| Author | Message | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 475 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
Have any 4104 owners swapped out the special pokey governor for a truck governor? And if so, how did that work? | ||
| Jack Fids (Jack_fids)
Registered Member Username: Jack_fids Post Number: 73 Registered: 1-2009 Posted From: 69.171.160.137  Rating: N/A |
My 4106's is set for 84 mph, at that speed all colors are turning white outside my windows, as are the faces of the people in the cars whom I am passing & my hair. Throw your time pieces over the rail and enjoy the scenery, time is just a device for accountants anyway. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1174 Registered: 11-2005 Posted From: 24.251.120.104  Rating: N/A |
4104s are pokey, that is part of it's charm. Mine protests loudly at much over 63mph!g | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 911 Registered: 3-2007 Posted From: 71.53.153.91  Rating: N/A |
My 4104 I don't think is limited to 70 mph. I drove it from Charleston SC to Ocala in about 6 hours and stayed with the flow of traffic which as you know can vary from 50 to ?? I passed some but for the most part it cruised around 70-75 without any problem. Maybe your engine governor is turned down and won't allow any faster rpm. Have it set for 2150 and I think you will be A+OK. Gomer | ||
| Dallas Farnworth (Dallas)
Registered Member Username: Dallas Post Number: 49 Registered: 7-2004 Posted From: 75.91.194.193 Rating: N/A |
Ummmm, nope. It won't matter whether you have a truck governor or a bus governor, they will both be DWLS or SWLS, (Dual weight-Limiting speed or single weight-limiting speed). If you have the stock 4.125:1 ring and pinion, 43" tires and are governed at 2150 RPM with the stock 4 speed spicer, your maximum speed will be 66.68 mph. In order to do 74.33 mph you would need a ring and pinion of 3.70:1 With a governor set at 2350 rpm, the 4.125 differential will give you 72.8 mph. The 3.70 will give you 81.24 I'm not sure... were there any 3.70 differentials for our V-drives? I remember looking in my master parts book for many GMC's from 1946 to 1958 and there was a differential listed that was somewhere in the high 2.XX:1 but I've never seen one. | ||
| J.L.Vickers (Roadrunnertex)
Registered Member Username: Roadrunnertex Post Number: 76 Registered: 10-2006 Posted From: 76.6.79.217 Rating: N/A |
Standard rear end for the PD-4104 is 4.125:1 optional 3.56:1 The Greyhounds 4104's had the standard rear end. Other carriers had the optional rear end in their coaches. I use to own a 1960 PD-4104 that had the 3.56:1 rear end and at 2100 rpm it would run over 80 mph plus. Get in the hills it was a slow old bus flat land it would fly. Sort of miss that old PD-4104. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 476 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
Ah, thanks for the replies. But it's not top speed I refer to. My bus has the 3.56 ratio and N65 injectore and at 2150 it will go about 76 which is really fast in a 4104. What I refer to is that the bus governor makes takeoffs & speed changes very soft. I understand that this may have been desireable in a bus with 40 passengers wanting a gentle ride but this results in really slow acceleration and too much clutch slipping when trying to back up a slight grade. (especially in my yard at 3200 ft!) A truck governor should let you really open the rack, not "pushing on a spring that pushes on a spring" with the downside that you might make stuff fall off the table. Just wondered if anybody could confirm or deny this theory. | ||
| Dallas Farnworth (Dallas)
Registered Member Username: Dallas Post Number: 50 Registered: 7-2004 Posted From: 75.91.194.193 Rating: N/A |
I think your looking at it from the wrong direction.. The problem you are having isn't related to the governor at all. As I said before, either the truck or the bus, the governors are the same. Your acceleration problem is related to the gearing. I have the 4.125 differential on my PD4103 and it's slow to accelerate and the gearing is so high that I have to slip the clutch when starting out on a steep incline. These buses weren't built to do what we do with them. They were built to start and stop and back up on flat ground, like in a terminal or repair yard. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1183 Registered: 10-2006 Posted From: 76.248.150.30  Rating: N/A |
If you look in Da Book, the gear ratio for GM reverse stinks , its between 1st and second. 04 06 doesn't matter reverse is really weak! FF | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 480 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
