Aces High Bulletin Board
General Forums => The O' Club => Topic started by: Rondar on June 28, 2011, 11:42:05 PM
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Our farm has had a Kenworth tandem truck for a few years with a jake brake that never worked, as we bought it used. We got the truck worked on this year and got the jake brake working. What is the proper rpm's to engage it or disengage it? Or does it matter, just turn it on till you get the rpm down then shift gears again? Its a cat engine if that matters, 400 hp.
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The Jake is an ADDITIONAL brake assist. It's not a primary brake to slow down with. It chokes the exhaust valves to create back pressure and give some assistance when long braking is required, like down a grade. You can run a Jake at any rpm, but higher gives more resistance. It's just like gearing down, but with a little more resistance.
One thing, make sure the throttle cut-off switch works. You don't want a Jake engaged when you are under power, only when you are completely off the throttle.
If you run straight 6" exhaust, a Jake on a 3406 Cat sounds sweet. :rock
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Watch for signs regarding use of jake brakes..... some places frown on the noise.
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rpm, the jake brake doesn't "choke the exhaust valves", more like it opens them slightly on the compression stroke to prevent ignition in the cylinders and it doesn't do all cylinders.
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I use my jake going down long or steep grades so I don't burn my brakes off. Also if I'm heavy ill use it to help stop but the rpms don't matter it kicks in when you let of the gas. Downshifting take time to learn your trucks engine and what range you can downshift.
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rpm, the jake brake doesn't "choke the exhaust valves", more like it opens them slightly on the compression stroke to prevent ignition in the cylinders and it doesn't do all cylinders.
I could be wrong. I believe it opens the valve just before starting the power stroke so the compression stroke can be used as a brake. If it opened on the start of the compression stroke little to no brake benifit would be had.
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I could be wrong. I believe it opens the valve just before starting the power stroke so the compression stroke can be used as a brake. If it opened on the start of the compression stroke little to no brake benifit would be had.
Yes the piston comes up on the compression stroke which the jake brake uses to help slow engine rotation as the piston reaches TDC the exhaust opens to release the pressure so it does not push the piston down with force. So the unit uses cylinder pressure on the pistons to slow rotation thus helping slow the vehicle or hold speed on steep down grades with clutch engaged and in proper gear.
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That is what I figured. Sounded funny to open on the compression stroke.
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Truckers running straight pipes make a lot of noise. That's the reason you see signs stating no exhaust brakes in town specific location. Pissing off the local population because some of the truckers don't feel "manly" without a lot of noise cost everyone the use of a good tool. The actual muffler of a semi isn't much of a restriction at all. I just swapped mine out last month. There was one swiss cheese cone shaped baffle across the opening of the pipe. The rest of the sound management was the series of holes surrounding a straight open tube to the outflow. It keeps the sound low but the "billy big rig" attention deficit folks who like to make noise dump the mufflers for straight pipes.
I use my jakes all the time except where restricted. It save the brakes on the truck and RV (5th wheel) on mountain grades. It also is a 3 stage jake. It will operate on 2, 4 or all 6 cylinders as needed selected by the driver.
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I owned two trucks when i was hauling containers up and down the west coast for Sealand, My 78 Kenworth COE had the 350 Cummings bigcam 10sp with the Jacobs brake 3 way switch to either pop off 2, 4 or all 6 cylinders, the other Truck was a 86 Kenworth Ta600 Cat3406B-425hp 15sp with a Hydraulic Retarder, IMO the Retarder is the better way to go, just set the amount of hydraulic resistance you want and you hardly ever touch your brakes. jacobs brakes you still have some braking depending on the percentage of the Grade your going down and the gross weight of the load.
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Our farm has had a Kenworth tandem truck for a few years with a Jake brake that never worked, as we bought it used. We got the truck worked on this year and got the Jake brake working. What is the proper rpm's to engage it or disengage it? Or does it matter, just turn it on till you get the rpm down then shift gears again? Its a cat engine if that matters, 400 hp.
After re-reading this here's some help, the operating range 1200 to 2200(governor) all your torque will be around 1400 without knowing the exact engine model# , your shift points will always depend on how much your weighing and gearing you have, but a safe range would be 1200 to 1800 rpms and never use the Jake to shift it drops the RPM's way to fast to hit the next gear, just ease back the pedal till you feel it slide out gear (little pressure), as your RPM's decrease then go for the next gear it will slide right in. just use the jake to get you into the right RPM range before you shift.
