Help, Speedometer and rev counter.

ice man · Post by **ice man** » Thu Nov 13, 2008 9:57 pm

Hello All,

Another problem worth discussing... My 1.8 sdl has a few instrument problems.

My speedometer when I bought the car was from a 1.3, which didn't match the 120 mph surround or the dif ratio, also the rev couner didn't work.

I got a speedometer cluster from a Mk1 TC of the well known auction website but it doesn't work properly.

1) the speedometer seems to read about right upto 35 mph then it starts bouncing and reading optimistic by 10 mph. I was following a lorry on the Motorway reading 68 mph... (felt like 58 mph) When the rev counter is behaving 3000 rpm is 54 in top, actually reading 64 on the speedo...

2) the rev counter reads correctly for a few minutes but when it goes over 3,500 it suddenly jumps up 50% then reads optimistic and varies. I know the sound of A / B series engines well and I can tell by the sound how many revs they are doing within about 10% . I know when I'm doing 58 mph, speedo is reading 68 and tacho is reading 4750 rpm in top something is wrong! also It shot up to 8000 revs in first at 15 mph!

Can anyone help? what cold be causing these phenomenae?

Is it just that they are 35 years old or is there anything I can do...

PS the engine misses a little bit, maybe the coil or condensor are at fault??? for the rev counter anhow.

Any help, advice or tips will be gratefully received.

Trevor.

Post by **MarinaCoupe** » Thu Nov 13, 2008 10:17 pm

The revcounter reads its signal from the coil, so as long as the coil is OK, the rev counter will be reading its signal.

However, most of the dials run on 10 volts, through the electro-mechanical voltage regulator, if it has broken down then it will give 12volts and this could be the reason for the approx. 20% increase in readings. The voltage regulator may be OK when cold but break down as it warms up, which would account for your readings only going wrong after a few minutes.

The Marina voltage regulator is a little silver box which plugs into the back of the dials, into the printed circuit board. It is shared with the Mini Clubman and the Mk1 Range Rover, they come out at about Ã‚Â£30+, it is listed on Rimmers. There was a guy who sells an electronic voltage regulator on Ebay but not at the moment. I have used one for the last 18 months with no problems.

I'm not at home at the moment so I can't give you the part number.

ice man · Post by **ice man** » Thu Nov 13, 2008 10:22 pm

Thanks chris - I'll check it out. I still have my other clocks so if I can locate the regulator i'll swap them over.

When it comes to the speedometer. I might leave it optimistic and gear it up to 3.27 or even adapt a 3.08 rover SD1 axle (I have the technology... just lacking time and money!)

Post by **MarinaCoupe** » Thu Nov 13, 2008 10:25 pm

Let us know how it goes.

ice man · Post by **ice man** » Thu Nov 13, 2008 11:17 pm

Well Chris, I changed over the voltage regulator and a couple of blown bulbs, took it for a spin and its got worse! well the same. but only straight from the start, instead of being ok for a bit.

The revs are between 30% to 50% optimistic.

I think I'll buy another set of Dials and see how I get on. I may have two faulty voltage regulators as my previous tachometer did not work at all.

When I get the chance i'll borrow my dads volt meter and check it out!

Thanks for the help Chris! A+

ado28 · Post by **ado28** » Fri Nov 14, 2008 12:24 am

I had that problem with my blue 1.8 coupe. I changed the rev counter and it cured the problem. With regards to the speedo, it might be the drivegear or the cable thats at fault I would think?

ice man · Post by **ice man** » Fri Nov 14, 2008 12:26 am

Well, I've been back on the auction site and I am now bidding on another set of clocks! Wish me luck!

ice man · Post by **ice man** » Fri Dec 19, 2008 8:14 pm

Latest situation -

Speedo #3 works correctly - 4.1 diff in a 1.8 means it reads optimistic.... i'm working on that.

The Rev counter is still playing up.

it reads correctly most of the time but the revs go up when I turn on the headlights and blower.

occaisionally it goes mental and is 3x optimistic.

