Armand Posted December 13, 2006 Share Posted December 13, 2006 Hey guys, I just got a 1971 240z on friday as a car to work on. So far I have fixed a broken front headlight, seatbelts, interior lights, door locks, and the windshield wipers. But yesterday I got pulled over for speeding and got lucky with a warning. I want to fix this speedometer next. I'm only 16 years old, I have ordered "How to Restore a Datsun 240z" and the Haynes service manual but I would like to know what to look for and troubleshoot to fix the speedometer. As for the Tachometer, I don't know if I can still use the factory gauge because the previous owner installed an MSD electronic ignition system. A local 240z mechanic told me that the stock tachometer cannot accept the new ignition system, and that the tach has to be electrical not mechanical. Is there any truth to this? Forgive my ignorance, I am only 16 and still learning. I plan on reading both books from start to finish as soon as I receive them, and as soon as I become a senior w/ half days, I plan on taking some automotive classes at the local community college. Thanks in advance, -Armand Quote Link to comment Share on other sites More sharing options...
Yorgee Posted December 13, 2006 Share Posted December 13, 2006 Damn, I've got the same problem with my speedometer; I never know how fast I'm going. I'm just planning on getting new gauges, yet it would be a shame to get rid of the old school look of the stock gauges. If there's a way them, that'd be awesome. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 13, 2006 Share Posted December 13, 2006 is it broken and just not reading? or reading higher or lower? Quote Link to comment Share on other sites More sharing options...
roger.svoboda Posted December 13, 2006 Share Posted December 13, 2006 You can test the speedo itself by running it with an electric or battery drill. on the zx speedos there is a legend that says something like 1000 rpm is sixty mph. a wooden match stick has about the right square section and strong enough to run the speedo. (course you need to take it out to do that). If speedo checks I would give the speedo cable a close visual inspection from the back of the speedo to the tranny. On two of my z's the cable had been pulled from its brackets giving me erratic operation. Once I put the cable back the way it was supposed to be everything worked fine. Don't know about 240 but on zx there is a short cable from the speedo that hooks to the long cable from the tranny and there is a plastic joiner piece where the hook up that falls out and if so no speedo reading. Hopefully someone else can confirm what you have on a 240. good luck nice to a young guy getting into z's. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 14, 2006 Share Posted December 14, 2006 on my 78 280z the speedo cable goes from the back of the gauge all the way to the tranny... one solid cable. I would assume the 240 is the same way. Quote Link to comment Share on other sites More sharing options...
Armand Posted December 14, 2006 Author Share Posted December 14, 2006 Thanks for the help guys, I'll give it a shot this weekend. Btw, the speedo doesn't work at all. It doesn't move. It's not that it jumps around or is incorrect. Quote Link to comment Share on other sites More sharing options...
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