| Author | Message | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 43 Registered: 3-2011 Posted From: 173.8.221.225  Rating: |
Hey all, I just wanted to update and mention that I got the VS2-8 mounted to the 6-71 (with x2 spacers) and fully operational! The 'test drive' was first a 90mi round trip out to a local event (www.northwestmogfest.com) and since all was good, headed the next weekend to BurningMan 2011 (1200mi round trip). The transmission, with the rear end gearing of the TDH-4512, seems to be right on-par for climbing hills and using overdrive on the flats/minor grades. At 64MPH my tach shows about 1700-1750 RPM. Need to replace the front king pins so can't travel at much above that (although the 6-71 wants to shove it up beyond 70!) When I drop down into 'direct drive' I get the stock ratio that the original VH had (55MPH = redline at 2250RPM). Great for pulling hills at 35-45MPH. The transmission generated some SERIOUS heat on the first leg of the trip (all freeway)...enough that I consulted the borrowed manual briefly and found that an overfull/low fluid level can cause overheating. I used the 'approved' check method (start/warm system...then shut down and immediately read dipstick). Showed a couple quarts (or more) overfull. Lowering this level (as well as setting the engine shutters full open) seemed to help the situation. I broke a spring in the OD valve body somewhere near Kalamath Falls, OR (exhaust port spring for the OD) and it seemed to never want to go back into OD again (haven't got new spring yet). This worked out okay since I had already done 2/3 of the trip (mostly flats) and picked up good fuel economy. So for those that are curious, it can be done (although it is a LOT of work). Modifications to the body of the bus as well as the engine cradle structure were required. All in all, I think the modification is worth it. Now I just need to complete the turbocharging setup and fix the overdrive. The jake brakes worked flawlessly even though it required some 'customizing' of the valve cover to make it fit. I used them heavily in the hills of SE Oregon and NW Nevada. Kept the bus moving slow enough that I only had to use the service brakes for a short peck once or twice a grade. I also had the stock emergency hand-brake as well as the newly installed Spring Brakes on-board. The 4-valve head and Jakes installed: http://www.youtube.com/watch?v=1kEJxjevskE The jake brakes activating with the valve cover off: http://www.youtube.com/watch?v=1kEJxjevskE I have lots of pictures of the installation of both the transmission and jakes for future reference. Special thanks to my father for setting up the head, helping with the installs and offering some words of wisdom when my brain shifted into neutral. As a side note, for that trip I also built a 55gal stainless black water tank, built 2/3 of the bathroom, finished the bed frame/setup, and built the pressure water system complete with kitchen sink, shower, water heater, and filtered water tap. Built the framework for the kitchen counter and put the laminate down and installed the oven/stove. More pictures soon to come! A teaser from Burning Man:  | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 2127 Registered: 12-2000 Posted From: 174.89.179.195  Rating: N/A |
Excellent report! Keep us informed. happy coaching! buswarrior | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 1547 Registered: 3-2007 Posted From: 76.4.118.199  Rating: N/A |
thanks for the update GOOD JOB gomer | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1603 Registered: 10-2006 Posted From: 76.195.74.242  Rating: N/A |
redline at 2250RPM Very brave , unless you balanced the crank & rods end for end , matched the pistons and all the usual hot rod techniques. For huge hours 1800rpm works better than Fire Truck ratings. FF | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 703 Registered: 2-2001 Posted From: 184.0.13.120  Rating: N/A |
DD 71 series are rated at 2300 in pleasure boats. The very similar 53 series is rated at 2400 continuous and max hp @ 2800. Millions & millions of 71 series have spent their lives at 2300 shoving boats up on a plane. I've seen fire pumps rated at 2800. I don't think any of us are going to put huge hours on our busses. We've had ours about 12 years and put about 4,2000 miles on it. At 60mph that's just 700 hours, with most of the highway driving at about 2100/70 mph. The danger for the older engines is the crankshaft vibration dampener which needs to be changed from the old rubber isolated type to the viscous dampener if the engine is used above 2100. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 339 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
The last version of 6-71TA for pleasure boat rating straight from Detroit Diesel was 485hp @ 2,500rpm. The 6-71 actually has twice the rod bearing area of the V blocks. Getting 50hp a hole for bus use (300hp) is very conservative. Good Luck, TomC | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 704 Registered: 2-2001 Posted From: 184.0.13.120 Rating: N/A |
Jeez Tom, wouldn't it be great to get that kind of HP in an old coach???? Unfortunately, you need a cool ocean to carry away the heat generated. Those high HP marine engines even have fuel coolers. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 1548 Registered: 3-2007 Posted From: 76.4.118.199 Rating: N/A |
IT CAN BE DONE TOO!! All it takes is $$$$$$ No taxes tho! Gomer | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 44 Registered: 3-2011 Posted From: 173.8.221.225 Rating: N/A |
