Dynatard vs Jacobs

[jonk32000]

I was asked today... "what makes a Dynatard less effective than a Jacobs engine brake?". I think the two operate similarly but I don't know exactly what makes them different. Anyone know???

Thanks, Jon

[theakerstwo]

I have one each and have found that one don't do any better than the other and this is on the E6 engines.

[brutis77]

Dynos make noise jakes slow you down

[Lmackattack]

I have never been impressed with any Mack engine brake. This E7 400 I drive has a jake brake and it does very little to slow the truck. I with the mack on full engine brake i would compare it to the first stage of any cat or cummins equipped engine brake. I can't comment on the new motors but on the e6 and e7 they are just noise makers. The best thing the do is help you shift a little faster ...that's it.

[theakerstwo]

For them to do any good first used your imagination and then open both doors when you want to slow down. I only use it to up shift when going slow up hill.

[j_martell]

I have not run a dynatard, but the powerleash on my mp7 405m does a very good job holding back 85000#.

[41180]

jake brake is by far better. mack eas always at a disadvantage with there engine breaking due to the small 673 and then 728 cubic inch engines. cummins were 855 and cat was 900 or so cubic inch. them bigger pistons slow the emgine down alot better. i know most people on this site dont like the mack/volvo engines but the mp engines have great engine breaks. just as good as any other make. id like to know how a e7 jake brake would compare to a cat c12 or cummins m11 jake brake ?

[4020dt]

I have a 1997 E7-427 with dynatard or whatever + the stealth exhaust brake . My son owned the truck before me , bought it around 500,000mi now has 775,000 on it . The whole deal has never worked good I think . Previousy I had a 1988 E6-350 4 valve with Dynatard it worked much better than this one . Between he and I the system has been worked on 3-4 times , o rings solenoids and a bunch of other things . Work was don at Mack dealership I really think they don't know what's going on . The exhaust part is working sounds like anyway , but the other part seems useless . Honestl;y I have little faith in the so called mechanics out there today seems they are all plug in and parts changers of course that's just my old timer opinion . My kids say I demand too much perfection , $100+/hr and price of parts how much should I expect .

[RFCDrum]

The Jake is derated for the exhaust brake on the Stealth system. I delivered a CL with a 454 and Stealth and wasn't impressed. Some Dynatards were better than others. Some Jakes were better than others. Every truck that rolled out of the factory were all a little different.

Cheers, Rob

[41180]

the 98 CL we just sold had a 454 with a jake and a stealth exhaust brake, your right the jake part of it wasnt to great but in combination withe stealth it worked pretty good, better than our other e7 powered trucks that had just jake brakes, the stealth broke when the truck was about 10 yrs old and we tried to run it with just a jake and it sucked so we bought a pacbrake exhaust brake for it and it worked great. we have since put pacbrake exhaust brakes on our E9 and E7427.

[RFCDrum]

So you're running the Dynatard on the E9 with the exhaust brake? That would be cool. I know in New Zealand the loggers that were running the CL's with E9's with Dynatards and Voith hydraulic retarders. I run a Brakes Systems Blue Ox on my International which is a Guillotine style exhaust brake which works a lot better than a butterfly type.

Cheers, Rob

[57 bcr]

I liked the "bolt-on" aspect of the Jake.The Dynatard system required a different cam to operate.I had Jakes on both my '79 with the 300+,and my '90 with an EM6-300L.I thought they worked OK.Nothing like the Jake on an 855 Cummins,for sure!

[41180]

yeah dynatard with the pacbrake it makes a big differance. i wish those hydraulic retarders were available in this country

[kscarbel]

i wish those hydraulic retarders were available in this country

Eaton is redesigning the rear housing of their current heavy transmission range to accept an integrally-mounted Voith retarder, for both the U.S. and global markets.

Interestingly, Voith has been the Eaton/Fuller transmission distributor for Austria, the Czech Republic, Germany and Switzerland since 1999.

[Superdog]

The key to a Dynatard was having the valves set right and keeping them set ,they wouldn't thrrow you thru the windshield like the Jake on my blue '86 with the Cummins but they done a good job.

I had a '97 with the Stealth Jake Brake,also,it was worthless.

[RFCDrum]

I agree you had to keep the Dynatard dialed in or even just a little tighter. The same for the Jake too you had to maintain them.