It's the opposite thing for up shifting to a lower gear going up a hill or preparing to stop instead of dropping the RPM's slowly you bring the RPM's up slowly and it will go right into the lower gear. i used my clutch for starting and stopping that was about it, but never use a Jake for shifting I've seen to many people either blow a shift or worse kill the engine while in the middle of a shift on a Hill.
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The Jake is an ADDITIONAL brake assist. It's not a primary brake to slow down with. It chokes the exhaust valves to create back pressure and give some assistance when long braking is required, like down a grade. You can run a Jake at any rpm, but higher gives more resistance. It's just like gearing down, but with a little more resistance.
One thing, make sure the throttle cut-off switch works. You don't want a Jake engaged when you are under power, only when you are completely off the throttle.
If you run straight 6" exhaust, a Jake on a 3406 Cat sounds sweet. :rock
Don't run it over 2000rpm... Builds to much compression and can blow top end of ur motor..A jake and an exhaust brake are two different things.. I hope u don't drive anybody Else trucks Rpm :uhoh.. Hopefully ur an owner operator if you even do drive truck..An exhaust bake by the way shuts a butterfly valve on the exhaust side of the turbo witch causes hold back kinda like putting ur finger over a straw. Jake's have way more hold bake than exhaust brakes do... I am no mechanic but my family owns a trucking outfit here in Idaho.. Anyway before you take any advice from people you don't no just ask the mechanic that fixed the thing.. A cat is pretty spendy.. Good luck
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I owned two trucks when i was hauling containers up and down the west coast for Sealand, My 78 Kenworth COE had the 350 Cummings bigcam 10sp with the Jacobs brake 3 way switch to either pop off 2, 4 or all 6 cylinders, the other Truck was a 86 Kenworth Ta600 Cat3406B-425hp 15sp with a Hydraulic Retarder, IMO the Retarder is the better way to go, just set the amount of hydraulic resistance you want and you hardly ever touch your brakes. jacobs brakes you still have some braking depending on the percentage of the Grade your going down and the gross weight of the load.
If u can get a retarder and a jak then your sitting sweet! I never drove a truck with a retarder ,but I heard there sweet.. There is a local guy who has a retarder and a jake set-up for his lowbay outfit.. Although he did reck his last one do to his forgetting about his retarder still being on when it was slick out..
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Cats will run happily between 1200 and 1800 rpm. Never jake above 2000 rpm. You will first stretch the head bolts then the poo really hits the fan. Give us the year and model if you can. 3046 B is a good reliable engine when cared for.
All of our power units are Cummins N14 rated at 435 horse 1800 rpm with 1650 ft/lbs torque at 1250 rpm. Some of the newer units are the ISX at 475 horse and about the same torque. They have all that emission garbage on them. Three of them have the diesel catylist on them. Pain in the hind end when you idle them for too long.
I pay no attention to signs telling me i need to heat up my brakes for some putz that doesn't want to hear my compression brakes.
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Don't run it over 2000rpm... Builds to much compression and can blow top end of ur motor..A jake and an exhaust brake are two different things.. I hope u don't drive anybody Else trucks Rpm :uhoh.. Hopefully ur an owner operator if you even do drive truck..An exhaust bake by the way shuts a butterfly valve on the exhaust side of the turbo witch causes hold back kinda like putting ur finger over a straw. Jake's have way more hold bake than exhaust brakes do... I am no mechanic but my family owns a trucking outfit here in Idaho.. Anyway before you take any advice from people you don't no just ask the mechanic that fixed the thing.. A cat is pretty spendy.. Good luck
Just FYI. I was raised around trucks, too. My Dad also owned a trucking company and I drove OTR for 15 years and local for another 10 hauling oversize equipment until my eyes got too bad to drive at night anymore. I have more miles driving an overweight rig riding the Jake down Tehachapi, Cabbage Patch, The Grapevine, 9 Mile Hill, Morongo Canyon, Montrose Pass and 1000 other grades you've never seen than you have riding in a truck.
My first OTR trip was riding on the doghouse of my Dad's KW from Texas to California to Maine and back to Texas in 1966. That was truckin'! Hendricks suspension, twin sticks and no a/c or CB. I know the difference between a Jake and a Pacbrake. I might not know how to take one apart and put it back together again, (ok, I could take it apart but I'm a horrid mechanic) but I know when and how to operate one.
