Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: 450sl on July 22, 2012, 12:27:13
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Hi All,
Can anyone of you Gentleman tell me if my speedo needs recalibration after installing the Getrag 265 5sp-overdrive box ?
As, is the cableoutput of the Getrag similar to the originalbox ?
Mark
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Mark,
The original output of the Getrag is electronic and is converted with a worm drive that can be purchased from BMW to convert the digital output back to a mechanical output to take the speedo cable. After the gear box conversion the speedo will read under its true speed. There are several ways to correct this either by trying to have the speedo re-calibrated if possible or by putting in a conversion unit between the output of the gear box and the speedo, some consider the easier option.
Here is an example of one
http://www.speedometershop.com/ratio.html
Garry
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Mark,
A way to solve this with less math is with a Cable-X box that is available from the factory in Alabama and from some performance shops. It takes the output of any electronic transmission and converts it to mechanical rotation.
I installed mine with industrial strength velcro under the driver's seat. I routed the output wire from the transmission under the tunnel carpet to the box under the seat. I pulled one 12v. wire from the back of the fuse box and ran it under the carpet. I had a local speedo shop make a new, slightly shorter speedometer cable and ran it under the carpet in the groove stamped in the floor pan. There are holes already in the crossmember under the front of the seat that are just large enough for the speedo cable to pass through.
The calibration of the box is done with dip switches and I used a GPS to check that it is spot on. This allows you to make easy adjustments if you ever change the rear differential ratio too.
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Thanks Garry & Raymond, but this is a bit confusing for me.
I assume
on 2951.jpg is the electronic speedo output (or is it an internal backlights switch?)
on 2949.jpg is the mechanical output provisions
For my understanding if i buy Bmw.parts.jpg i get a mechanical cable output to my original speedo.
Mark
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You are correct, the item in your third photo will replace the electronic output and provide you with a mechanical drive, however the ratios are such that the speedo will read incorrectly. here is a photo of the input on a fitted Getrag box I think
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Can the Speedo be recalibrated to suit the getrags mechanical-output ?
If Yes : Anybody know by which "Wegdrehzahl " ( W ) conversionratio ?
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Some of the Getrags did in fact already have the mechanical speedo drive installed but you'll be lucky to find one.
There's a company in the UK that can re-calibrate the speedo.
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Hi All,
Got my new Speedogears from the friendly BMW-dealer for the Getrag 265 in today , turns out to be a drive ratio of 2,5:1 (teeth 10/4)
To compare i just need the Mercedes (4speed-Manual-1970) speedometer drive ratio at the transmission
Anybody outhere witch a tranny on the workbench who is willing to check the ratio of the mercedes for me ?
thanks
Mark
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Hallo 450SL,
the getrag 265 has a Wegstreckenzahl of about 756, the 230SL manual 4 speed transmission G72 has 869, but 892 in fact. That means, the 230SL speedometer shows about 15 % to less speed, when using the getrag.
You will probably have another problem, that has nothing to do with the getrag conversion:
The 230SL speedometer shows the right speed up to 80 km/h and shows about 6-7 % too less speed above this speed, even when using the mercedes G72 gearbox.
The reason why is the age of our speedometers. During the nearly fifty years beeing used, they loose their Magnetisierung, sorry i do not know the word in english.
That means, if you use a conversion unit, as i did, your speedometer will show the right speed with the getrag up to 80 km/h and then shows too less speed from 80 km/h up to max speed; and the odometer will show right distances.
I did not know this before and i prefered a conversion unit, because i did not want the VDO people in Vienna to open my speedometer and to calibrate it.
Nowadays i would prefer a calibrated speedometer.
regards Franz
very happy with my getrag 265 on the Autobahn in Austria and Germany
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Thanks Franz,
""""""For over a century the mechanical (eddy current) speedometer has been used and is still in widespread use. A rotating flexible cable usually driven by gearing linked to the output of the vehicle’s transmission inputs its signal. It was the only type commonly used until the 1980s and the appearance of electronic speedometers.
When the vehicle is in motion, a speedometer gear assembly at the rear of the transmission will turn a speedometer cable that then turns the speedometer mechanism itself. A small permanent magnet driven by the speedometer cable interacts with a small aluminum cup attached to the shaft of the pointer on the analogue speedometer. As the magnet rotates near the cup, the changing magnetic field produces “eddy” currents in the cup, which then produces another magnetic field. The effect is that the magnet exerts a torque on the cup, "dragging" it, and thus the speedometer pointer, in the direction of its rotation with no mechanical connection between them.
