Installing a tacho gauge

[1049Participant]

Has anyone fitted an RPM gauge, and if so do you have any experiences to share? Is it easy to do? My car is a Paris built car, with 6v electrics (which I would be reluctant to change).

I’d like to fit a small gauge – perhaps 2″ diameter – in a bracket screwed on to the lower edge of the dashboard.

Does anyone know what the “red line” is for a 1956 11D engine? (Not that I would want to run the engine anywhere near red line!)

Many thanks,

Julian

[Larry LewisParticipant]

MG T types have a tachometer running off the back of the dynamo- That might be something to consider but you’d have to talk to MG guys to get any real info about how to do it. It’s a mechanical connection, so voltage should not matter.

[Paul BarnardParticipant]

I also have a 6v and when setting up the tick-over speed I used a small electronic rev-counter I bought some years ago. I got it as a spare when I had trouble after an engine rebuild on another 12v car. It is a modern one but like most modern ones, it does have the facility to switch between 4, 6 and 8 cylinder engines. It has four wires – one is attached to the negative side of the coil(green), one to the positive(red), one to earth(black) and of course there is a wire for light. I just ‘jury rigged’ it in the engine compartment, temporarily. It worked perfectly and gave me a nice steady rpm reading while I adjusted the idle speed. I am toying with fitting it permanently but thought I would mount it on a swing bracket so I can tuck it away out of sight when not in use.

It is made by TIM – model TIM/014(B) – 52mm diameter. and of course comes with fitting instructions. From memory it was about £25

Here it is on good old Amazon – but currently unavailable. https://www.amazon.co.uk/Time-Instruments-TIM-014-Tacho-52mm/dp/B0049MPU1E

One word of caution though, if you have electronic ignition fitted you may have a problem if you fit an electronic rev counter. On another car the rev counter interfered with the amplifier on the electronic ignition causing overheating of the coil among other things, this in turn led to misfiring and cutting out.

 

Hope this helps

[1049Participant]

Thanks Larry & Paul – very helpful. FWIW, I don’t have electronic ignition.

Paul – do I take it from what you said that the TIM tacho worked OK with 6v? I presume it is designed to run on 12v, but it may be that 6v “at the coil” will still be enough for it to “record” & thus produce an rpm value.

I’m making a distinction here between the 12v feed for the internal illumination, and what feed is required to generate the displayed rpm.

A friend has offered to lend me an old 12v tacho, so I’ll see if it works & will report back; I’m not bothered about internal illumination as I rarely drive my TA at night. If it does work then it does open up a whole load of options, and something like this might be just what I need.

https://www.ebay.co.uk/itm/Tachometer-0-4000-RPM-52mm-W-input-terminal-Alternator-or-ignition-coil-Rev/392045783591?hash=item5b47bfea27:g:bM8AAOSwFL9TvCzF

Thanks again,

Julian

[Paul BarnardParticipant]

Re : RPM

Julian

 

I came across a diagram in Daniel Eberli’s most useful book which gives the following info.

1st to 2nd…. 33kph @ 3000 rpm

2nd to 3rd….46kph @ 3000rpm

Hope this helps!

Paul

 

 

 

 

 

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