Timing disk

Have been coveting a proper timing wheel ever since watching Mick Hemming's engine rebuild video a couple of years ago.

I cant find anything that comes close to his disk.

Found a metal one from Pro-wheel.



Had a buddy make up a 5/8 20tpi bolt and used a spare crank/rotor nut to secure it using a spacer that I had lying around.





Worked out ok.

Hardest part was finding the 5/8 20tpi tap and die.

FF
Finding how to hook up to the disc to crankshaft is Job 1. great you got it.
Now for job 2 is to figure out what to do with it.
I figure you will guess... same as me... that the disc you have is for a CW engine. Norton is CCW from the drive end.
Not to matter :mrgreen: so does mine. LOL
That's where the sharpy marker come in..... to "edit" as required.
I did mine 0-360 and a second ring of numbers 360-720. Now I'm good.
Nice tool... I use it when I'm not sure of something. Mainly Norton, BSA or Lotus.

7/16" - 3/8 small socket is a nice, snug interference fit into the end of the crankshaft... that's how I have mine mounted anyway

I've been wanting to check my timing marks also.
Why is the bolt so long? and how long is it?
I found the die https://drillsandcutters.com/5-8-20-car ... l-hex-die/ and can make a bolt. Will I need 2 of those nuts also?
Thanks!

Good looking wheel, mine is plastic and does not look as good.

If you want to have Norton specific info on it you can use this site below and print out a new set of markings for the blank side.

http://www.blocklayer.com/degree-wheeleng.aspx

and customise your own degree wheel, set your cam timing etc so it displays on the wheel and then select the size you want.

Mr Rick,

The nut is just the rotor nut, item marked 36 on the below diagram

https://andover-norton.co.uk/en/shop-dr ... alternator

My buddy used a lathe to make the threads. Length of the bolt is about 3 inches.

cheers,

Joe

I have this timing disc



I planned on buying an adjustable sprocket for my camshaft and micro adjusting the cam timing, but at the time when I was all motivated to do this, I recall numerous people saying that the adjustable sprocket was not a good product. The solution that was offered instead was filing a custom offset sprocket key which was more difficult to do, but a better solution so I never undertook the whole process or mounted the timing disc.

SO,... What method are you timing disc people using to adjust valve timing?? adjustable sprocket? custom made offset sprocket key??

TIA...

o0norton0o said:

I have this timing disc

I planned on buying an adjustable sprocket for my camshaft and micro adjusting the cam timing, but at the time when I was all motivated to do this, I recall numerous people saying that the adjustable sprocket was not a good product. The solution that was offered instead was filing a custom offset sprocket key which was more difficult to do, but a better solution so I never undertook the whole process or mounted the timing disc.

SO,... What method are you timing disc people using to adjust valve timing?? adjustable sprocket? custom made offset sprocket key??

TIA...

Click to expand...

I have 2 Norton Norvil vernier cam sprockets, a single chain and a twin chain.
I figured to use them for doing dyno runs or getting measurements and set up data.
Long term, I would make and use offset keys.
I have a Domiracer timing wheel like yours, and a few others.

Offset key for me as well in my 850 race motor, JS2 cam
Regards Mike

With the blocklayer.com website, I was able to print out a paper degree wheel on regular paper (set the diameter to 7 3/4 inches so it doesn't run off the page).
With my pal Dave supplying a pc of 1/8" or 3mm polystyrene (which snaps off most conveniently when scored), I just used some clear spray lacquer to glue the paper down (you have to scratch up the plastic a bit so tthe lacquer bites).
When the 5/8-20 die and the die holder arrive, I can thread the end of my 5/8 aluminum rod (tapped on the other end to permit grabbing the wheel) into the crank nut. I think.

Knocked hell out of an old spark pug, jammed an oversize 1/4-20 nut into the top section and now I have an adjustable piston stop.
So the question is: APPROX how far should the bolt stick out the bottom of the plug to get a meaningful read on the degree wheel? With the bolt I have now (carefully chamfered at the tip to avoid scoring the piston top), I can reach past the bottom by about 1.375" or 35mm. Is that too much? Not far enough?
And do we really have to remove the stop as we spin back and forth, to avoid the valves? If I grind the bolt threads off, would they miss the valves, maybe?

I see your enthusiasm...
Like me 25 years ago... :mrgreen:
about 3/4" beyond the plug will hit the piston @ TDC
May depend on cam #'s to clear your piston stop. Stock 1S may/probably clear.
Safer to stay on compression stroke and leave the valves on the seat. :mrgreen:
Once you have TDC and wheel calibrated , retract piston stop. :!: and continue work.

