Fitting a tachometer to an old MD2 with dynastart

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cass123

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Seem to remember this was asked quite some time ago but cannot trace.
Apart from a water temp guage , I have no instruments fitted
for my old (1972) MD2 and have just been given an old tachometer. Can I use it with the dynastart ? and if so , how
do I connect it up ?.
Tachometer is VDO 0-6000 rpm type 230/9/1 12v/1200001
mp. sw 5.76.
top connection is for illumination and at lower rear side are
4 terminals marked G, W, +12, - .
Any help/advice most appreciated.
 
A dynamo doesn't produce a pulsed output, so I don't think it is of any use for triggering a tachometer.
(An alternator does, and the output is then converted to a flat DC voltage, but the AC output can be internally tapped to work a tacho.)
I think you need either the kind of tacho that works from a sensor detecting a special notch on the flywheel, or a stroboscopic kind that can read the rotation of any turning shaft or pulley.
 
Thanks to you both for the fast replies. "tiny tach"looks interesting. Clifford , do you have any contact info for the
flywheel sensor type tachometer ?. Had first thought of
something along those lines but have been unable so far to
find any info on them ( over here , anyhow ).
Most appreciated and again, thank you both
 
Sorry, I've no idea. I only know that is the preferred option for Yanmar engines, as it is made deliberately difficult, but not impossible, to tap into a Yanmar alternator.

I didn't know a Tinytach would work on injector pulses - that sounds good. But I think they only have a digital read-out, not the old fashioned round dial?
 
The MD6a tacho runs of a sensor in the block, measures a timing gear teeth, drives a VDO gauge with the same terminals as yours.
It's a big chunky hex thing, about 1" AF, with two spade terminals.

Anyone got a old sensor lying around ?, I think mine has died.

Brian
 
[ QUOTE ]
only a digital read-out.

[/ QUOTE ]And what pray tell is the problem with a digital readout?
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
[ QUOTE ]
[ QUOTE ]
only a digital read-out.

[/ QUOTE ]And what pray tell is the problem with a digital readout?

[/ QUOTE ]OK, you're probably stirring, but here goes ...

I was replying to Clifford's question which implied that he'd prefer a dial but thought the Tiny Tach didn't offer that. I don't know what his needs are, for me a digital read-out is fine.
 
It looks like a large oil pressure switch.
About 3/4 - 1" A/F sticks out about 1 1/2" and has two terminals sticking out. The MD6A one is mounted by the gear train that drives the cam shaft, rear left hand side of block.

Brian
 
second the tinytach. I fitted one this weekend to a Yanmar 2GM20. It does indeed run off a transducer that clamps around the high pressure injector line.

it took no more than 20 minutes to fix and at just over £50 it was much cheaper and easier than buying the bits for the yanmar or fiddling with the alternator. The guy at tinytach is very helpful. It's not often that i reccomend a product but the tinytach really is superb.

No connections to them at all just a very very satisfied customer.
 
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
only a digital read-out.

[/ QUOTE ]And what pray tell is the problem with a digital readout?

[/ QUOTE ]OK, you're probably stirring, but here goes ...

I was replying to Clifford's question which implied that he'd prefer a dial but thought the Tiny Tach didn't offer that. I don't know what his needs are, for me a digital read-out is fine.

[/ QUOTE ]Moi? stirring it? never........ /forums/images/graemlins/grin.gif

TT updates the display every second so reading the display should be no problem. (older versions update every 2½ secs).

Some digital instruments do update the display too fast making them difficult to read with any accuracy well the last couple of digits anyway.

Personally I like the dual display - digital and "lcd" analogue - I find with that type of display it is easy to "read" a mean value when the reading is fluctuating - with only digital (numeric) displays this can be a real PITA.
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
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