The torque on the cup increases with the speed of rotation of the magnet. Resistance to movement is created by the spring trying to hold the pointer at zero. At a given speed the pointer will remain motionless and pointing to the appropriate number on the speedometer's dial. This is fixed at a preset number of revolutions per mile (usually 1,000 rpm per mile). You will need to determine what is the correct number for your application. At this point the corrections need to be made by allowing for the variations in the vehicle from stock.""""""
I figure your Magnet or the spring mentioned has weakened.
Thanks
Mark (who is still looking for the Mercedes (4speed-Manual-1970) speedometer drive ratio at the transmission .......)
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doubleposted
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Mark (who is still looking for the Mercedes (4speed-Manual-1970) speedometer drive ratio at the transmission .......)
Depends on your rear end ratio
Achim
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Hi Achim, Has nothing to do with rear end , i am talking about rearend gearbox......
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I think I understand that the ratio of the speedometer drive gears at the rear of the transmission varies with the ratio of the particular final drive (ring & pinion gears, or crown gear set) installed in the car's rear axle.
In other words, it varies from car to car and does depend on -- or is matched to -- your rear end ratio. It can be counted in a disassembled transmission, and surely must appear somewhere in some technical tome such as the TDM. I haven't come across it, but if that reference can be identified by someone here, then the final drive ratio -- as inscribed on the exterior of your differential housing -- would provide the key needed to solve this question with no disassembly required.
Failing that, I'm pretty sure I know where there's a manual transmission sitting open and eviscerated in North America which could be useful. Either way, though, the inscribed ratio is a necessary piece, as the one I have in mind is near to yours in age and model but not necessarily a match, and for that matter, none of us yet know which ratio your car has in it's rear axle. [Mine doesn't even match the information on it's data card, as the axle was swapped for one with a preferred ratio, demonstrating that it's best to crawl under and check for sure.]
You'll be looking along the bottom left edge of the differential housing, on a flat, smooth area of the vertical surface ~ 13mm high and running along pretty much the length of the housing if I remember correctly. There are two groups of numbers lightly incised -- manually inscribed -- on this surface. The set of 3 digits toward the rear, separated by a comma, give you your ratio. Odds are it's "4,08". Take a good light and a sturdy cloth, and maybe a little solvent with you, as the figures are not deeply stamped such as you may be used to on our domestic iron; it's more like fine pen scratches ... very graceful.
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Hi Pagoden,
In the mercedes G72 gearbox there is a wormgear mounted on the outgoing axle , this drives a pinion gear that is connected to the end of the speedometer cable.
This is the ratio i need, wich i presume is the same for all mercedes gearboxes off the sixties.
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Hello all, nice to find this forum. I have a '69 280SL, which I converted a few years ago to the 3.27 axle from a 4.5 sedan. That solved the problem of too many revs at highway speeds, but did not solve the problem of the fact that the ratios of the four-speed manual gearbox are too widely spaced. I don't need an overdrive fifth, but I would like a shallower (numerically lower) first gear, and closely spaced ratios up to a 1:1 non-overdriven fifth. Changing the rear axle made the acceleration leisurely, to say the least...
To use the Getrag gearbox I would have to go back to the original rear axle, which I think was a 3.92 or a 4.08, and I don't have it anymore. Has anyone done this conversion using either a Tremec gearbox or a BW T-5? Maybe I could get the ratios I need with that. If anyone has, could they let me know and maybe I could find out what problems I should anticipate. Thanks in advance for your help. I do have access to a good machine shop and an expert transmission man to help me, so this isn't impossible. And I do like the car enough that I can imagine what it would be like with a 5-speed close-ratio box, which would be a great deal of fun.
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Jim,
I did the Getrag conversion on a 280SL after I had done an axle change from 4.08 to 3.46. The car needed to have the axle changed back as the drop was really too great. Made it a beautiful highway machine but strictly an overdrive for 5th.
There is one member here that has done a Tremec and swears by it bit you will have to get the axle back to 4.08 otherwise you will have the same problem.
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The Getrag 5 speed comes in two guises that one might call "sport" or "touring". The sport one has a 1:1 5th gear whereas the touring one has a 1:0.89 5th (overdrive).
Both have "dog leg" 1st and are fairly difficult to tell apart until you know what you're looking for.
The "sport" might well suit your application Jim.
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Just posting to avoid more confusion.
From above....
"Both have "dog leg" 1st"
On the 2 conversions ive seen (one is mine) the overdrive getrag 265 does not have a dog leg first gear. ie the first is in the 'normal' position. Reverse on this unit is the same as modern german cars ... to the left of first gear
Although i have'nt seen the 1:1 unit, my understanding is that it is a dogleg.
Hope that helps!
