Anyone out had any experiance with making a degree wheel that can be applied to the crankshaft pulley. I would like to play around with setting the valve opening by using the crankshaft position as a reference rather than setting the valve clearance with to a specified clearance.
No experience, but found this to be an interesting read:
Question: do you actually have a spec sheet which tells you what valve event should occur at a particular degree position? I suspect that you do not.
If you have a new cam, you will not do better than to follow the cam manufacturer's advice of .010 - .015 depending on manufacturer/cam.
If you have an old original worn out cam, you can Google for "setting valves to piston position" which will give consistent valve events, but will end up with some large valve/tappet clearances on several valves, which will make the engine more noisy and lose some valve lift. My experience with this is the car will run smoother, but will be noisy and will have little to no gain in power, which I think makes perfect sense considering what the procedure is trying to accomplish. A good explanation of setting valve lash is given by Glen Chaffin here: http://www.mtfca.com/discus/messages/29/10101.html?1202339869
If you are truly intending on following your path with a degree wheel, be sure to post how it all turns out. I suspect that it will be a lot of work for minimal results.
To your reply, I am not attempting to compensate for a worn camshaft,valves, cam followers, or gears. My engine is a recent rebuild, within 1500 miles or there abouts. The cam grind I requested was stock for a model T.
My thinking is,if by using the piston position reference for initial valve opening and closing and as a result the clearance varies by .003 or .004" how can this hurt.
The model T engine at 20 hp needs all the help it can get, as it is the piston along with the valve opening that creates the vacuum which fills the combustion chamber, having all the components working together should help I would think.
Well, if you start with adjusting your lifters to match piston travel, the only guide I know of is the KRW or Ford method (for worn camshafts) which gives specific piston positions for a given event (open or close).
You will be off in the weeds if you try this with a reground cam, I'll bet. The reason I say this is that most regrinds that I am aware of have some modern "swag" in them regarding advance, etc, in an attempt to get some "oomph" out of the T.
Be really sure that you have a purely stock regrind...check with your supplier.
Even at that, I see no need for a degree wheel given that I know of no source for info on degrees vs events for a T...only piston travel vs events...
to each his own, but if you have a fresh rebuild, new cam, and only 1500 miles, I still recommend that you keep the manufacturer's recommended valve/tappet clearance for a quiet, well performing car
I check cams using a degree wheel, but i never set valves by piston position. This is a procedure as old as the model T. The theory was that if you use this procedure you compensate for cam wear. while that is true the improvement in performance is so slight that it is not worth the noisy engine. A worn camshsft will perform just fine with all of the valve clearance set to the same clearance. You will never feel the difference. A new or reground cam will give you improved performance because they have an improved grind to provide low end torque and horsepower and an improved high end. Be sure to ask for the cam specs so you can check them against an original cam.
That took alot of time but It's done. I fashioned a degree wheel today and installed it onto the crankshaft pulley.The specs i used for a stock camshaft were IVO@15aTDC IVC@63aBDC
EVO@38bBDC EVC@15aTDC with valve clearance at .020"
Number one cylinder was right on, after setting the valves to open and close as per the crankshaft position, the valve clearance was
.020" exh and .017" int.
Checking the ex valve opening is really time consuming and there is no way of adjusting, all you are doing is verifying the cam lobe design, so for the other 3 cylinders I just adjusted for IVO and EVC both at 15aTDC.
The rest of the cylinders turned out like number one with no more than .004" variation in valve clearance with .020" the maximum
Not sure what I proved if anything but I'll know better once I get the head on and test run
Why not use an adjustable cam gear?
Interesting thread! I use a fifteen year old clip on dizzy----without the tools it seems to me the firing of the plugs in the proper position can be checked using this method.
My understanding of adjustable cam gears is it gives you the option to change the timing of the camshaft in relation to the crankshaft.
However in order to change the timing of valve opening and valve closing within the same lobe, you would have to have the cam reground ?