2300RPM is for the top of the first locked up gear. Normal cruise is about 1750RPM on the highway. Very nice to be able to be a little easier on the engine. :-) Hope ya enjoyed the videos! I've never seen a video on youtube of under the valve cover while jakes are operating. Very cool. Later, -Brandon | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 1280 Registered: 8-2006 Posted From: 184.12.160.98 Rating: N/A |
The DDEC inline 6-71 330hp is a sweet little engine we installed one in 4104 with the same set up on gears as Brandon 12 mpg is the average for it good luck | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1604 Registered: 10-2006 Posted From: 76.195.74.242 Rating: N/A |
"Millions & millions of 71 series have spent their lives at 2300 shoving boats up on a plane. YES , but, GETTING UP IS A 15 TO 45 (REAL PIECE OF CRAP) SECOND EXERCISE. The Johnson & Towers 6-71 sport fish killers are delighted to see 1000 hours before replacement . That's 50,000 miles in a bus, FF | ||
| David Evans (Dmd)
Registered Member Username: Dmd Post Number: 627 Registered: 10-2004 Posted From: 74.191.76.105  Rating: N/A |
i have been between a set of 6-71TA's screaming and burning (with full ear protection, inserts and earmuffers) crouching under way. it was fun a couple of times.....Brandon, great post and congrats. I am pretty sure what you have done, cant be done ;) Thanks for the info and updates. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 340 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
Then you have commercial fishermen that have continuous rated 6-71N's @ 165hp @ 1,800rpm that only run them at 1,500rpm probably producing maybe 100hp. These engines will run years and thousands of hours before overhaul. Caterpillar rates their engine life by how much fuel flows through the engine-and on their electronic engines the oil changes are determined this way also. Good Luck, TomC | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 552 Registered: 3-2006 Posted From: 216.144.216.234  Rating: N/A |
Brandon If you have a chance put gauges on each clutch pack. When I ran a VS2-8 it would hang up in direct drive when the O/D clutch was engaging. It would heat up from this. There is also a way of putting in a switch to force a downshift to direct drive from O/D when needed to keep your revs up on a hill. If interested let me know as the diagram is at home. We are there mid Oct. Bill | ||
| Jack Tucci (Tuccitown)
Registered Member Username: Tuccitown Post Number: 31 Registered: 3-2006 Posted From: 70.90.177.26 Rating: N/A |
Nice work Brandon, glad the transmission worked out for you looking forward to seeing the instillation pics. Jack | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 45 Registered: 3-2011 Posted From: 173.8.221.225 Rating: N/A |
Bill, I thought about doing a controlled (valve bleeder type) 'leak' from governor pressure line back to the sump. This would, in effect, fool the valve bodies that the bus was going 'slower' than it really was. Good for approaching a grade and also good for descending one (ideal jakes effect is in direct drive). I'd like to see how you did it as I'm sure there is a more elegant way than I've thought up so far. I have gauges and lots of Aero-quip line/fittings so could easily make a 'diagnostics' setup for the transmission. With the exhaust spring currently broken, it creates this very strange feeling when it SHOULD be shifting into OD. I think it tries to but the spring is overcome and creates some sort of bypassing leak. Then, as I come down to about 45MPH on deceleration, I feel the same little motion in the bus like it was trying to shift out. Very odd, I suspect it's just initiating a shift but failing to execute it and then doing the same on the decel. With the dual adapter plate setup, my stacked height is somewhere just over 5" (I have the exact numbers in the photos). This gave the whole flywheel/OD clutch/planitary/etc. setup about .20-.250 inches of end play. Not sure what stock specification is as I don't have an applications manual for the later new-looks w/ this transmission. With a little bit of customizing, I think I will be very happy with this transmission. I'll throw some photos up soon for the archives. :-) -Brandon | ||
| Brandon M (Brandon314159)
Registered Member Username: Brandon314159 Post Number: 46 Registered: 3-2011 Posted From: 173.8.221.225 Rating: |
Here are the photos of the new VS2-8 to 6-71 transmission installation: https://picasaweb.google.com/Brandon314/VS28TransmissionForThe1955TDH4512671Detroit?authus er=0&feat=directlink Here are the photos of the old VH being removed from the 6-71: https://picasaweb.google.com/Brandon314/OriginalVHTransmissionOn1955TDH4512Removal?authuse r=0&feat=directlink You do not need a google account to view the photos. They are public on Picasa. Enjoy, -Brandon M | ||
| Paso One (Paso_1)
Registered Member Username: Paso_1 Post Number: 195 Registered: 11-2004 Posted From: 142.165.246.240  Rating: N/A |
Great update Brandon, with pictures yet, Nice bit of engineering who would have thought dual spacers was the solution. ( you I guess  ) | ||
| Jack Fids (Jack_fids)
Registered Member Username: Jack_fids Post Number: 957 Registered: 1-2009 Posted From: 72.211.145.15  Rating: N/A |
Any job worth doing is worth documenting with a camera, the older you get the more you'll learn to rely on those photos for memories AND for all of technical aspects you dreamed up on the fly to make it work. What was the topic again..? |
