| Author | Message | ||
| Roy Jones (Warthawg)
Rating: N/A |
How does one put a tach on a 4-71 4104 with no no original tach? Also, need to find VIN on same coach and haven't been able to locate it. Thanks in advance Roy | ||
| Jim Bob Rating: N/A |
There are three popular ways to put a tach on your 6-71 in the 4104. There should be a tach drive on the power steering pump drive no the flywheel housing. You could install a tach generator/sender there, then wire to your tach up front. If your 4104 has had a conversion from the gear driven generator to a modern alternator then you can get a tach that runs off of the alternator pulses. There is a square plate covering an access hole in the flywheel housing. You could install a magnetic pickup type tach sender there that counts the flywheel teeth. (You'd need to drill a hole in the access plate, then weld a nut on it to thread the pickup into. The pickup will have instructions for adjusting the pickup so it doesn't hit the flywheel teeth. In each case you will need the appropriate tachometer. (no sender needed with the alternator reading tach.) But why do you need a tach to drive a 4104? Once you have the engine tuned for top RPMs, you use shift speeds. 20, 30 & 50 is normal for that bus. | ||
| RJ Long (Rjlong)
Rating: N/A |
In addition to what Jim said, here's the answer to your other question: The VIN on your coach should be in two places: a placard riveted on the dashboard above the second entry step and emergency equipment access door, and inside the exterior compartment directly underneath the driver, stamped on the "frame rail". See the pics:   BTW, what is the VIN on your 4104? HTH, RJ PD4106-2784 Fresno CA | ||
| Roy Jones (Warthawg)
Rating: N/A |
Thanks for info on both posts it answered my questions. Roy | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I found it much easier to use a tach on my 4104. Especially going up in gear or going down, since the speeds are different. BTY, I believe it is a 671, not a 471 engine. Richard | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
If shifting is "driving" your need for a tach, I can say that after 3000+ miles in my new '06, and some quality time on a long stretch of two-lane through the tiny "slow-down towns" of the Texas panhandle, I can now hit the downshifts at least 85% of the time tach-free and (almost) grind-free. Upshifting was much easier to learn. I wouldn't personally add a tach at this point and would spend my $ and energy on other upgrades, but that's just me. A great shifting primer (thanks to RJ and other sage contributors) is on this thread, started by a noobie yours truly a few months and many, many grinding noises ago... http://www.busnut.com/bbs/messages/233/9860.html It's strange to admit, but conquering the Spicer has been one of the most self-satisfying pursuits of this busnut. Good luck, Brian Brown Longmont, CO PD4106-1175 | ||
| TWODOGS (Twodogs)
Rating: N/A |
lots of people think they can solve their problems by buying something,....easier than learning...you still will have to learn to double clutch,no matter what you buy..lots of people think they can get around the learning,anything you learn is beneficial,it's what you don't learn that hurts ya' | ||
| gusc Rating: N/A |
I have to agree with Roy and intend to install a tach on my 4104 when I get it home. After driving trucks for years I feel lost without a tach. Since the 6-71 torque peak is at 1200-1600 rpm for most models I would like to be able to tell for sure. One thing a DD does not like is lugging and I intend to keep from doing that. My money and my choice. Some of you guys sound like truckers who say "a real man uses two sticks". Well, two sticks may be fun but for serious driving all day long a RoadRanger is sure nice and my choice every time. | ||
| FAST FRED Rating: N/A |
Add "pips" (little triangles of tape) to the face of your speedometer , and you have a tach. Use the Daris calc to find what ever rpm you think you need. But remember DD set the engines up to work correctly , so the top of 1st is the proper no lug spot for second etc. Just put one pip at the gov speed in first 2 on the gov speed in second and 3 in the gov speed in 3rd. A glance will show what gear you should be in and how close to lugging or the gov you are. Works for me , no wires to run ,KISS FAST FRED | ||
| gusc Rating: N/A |
FF, Sounds simple enough, you may have convinced me. With four gears this is not so bad, with 9-15 it is impossible. | ||
| Roy Jones (Warthawg)
Rating: N/A |
Actually, I was wanting to run the rack, check governor air gap, idle, no load, etc. But I think the suggestion on the flywheel should be an easy fab. was just wondering if I'd overlooked a mechancal output somewhere. Thanks for all the other suggestions though as they were quite insightful. Roy | ||
| Jim Bob Rating: N/A |
Hey, Roy, you mean your original post meant to ask "How do you read the RPMs on a 4104 while you are doing a tune up"??? Wow, did we get it wrong. In that case, you beg, borrow, buy, a phototach. It's a hand held optical tach whech reads a little piece of reflective tape you stick on either the flywheel or the vibration dampener. Once you have the revs set right, you can return it to it's owner. Now setting the rpms while holding this device is a job best done with an assistant and two sets of hearing protectors. If you were determined to install a tachometer in the dash anyway, you'll need one of these to check the calibration of the dash tach. If I were doing this, I'd do a temporary hookup of the dash tach at the rear, get it set correctly by the phototach, then install it permanently up front. But other than tune up, you don't need a tach to be in the right gear. You can put little colored spots on the speedo or just remember the three speeds. After you've lived with her for a while, you'll be able to hear what gear she is or should be in even when someone else is driving. |