Replacing Coil Changes Dwell, Timing?
Thread Starter
Le Mans Master
Joined: Jul 2003
Posts: 6,808
Likes: 24
From: Westport CT
Replacing Coil Changes Dwell, Timing?
Since I am ever curious and want to learn more about how these things tick, I have to ask - why, upon installing a new, actually old Delco Remy '202 "restoration" coil (no big loss of originality it seems since the one I took out was a "Guaranteed" brand coil from Seneca NY - nothing but the best for Bubba it seems) did my dwell and timing go out the window? Aren't both of these specs a function of mechanical actions (gap between points, and the timing of such opening and closing relative to the piston stroke). Ater installation I noticed the car acted like the timing was all off, and like a good boy I checked the dwell first (waaay out of whack) and then the timing (also wwway out of whack). At the risk of sounding like my nearly three-year old, why?
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,270
Re: Replacing Coil Changes Dwell, Timing? (ctjackster)
Dwell and timing have nothing to do with the installed coil, but change with use. Rubbing block and contact face wear change the dwell and changes in dwell affect timing. Chances are your dwell and timing changes are just due to wear from the last time you set them, which I assume was sometime before you changed the coil.
As you did, the dwell should always be checked and set to spec first, then check and set the timing as necessary. A larger dwell angle means less point gap and the points open a bit later, which retards the timing slightly.
Normal dwell angle is 30 degrees. For racing I would set it at 35. Slightly higher dwell means the points open a little less, which will give you more point bounce rev margin, and it also means the points are closed longer, so coil saturation is better a high revs, which yields a bit more spark energy. The downside of higher dwell angle is that the points can burn more easily and will have shorter life.
Duke
As you did, the dwell should always be checked and set to spec first, then check and set the timing as necessary. A larger dwell angle means less point gap and the points open a bit later, which retards the timing slightly.
Normal dwell angle is 30 degrees. For racing I would set it at 35. Slightly higher dwell means the points open a little less, which will give you more point bounce rev margin, and it also means the points are closed longer, so coil saturation is better a high revs, which yields a bit more spark energy. The downside of higher dwell angle is that the points can burn more easily and will have shorter life.
Duke
Race Director
Joined: Nov 2000
Posts: 10,340
Likes: 664
From: Beverly Hills (Pine Ridge) Florida
Re: Replacing Coil Changes Dwell, Timing? (SWCDuke)
:iagree: Have to agree completely with Duke, but always open to learning something new. Try the old replaced coil again, and see if the dwell/timing stay or "go". Bet it will stay, but?
Plasticman
Plasticman
