mk1-forum.net

Hello

I would like to fit a mecanical chronometric rev counter to a mini engine. Who can help? Need an Davide where and how to fit the drive...
Thank you very much

Thomas

You need a lucas dizzy 4 cylinder with the drive already built in, then you rebuild you existing mini dizzy into that. You can find these on quite a few triumphs, ealy spitfires, 2.5PI and a couple of others iirc.

Typically they use a distributor with a different body that has a take off for it, but it's an awful lot of work and expense to go to for a Tacho.

Here is a complete kit with all that you need. you only have to drill the timing cover.
http://www.spridgetmania.com/part/C%2DS ... I-COOPER-S
They had a installation kit before but now you only get it with the tacho…
You can find other chronometric drives but i did not find the intermediate adaptor somewhere else.

Do you know if the triumph dizzy fits into the engine or do I have to change the spindle as well?

As much as i know the chronometric tacho on a mini is cam-driven… i will look if a find a picture.

I showed interest in doing this a while back... I've uploaded an image above, just because they look awesome fitted! (The second image is of course the famous UHR 850!)

Just food for thought, if you fit a mechanical tachometer with a drive mechanism going through the timing cover, you cannot use just any mechanical tach. The cam turns at 1/2 engine speed so the gauge would have to be calibrated for 2:1 (2 RPM on the face for every one rev of the cable).

There used to be a kit supplied by Minispares (C-STR1058 I think), this included a boss that you fitted to the existing timing cover and a driveshaft that fitted into that. It was coupled to the cam by replacing the cam nut with a specially milled one that was much deeper with a slot across the face. The driveshaft had a flat end that slotted into the nut and formed a sort of half Oldham coupling to allow the boss position in the cover not being exactly centered.

Here is a picture of the timing cover, nut and angle drive.

They sell electric tachs with the chronometric movement, if that's what you are looking for. As others have said, fitting a mechanically driven one would be quite a bit more difficult.

http://www.stackltd.com/chronotronic.html

Here's one from Bulee that drives off the back of the dynamo

Nice looking engine bay, could've found a more period Fairy bottle though

That's off a Sprite, they had the tacho drive on the dynamo.

Smiffy wrote:That's off a Sprite, they had the tacho drive on the dynamo.

Also seen a early MGB with this.

YVJ, My 850 is driven off the back of the Dynamo, like UHR 850. Easy to do, but only accurate if your Dynamo is driven 1 : 1 off the crank. The reproduction gearboxes from Speedy Cables are also notoriously unreliable, it took me ages & a good few quid to find a genuine Smiths one. The dynamos are pretty easy to find or at least they were when I did mine.

Chono's do look great BUT are nowhere near as cheap & reliable than a modern electronic one. You can even get electronic ones that look like a chrono.





The car in the previous pic is also sporting a very nice MK1 Perf Cons "Speedwell R/C badge"!

M

JC T ONE wrote:

Smiffy wrote:That's off a Sprite, they had the tacho drive on the dynamo.

Also seen a early MGB with this.

Early MGB's (3 main only) had a mechanically driven tach, but the drive came directly off the cam, and was connected to via a boss on the left side of the block, near the rear.

Benny wrote:

JC T ONE wrote:

Smiffy wrote:That's off a Sprite, they had the tacho drive on the dynamo.

Also seen a early MGB with this.

Early MGB's (3 main only) had a mechanically driven tach, but the drive came directly off the cam, and was connected to via a boss on the left side of the block, near the rear.

As above the drive on MGA's and early MGB's etc, is on the back of the block. But if your looking at the back, it's on the righthand side.

Smiffy wrote:

Benny wrote:

JC T ONE wrote: Early MGB's (3 main only) had a mechanically driven tach, but the drive came directly off the cam, and was connected to via a boss on the left side of the block, near the rear.

As above the drive on MGA's and early MGB's etc, is on the back of the block. But if your looking at the back, it's on the righthand side.

It's on the left when sitting in the car, which is how everything I've ever dealt with gets designated.

Benny wrote: Early MGB's (3 main only) had a mechanically driven tach, but the drive came directly off the cam, and was connected to via a boss on the left side of the block, near the rear.

As above the drive on MGA's and early MGB's etc, is on the back of the block. But if your looking at the back, it's on the righthand side.[/quote][/quote]

It's on the left when sitting in the car, which is how everything I've ever dealt with gets designated.[/quote]

More a tongue in cheek comment benny, after all isn't it the same thing. Right from the front left from the back