In the 1924 engine I am rebuilding I found a fiber timing gear that I am willing to change but what is the best?
Lang has Nylon, Aluminum and Brass gears.
What do you think about the 7.5 degree advanced gear??
How do you set the ignition timing right? The timing gauge T-3170 is it usable?? Should it be done with The timing indicator T-3171?
I have never tried brass timing gear, but find aluminum to be very good. If you advance the valve timing, you will find a bit more low end torque, but could sacrifice high end speed. Timing of spark would remain the same. You would time the spark to come right after the piston passes top dead center with the spark rod all the way up. That is the way to time it anyway, because the timing gauge only works with the original timer that came with the come or a NOS one of the same kind. If you have a modern camshaft ground for speed or torque use the standard timing gear unless otherwise instructed. All valve adjustments are ground into the camshaft. I don't like fiber gears. They could be quieter and might be OK on crank only cars, they will not last long when turning a generator.
Timing: As Norman says, "Could sacrifice high end speed".
I have never heard or read that anyone noticed the difference at high speed.
That timing gauge will not work with an advanced gear as the rotor on the camshaft is physically advanced from its stock position. Folks don't often think about that but the hole for the pin advances with the cam.
Also, if one installs an advanced gear they will have to re-bend the timing rod from what it was with the stock gear. If you don't re-bend the rod, the timer lever will not be in the normal position as you are used to it.
Don't get me wrong, I'm a huge fan of the advanced gear and run them myself. They are worth the effort to install.
Andre -- I have used lots of the nylon gears with the advanced timing, and I like them a lot. The valve timing advance improves low-end torque. You don't need "top end" to climb hills.
My choice would be an aluminum camshaft gear.
If you're putting on a new camshaft gear, you should also put on a new crankshaft gear.
A new aluminum camshaft gear is on its way, by UPS, to Belgium together with a new nut and the special tool.
Just finished to clean up the valve seats and honed the cylinders. Now I am waiting for the new parts I ordered last monday. (USPS sending)
They are in Brussels airport since thursday but there they had to pass the custom-service and that is an other story.
How would one go about drilling a standard gear for the 7-1/2 degree advance?
The bronze gears are noisy (they knock), I have 2 of them that are about to be replaced with nylon.
If the block is line bored correctly and you use DMC 's gears there is nothing better!!
I use an old gear with a piece of shafting brazed into it. I place the new gear on top of the old one over the shaft with the high points on the gear teeth aligned. Next, turn the new gear on your fixture 12 teeth clockwise. Now turn clockwise by half a tooth and clamp them together. Turn this setup over and use the holes from the old gear as a drill guide to back drill your new dowel pin holes.
Next, I mark the gear with a new timing mark. The original gear timing mark is 2 1/2 teeth from the center line of the dowel pin holes. You new mark will be two teeth away from the centerline of the new holes. I use an engraving tool to clearly mark the advanced dowel holes and the advanced timing mark.
There is a photo on the forum I posted years ago that shows this quite well. Don't try to rethink it as others have and then swore the picture was wrong. Counting 12 1/2 teeth separation had nothing to do with the timing, it was only for the purpose of finding a location for the new holes that would be the strongest. As long as your new dowel holes are only 2 teeth from the mark and not 2 1/2 you have advanced your gear.
Thanks Gary that is easier than I tried to imagine.
Look up my name on google and then click images. You will find that picture and it is self explanatory.
Oops! I had the distance wrong. Look at the following link as the photo shows it well.
If you replace with nylon gear, I would suggest using a 7 1/2 degree advanced for improved performance. I have three installed and they have really helped. Quiet too!
Thanks Tom, I have plans for the advanced gears but always good to hear positive feed back.