Well, this is embarrasing!!

[Anadinolin]

I think iv broke my speedo.

Now that i have sorted the minor leak from the sump and gave the car a wash, i filled the tank up with a 25/75 methanol petrol mix i thought i would open up the taps last night on the M11...i got the speedo to go over-range and it promptly came back down, and stopped telling me how over the limit i was. so i stopped and pulled over into the hard shoulder for a few minutes, i couldnt see sod all as it was 1 in the morning.

i re-started the car and the speedo came back to life, but it dosent like the range between 60-80mph and jumps between the two. not sitting in the middle at 70 anymore.

i dont even know where to begin looking for a cable or any fly by wire type stuff. any ideas people?

ps that cooling problem is back, after brifly solving it, it dosent stay warm, I am on the highest thermo i could get which is 102C - it sits ok on idle, but when at high revs the temp goes down :/

[doingitsideways]

Hmm... If you have a cable driven speedo (which I'm pretty sure you will have) then I thonk you've probably knackered the internals of the speedo head.

So, are you seriously saying that you managed to get your 1.8 spi up to an indicated 140+mph, by doing nothing more than run it with ethanol mix?!

Investigate further, if you need a speedo I might know a handsome chap who has one!

Oh, the overcooling thing: My B18u used to do it too, never did get to the bottom of it. Maybe worth a punt at the sender to the guage as they're only a couple of quid off ebay. Either that of a piece of card in front of half the radiator!

Steve

[Anadinolin]

It was downhill + not sure what grandad did to it hehe. He used to be in engineering for the dept of admiralty and designed refits during ww2 my 2 aunts dont know what he did, all they know is he spent a few days doing things to it while he was retired lol wish I could ask him...my mechanic m8 spotted that its not standard because a few things have been bored out...might just be hoohaa or just the downhill slope lol...ill see if I can fix the instrument panel at work, I do pressure gauges so this might not be too tough

Oh and im catless - meow

[jamesy12345]

Good effort matey, nothing like a bit of manly speedo breaking

When I worked in Norway with my 440, a piece of carboard shoved down behind the grill blocked the cold air to the radiator

[dcw]

At least you broke the speedo in style, from the sounds of it!

Can't really add to what's been suggested here by way of fixes, I'm afraid - probably a replacement speedo head job, though; given how often questions about speedo's come up, I think the 400 speedo set up may have been a bit fragile generally (certainly the one on my 480 gave up the ghost).

Keep us posted!

David

[Anadinolin]

Plenty of 480 speedo information and 460 turbo speedo info, but not the cable driven 460 - spent the morning searching for information, couldnt find a great deal except for a 240 speedo extraction on dave bartons site.

seeing that, and its no less fiddly than the things i do, i took the plunge and seperated the dash and dials. The speedo has two black screws on the face,they where quite loose and the needle was getting caught on the face, doing these two screws up helped in final assembley.

i then took the back off the unit (white plastic bit) and took out the pcb and extracted the speedo gubbins. there is a spring in the back of the bit with the needle, this helps the return of the needle, it was kinked. i took one from work that had a similar tension.

while i had the dash out, i redid the joints with fresh solder and cleaned the pcb with flux washing solvent (IPA) and waxed the edges with a wax block. the mechanical functions got the grease so to speak, i actually used a bit of lithium based oil and dabbed it onto the bits that seemed relevant with a cotton bud. and dusted anywhere that needed it with a compressor.

re-assembled the dash and took it for a spin, all seems ok. the needle now steadily goes through 70mph like it used to before the tension spring which i replaced seems to have been a good bet, the speedo reads 9mph above the sat-nav at 80mph and increases logically - so in essence iv lost 1mph, but gained a few percent mph accuracy :P

[dcw]

Well done!

David

[doingitsideways]

Good lad!

Wanna buy a spare in case you can't fix it next time?!

Lol

[Anadinolin]

The speedo is hunting again, this time worse, im pretty sure its not the dials this time. Any thoughts?

[Magnumpi]

Is the plug in idle speed controller attatched properly?