TOPIC:

I have an old analog Sun dwell/tachometer, probably from the 70's.
It has a range for 4/8 cyl and 6 cyl.. Am I correct to assume I can put it in the 4/8 range and multiply the reading by 4?
When adjust points doing it this way, point gap with feeler gage is slightly smaller than service manual specs of 3 - 4mm. I get about 2.7mm

I am not sure this will be of help to you, but it has been discussed  see forums.sohc4.net/index.php?topic=61607.0

I am sure others will chime in on this topic. 

Yes, you are correct in your assumption to multiply your readings.

Does this help.

 

You multiply the 8cyl dwell reading by 8 to get the Kz's dwell reading in crank degrees..

here are a couple links to the same answer with more detail..

www.kzrider.com/forum/2-engine/611996-ig...ting-question#816016

www.kzrider.com/forum/21-tools/599346-ti...meter-options#686524

ckahleer post=850186I have an old analog Sun dwell/tachometer, probably from the 70's.
It has a range for 4/8 cyl and 6 cyl.. Am I correct to assume I can put it in the 4/8 range and multiply the reading by 4?
When adjust points doing it this way, point gap with feeler gage is slightly smaller than service manual specs of 3 - 4mm. I get about 2.7mm

The short answer is, we use 23 ~ 23.5 deg. with the dwell meter on the 8 cyl. setting.  We confirmed this many years ago after researching the question on the interwebs by very carefully setting new points with a gap gauge, then checking with a dwell meter.

Unless the points are brand new, there is usually a little material transfer between the contact surfaces due to arcing.  A pit on one contact that has lost material to the other contact, creating a high spot.  Which contact loses material depends on the +/- mismatch of condenser value, which is virtually never a perfect match.  That high spot will create an error when using a physical gap gauge, resulting in a larger gap than specified.

Good Ridin'
slmjim & Z1BEBE