Taped_Finger Posted August 26, 2021 Share Posted August 26, 2021 Wondering if someone is able to help me with the issue I am having with the speedo on my 310R.When the speedo reaches about 70mph it starts to stutter then as I increase the speed the speedo just gives up and drops to zero, once I lower my speed to below 70mph the speedo springs back to life.When I build the car in 2020 I installed the speed sensor with the earth modification wire to the rear ARB mounting bolt.Not sure if it's the actual speedo causing the problem or the sensor, I've had a look at the sensor tonight and all looks fine and I'm getting the light beam switch on and off when I rotate the wheel.Any ideas what it could be?ThanksDavid Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 26, 2021 Member Share Posted August 26, 2021 That aberrant behaviour with high speed has been observed a few times. Even though the indicator light is working OK I'd suggest resetting the gap.Previous discussion of gaps.Guide on "Speedometers"Jonathan Link to comment Share on other sites More sharing options...
Taped_Finger Posted August 26, 2021 Author Share Posted August 26, 2021 Thank you Jonathan, I'll have a play with the gap Link to comment Share on other sites More sharing options...
Taped_Finger Posted August 26, 2021 Author Share Posted August 26, 2021 Having another look at the speedo sensor, it actually looks like the prop shaft may not be seated correctly.As the sensor is only covering half the teeth faceIt's just come back from a Caterham dealer after a service, great!This asks the question why has the prop slipped out the diff? Link to comment Share on other sites More sharing options...
ChrisC Posted August 26, 2021 Share Posted August 26, 2021 The trigger wheel is known to move on the tripod joint. Caterham replace the driveshaft if this happens under warranty, after all its a part suppliers problem (GKN). If your car is under warranty contact Caterham, if not then consider cleaning the rust, applying some strong Loctite and pushing it back into position. As how I know Link to comment Share on other sites More sharing options...
SM25T Posted August 27, 2021 Share Posted August 27, 2021 PS .... as above... drive shaft, not prop shaft Link to comment Share on other sites More sharing options...
Taped_Finger Posted August 27, 2021 Author Share Posted August 27, 2021 My bad on the wrong part naming I've spoken to Caterham as it is still under warranty and will wait and see what comes back.Chris - Has your issue occurred on your latest build? Link to comment Share on other sites More sharing options...
ChrisC Posted August 27, 2021 Share Posted August 27, 2021 Yep, this is a picture of my 420R. It happened at the first proper dry track day, where I assume the driveshaft got hot from the disc. It's a 2020 registered car, but the kit was supplied October 2019. Apparently GKN now apply some form of green substance to secure the trigger wheel to the tripod joint, I wonder what that could be :-). Took as week to confirm the course of action (replacement driveshaft), but I am still waiting for parts. That said I am not in a rush, I pushed the trigger wheel back into position to get a working speedo. Link to comment Share on other sites More sharing options...
ScottR400D Posted August 27, 2021 Share Posted August 27, 2021 Any idea when this became an issue Chris? I don't recall having heard about it until relatively recently? Link to comment Share on other sites More sharing options...
ChrisC Posted August 27, 2021 Share Posted August 27, 2021 It seems to have started sometime in 2017 (ironically when the new sensor was released). I know of one fellow builder with a 2020 delivered kit that had the issue. So sometime between 2020 and 2021 the fix has been applied by GKN. Link to comment Share on other sites More sharing options...
John Vine Posted August 27, 2021 Share Posted August 27, 2021 Once I get my engine back in, I'll turn my attention to updating the Speedo Guide to include the above problem.If GKN are CC's official supplier of driveshafts (CC Parts are reticent on this point), has anybody asked them if they can supply spare reluctor rings?JV Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 27, 2021 Member Share Posted August 27, 2021 "Once I get my engine back in, I'll turn my attention to updating the Speedo Guide to include the above problem."That would be great. Thanks. I wonder if there's a factory workshop notice?Jonathan Link to comment Share on other sites More sharing options...
Taped_Finger Posted August 27, 2021 Author Share Posted August 27, 2021 The warranty contact is on annual leave for the next week for so, so I will not hear back from Caterham in a while.As I was wanting to take advantage of the nice weather, is there a quickish way to push the trigger wheel back in place or is it a case of stripping the rear hub components off?I don't have torque wrench that goes up to 270Nm for the hub nut, so if possible would like to avoid removing that nut.My car has only done 1800 miles and I've not done a track day Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 27, 2021 Member Share Posted August 27, 2021 "I don't have torque wrench that goes up to 270Nm for the hub nut, so if possible would like to avoid removing that nut."If it does come to that there are several in the Equipment Register.... and several Members have used levers and weight x distance...Jonathan Link to comment Share on other sites More sharing options...
ScottR400D Posted August 27, 2021 Share Posted August 27, 2021 You can remove the drive shaft leaving the hub and DD ear in place. Access is pretty good then. Link to comment Share on other sites More sharing options...
ChrisC Posted August 27, 2021 Share Posted August 27, 2021 Mine moved back with a simple plastic trim leaver. I removed the wheel and cleaned the rust from the area, then cleaned it again it's rubbing alcohol to promote good adhesion from the Loctite. Applied strong Loctite and pushed it back. I didn't remove the driveshaft from the hub, but I did remove the ARB bracket for better access (if you have one fitted). New driveshaft arrived today, which is about a month since reporting the problem, the delay was mainly due to part lead times. Link to comment Share on other sites More sharing options...
ScottR400D Posted August 27, 2021 Share Posted August 27, 2021 #11 John, last year when my Titan fell apart and I was thinking of fitting an SPC, at first I thought the SPC LSD only fitted the Ford diff so I considered changing the lot - diff, prop and driveshafts. After seeing the quite unusually costly shafts that CC offer I tried to find a source at GKN but had no luck at all. That would be a good resource to have if anyone had a contact. Link to comment Share on other sites More sharing options...
Taped_Finger Posted August 28, 2021 Author Share Posted August 28, 2021 I managed to move the trigger wheel back yesterday using cycle tyre levers, it's not perfect but it's an improvement, I'll test over the weekend and I'm still going to try and get a replacement from Caterham.Thanks for everyone helps Link to comment Share on other sites More sharing options...
Tuck2020 Posted August 30, 2021 Share Posted August 30, 2021 I tried and tried to get an answer from CC about who supplies the reluctor rings, as my car doesn't have one and I wanted to fit a speedo. In the end I just downloaded a speedo app for my phone. So I'm following this with interest! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 30, 2021 Member Share Posted August 30, 2021 What sort of speedometer has it ever had? And what sort of gearbox does it have now?Jonathan Link to comment Share on other sites More sharing options...
Tuck2020 Posted August 31, 2021 Share Posted August 31, 2021 Hi JonathanIts a Ford box with the caerbont programmable speedo, you gave me some help with it when I bought the car, but unfortunately I had to shelve my plans for retrofitting something due to a house move and putting the car in storage (and a pesky virus!)My car has driveshafts without reluctor rings, and I made several enquiries to CC to see if I could get one and retro fit, to no avail. I've bought a sensor, and one of my winter projects is a bracket to pick up the hub bolts at the front wheel. Apologies for the derailment OP! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 31, 2021 Member Share Posted August 31, 2021 Thanks.I was wondering if it would be worth considering an electronic drive from the gearbox.Jonathan Link to comment Share on other sites More sharing options...
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