Kay
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Can anyone educate me as to the way to distinguish the 1:1 Getrag 265 from the overdrive model of that unit? I could live with a 1:1 5th gear and a 3.27 final drive, or change it to a 3.46. I found one 265 on CL in NC and my transmission technician friend is willing to take on this project.
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Have a read of this post, there is a photo of one there that is the correct one. Raymond also talks about his Tremac conversion. And Mark Bull also is the supplier of the conversion kit.
Colin, (Stickandrudder) does the 1-1 box have a suitable gear shift link?.
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The reason I know a little about these is that I bought a couple of boxes that turned out to be the 1:1 5th "sport" boxes. As I remember it the gear linkage was the same for both types. The sport boxes are in great demand for racing applications so comand a greater price. The only visual difference is the layout and number of some small plugs that fit into the rear casting. Unfortunately i didn't take any photos of the ones I had before I sold them but IIRC the sport box has three small (about 10mm dia.) core plugs in the rear casting which are absent on the o/drive box. I'm sure someone will be able to clarify shortly.
Kharam has it right about the dogleg issue, contrary to what I posted before, only the sport box has the dogleg..
So, to answer your question Garry, the gearshift linkage is "suitable" in the same way that it is suitable with the 0.89 5th box.
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Thats interesting as the box that I had did have the dogleg, with 5th on the opposite end (right and up) to reverse (left and up) and a standard H pattern in the middle for the first 1- 4 gears. It came from an M5 so maybe I had the sports box all the time. The photo in the link was my gearbox.
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I think it's the three small plugs in a vertical line that are the tell-tale for a sport box.
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Then if that is the case and it sure looks like it and my 280 did have the sports box, the 5th gear was strictly an overdrive with a 3.46 axle and had no pulling power for hills at all. With a lower axle it definitely would not be any good in Jim's 3.27 axled car. The old 4.08 axle would need to be put back in.
I liked it as all my driving was on long country roads but you needed to change gears for any hills. If I was driving around England that It would have been only good for the motorways.
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Garry, having re-read your earlier post:
The dog leg is for 1st gear. To select first the lever should be moved to the left and to the rear. 2nd, 3rd, 4th and 5th are then in the standard "H" pattern.
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That makes more sense but the photo I posted was of my gearbox that I fitted and it has the three small plugs on the side so must be the telltale for the overdrive box
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For everyone's reference this is what a sport box looks like.
http://www.ebay.co.uk/itm/261140466826?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
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Hello All
There are two types of getrag265 5 speeds
the sports(dogleg) also known as the close ratio, and the overdrive model ( the one needed for the conversion),
These boxes look very similar and have caused a bit of confusion especially since the casting no on the side of the box is common and cannot be used to help identification.
I have written an article with pictures of both transmissions and clear descriptions of the external differences which are easy enough to help differentiate.
The article was printed in a recent pagoda world but for anyone who wants a copy please just pm me with your regular email address and I will forward you a copy.
Best Regards and all the best wishes for the New Year to all members.....
mark
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Mark, I finally located one of the dogleg gearboxes here in the USA, a rebuilt one from the correct BMW. For my car, I got the close-ratio box with the 1:1 fifth gear, not the overdrive. If the ratios are too tall once I get it driving, I will change the rear axle back to a 3.46 from the 3.27 in it, but I suspect they will be fine. I like the rev level on the highway with the car as it is: direct drive top gear with 3.27 axle. What I need is more closely spaced 1-4 gears so the engine stays revving. Hopefully this will make the car better to drive, as I have felt that the original four-speed's ratios are too far apart for the size and power of the engine.
I will PM or email you off line. I would like to order the kit you make which adapts the Getrag gearbox into the 113 chassis and mates it to the 280SL engine/bell housing..
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Jim,
I had a Getrag installed with a 3.46 rear end in my 280SL after changing from a 4.08 rear end some time earlier. I fould even with a 3.46 that the gearing in the 5th gear was a bit high and was considering re-installing my 4.08 before selling it to concentrate on my 230SL.
I suspect you will find that the 3.27 way too high and may save your self some work by at least bringing it back to the 3.46 whilst doing the gear box.
Garry
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For Those interested :
The Getragbox has 10/4 , while the Mercedesbox has 20/10 ratio
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For Those interested :
The Getragbox has 10/4 , while the Mercedesbox has 20/10 ratio
You are referring to the speedo gear I guess. Another thread says the difference is 15%, but it seems it's more like 20% then.
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there is a 19% higher transmission
Here you can read it accurately. Originates from the Pagodentreff.de.
Will install in my silver pagoda in January a 5-speed Getrag. Transmission and conversion kit are already there.
Peter
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Yes , speedo ratios