E: Engine Mounting a Degree Wheel/Timing Disc

[gmax137]

I have read in KTB and elsewhere to mount in place of the big end quill, using a 7 inch rod that tapers from 1/4 inch to 5/16 inch at the wheel end. Is the idea to push the mounting rod in far enough to get a friction fit? I have been trying this on my C Comet engine, but the hole in the crankshaft won't accommodate anything larger than 1/4 inch. Using my drill set as gauge rods, the 1/4 will slip into the hole but the 17/64 won't go in at all.

Maybe my quill hole end is buggered up?

Thanks for any advice
Gregg

 

[Vincent Brake]

If you search forum. Theres a lot to find

 

[timetraveller]

Why not use a rod that goes from, say, 20 thou under quarter inch to one that goes up to, say. 20 thou over quarter inch. You can check exactly what sizes you will need with the drills as gauges. Then when you are outside the timing cover just let the rod increase in size to, say, 8 mm and use M8 nuts and washers. If you do not have a lathe, or a chum with a lathe, then just get a bit of 8 mm bar, put it in drill cuck and spin it and then use a sander to reduce the diameter of the rod to a long slow cone. It is not an accurate job that is needed. What I did many years ago was to get a bit of quarter inch copper rod, hacksaw one end with two cuts at right angles and then with a screwdriver open out and then bend in the cut end to make a barrel shape and then tap the outer end quarter BSF or Whitworth or even M6. I use a rubber mallet to tap it into the main shaft and have been using the same copper rod for over sixty years

 

[Normski]

I have read in KTB and elsewhere to mount in place of the big end quill, using a 7 inch rod that tapers from 1/4 inch to 5/16 inch at the wheel end. Is the idea to push the mounting rod in far enough to get a friction fit? I have been trying this on my C Comet engine, but the hole in the crankshaft won't accommodate anything larger than 1/4 inch. Using my drill set as gauge rods, the 1/4 will slip into the hole but the 17/64 won't go in at all.

Maybe my quill hole end is buggered up?

Thanks for any advice
Gregg

You need a 1/4” or 6mm rod which tapers down where it inserts into the crank. I don’t know where you got the 5/16” measurement from but that is too large for the crank end although it’s good for mounting the disc.

 

[b'knighted]

I found that a standard pushrod would fit the mainshaft but fitting the disc was more of a problem.
I screwed the disc to a block of hard rubber which was a tight fit on the pushrod.

 

[gmax137]

You need a 1/4” or 6mm rod which tapers down where it inserts into the crank. I don’t know where you got the 5/16” measurement from but that is too large for the crank end although it’s good for mounting the disc.

The 5/16 is from Know Thy Beast (3rd Ed, Chap 19, page 188). You're right, the 5/16 is too large, which is what made me wonder if I was interpreting this incorrectly.

Now that I am sure the idea is to make a tapered shaft that fits deeply & snugly in the bore, I can make one to suit.

Thank you all for your help!

Gregg

 

[Robert Watson]

What you need is a piece of 1/4 tubing, I use stainless steel and a spoke. and make something like this. Just sort of straighten the head of the spoke and grind a bit of a taper to spread the slit tube. Pull it tight with the nipple, to loosen it off, unscrew the nipple and give it a tap.

 

[stu spalding]

Get a piece of 1/4" rod and 'ititwivanammer so it's a tight fit in the mainshaft. Cheers, Stu.

 

[Bill Cannon]

About 30 years ago I used a suitable sized rawlplug and a long thin wood screw with some suitable washers and grommets to mount the disc as a temporary measure.

Guess what, It's still the same!

 

[bmetcalf]

Get a piece of 1/4" rod and 'ititwivanammer so it's a tight fit in the mainshaft. Cheers, Stu.

A steel rod would require a light touch. Mine is a brass curtain rod that I salvaged.