Jump to content

Distributer One Gear Off?


zinz

Recommended Posts

Do I have the dizzy installed one gear off?

 

Installed an older, mechanical advance Bosch 033 (off a Ti) and set everything to TDC on #1.  Checked the crank pulley mark, cam shaft mark and set the rotor to the mark on the top edge of the dizzy case. 

 

When I try to set the timing, I can't get the engine to run anywhere near the marks on the crank pulley. But I can set to the ball on the flywheel...This is with an advance-able timing light set to zero and about 2200 rpms. 

 

I've been setting to the flywheel ball and playing with the rpm levels in an effort to find a happy place that this engine likes. (freshly-rebuilt, perfectly-synched Dual Solex 40DDHTs, 292 cam, header, hi-amp alt, red coil, etc...)

 

I'd like to use the crank pulley marks but where I have it now, the pointer is strobing about 20-30 degrees retarded (that's a best guess) 

 

Should I restab the distributer one tooth in the advanced direction to get the timing marks to align with the strobe?

 

Link to comment
Share on other sites

Well if there are no clearance problems it really does not matter how you put the distributor in. A long as you rotate the distributor such that the rotor and the #1 spark plug contact in the cap are coincident at the point you want the spark to fire. If the engine is at TDC by the mark on the crank pulley then the #1 cylinder has already fired since spark occurs well before TDC (as you have found, 25° BTDC @ 2200 rpm seems to work for your engine). If it ain't broke don't fix it...

 

--Fred '69 & '74tii

Link to comment
Share on other sites

Thanks, y'all,

 

Just to be clear... The flywheel ball is 25 degrees BTDC for a standard M10, non Tii, engine?  My confusion is that I can time to the ball, but when I check against the crank pulley, is doesn't correlate.

 

This set up is running very well, I'm just fine-tuning it as best as I can without a WBO2, and not knowing how this old dizzy is really advancing.  It's in good condition and the springs are not loose (can't make the weights extend when I spin it by hand) and once tightened down, the ball doesn't dance in the strobe.

 

I was hoping to use the Crank Pulley marks (they seem to make more sense to me than the single ball) but I'll continue tweaking it.

 

Is there a maybe a trick to map the curve by using the advance on the timing light and increasing the rpms and making notes along the way? I was able to retrieve a factory curve table off FAQ for this particular Bosch, so that is helpful for reference.

 

I don't have an extra dizzy, or I'd just send to Advance Distributers and be done with it. Looks like they are still many weeks out on turnaround times.

 

Thanks again for the help.

 

Ed

Link to comment
Share on other sites

I believe the ball is at 25° BTDC on all M10 flywheels. The difference is the RPM it is measured at, my tii liked to be at about 2400 RPM, but one time on a dyno it made better power at 2750 RPM at the ball.

 

I am unclear to what your confusion is. If you set the engine (not running) such that you can see the ball 1/2 cut off in the slot, the TDC mark on the crank pulley should not be at TDC, but 25° before TDC. The flywheel only goes on one way and the crank pulley only goes on one way and the ball is fixed so there should be no issue. Clear as mud? --Fred

Link to comment
Share on other sites

All I know is, the M10 runs (or doesn't very well) with the distributor "off" or out of synch.  Typical engine responses are backfiring thru the carb/intake manifold and hesitation to start.  Happened to me when I tried another distributor in my tii (and again when I re-installed the old one).

 

My first car (crappy 66 VW) had a stock dizzy with vacuum advance.  I got it to run and then it slowly lost power while driving around the neighborhood (I was  16).  I hadn't tightened the securing clamp so it slowly rotated (and retarded the timing).

 

Another lesson learned (and will be forgotten).

Link to comment
Share on other sites

I suggest you use the front pulley rather than the flywheel - its easier to see. I used a Tupperware lid about the same diameter as the front pulley. Figure out some way to mark several useful reference points - I did 25 and 33 deg using a degree wheel form my small block Ford days. Use the lid to transpose the marks onto the pulley, along with TDC. IE's advice is to forget the ball, and rather set timing so that maximum advance of 33 +/- is in by about 3200rpm. I'm using a bit more with twin Weber 40's without pinging. According to Haynes, stock Ti was 35-39 at 2700, but I suspect that was on late 60s fuel.


 

 

Link to comment
Share on other sites

rather than doing all that marking on the crank, just buy and use a timing light with adjustable advance and built in tach and then time off the tdc mark.  ez......WAY better than trying to use a fixed timing light.  they are not that expensive and you will wonder why you ever used the old style "dumb" lights.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Upcoming Events

×
×
  • Create New...