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MG Midget and Sprite Technical - Timing marks on crank pulley

Did I dream it or did someone on this BB mention that it was possible to buy a plastic strip that was marked up in degrees and stuck to the bottom pulley to aid cam and ignition timing? If so, where from?
Chris H (1970 Midget 1275)

Yes, I'm fairly sure it was Prop.
D O'Neill

I also thought it was Prop.
Chris H (1970 Midget 1275)

I'm sure it was Prop.
Alex G Matla

I've put one on the Frog so it's visible from above. Printed it from the PC and double sided it to little carrier -

F Pollock

Jeff at http://advanceddistributors.com/ is having another batch printed.
Trevor Jessie

Trevor,

Only problem with that, is that if you inadvertantly bang/bend the pointer, you'd have to use a dial gauge or the like to set it again.
Lawrence Slater

Yepp that was me... And treavor posted the link

Email me ....off board

Prop46 (at) gmail (dot) com

Prop
Prop

Lawrence, just make sure you fab up a good strong pointer that doesn't bend. The tape can be applied when you get TDC set with the dial gauge and then you're good to go for a long time.
B Young


Fergus,

what's the total length, from the -10 to +30 lines? I can easily generate the chart, but an overall scale would make sure I can do it accurately in CAD... otherwise i will need to measure the pulley and get my calculator out...

thanks

Mark
MarkH1

That's what you really need to do. I ran non stretchy tape around the pulley to give me the circumferance. That was divided by 360 and multiplied by 40 to show the total length for the strip. I downloaded some lines and adjusted the percentages till it printed bang on the right size. Then it was just a case of making up a little carrier and bolting it up to the timing case.

F Pollock

Hey Pollock,

Do you still have the measurements for your pulley? It might be the same as someone elses and then you're already calculated strip will fit their car. If not they could still use it and just change the proportions based on calculations from both pulleys.
Alexander Sorby Wigstrom

...or, buy a timing light with a vernier adjustment dial on it, and simply have a single TDC mark on your pulley (much easier to use after years of road grime have accumulated on the pulley)


Norm


Norm Kerr

I agree with Norm about the use of an adjustable timing light (makes timing easy and also gives accurate measure of revs) - but if you want to do it the hard way, here were my measurements:

pully diameter = 120mm
circumference = 3.142 x 120 = 377mm
1 degree = 377/360 = 1.05mm
5 degrees = 5.25mm
7 degrees = 7.35mm

and so on! -10 = -10.5 and +30 = 31.5mm

Simples!
Chris H (1970 Midget 1275)

This thread was discussed between 08/11/2011 and 20/11/2011

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