2/17/02 This weekend it warmed up enough to take the car out again. I had been thinking about how much work it was going to be to put the heavy duty clutch in , and decided it was time to shake the car down a bit to make other changes will the car was up on jacks again. Well, I got out on the open road and noticed that I was still off on the timing, and that the A/F voltage was still not getting up into the 0.9 volt range. I did notice how much the power application changed with changes in the timing. The fuel pressure is reliably 6 pounds plus boost, and my 20 pound gauge gets pegged as the boost soars up to 15 pounds on occasion. I now know what pinging sounds like on a flathead six, and better go to a higher octane gas. So I get off on the side of the road and adjust the initial timing on the passenger side of the engine. Note that oil is seeping from the head gasket joint. Get home and let it cool down over night. Ruminating on the immensely tedious job that it will be to replace the gasket over night, I come out in the morning and look at the plugs……all look normal, maybe the center plugs are a little richer. Some oil in the antifreeze. Decided to retorque the head. Standard torque on a Champ is 40-50 ft-pounds. I figure that with the grade 8 studs instead of headbolts I could go up some. I did find them to not be 40 ft-pounds when I started to torque down to 60 ft. pounds. Took it out for a run and continued to diddle with the timing. Definately the A/F ratio changes with the timing, and I have decided that I still need to go richer on the jets! I get close to home and figure I’ll check the dwell and see what the timing light says. One more power run and I hear a ‘pop’, then a clatter, and finally the engine stops and I coast a hundred yards to a safe place on the side of the road. Hood up I see the damage thru the steam. Behind the car is a trail of what I now know is antifreeze….. On boost, (I suppose somewhere up in the teens), the bung I had hose clamped and safety bridled on at the front of the intake manifold (where the ‘plenum trombone’ will be fit) has popped off, rocketing forward at just the right time to bend one of the furiously rotating fan blades forward until it hits the radiator core, plowing a circular furrow in the core, which in turn spews antifreeze over the front of the motor until it wets down the ignition. Bent the fan blade out of the way and drove home (not too far) as well as the wet engine would allow. Well, anyhow, the head gasket stopped leaking!…….. Guess this is fate telling me to stand back and re-engineer a bit. I’ll put her up on jacks again and go down my to-do list: new clutch, disk brakes for the front, maybe a dual master cylinder, bucket seats, 4.10 pumpkin in the rear-end, make a few changes in the distributor.
3/4/02 Well, the champagne cork incident was probably a hint that perhaps I should take the concept of timing a bit more seriously. Since the game has really changed when you turbocharge a 55 year old flathead, one would expect that the stock timing would no longer be appropriate. I have modified the distributor so that between the variations possible to the initial, mechanical and vacuum advance, I should be able to come up with a reasonable total advance curve, IF I have some way to read the timing off the harmonic balancer. With that in mind, I got an extra harmonic balancer and looked carefully at it. It had a mark for “UDC” which is top dead center. It also had a mark for the factory setting of 2 degrees BTDC
and a mark for the point at which the intake valves open on cylinders 1 and 6 (15 degrees BTDC). I figured it would be nice to have initial advance of around 15 degrees and mechanicals another 12 earlier than that, give or take a few degrees. I decided that some marks every 2 degrees would be good, clustered around those approximate areas of interest. (Those of you who know about degreeing wheels need not read on). To calculate how far apart to scribe lines at 2 degree increments, first measure the diameter of the circle to be indexed in millimeters. Multiply this times pi (3.1416) to get the circumference. If you divide by 180 you will get the distance in millimeters for each 2 degrees. My wheel is 202mm across. Multiply times pi to get 634.6mm around. Divide by 180 (to get every 2 degrees, by 360 to get every degree, 72 to get every 5 degrees……) and get 3.53mm per 2 degree increment. Now mark every 3.5 mm off in the areas of interest (so 15 degrees would be out about 7.5 times 3.5 which is 26.4mm in front of top dead center, and maybe put some marks every 2 degrees around that mark. You get the idea. I made the marks very legible by filing narrow grooves with a rat-tail file, dabbing some white-out on, letting that dry and then sand-paper off the surface to leave the white in the grooves only. We’ll see if indexing helps me now!