Hypothetical points etc. Question

FA-18C · 01-19-2002, 12:47 PM

OK, hypothetically , what would happen if you pulled your distributor and found that your points had NO gap...what would the effect be? Would this cause your plugs to carbon foul and weak ignition at higher RPM's? And also hypothetically, can someone please walk me through setting the dwell with a meter..I have already idled the car (has sat for awhile so some smoke for a few) and reset the timing to 5 BTDC, so how then do I check the dwell on the distributor to start the points gap etc.. all over again, hypothetically.

Tyson Schmidt · 01-19-2002, 02:16 PM

If you have CD ignition, then all you really suffered from the gap closing is retarded timing. Point-triggered CD doesn't much care about dwell like conventional contact point ignition. The Cd box feeds high voltage to the coil and the Voltage Transformer (coil) has a much quicker rise-rate. All it needs, basically, is a trigger signal from the points.

So, as the block wears, and the points close, the timing is gradually retarding. That's the main drawback. You really don't lose ignition power from the points gap closing up. That is, until they close up altogether and it won't run at all.

FA-18C · 01-19-2002, 02:22 PM

Hmm, if they werent closed up entirely, it was damn close. since Im a novice, when you mean retarded timing, would that be greater than 5 deg BTDC? If the arc length for 5 deg continues in the same measure, this was something like 35-40...very odd. Put in new plugs, reset the points gap, set static dwell and then reset the timing with the timing light to 5 deg before. How do I go about checking the dwell?
Oh, and thanks by the way. I am having a blast playing with the car since its raining, ventured out only to buy a steel S front bumber, a tad bit rough but am looking forward to fixing and putting it on.

Tyson Schmidt · 01-19-2002, 02:40 PM

If your timing was fine, it's entirely possible someone set the timing with the point gap already closed up.

Also, if the gap was nearly closed up entirely, then you very well could have moments where the points weren't opening at all due to slight slop in the distributor shaft. That would certainly cause power loss.

I usually set dwell with my timing light which has an extra lead for checking dwell. I attach it right to the points wire coming out of the distributor. If you do not have the right equipment to do this, you may risk frying the CD box. I highly recommend that you simply set the points with a feeler gauge to .016". Dwell is simply not a huge deal on point-triggered CD ignitions. The gapping method is perfectly acceptable.

FA-18C · 01-19-2002, 02:45 PM

Appreciate the info, set and reset the points to the correct gap rant he motor and then checked after that fact as well. Put in a new rotor, as the old one was a bit worn, the points looked fine, but will replace when new ones arrive. Seemed to decrease some of the popping in the MFI stacks. Didnt drive due to weather. thanks again!