So I've had
#1 rev counter doesn't work
#2 rev counter ok - optimistic -mental - ok again
#3 2/3 pessimistic

any advice? get a new rev counter? could the condensor failing allow interference from the alternator to give false signals?

Also if I put in a 1.3 speedo drive in the gearbox, to suit the 4.1 diff, will the 1.8 clocks read correctly or do I ned a 1.3 speedometer?

Trevor

stuthegasman · Post by **stuthegasman** » Fri Dec 19, 2008 8:32 pm

I would have thought any problem with the condensor would cause running problems like not running at all in some circumstances, it must be a voltage stabilisation fault as the rev counter works off the coil pulses, maybe another coil might cure it or as has been said before a voltage regulator/stabiliser fault ?? I would have thought the rev counter will only read what is going into it so a higher than normal signal will give a higher reading ??

Uncle Frank · Post by **Uncle Frank** » Fri Dec 19, 2008 10:03 pm

Stu might be on to something there mate, try swapping the voltage stabiliser on the back of the clock set

ice man · Post by **ice man** » Sat Dec 20, 2008 12:13 am

Hi, Thanks.

I have two voltage stabilisers, and with both I get the same results...

Fuel and Temp gauges are consistent, however the rev counter sometimes goes haywire!

New coil and electronic ignition are coming soon. but I think I'll chance it and buy one more rev counter...!

I hope that I will also get a new voltage regulator to play with..

Ps can anyone help with speedo cable ratios - I have a 1.8 engine and speedometer, but with a 4.11 diff from a 1.3 - how can I get the speedo to read the correct MPH (ps I am already looking for a Diff but just in case I cant get one) - Maybe I could keep the 4.11 diff and use a ford type 9 conversion. Man I could really use an extra gear. My last car was a six speed calibra pulling 3000 rpm at 80 mph, at 80 the poor marina is doing 5,000 rpm!

Trev

Post by **MarinaCoupe** » Sat Dec 20, 2008 10:53 am

Trev

I can help with the 5 speed gearbox conversion, I have adaptor plates, bolts,washers,special spigot bearing, special gasket and instructions. PM me for more details. I am doing this conversion on my 1.8 over the next few weeks and had some extra plates made up.

Alternatively, you need the Triumoh Dolomite 1300 speedo drive wheel part number 219006, same as Marina 1.3 and switch it for the one in your existing gearbox, then at least you'll be reading the right speed.

ice man · Post by **ice man** » Sat Dec 20, 2008 9:43 pm

Excelent advice Chris as usual,

I'm keeping one eye out for a v6 type 9...

PM sent

Thanks

Trev.

marinamad · Post by **marinamad** » Fri Dec 26, 2008 7:22 pm

Are you using a voltage resistor in the main + power lead to coil ,the early model marina's did not come standed with these they are need for rev counter, my marina mk1 ute did not have one off these standed and i put rev counter in out off mk3 it did as you have said when i put voltage resistor in it worked mint

ice man · Post by **ice man** » Fri Dec 26, 2008 9:43 pm

marinamad wrote:Are you using a voltage resistor in the main + power lead to coil ,the early model marina's did not come standed with these they are need for rev counter, my marina mk1 ute did not have one off these standed and i put rev counter in out off mk3 it did as you have said when i put voltage resistor in it worked mint

Hi,

Thanks Marinamad!

I'm about to replace the coil and fit magnetronic ignition.

If that doesn't sort it I'll get a voltage resistor and failing that then it's a new rev counter (#4)

All three rev counters have behaved completely differently, and they've all been stood.

The current one is getting better with use but is still has issues! 3/4 of the time it is OK and 1/4 of the time it has a mind of its own!

It increases revs when the lights go on, making me think it has an inerference issue more than a voltage issue, unless less voltage increases the rev display? or just rubbish coil, condensor poins and distributor???

Thanks again, any progress i'll keep you posted.

Also I will be able to post photos soon, shes off the road for xmas while I do a bit of welding for the re MOT 5th Jan.

Fast Marina Magazine

Help, Speedometer and rev counter.

Help, Speedometer and rev counter.

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