Thanks guys. Most of you are telling me what I already know. What I am gathering is that nobody on the board these days has tried a governor change though. I also know for a fact that the 4104 governor is different than "truck" governors. That's part of the reason they don't usually smoke on takeoff. The acceleration is so gentle that fuel is matched more to RPMs than to demand. Other types of equipment will pull harder but have transient smoke and more torque. The governor on my 4104 is a "Fuel Modulating Variable Speed Governor". The "truck" type is a variable speed governor but without the fuel modulating part which seeks to reduce fuel (read that HP) at mid throttle position. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1897 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
They are all missing the point of your post. 4104's had a fuel modulating governor. It eliminated excessive smoke upon start out. The penalty was a more leisurely rate of acceleration. Similar to the fuel modulators and delay settings on the turbo engines. Ours was converted to a mechanical limiting speed governor, which gave quicker acceleration, but with more smoke. Both can be set for same max rpms. 2300 approx 70 mph with 4.11 ratio; 2300 approx 80 with 3.55 ratio. Hydrashift with 4.11 ratio in 4th overdrive was over 90 mph and would blow the doors off a "sports car" on the level. Unfortunately, Hydrashifts are quite rare. The guy that purchased our 4104 is going to attempt adapt a Gear Vendors overdrive unit at the rear of the trans. Since there is 4 feet of driveshaft, there is room. He is confident it will survive, as they are used in high horsepower drag racing and are holding up satisfactory. We'll see how he makes out. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 218 Registered: 5-2007 Posted From: 174.93.212.231  Rating: N/A |
Seems to me in Da Book there is a section on the fuel modulating governor....maybe with a little smarts you could tune it out.....I actually have a spare governor with my bus....have no idea what it is from....just spares...think it has a high idle air/solenoide....this helps you not a wit! | ||
| Dallas Farnworth (Dallas)
Registered Member Username: Dallas Post Number: 51 Registered: 7-2004 Posted From: 75.91.205.231 Rating: N/A |
See what you get when you assume? I've looked at a bunch of 6-71's in 4104's and as far as I recall, they were all LS governors. Now, as for the fuel modulator.... have you looked under the valve cover to see if possibly it's the type that is connected to the rack and is basically a piston that pushes oil through in a cylinder and has a restricted orifice on the back side? If you have that type, just remove the orifice or the piston. I'm not certain they have that kind on the 4104's. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1899 Registered: 10-2003 Posted From: 71.58.71.157 Rating: N/A |
we had to add that type after turbo install to eliminate too much black smoke upon start out. It reduces smoke but lowers torque output till turbo spools up. A wastegated turbo would be better or variable vane version. But who is going to spend the time and money to get the perfect setup? Other than that, it worked great with no problems. Mounted directly to exhaust manifold on rear of engine. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 481 Registered: 2-2001 Posted From: 184.0.3.170 Rating: N/A |
Wow, John, just what I was looking for/thinking about. Before the turbo, what size injectors were you running? I am also assuming your engine had a 4 valve head & cyl kits? My bus came to me with N60s and I upsized to N65s and still never any smoke. I have had my nephew following (drafting) me in his motorhome for 8 years on flats & up mountains with narry a smoke comment. He did say it stinks like an old bus though! Did the non modulating governor give you more grunt "off the line"? | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1901 Registered: 10-2003 Posted From: 71.58.71.157 Rating: N/A |
The limiting speed governor helped off the line pre-turbo and improved acceleration rate. Bus originally had HV9s with 2 valve head, with high block.Smoked like crazy, but had lots of power. Went to 4 valve head with n65's adv. time. Later years went to rebuild and turbo and n75's std. time. What a difference in power!Some smoke on start out but none once on turbo and less when fuel went to low sulfur.Gained a gear on any hill and would run with most other coaches except the new ones with 400+hp and overdrives.Did go back to 4:11s later as starting out on a steep hills was too hard on clutch and overall performance was better, except for the loss of top speed; 69 instead of 79. You need to make sure the orifice in the fuel return in the end of cylinder head is sized for the current injectors. Bigger injectors require smaller orifice. Specs are in DDA manual. I can get it if you don't have a book. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 483 Registered: 2-2001 Posted From: 66.147.116.90 Rating: N/A |
