3 replies to this topic

[birdy b4]

Been lent a dwell meter as apparently this is far more accurate that using feeler gauges ? i assume there is a value that the dwell must be set to ? what is this and do i adjust it the same way as the points gap ?

[pierres]

Depends on what disributor you have you will find figure in degrees in the hayne manual and yes adjust points as you would if using a feeler gauge

[sledgehammer]

Start with 15 thou gap ( 0.35 to 0.40 mm )

reduce gap to raise dwell angle

Lucas 23d4 and 25d4..................................60 degrees +/- 3
lucas 45d4:non-sliding contacts...................51 +/- 5
..........................sliding contacts...................57 +/- 5

Ducellier.......................................................57 +/- 2

hope this helps

Edited by sledgehammer, 16 November 2011 - 05:11 PM.

[dklawson]

I also wouldn't consider going by dwell to be any more accurate than setting the points gap... at least not on Lucas distributors. To set the dwell you have to use the feeler gauges to set the points, then start the engine and measure the dwell. If the dwell reading is wrong, you use the feeler gauges again to set the gap (wider gap = lower dwell, narrower gap = more dwell). Then check again with the dwell meter. It is just a way to check what you've set with the feeler gauges.

Now on old American engines like GM V8s from the 1970s... setting the dwell is MUCH easier than using feeler gauges. The Delco distributors had a little window on the distributor cap. You would connect your dwell meter, start the engine and use a small hex key through the distributor window to adjust the dwell with the engine running. It made the whole process SO easy. Sometimes I wish Lucas distributors were like that.