Cheers, Rob

[RFCDrum]

yeah dynatard with the pacbrake it makes a big differance. i wish those hydraulic retarders were available in this country

I thought they were. I know when I worked for H And H Mack we became a Telma dealer. You could have put the electro magnectic on her. But I think the Pac Brake and Dynatard is pretty cool.

Rob

[41180]

i think the dynatard on our v8 needs to be adjusted or something if that is possible? i used to drive it everyday and the engine brake worked fine as good as our jake brakes on the older e7 engines. now it just seems like something isnt right with it, also on our e9 the air throttle pedal doesnt work the way it used to work i dont think its getting the right amount of air but we had it checked and they said its fine,

[41180]

I thought they were. I know when I worked for H And H Mack we became a Telma dealer. You could have put the electro magnectic on her. But I think the Pac Brake and Dynatard is pretty cool.

Rob

id be interested in putting a magnetic brake my CL the jake on it just doesnt cut it on some of the steep hills in vt. most of the other trucks on the road have alot better jake brakes than i have . our titans engine brakes work better on low than my etech 460 does on high

[slpwlker]

I wanted to put a Brakesaver on when I had the engine out. See how far that got me still reliying on the Jake alone. It works just got to start getting in the lower gears. sometimes 5th on some hills others like coming down cabbage tomorrow I'll be in low range with the splitter in low or direct.

[RFCDrum]

The Telmas are very expensive. There is a guy from Newark who is installing another brand of electro retarder and had a Granite at Englishtown with it on. I think this guy also runs dump trucks too. Maybe Reel can add to this. I remember back in 97-98 when at Mack they were at least $5,000.00 then. I would think if I was doing heavy haulage or heavy timber I would want two systems. I don't like to do brakes. I put my Blue Ox on in 88 and had the same front brakes on for 20 years. I know the fronts aren't doing as much but I thought that was pretty good.

[rsb502]

Well I have had every engine brake on a Mack so far, the dynatard on an E6 aint much, the dynatard on an E9 aint much, the Jake on an E7 aint much same for an Etech, the Powerleash in the ASET engines is actually pretty good I would compare it to an M11 Cummins for sure it did a great job on my 04 Granite, ther MP series is a great nbrake for the engine sizze it is the best so far but not being true Mack engines I dunno I would have to go with an Aset Powerleash for the best true Mack brake. The Jake on an E6,E7 and Etech can be helped along quite a bit with the use of a high volume oil pump and a little tighter setting, on a 2000 D with a 350 Etech it probably added a third more brake horespower to the truck, I was very impressed. I still think the king of the hill engine brake is on an ISX Cummins they will flat put you in the dash if theyre right, but I would settle for a Mack 427 Etech with a Jake and a high volume oil pump for reliability.

[oilburner]

The dynatard is on the rocker arms. They are pluggers that keep pressure on the push rod and hold the valves open and i have seen the cams go down with the dynatArds the jake is a box that bolts on between the head and valve cover that has slave pluggers in them that make contact with the vavles and hold them open while the push rod still do there thing and I believe the jake is not as hard on the vavle train. The stealth set up works good when it is right I would say the best jake on a Mack but they are hard to get parts for the exhaust brake.

[RFCDrum]

I hate butterfly exhaust brakes. When my Blue OX wore out I found out that Williams went out of business but didn't know Brake Systems had bought them out. I wound up putting a BD exhaust brake on. What a POS!. Had to modify the crap out of it to get it to do something and then eventually it got all carboned up and broke. Went back last year put a new revised Blue Ox on her. Works very well. About as good as a good Dynatard. Give me guillotine style any day. Simple, self cleaning and reliable.

Cheers, Rob

[rsb502]

I hate butterfly exhaust brakes. When my Blue OX wore out I found out that Williams went out of business but didn't know Brake Systems had bought them out. I wound up putting a BD exhaust brake on. What a POS!. Had to modify the crap out of it to get it to do something and then eventually it got all carboned up and broke. Went back last year put a new revised Blue Ox on her. Works very well. About as good as a good Dynatard. Give me guillotine style any day. Simple, self cleaning and reliable.

Cheers, Rob

go with a jacobs engine brake and that exhaust brake and you would be REAL happy, most people think the exhaust flow slows with the engine brake on but it has the opposite effect it speeds up thats how you build boost with it on, theres not as much cylinder pressure when the intake valve opens so the pressure differential is such that you dont make as much boost but it helps.