Setting the Timing on the 1969
Maddening, I tell you, is setting the timing on an old Tecumseh. Nothing ever seems to go right the first time. Remarkably, the points were in pretty good shape so I kept them. I disassembled the entire assembly and degreased and cleaned it with Brake Cleaner. I had two timing cams: 1) the original and 2) one sent with the new crank. I matched them and they were the same, so I used the one from the new crank....somebody had forced the OG cam on backwards and the key was damaged. Put the baffle on first....
[MENTION=53799]control4userguy[/MENTION] and I went back and forth one day a while back comparing notes on getting the timing set on an older, more senior (read worn) H-series engine. We both concluded that there were no tricks making life any easier.
The manual simply says both valves closed at TDC...I make it point to be at TDC on the compression stroke, though it shouldn't make any difference--the cam and points are in the same relative position when at TDC and both valves are closed.
Points get set at 0.020" and a snug fit.
Hint: the points will move when you tighten the retaining screw. I used a feeler gauge setting of 0.018," after tightening I checked at 0.020" and it was dead-on and snug.
Since I don't have the Tecumseh dial indicator, I do the set up with the head off. I also locate the indicator as close to the center of the piston as my jerry-rigged base will allow. The points are set 0.080" before TDC. Getting there is a task. Be sure to take the play out of the crank, first and locate TDC. Then rotate the engine
clockwise to 0.080". You need to be as close to this reading as you can get (it'll move if you breath on it).
What ends up happening is the crank cam nose is now in the "11:15" position. Then it's a matter of rotating the magneto housing until the meter shows no resistance or tones, if you have that feature.
As usual, I could not get the meter to tone when twisting the magneto assembly. I took everything apart, cleaned everything again (including the crank cam) and reassembled. Set the points again, reset BTDC and tried again. NADA.
After fiddling for a while, I decided to see at what point BTDC I did get a tone. The meter toned at 0.086" with the magneto fully clocked clockwise. I became convinced that I didn't have the dial indicator set right, so back to TDC, back it off counterclockwise, gradually move the piston to TDC and beyond, bring it back to zero and I might have been a degree or two off. Back to 0.080" and no tone. Magneto still clocked all the way, and I checked for tone and at 0.084" it toned. But no wiggle room.
I removed the magneto again and I looked at the mounting flanges closely. It appears the magneto had been at full clock (clockwise) from birth. Looking at the flange still more closely, there was a good 1/16" of casting flash inside, so I took my dremel and a sanding drum and removed the flash. Reassembled, tried it again and got to 0.082". Took the magneto off, worked on the flanges again and cleaned it one more time. Mounted and she toned at 0.080." I suspect she would have ran at 0.082" +/- but I wanted to be dead on.
I also checked valve lash today, and it measured at 0.005 at TDC, valves closed on the compression stroke.
. The engine is a torque monster as it is, so why risk blowing a hole in the case?
