TheSamba.com :: View topic - 74 Super

Fri Oct 24, 2008 1:54 pm

My pulley only has one notch in it. I know that the timing should be set at 7.5 BTDC but where is that? Also, the throttle valve positioner should be hooked up to something, but what? Please educate me, had this for a day and it is pretty fun so far.

THANKS

Fri Oct 24, 2008 1:57 pm

Take a look here: Timing Marks on Stock Pulley

Fri Oct 24, 2008 2:28 pm

I read that whole string and I am more confused than ever. There was no difinitive explanation about the single "v" notch pulleys. I hope I can assume that it is NOT a TDC mark, so I'm left guessing if it's 7.5 BTDC or 5 ATDC. The car runs pretty good now, but backfires ocassionally so I figured I'd follow the tune up steps in my Haynes manual. Everything so far has been simple to figure out. I'm sure this is easily answered as well.

Fri Oct 24, 2008 2:37 pm

not sure if this helps.. but it gives a measurement..

# Setting the 009 Centrifugal Advance, Single-Vacuum Dual Advance (SVDA) and Vacuum-Only Distributors with a Strobe -

Note: The approximate idle timing setting for the centrifugal advance distributor (009), the single-vacuum distributor, and the vacuum-advance only distributor, is 7.5o Before Top Dead Center (BTDC). This means that as you view the 7.5o mark at the crankcase split (with the strobe), the TDC mark on the pulley will be about 11.5mm to the LEFT of the crankcase split when the distributor is properly timed. Again, this is the APPROXIMATE timing setting at idle.

or this:

# Make Your Timing Marks -

* The distances around the pulley (arc distances) for the various timing marks are calculated using the following formula -

arc distance = 2(pi)(r)(alpha)/360

where -

pi = 3.1416
r = the radius of the pulley (in mm)
alpha = degrees of the appropriate arc
(e.g., the appropriate timing advance).

The arc distances that follow are based on a pulley diameter of 175mm, thus a radius of 87.5mm. Be sure to measure the diameter of your pulley and use the radius of your pulley in the following calculations.

Fri Oct 24, 2008 3:00 pm

VladeSpado wrote: I read that whole string and I am more confused than ever. There was no difinitive explanation about the single "v" notch pulleys. I hope I can assume that it is NOT a TDC mark, so I'm left guessing if it's 7.5 BTDC or 5 ATDC. The car runs pretty good now, but backfires ocassionally so I figured I'd follow the tune up steps in my Haynes manual. Everything so far has been simple to figure out. I'm sure this is easily answered as well.

Read it again.... Glenn, Randy and I went over it repeatedly to make it clear with pics and all.

By the looks of the pic you posted in this thread ( * it's best if you keep it to one thread and you really should have continued in the other you started... but since this one is rolling we will just continue here)
Your pulley has the TDC dimple and the notch is to the right which is 7.5 BTDC... odd mismatch ( common on these old cars) as you have a DVDA which if you wanted to hook it up correct would need to be timed at 5 ATDC.

Did you correct the way the vac hose was hooked up wrong as per the tips in your original thread? Have you sucked on the advanve side of the cannister to check and see if the vacuum can is even good?

I would not worry about that throttle positioner... you can take that plastic POS off and toss it. If you go trying to figure that in the mix it's just going to cause you more issues.

Fri Oct 24, 2008 3:22 pm

Sorry about the new thread....but yes I did connect the vacuum hoses correctly this morning. Took 10 seconds. Started right up and ran great. I removed the throttle positioner this morning also, car wouldn't start so I put it back on, started up and ran great again. I have the other distributor line connected to the spot right in the middle of the carb, just under the throttle positioner rod now. Don't know why I did that, but hasn't affected the performance a bit. Before that was plugged from the carb. I will take out the #1 plug and measure were the cylinder tops out to measure the correct TDC, I did figure that out finally (many, many, beers downed in this lifetime). I really just want to adjust the valves and timing before I do anything else, as the car does still backfire ocasionally. The dwell was 53 this morning after gapping a new point at .016. One more thing, my picture must be deceiving because there is no dimple. Thanks again.

Fri Oct 24, 2008 4:46 pm

VladeSpado wrote: Sorry about the new thread....but yes I did connect the vacuum hoses correctly this morning. Took 10 seconds. Started right up and ran great. I removed the throttle positioner this morning also, car wouldn't start so I put it back on, started up and ran great again. I have the other distributor line connected to the spot right in the middle of the carb, just under the throttle positioner rod now. Don't know why I did that, but hasn't affected the performance a bit. Before that was plugged from the carb. I will take out the #1 plug and measure were the cylinder tops out to measure the correct TDC, I did figure that out finally (many, many, beers downed in this lifetime). I really just want to adjust the valves and timing before I do anything else, as the car does still backfire ocasionally. The dwell was 53 this morning after gapping a new point at .016. One more thing, my picture must be deceiving because there is no dimple. Thanks again.

My eyes are old and it's not a great pic but I swear I see the oval shaped outline of the dimple... if you were to grind off the ten layers or so of shitty silver paint it might be there.. but I could be wrong :P :lol: :wink:

Fri Oct 24, 2008 5:27 pm

and when you do clean off that old paint.....

Make a mark like this "l" for TDC and a mark like this"ll" for bottom dead center using some model airplane white paint to assist you in adjusting the valves. I like to make an additional mark at 30º BTDC for timing purposes.