 06, 2014, 06:00:09 PM »

Jakes are wonderful!  I do not know the issues with mounting them with your particular set up, but I would just about consider it essential.  Of course, I think automatic transmissions are great too, so what do I know.

If you do get one, set it up for 2 stage use.  Although there are some very reputable people that condemn the idea, I actually find that I use them in the first stage more than I use it on full.
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luvrbus
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« Reply #8 on: February 06, 2014, 06:28:46 PM »

I don't condemn the 2 stage brake I just think it is a waste of wire with 3:33 rear gear in 4th with a Allison it does nothing creeping down a hill in 1st or 2nd with lower rear gears they work ok not great compared to a 4 stroke engine
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lostagain
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« Reply #9 on: February 06, 2014, 08:53:30 PM »

This is only my personal opinion, but while Jakes are nice to have, they are certainly not essential. Especially on a two stroke where they are not as effective as on a modern four stroke. When I drove bus, all with two stroke DDs, we didn't have Jakes. We went down the hills in whatever gear was necessary to not use the brakes much. Yes that is one or two gears lower than you would use with Jakes. But this is how we were trained, and it was not a problem. I like Jakes like the next guy, who wouldn't? But I guess you have to weigh the cost against the benefits.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
TomC
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« Reply #10 on: February 06, 2014, 09:11:30 PM »

JC-as stated before, the Jakes for a 8V-92 are VERY effective-just have to have someone who knows what they are doing to get the best performance. I live in California, and there is no way out of Los Angeles but go over mountains (not like the hills on the east coast). Rule of thumb-if you're going to come west of interstate 25, then you really should have Jake brakes. Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
luvrbus
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« Reply #11 on: February 07, 2014, 04:15:13 AM »

Good grief the adjustment thing all started with the old 71 and the master housing that was set on 0.65 one does not have the luxury with the 71/92 masters you set the things on 0.59 with the Jacob gauge and you have what you have unless one wants to spend the big bucks to shim or add valve springs to the engine.

Just in case some don't know Don Fairchild and I are the best of friends so no way am I putting him down, back to question are they worth the price for Scanzel with a 6 speed manual transmission I doubt it but if he wants a set I have plenty with the valve covers,bridges,oil bolts and buffer switches lol

good luck 
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tomhamrick
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« Reply #12 on: February 07, 2014, 08:01:48 AM »

I set the Jakes on our Eagle 6V92 at 57 and I would have to let off them to keep from slowing down too much on a 3 mile 6% grade near home. That bus weighed 32,000 pounds and we were towing a car. Our current coach is 42,000 pounds + the car and has a DDEC 2 8V92. I don't think the Jakes are adjusted as tight and I have not checked them, but it will maintain speed or maybe slow just a little on the same 3 mile 6% grade. I like not having to use the brakes in the mountains so it is worth it for me.
As Clifford says just make sure you are getting all the needed parts.
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Tom Hamrick
1991 Prevost H3-40 VIP
1981 Eagle 10
Forest City, NC
luvrbus
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« Reply #13 on: February 07, 2014, 08:12:34 AM »

You better be careful setting the DDEC engine @ .57 Tom they have a different cam lift than your mechanical 6V92 had  

This adjustment thing drives me crazy the Jakes releases the compression using 2 valves out of the 4 what difference is a 2 to 5 thousands setting going to make releasing the compression ? It is 0.59 for me just like Jake says I am not about to bend 2 valves fooling around with the adjustment JMW good oil pressure is your best friend on Jakes on a 2 stroke engine
« Last Edit: February 07, 2014, 08:36:34 AM by luvrbus » Logged

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wg4t50
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« Reply #14 on: February 07, 2014, 01:04:07 PM »

Having sperience with em jakes, I must say they are not idiot proof, for an experienced driver, they are great, for the typical car/pickup operator they need to get some sperience to fully appreciate the goodness of the Jakes and clearly not as effective as on a 4 stroke, but still much better than without.
The best Jake sperience for me was on the 12V-71 mini mufflers in a tunnel, Oh Yea !!
Cars stopped behind the MC7 in tunnels. Truely amazing how a little sound changes minds.
Dave M
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