Help with setting Dwell..

[brokemerc]

I'm Back.. Boat has been running great until the last time out when it started running very rough. 1995 Bayliner Capri F/S 3.0 out of a 1989 Searay, Alpha 1 with Breaker Point Ignition. I pulled the plugs and they were very fouled and black,, replaced them, figured carb was rich, adjusted the carb. Figured I'd change the points while I was at it since everything else was new Plugs/Wires/Cap/Rotor/Condenser/. I set the motor to #1 tdc before pulling the old points,, had it on the high lobe of the distributor, pulled old points, installed new and set gap. Motor started and ran great on ears.. Thought I'd check timing but it states in the manual to set dwell first,,, that's where I am now. It also states that I need an actual Dwell Meter??? Can I use a regular volt meter?? If so how?? Thanks..

 

[Don S]

Re: Help with setting Dwell..

No, a voltmenter will not work, you need a dwell meter that is calibrated to show degrees of dwell. not volts. The dwell meter just verifies the point gap is correct. Then, after you set the dwell, you will have to reset the timing as well. Since angle of dwell affects degrees of timing.

 

[ziggy]

Re: Help with setting Dwell..

Can I use a regular volt meter??

sorry. nope. ya need a dwell meter. yes ya do set dwell first. as dwell effects timing. so, set dwell, then set timing.
to set the dwell. i ground the coil wire. i use a remote starter switch so i can turn the starter from the back. cap off. ya can set a guess for the gap. then i crank the engine with the points loose. adj. them to the spec. in yer service manual. after ya get yer spec. tighten them down. recheck again to be sure the points haven't moved. put the cap back on, put the coil wire back on and recheck again to make sure yer within spec... then time it...

 

[brokemerc]

Re: Help with setting Dwell..

OK.. My son (Ford Mechanic) don't hold that against him,, but he says his timing light can me used to set dewell,,, does that sound right?? I understand the theory that dwell is duration and the amount of time the points are allowed to stay open.. But according to the last post your saying guess on the gap setting,,, set the dewell and don't worry about the gap?? I think where I'm confused is the same screw is loosened to set gap and dewell,, and if I set gap-then adjust dewell-then that will change gap.. Like I said I set gap to .016 and it runs great.. But I really want everything correct,, rowing in from bluewater isn't fun.. Thanks for taking it easy on me..

 

[ziggy]

Re: Help with setting Dwell..

OK.. My son (Ford Mechanic) don't hold that against him,, but he says his timing light can me used to set dewell,,, does that sound right??

hum, i am gonna hold it against him. and i ain't a mech. a timing light sets timeing, a dwell meter sets dwell. the secondary high voltage is produced by a transformer (coil) from the on and off opening by the points which sets up a magnetic field that induces votage to the secondary windings in the coil. there is 0 connction between the primary (points) circuit and the secondary circuit that produces the voltage high engouh to jump the gap at the plug. ya need a dwell meter..... unless its a ford i guess......
and yep. ya may end up with the point gap not being where ya think it should be, but it don't matter. dwell is what matters..... it is the same screw that ya use to adj. both. it's just that the gap is almost right. dwell is right....

 

[Silvertip]

Re: Help with setting Dwell..

Don't confuse gap and dwell adjustments. They do the same thing. Gap adjustment sets the point gap mechanically (using a feeler gauge). Dwell adjustment sets the gap electronically (using a dwell meter). Set the gap using a feeler gauge and be done with it -- unless you happen to have access to a dwell meter in which case it is a little more accurate. The dwell meter can also indicate distributor wear. With the engine running the dwell should be stable. Blipping the throttle should have no effectd on dwell reading. If you do get a significant change in dwell reading, the distributor bushings are probably getting a little sloppy.

 

[brokemerc]

Re: Help with setting Dwell..

Yea what do ya expect from an 18 yr old ASE Master tech and Ford Master tech who grossed over 100 grand for 2007. But he says his timing light has a needle indicator specifically for setting dwell.. Setting points is becoming very old school so thank goodness for you guys.. I did get ahold of an actual dwell meter so one way or another I'll get to checking timing tonight.. Thanks..

 

[MikDee]

Re: Help with setting Dwell..

Don't confuse gap and dwell adjustments. They do the same thing. Gap adjustment sets the point gap mechanically (using a feeler gauge). Dwell adjustment sets the gap electronically (using a dwell meter). Set the gap using a feeler gauge and be done with it -- unless you happen to have access to a dwell meter in which case it is a little more accurate. The dwell meter can also indicate distributor wear. With the engine running the dwell should be stable. Blipping the throttle should have no effectd on dwell reading. If you do get a significant change in dwell reading, the distributor bushings are probably getting a little sloppy.

Silvertip's right on! After much experience with many early GM (automotive) external adjustable points distributors with a hex (allen) wrench, with a .016 gap setting you'll be fine! (I just check, and recheck, before buttoning it all up), in case there is play in the distributor shaft, Dwell will be close enough

 

[thunderroad]

Re: Help with setting Dwell..

Uh...my timing light also has a dwell meter built in. Very handy. Obviously the kid knew what he was talking about.

 

[Don S]

Re: Help with setting Dwell..

With EXPERIENCE, anyone can set dwell with a feeler gauge, but someone doing it the first time will usually be way off. That is why I suggested he check the dwell with a dwell meter, just to make sure the adjustment with the feeler gauge is correct. You do not set the dwell with the meter, all it does is check the degrees the rotor turns with points closed. You still have to manually open and close the points a little to adjust the dwell reading.