Thank you, Dave.
I recall someone saying that at least 30 or 40 degrees either side of TDC was a good place to calibrate, seeing as how the piston isn't moving much in this area.
According to motorson on page 3 of his "linear piston travel" thread, 30 degrees BTDC represents 0.340 inches.
Adding your number to his, gives just over an inch. Sound right?

Also, watching the calibration videos, I see guys going backwards to reach the second data point. Which of course you must do if the piston stop is left in the plug hole.
Are you recommending pulling the stop after getting the first reading, going "over the top" and re-installing the stop, to stay on the comp stroke?

Here's where my ignorance really shines through: does it matter which cylinder is used? Do I have to do this on both sides?
All I really wanna do is verify (or refute) the factory marks.
And Is it true that the reference changes every time the primary cover is re-fitted? If true, maybe I'm just "spinning my (degree) wheels"? :roll:
So many questions, so little time! I appreciate your help and expertise.
Thanks again--
Rick

RIck
For me the stop is only for finding TDC. Whether 10º or 25º is used doesn't matter. Then it is all on the degree wheel.

I don't usually go around and around with the crank but....All measurements are made only after turning the crank in the forward direction to take all the igniton components and cam gear and chain slop out.
Only as a matter of standardization I always use the timing side as #1. You could check both pistons for super accuracy and then all cam events on both cylinders. Unless you are building a super duper racer to be followed by several full blown dyno developement sessions, you can tend to get carried away. It is however confidence building to properly set up the primary timing mark and checking the alternator rotor's mark.

Thank you, Dave!
I do appreciate the need to take the cam chain slop out, and see the need for reading after a forward CCW rotation to accomplish this, but I'm not particularly religious.
Seems to me that one wd have to rotate the crank in a clockwise direction at some point, just to reach the piston stop on the "back side", ATDC.
Are you suggesting we go CW to reach the piston stop ATDC, then go CCW to take the slop out and get a reading, while praying that the piston doesn't move off the stop during that final step?

calibration/synchronization of degree wheel:
For me the stop is only for finding TDC. Whether 10º or 25º is used doesn't matter.
CW make mark/reading at stop...CCW make mark/reading at stop
divide by two set wheel to this mid point number represents TDC. do not move crank
now loosen wheel and set to zero... lock to crank
calibration complete



Then it is all on the degree wheel. for MEASUREMENTS

I don't usually go around and around with the crank but....All measurements are made only after turning the crank in the forward(ccw)direction to take all the igniton components and cam gear and chain slop out.
Only as a matter of standardization I always use the timing side as #1. You could check both pistons for super accuracy and then all cam events on both cylinders.

Well I wrapped up this job today, have a few observations to offer.

If you plan to put a 5/8-20 die on a pc of 5/8" round stock and thread it to mount your wheel on the rotor nut: Make sure your rotor nut 060387 is threaded all the way out. Mine was not, had to be removed and replaced with a fully threaded version. Grind or file a couple of flats on the round stock so you can turn it firmly up inside the rotor nut.
If you do have to remove/replace the rotor nut: Get the rear wheel off the deck (ctr stand is fine) so you can bump up into 4th gear. Forget about standing on the brake while you try to get the nut off (and on again). Just run up the rear brake adjusting nut all the way, and leave it there until you're done. But don't forget to back it off either!

If your rotor nut will not come off even when you are reading 150 lbs on a torque wrench: Borrow or buy a used impact gun, electric if no compressor or if compressor won't push at least 120 psi. No drama with the gun, no extension bars or hammers on the wrench. And don't feel you have to spend $90 for a set of Whitworth impact sockets; a regular Koken 1/2 WW did the job fine.

Poke the shaft of the disk through a 1/2 WW box wrench as you mount it so you can easily turn the crank without touching the wheel. Pull both plugs to lose compression, but all this work can be done from the left side.

A piston stop with a 1/4" bolt threaded down the middle WILL touch a valve; better to pull it out between readings.
Running the piston stop down very close to one inch below the bottom of the plug will put you close to 30 degrees off TDC.

Use a stiff wire as a pointer, hold it to the chaincase mounting stud with a spacer and washer and the chaincase attachment nut 060367 (3/4 socket).

Here's an important tip!! If you are doing this for a Commando, don't leave the crank at TDC as you mount the outer cover. There is no reference for TDC on the scale, it goes from 20 to 40, so after you are confident you have the wheel "calibrated", use the pointer (which you've been careful not to disturb yet) and turn the crank to 30 BTDC. Now you can remove the pointer, and holding the crank still with the big wrench, remove the disk, remount the outer cover and see if you are reading 30 on the rotor's mark.

All this fun to find out my factory mark is within 1/2 degree of right on! And the payoff is confidence, no more wondering if I'm really reading 28 or 31 or whatever I need. Priceless!
If you wanna borrow the wheel and piston stop I made (or the 5/8-20 die I bought) and have a go at it yourself, send me a PM.