| Author | Message | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 48 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
Is it possible to install a "Blue Ox Exhaust Brake" instead of Jake brake on a DD 6V92TA? If not, does an 'exhaust brake' for the DD 2 strokes exist? Thanks | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 464 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
Not sure about the Blue Ox brake, but "Jake Brakes" definitely exist and have been used on DD 2 strokes for many years. Occasionally guys on this board will offer a set or they can be found on the E place & elsewhere. Truck junkyards and maybe DD Dealers may have take offs. | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 49 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
Thanks, but I was referring specifically to an exhaust brake. I'm aware of the Jake Brake which is installed under the valve covers and uses the exhaust valve to make the engine a compressor. An exhaust brake installs in the exhaust system and basically restricts the exhaust as an alternative to a Jake. I've seen these advertised for 4 stroke diesels, but do these also work on the DD 2 strokes? | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1117 Registered: 7-2006 Posted From: 74.235.211.61  Rating: |
There's going to be a lot of debate with this one, so..... Info worth reading? http://www.turbodieselregister.com http://www.heavydutytrucking.com http://www.busconversions.com http://www.pardo.net/ (scroll down to "exhaust brakes") But the Blue-Ox info states the use for a 4 stroke only! http://www.brakesystemsinc.com/pdf/blueox_11_07.pdf Wadda let down, ehh? | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 50 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
Thanks so much John. As a matter of fact I'd already seen most of those sites and even called Blue Ox. They don't have a listing for a DD 6V92TA only series 50, 60 and a '6.2 Litre 1982 - 1984' Leads me to think these can't be used on a 2 stroke. Surely someone out there can provide a definitive yes/no? | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1269 Registered: 12-2000 Posted From: 99.204.252.175  Rating: N/A |
I think this would cause the pressure to back up through the intake ports in the clyinders into the air boxes and against the blower. Possibly Not Good. Jack | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 465 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
I have an exhaust brake on my 7.3 F250. Doesn't work as well as true Jakes but it does slow the truck and a trailer so I only have to touch the brakes once in a while. | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 983 Registered: 8-2006 Posted From: 99.37.31.150 Rating: N/A |
An exhaust brake won't work at all on a DD 2 stroke, because the exhaust valves don't open on the effective upstroke of the piston. They start to open just before the piston clears the intake ports on the way down, to start the scavenging flow, and stay open until the piston covers the intake ports on the upstroke. Exhaust brakes are effective on 4 cycle engines because the piston pushes up on the exhaust stroke with the exhaust valve open, against the pressure created in the exhaust manifold. This pressure doesn't push the piston back down, because the exhaust valve closes essentially at the top of the exhaust stroke, and the intake valve opens, leaving the engine to pull the piston down on the intake stroke. G | ||
| David Evans (Dmd)
Registered Member Username: Dmd Post Number: 443 Registered: 10-2004 Posted From: 173.77.207.138  Rating: N/A |
George, i am out of here! Only people with the letter J in name were posting on this topic. Please show some restraint. Sorry i am feeling good tonite after taking the Moe for a run and then ripping out the hotwater heater and most of the head area. It feels great to have daylight and warmth, and make some backwards progress! | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 985 Registered: 8-2006 Posted From: 99.37.31.150 Rating: N/A |
Dave, I appreciate the humor, we've all got to have some fun! It was 67 out here today... I was afraid I was going to get into trouble on this, but so far it isn't too bad! KUTGW! G | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 207 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
DO NOT USE AN EXHAUST BRAKE ON A 2 STROKE DIESEL ENGINE! Reason-with the butterfly valve in the exhaust closed, you create back pressure-which on a 4 stroke engine creates resistance on the up piston exhaust stroke, hence then braking action. On a 2 stroke Diesel, the exhaust will not exit the cylinder since the piston is on the down travel and the engine relies on the blower to push the exhaust out of the cylinder. With the additional back pressure, the blower takes all the force of the exhaust brake, and you blow the blower up-that simple. Good Luck, TomC | ||
| George Martinez (Foohorse)
Registered Member Username: Foohorse Post Number: 71 Registered: 1-2010 Posted From: 174.48.6.180  Rating: N/A |
Hey Jim I can post here because I also because have the required J, Jorge in Spanish. Listen to Jack George and tom even if the latter two do not have the J. nonetheless they are correct. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1226 Registered: 7-2006 Posted From: 75.243.97.164 Rating: N/A |
?????? RCB | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 51 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
I appreciate all of this information. I certainly can't dispute anything Tom and George have said. I'm a total newbie to the bus world, and there are a thousand new things to understand and I'm trying to make the right decision. Should I have Jakes installed or should I have an exhaust brake installed? That is the decision! However, on this one, I've got totally conflicting information from the current owner of the bus I'm buying. He's been in the bus charter and repair business for 40 years and he says that he's used exhaust brakes on lots of MCI buses (2 strokes), they've never caused any problems and in fact, it's the Jake Brakes that will cause the engine to start slobbering oil, blowing head gaskets and other bad things. Still confused. | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 520 Registered: 10-2003 Posted From: 66.165.176.62  Rating: N/A |
Jake is my vote. There is a reason the maufacturer doesn't list a 2 stroke application | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 210 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
As stated before, an Exhaust Brake (butterfly valve in the exhaust to make back pressure) is useless on a 2 stroke and will only cause blower failure. Just because you install a Jake brake doesn't mean that you automatically will get engine slobbering oil, blowing head gaskets and other bad things. I've had Jakes on my 8V-92TA, 6V-92TA, 8V-71TATAIC, and my Cat 3406B-of which NONE have had those problems. Just about virtually every on road truck has Jake brakes. If you come west of Interstate 25, you'd be crazy NOT to have Jake Brakes. Good Luck, TomC | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 990 Registered: 8-2006 Posted From: 99.68.225.138 Rating: N/A |
Jim, 1. Your current owner apparently doesn't know the difference between an exhaust brake and Jake brake. 2. Your current owner apparently doesn't know how a 2 stroke operates. 3. Jake brakes will NOT CAUSE any of the problems he mentions. 4. Read #1 and #2 again, then think about his qualifications to talk about #3! 5. Although I differ with Tom on damage done to a blower by EXHAUST brakes, an EXHAUST BRAKE JUST WILL NOT WORK ON A 2 CYCLE ENGINE, PERIOD. Lets think a little further; The blower is being turned at twice engine speed, its 100% machined steel, and supplies air to the air boxes under less than 5 pounds pressure at full speed. The intake ports on the cylinders are at the very bottom of the stroke, and are open less than 10% of each revolution. So, aside from the fact that all of the combustion pressure has not left the cylinder when the pistons clear the intake ports, more than 90% of the time, per cylinder, the blower is running against the back pressure of all ports closed as a normal condition. Not to mention that during exhaust braking, there is no exhaust, only compressed air. As Tom says "...an exhaust brake is USELESS on a 2 stroke..." { I say "it just won't cause blower failure!"} More ammo, what about the later turbo engines with a bypass valve? They just couldn't make the blower push against 30 psi instead of 3-5 psi all the time the engine is under full throttle now could they? G | ||
| George Martinez (Foohorse)
Registered Member Username: Foohorse Post Number: 85 Registered: 1-2010 Posted From: 174.48.6.180 Rating: N/A |
Jim I am also new new to buses but not to things mechanical. I can surmise that your PO is telling you what you want to hear. and if you are not mechanicly minded which is ok. I can rebuild Lambo V 12s but can't balance a check book, all the technical reasons why it cant be done that you are hearing here may sound like Swahili. but rest assured it is correct. gearheads see things that mere mortals can't. |
