Quick update, did a tour last weekend and put about 1000 km on the converted Speedo, no dropouts or failures so far The ODO distance displayed on the Speedo was about 1.2% higher than the Garmin GPS i've used as distance reference, looks good!
Excellent work. The visible linearity (at the needle) is affected by a mechanical/magnetic adjustment at the back of the meter assembly. There is a way to rotate something there. I no longer have one to take photos of, sorry. Gerrit
Have asked Rob and it is ok if i offer them here on a self cost price. Will get some pricings for the manufacturing as soon as the testing is finished. I believe the production cost will be at or below $90 excluding tax for an assembled and tested PCB (assumption: $10 parts, $15 circuit board production, ~$65 for tooling setup, assembly and testing) when doing a batch of 20 circuit boards.
Adrian, Good solution to a known problem... Please consider posting a "how-to" for PCB swap and calibration (I assume any programming, and possibly calibration, would be done by you at your shop...if not tell us that too) and show some pics. This would become a sticky here and you could sell a bunch (lots more than 20). Just a thought.
No problem! Yes, will do a documentation including photos. The boards will come ready to install, you only need to swap the board against the new one and then do the calibration of your Speedo by turning a trimmer with a small screwdriver until the Speedo needle points to 130 kmh/81 mp/h. The only ugly part is removing the chrome bezel of the Speedo, i'll have to think about how to do that without having access to special tools. '74 GT4's up to mid '81 GTBi/GTSi cars are fully supported. Late GTBi/GTSi starting from summer/autumn '81 and QVs (using the newer 116987 speed sensor) are not yet supported as i do not have access to a Speedo from one of these cars yet, but should be no problem to support in the next board update. Image Unavailable, Please Login
Adrian, I have a few speedos laying around. Show me a pic and part number of what you need and if I have one I'll send it to you for your work on those models. I am just a few hundred K's south of you in Bayern.
great info, I need one now !!!, im dissasembling my instrument panel next week, if you can sell it to me, Ill be a happy camper, its for a 1977 US 308 GT4 . thanks , and great work Anastasio
Thanks for the kind offer! I have to check the spare parts manuals what type was used in which model, and what the correct part number is. Should be a speedometer with a build date late '81 or newer. There should be something in the Ferrari Technical Letters and Service Bulletins but i did not find anything speedometer related yet. I'm still testing, this will take some more weeks. Please be patient, i need to be sure the new board is bullet proof before launching it to the public
Adrian, this is great work and your timing is perfect. I have been trouble shooting my speedometer and just recently ruled out the sending unit. Please put me on the list for when your first batch is ready and I will gladly buy one. Thanks
One of the Speedos i had in for repairs/calibration seems to be of the newer type, just discovered this yesterday when i started testing it. It displays just half of the speed when sending a signal for the older type (for which i did the replacement board), it seems to require 16 pulses instead of 8 for a wheel turn. The Speedo was bought by a friend as a spare, it's not clear in which car it was installed previously. It has the green needle as in the GTB/GTS (had carb and injection GTB/GTS the exact same faceplate/needle?) The electronics board the ODO meter motor are both different compared to the previous model. Interesting, now i need to find out when the change took place and from which date onwards this type of Speedo was installed. All the Veglia Speedos have a white type label on the Speedo body but on this one the text is not readable anymore unfortunately. More updates when i spend some quality time with this newer type. Image Unavailable, Please Login
Reminder: For those desiring calibration where a full speedometer change isn't practical, the RDR by 12oclockLabs is a viable and proven calibrator. Recall that it also requires the Ferrari inverter module for use with 308 Veglia. Speedo Calibrator FChat posts describing the installation in a 308 available using search words = speedometer calibrator Adrian - super job!
After browsing the factory manuals and talking to Steve Magnusson and Dave Helms i have a better idea now about where the two sensor types were used, see table below. Looks like the US cars had the first sensor/speedo type until '82, whereas the EU cars already started in '80 to deploy the bottom mounted sensor. The replacement board discussed here is marked as "Type 1" in the list. Designing a further replacement board (Type 2) for the new sensor/Speedo (shown in the photo in post #41) looks straightforward, i'll start on that one as soon as the first board has finished testing and is ready for production. Image Unavailable, Please Login
We are in the middle of testing right now, found an issue with driving ODO motors in mile speedos and fixed it last week. Will do a mile to km/h conversion this weekend. Going forward 5mph when stopped, do you refer to the pointer being located at the 10 mph position when the speedo is off?
Anyone have a euro speedo face lying around for an '85 308 GTS? When my car was originally converted to US specs (I think loosely converted, even though I do have all the conversion paperwork) they only changed the face and the odometer is still in KM. They also turned it up 7,500 miles (actually KM) to bring it directly to CA in '85. Paperwork shows this too. It was imported from France. Please PM if you can help. Thanks, Jim