Most of the 3406's I drove turned between 2200 - 2350. They are (or were, I'm sure specs have changed since then) rated at 2500, but I wouldn't recommend running one that hard or you will get new vent holes in the block. We also tweaked the transmissions to get more speed out of them (swapping gears around) . It made that top gear hard to grab, but when you did you could get on down the road.
We ran Detroits for a long time. I sure miss hearing those old Jimmy's scream. I wish you could have seen Dad's '66 Diamond T. It had a 238 that turned 2400 with oversized injectors. More than one 290 Cummins and 318 Detroit were put to shame. It was the terror of I-45 between Dallas and Houston. He ran twin resonators on straight pipes and you could hear that old Diamond T from 5 miles away. :cool:
So before you think about schooling me with your vast background in trucks and trucking, you might want to research who you are talking to. I'm definitely old school when it comes to trucks. M'kay?
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If u can get a retarder and a jak then your sitting sweet! I never drove a truck with a retarder ,but I heard there sweet.. There is a local guy who has a retarder and a jake set-up for his lowbay outfit.. Although he did reck his last one do to his forgetting about his retarder still being on when it was slick out..
Retarders were used mainly on Detroits. I've seen a few on Cats, too. I drove a V-16 R-50 Euclid for a few months that had one. They're effective, but you don't get the cool sound a Jake makes. Never seen a double setup like you're talking about. He must move some big iron.
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rpm, the jake brake doesn't "choke the exhaust valves", more like it opens them slightly on the compression stroke to prevent ignition in the cylinders and it doesn't do all cylinders.
You are correct, Sir. I didn't describe the mechanical process correctly, but my point was don't rely on a Jake to stop in a hurry. It's an assist, not a main brake.
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My first OTR trip was riding on the doghouse of my Dad's KW from Texas to California to Maine and back to Texas in 1966. That was truckin'! Hendricks suspension, twin sticks and no a/c or CB.
We ran Detroits for a long time. I sure miss hearing those old Jimmy's scream.
This is a '65 Kenworth. It's pretty close to the '66 KW Dad drove. His had a 15 speed instead of a 13 speed and no air ride. Dad called her "Old Maude".
http://www.youtube.com/watch?v=lkTeB-TCs54
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Cats will run happily between 1200 and 1800 rpm. Never jake above 2000 rpm. You will first stretch the head bolts then the poo really hits the fan. Give us the year and model if you can. 3046 B is a good reliable engine when cared for.
All of our power units are Cummins N14 rated at 435 horse 1800 rpm with 1650 ft/lbs torque at 1250 rpm. Some of the newer units are the ISX at 475 horse and about the same torque. They have all that emission garbage on them. Three of them have the diesel catylist on them. Pain in the hind end when you idle them for too long.
I pay no attention to signs telling me i need to heat up my brakes for some putz that doesn't want to hear my compression brakes.
Then who is the putz :)
A trucker that does not follow road signs is dangerous indeed.
Almost as dangerous is all the 4 wheelers who cut in and out of traffic.
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Just FYI. I was raised around trucks, too. My Dad also owned a trucking company and I drove OTR for 15 years and local for another 10 hauling oversize equipment until my eyes got too bad to drive at night anymore. I have more miles driving an overweight rig riding the Jake down Tehachapi, Cabbage Patch, The Grapevine, 9 Mile Hill, Morongo Canyon, Montrose Pass and 1000 other grades you've never seen than you have riding in a truck.
My first OTR trip was riding on the doghouse of my Dad's KW from Texas to California to Maine and back to Texas in 1966. That was truckin'! Hendricks suspension, twin sticks and no a/c or CB. I know the difference between a Jake and a Pacbrake. I might not know how to take one apart and put it back together again, (ok, I could take it apart but I'm a horrid mechanic) but I know when and how to operate one.
Most of the 3406's I drove turned between 2200 - 2350. They are (or were, I'm sure specs have changed since then) rated at 2500, but I wouldn't recommend running one that hard or you will get new vent holes in the block. We also tweaked the transmissions to get more speed out of them (swapping gears around) . It made that top gear hard to grab, but when you did you could get on down the road.
We ran Detroits for a long time. I sure miss hearing those old Jimmy's scream. I wish you could have seen Dad's '66 Diamond T. It had a 238 that turned 2400 with oversized injectors. More than one 290 Cummins and 318 Detroit were put to shame. It was the terror of I-45 between Dallas and Houston. He ran twin resonators on straight pipes and you could hear that old Diamond T from 5 miles away. :cool:
So before you think about schooling me with your vast background in trucks and trucking, you might want to research who you are talking to. I'm definitely old school when it comes to trucks. M'kay?
