Dwell angle?

I have a chevy straight 6 that I am trying to tune up, my engineer mate has asked me what the dwell angle is. Would anyone know what it is.

 

31-34

http://www.chevyc60.com/the_engine_page.htm

 

does somebody know the
gap V. dwell
like .019 = 29 dwell ....
and or a .020 gap = 30 dwell...

 

It's the time you let current run through the coil windings to build up a magnetic field. Basically how long the points are closed. Expressed in degrees because is distributor is round and spins. When the points open the magnetic field collapses and the energy is sent to the spark plug the rotor is pointing too.

 

Thanks guys il chat to my mate tomorrow and hopefully get some where with him.

 

a bit difficult to set while running
you set it (gap) and then run it to read the dwell....

 

some dwell reading gauges will / can be set to read
V8 or 6 cyl there is a difference.

 

Connect your dwell meter and then pull your distributor cap and rotor. You could even pull the spark plugs for that matter. Get somebody in the car to crank it over and watch your dwell reading while you're adjusting things. Tighten the hold down screw on the points and check the dwell again to make sure things didn't move around on you and you're good to go! It's like having your own giant, portable distributor machine!

 

Set the dwell so that as the points wear it is going in the direction of proper spec. You will do a lot less frequent tune ups.

 

Right. As the rubbing block wears, dwell increases, so if the spec is 31 to 34, set it at 31.

 

and don't forget - everytime you adjust the dwell, timing will change.

 

Does that distributor have a little slide up window on the side? If so you can adjust dwell with an allen wrench while it's running while watching a dwell meter.

 

Pertronix, only way to roll.

 

that might be the V8

 

Wasn't sure if the inline six had one...my old Buick V-6 did IIRC

 

There is no absolute correlation between dwell and gap, it depends on the breaker cam.



If you marked degrees around the distributor (360 deg) the interval between firing on a 6 cylinder is 60 degrees. If the points are set new on a 235 at .019 the dwell will be 31-32 degrees, meaning the points are closed for 31 of 60 degrees.

Closing the points will increase dwell, opening will decrease points closed time.

Once the points are run a peak will form on one point which makes it hard to use a feeler gauge between the points, so the concept of dwell or duty cycle. 32 degrees of dwell on a 60 degree cycle is 53.3 pct closed. Say 7 out of 13 if you don't have a dwell meter but have an old sweep analog voltmeter.

Don't try it with your dvom or you may fry it.

 

Set new points with a feeler gauge, check old ones with a dwell meter. Both will give the same result. It is easier to set new points with a feeler gauge before starting the engine. Old points may be slightly burned and a feeler gauge will not give as accurate a reading as a dwell meter.