I have an 88 8v gti ce1 electrics, with vdo 120 mph guages. The issue i am trying to fix is the rev counter bounces when the engine is quickly revved or when doing a quick gear change. It reads correctly when the revs are slowly increased or stable. I swapped in my spare clocks which are motormeter 160mph 16v spec and the problem is cured so definately a fault with the guage. Can the rev counters be swapped in the cluster, and will it read correctly, and are the dials interchangeable to keep the redline in the right place? Is there a fix for the vdo rev counter? If i fit the 16v clocks complete will the speed read correctly with a red speedo drive, they came in the car when i bought it but always seemed to considerably over read the speed which is why i swapped to the vdo set, but the needle may not have been calibrated after fitting a dial kit. T i a for any help from you knowledgeable people on here
unfortunately the CE1 VDO and motormeter clusters are mostly different inside so this probably isnt possible. if the issue is just with the rev counter motor then its possible you can swap that, but it may not read correctly with 8v face as the donor set will be a 16v. maybe try without the L shaped oil warning circuit clipped inside the speedometer, these tap into rev counter circuit and can go wrong though usually it just messes up the oil warning... if you fit the 16v set complete they'll work perfectly fine, the speedometer is the same calibration. or you can swap the 8v speedometer over, so long as you dont mind the dial faces not matching any more. I did this on my old driver, though I didnt notice at first. when I eventually spotted my speedometer was VDO and rev counter motometer I had to fix it sharpish
The complete rev counter can be swapped about, providing the cluster is the same era. Your redline is hard printed on the dial and are calibrated from the factory so each 1 cm arch of the needle = XXX rpm. That you cannot change as an enthusiast between 8v or 16v rev counters.
Thanks to you both for taking the time to reply, i have taken both clusters apart and indeed the motormeter rev counter does fit the vdo set, and with a tiny bit of re drilling the vdo guage face would fit the motormeter rev counter, as where the screws mount is a plastic bar. I have also taken the time to drill an access hole to be able to adjust the trim pot on the back of the rev counter without having to take it all back apart, should it be necessary or possible to adjust the guage. The dashboard is not in the car at the moment so i can easily get to the back of the cluster while testing. The two clusters i have are very close in design and seem to follow the same pattern just with different sized resistors etc. The motormeter cluster even has a vdo label on the outside. I have yet to fully reassemble the cluster as i am adding some extra leds for better illumination at the same time, but looking forward to testing at the weekend.
Another question has popped into my head, using the secret mfa rev counter, does this get its info from the rev counter mechanism or does it process its own info from ignition pulses or dizzy position, making it a very easy way to check if my hybrid rev counter is reading correctly. I can borrow a fancy snap on computerised timing system if not.
the MFA computer takes its feed direct from the rev counter signal after signal processing, before it is sent to the rev counter controller board. so regardless of the rev counter motor/controller configuration the mfa secret mode will read the correct figure and you can use that to check the rev counter calibration
So i tried it today with the motormeter rev counter fitted in the vdo gauge set with the vdo dial face, and whilst it did work and didn't bounce when blipped it would not sync up with the secret mfa rev counter, if adjusted correctly at idle it was wrong further up and vice versa. Still worth a go as it cost me nothing, but will have to live with it or get a ce1 8v vdo rev counter in g w o. Thanks for the wise words.
its possible you can separate the motor from the control board, will likely require soldering to do so however. would mean taking a gamble its the motor rather than a board issue though!