Like I said if u run a jake over 2000 ur going to hurt the motor! U could get away with it with the detroits because they were 2 strokes up until after the 92 series although still not recomended... Look it up :aok
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Retarders were used mainly on Detroits. I've seen a few on Cats, too. I drove a V-16 R-50 Euclid for a few months that had one. They're effective, but you don't get the cool sound a Jake makes. Never seen a double setup like you're talking about. He must move some big iron.
Yep lowboys usually do :aok
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Engine Compression Retarders
The engine compression retarder uses the engine's compression stroke to absorb energy from the vehicle's motion. Normally the piston compresses the cylinder air for the next power stroke, and this compression of the cylinder air takes energy. That energy is normally provided by another cylinder which is in its power stroke.
The engine compression retarder uses up vehicle motion energy during the compression stroke of each piston because the other cylinders are not producing power during their power stroke time interval. No (or insignificant) engine power is generated, because the throttle must be at the idle position for the retarder to operate.
During the retarder mode of operation, when the piston approaches the top of the compression stroke, the retarder system opens the exhaust valves for that piston, which vents the energy which was absorbed from the vehicle's motion. The retarder works by absorbing energy during the compression stroke, and throwing away this energy through the exhaust valves as the piston completes its compression stroke.
The most popular engine compression retarder is the Jake Brake. This retarder system is manufactured by the Jacobs Manufacturing Company, and their product is available for Caterpillar, Cummins, Detroit Diesel, and Mack engines, just to name a few.
The electric signal activates the solenoid valve. The active solenoid valve applies engine oil pressure to the control valve. The engine oil presure force moves the ported piston of the control valve up until the piston port aligns with the high pressure oil passage to the slave piston. The check ball in the control valve allows the engine oil pressure to fill the slave piston and the master piston voids via the high pressure oil passage. As the cylinder completes its compression stroke, the cylinder injector pushrod rises and lifts the master piston. This forces the oil out from above the master piston into the slave piston. Remember, the check ball in the control valve prevents the high oil pressure from bleeding back into the lower pressure engine oil supply.
As the injector pushrod moves upwards, the slave piston pushes down on the exhaust crosshead which opens the exhaust valves. This releases the compressed air which provided the retarder braking action. When the retarder is deactivated, the solenoid valve vents the engine oil pressure, which allows the control valve spring to lower it's ported piston, which seals off the high pressure oil passage.
To activate the Jake Brake, four requirements must be met, as shown in the diagram above. The dash switch must be on, the clutch must be engaged, the throttle must be at idle, and the driver and/or cruise control must have activated the retarder. Engine RPM must be kept high for the most retarder effect.
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Engine Compression Retarders
The engine compression retarder uses the engine's compression stroke to absorb energy from the vehicle's motion. Normally the piston compresses the cylinder air for the next power stroke, and this compression of the cylinder air takes energy. That energy is normally provided by another cylinder which is in its power stroke.
The engine compression retarder uses up vehicle motion energy during the compression stroke of each piston because the other cylinders are not producing power during their power stroke time interval. No (or insignificant) engine power is generated, because the throttle must be at the idle position for the retarder to operate.
During the retarder mode of operation, when the piston approaches the top of the compression stroke, the retarder system opens the exhaust valves for that piston, which vents the energy which was absorbed from the vehicle's motion. The retarder works by absorbing energy during the compression stroke, and throwing away this energy through the exhaust valves as the piston completes its compression stroke.
The most popular engine compression retarder is the Jake Brake. This retarder system is manufactured by the Jacobs Manufacturing Company, and their product is available for Caterpillar, Cummins, Detroit Diesel, and Mack engines, just to name a few.
The electric signal activates the solenoid valve. The active solenoid valve applies engine oil pressure to the control valve. The engine oil presure force moves the ported piston of the control valve up until the piston port aligns with the high pressure oil passage to the slave piston. The check ball in the control valve allows the engine oil pressure to fill the slave piston and the master piston voids via the high pressure oil passage. As the cylinder completes its compression stroke, the cylinder injector pushrod rises and lifts the master piston. This forces the oil out from above the master piston into the slave piston. Remember, the check ball in the control valve prevents the high oil pressure from bleeding back into the lower pressure engine oil supply.
As the injector pushrod moves upwards, the slave piston pushes down on the exhaust crosshead which opens the exhaust valves. This releases the compressed air which provided the retarder braking action. When the retarder is deactivated, the solenoid valve vents the engine oil pressure, which allows the control valve spring to lower it's ported piston, which seals off the high pressure oil passage.