Thanks John, You just answered my next questions to you and more. When you did the rebuild and added the turbo did you use turbo cyl kits and build a turbo motor or non turbo kits with a wastegate turbo? I am getting ready to rebuild my high block 2 valve to a 4 valve which should add about 25% hp per the books (170 vs 238) It will add more because I'm sure the 2 valve is tired. I use about a quart of 40 wt in 400 miles. I did NOT know about the different orfice sizes. Makes perfect sense though. I'll bet the one in there is for whatever the engine was built with. Thanks! | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 889 Registered: 8-2006 Posted From: 74.32.84.228 Rating: N/A |
Jim, before spending bucks on a old high block check around for a 330 hp DDEC inline 71 I saw 2 at a sale in Houston that sold for 3500 each in fact I bought one for a friend with 4104 made a rocket out of his 4104 and averages 11 mpg | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 221 Registered: 5-2007 Posted From: 174.91.226.89 Rating: N/A |
yeah there are some transits around with that engine....would seem the way to go if you want a 6-71 T | ||
| David Evans (Dmd)
Registered Member Username: Dmd Post Number: 462 Registered: 10-2004 Posted From: 173.77.207.138  Rating: N/A |
Jim, there was a ddec 6-71 inline in a Silversides at Arcadia. He is at Russell's Diesel in Mill Spring not sure how how far from you that is. He knows his stuff and seemed like a good guy. Did you check the dumpster in Durham for any more parts? | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1902 Registered: 10-2003 Posted From: 71.58.71.157 Rating: N/A |
go for the turbo engine- better deal if you find a good running takeout. We went with turbo piston/ liner kits, valves and seals. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 484 Registered: 2-2001 Posted From: 65.82.205.34 Rating: N/A |
I agree that a DDEC 6-71T would be the best power and engine profile for service access. But I would never put a computer engine in my bus. I take pride that my '04 has no metric fasteners, no plastic and no computers. I have a handful of cars and trucks in my yard that are electronic. They are nothing but a pain in the butt to troubleshoot and repair. If I wanted those woes I could pull the simple good running 8-92TA in my Eagle and install a 60 Series DD or a Cummins. By the way, my tired 2 valve 6-71 gets 10mpg without a computer. It takes a certain amount of fuel to move a given weight (with slight allowances for the efficient calibration of a computer.) Not enough improvement to invite the Devil aboard forever. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1177 Registered: 11-2005 Posted From: 24.251.120.104 Rating: N/A |
My 671 is probably pretty tired and leaks a lot through both main seals so I don't push it over 63 on level ground. The speedometer reads approximately 5mph fast at that speed compared to my gps. I get appx 10mpg on level ground and 8 in the hills. An AT or six/seven speed sure would be nice! | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1188 Registered: 10-2006 Posted From: 76.248.150.30 Rating: N/A |
By the way, my tired 2 valve 6-71 gets 10mpg without a computer. It takes a certain amount of fuel to move a given weight (with slight allowances for the efficient calibration of a computer.) Not enough improvement to invite the Devil aboard forever. A well matched and good running should make 16 HP from each gallon of diesel. A more modern non EGR 4 stroke will create 18 to 20 HP from the same gallon. A worthwhile change IF you do enough miles for 20%-25% better to actually matter. No way at the usual RV 5000 miles a year! BUT the install will require the full boat , a different rear final drive to actually see the improvement. FF | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 489 Registered: 2-2001 Posted From: 69.26.140.132 Rating: N/A |
Fred, I have nothing against a non computer 4 stroke. If GM had used standard rotation engines I proably would have changed to one already. I have the advantage of being in the engine business. I could easily come up with a take out or rebuildable core. It's the computer I want none of. That's the Devil I refer to. |