Points and Timing Setup Advice?

[andyzeetec]

Couple of things really..

What are the points gap on a zelmot distributer, Haynes states (0.37 to 0.43) for both the zelmot and marelli?
Fiat manual states they are different zelmot((0.47 to 0.55)  and marelli (0.37 to 0.43), I set them to the fiat manual at 0.47mm to 0.53mm for the zelmot, but they were set at Haynes values.

Stupid question  .. when using the static timing method (Pete’s method below), lining up 10deg BTC, I am guessing you use the spikes, not the troughs to align, not that clear on pic in manual.
Anyway used the 1st spike (10deg BTC) and had to rotate the distributor about 5mm, does that seem right as it has previously been running but difficult to start ,  haven’t tried to start yet as still doing other work and getting various bits set as they should. What I wasn’t sure on..  there is a fair difference when adjusting/rotating if you finish on the light coming on or going off. Is it best to move the distributor clockwise or anticlockwise before locking it up?

“Set the front pulley to 10 deg BTDC with the distributor loose the points should be just opening, to help setup if you have a 12 volt tester (screw driver with a bulb in the handle) connect the wire to earth and the point to the wire that comes out of the distributor that goes to the coil, with the ignition on , move the distributor so the light is just flashing on and off, As i mentioned my preferred way is to set the timing up statically.”

Thanks

[Pete126]

Hi Andy You are correct set it on the pointer and not the indent, Because the cam rotates clockwise I rotate the dizzy clockwise until the light goes out, then anti-clockwise till the light just comes on then lock the dizzy, Remember to adjust the points first before setting the timing

[Bambino126]

I have another question on the same subject...
I have a BIS with the Zelmot distributor and I've just fitted a brand new points contact breaker.
I set up the gap to 0.51mm (the middle of the allowable range), and checked the dwell.
It read 33 degrees in 4 cyl mode which equates to 66 degrees for a 2 cylinder.
I went back and closed up the points gap a little at a time to increase the dwell until I got the recommended dwell of 78 degrees.
By this stage my points gap was down to just over 0.3 mm!
Why is this? And is it more important to have the dwell right or the gap right?

[andyzeetec]

Hi Andy You are correct set it on the pointer and not the indent, Because the cam rotates clockwise I rotate the dizzy clockwise until the light comes on, then anti-clockwise till the light just goes out then lock the dizzy, Remember to adjust the points first before setting the timing

thanks Pete

[Pete126]

I have another question on the same subject...
I have a BIS with the Zelmot distributor and I've just fitted a brand new points contact breaker.
I set up the gap to 0.51mm (the middle of the allowable range), and checked the dwell.
It read 33 degrees in 4 cyl mode which equates to 66 degrees for a 2 cylinder.
I went back and closed up the points gap a little at a time to increase the dwell until I got the recommended dwell of 78 degrees.
By this stage my points gap was down to just over 0.3 mm!
Why is this? And is it more important to have the dwell right or the gap right?

Hi Bambino126

I think your reading too much into the dwell angle, I just set the points to 20 thou and reset the static timing to 10 btdc That's about as good as you are going to get on a bis, your not going to get another 10bhp by spending time trying to set the points up using a dwell meter, especially if its not calibrated for a 2 cyl engine

You have to remember that these engines are old school, If you would have asked mechanics in the 50's & 60's about dwell meters they would have looked at you daft

[Gadge]

They would have used an old bulb and a wire 

[Bambino126]

Ok. Ta.