To activate the Jake Brake, four requirements must be met, as shown in the diagram above. The dash switch must be on, the clutch must be engaged, the throttle must be at idle, and the driver and/or cruise control must have activated the retarder. Engine RPM must be kept high for the most retarder effect.
Or u can just google it copy and paste :aok
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You don't need jake brake pulling on flat roads around farms, if you smoke your service brakes sooner, np; you can get new brake shoes/drums for about 400$/axle, in any truck stop;that's nothing comparing with the amount of labour needed to open the engine and fix jake and maybe more. In 2004,using the jake brake i damaged my Detroit D60 on my last Volvo 770 truck; about 8000$ repairs on heads,injectors,towing and a week waiting for parts at Mountain Volvo, in Salt Lake City,UT. I have now a Volvo 780,volvo motor D13, with 350 HP jake brake power, but i use it only if i'm heavy on long downhills. Some samples of road pics captured in places where i usually turn my jake on;
1.Trans Canada 16/1/
2. I-15 N, CA-NV ,actually is worst south of this point; 17 miles downhill to Baker,CA and all the way to Sweet Grass, MT , it's hard for trucks
3. .. and I-70.....this is highest and imop ,the most dangerous place on all Intersate Highway System for trucks;sometimes it's snowing in June/July, violent wind gusts for light trailers, air density about half of what you got at sea level; the engines don't get enough oxygen for combustion and thin air can't cool down the radiator. Many drivers are experiencing hypoxia symptoms;beside good brakes, a chutte,pressurized cab and a Bible are recommended :lol
(http://farm6.static.flickr.com/5275/5892513856_0478c0dd33_b.jpg) (http://www.flickr.com/photos/44265847@N06/5892513856/)
(http://farm6.static.flickr.com/5038/5892513756_d8cd16b0f3_b.jpg) (http://www.flickr.com/photos/44265847@N06/5892513756/)
(http://farm6.static.flickr.com/5061/5892513968_238ce3f10a_b.jpg)[/url]
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Thanks for all the replies you guys gave. It sounds like to use it around 1200 to 1800 rpm if we do use it. Our old 76 ford diesel tandem with a cummins in it doesnt have a jake brake... I just slow down starting a mile or better from where I need to stop, without burning up brakes. Have done the same with the kenworth up until this harvest since getting the jake fixed.
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ghi u r making me jealous with those pics...
DROOLL
Lawndart
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Nice pics ghi. Have you run across southern Colorado? Some pretty country and a couple wild rides (Wolf Creek & Monarch). I remember the first time I drove across Monarch Pass. I didn't think I'd ever make it to the top. Once I finally did make it to the summit in my old '74 Freightliner with a 290 rebuilt to a 350, all I could think of was "it's going to be an interesting ride down".
Found this on YouTube, pretty good look at the road. Imagine hauling 80,000 lbs up and down that in a 74 Freightliner. Oh yeah, I was using my Jake.:devil
http://www.youtube.com/watch?v=XtDsDGg98J0
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Try a lowboy with a wa600 loader or one of our many heavy permit trucks. We have permits for 92,000 secondaries for all of Colorado. Thankfully this year we are only doing 70,000 tons on Hwy 115 between the Springs and Florence.
Gotta bring better bait Shuffler. I am more dangerous than 4 wheeler drivers cause I drive like they do but I have a 46 ton truck. ;)
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70,000 tons huh. And exactly how many wheels do you have on that boat? :huh
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Mav, I think he's talking about total loads moved. The heaviest I ever hauled was the dryer to an asphalt plant. It weighed 190,000 and was 70 feet long and 14 wide. We used an 85 Mack Superliner with a 550 Mack V8 to haul it from Sweetwater, TX to Crown Point, NM. The only big grades we went over were at Albuquerque and Crown Point, NM. I usually hauled the 90 x 14 asphalt tanks, but had to fill in for the guy that hauled the dryer when he got sick. Albuquerque wasn't too bad, but the hill at Crown Point was a short steep biatch I had to claw my way up.
I miss hauling oversize. :frown:
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Did someone say trucks?
http://www.youtube.com/watch?v=HWO_AIh8drk (http://www.youtube.com/watch?v=HWO_AIh8drk)
-Penguin
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70,000 ton mill and fill Mav. May be more now that they added the stretch from county line up to almost gate 5 at Ft. Carson. Thank god it's not that polymer crap.