Points timing question

[73 Cat guy]

Never thought to check one against the other but, if you set the timing using a TDC gauge ( with dial indicator) and then check it with the timing marks (with a light or a "buzz box"), it should be right on the nuts right ?

[Vintagesleds.com]

[AHood]

If your setting the timing with a dial indicator you should be using a light( not like a timing light gun) or a buzz box. Only way to know the points just crack when the indicator reading is correct.      Seperate from that would be using a timing light gun with the engine running and checking marks on the flywheel or making marks on the clutch.   If done correctly they should be the same.      Dont forget some systems have advance cams which may introduce some error.  So personally the be all end all imo you should check the timing with light and engine running.

[Ski of Plenty]

With an energy transfer ignition (breaker points) a timing light is only useful to merely check the timing with the engine running. You cannot adjust the timing while the engine is running as you would on an engine with a distributor. The adjustments that you may need to make can only be done with the engine not running...and are so minute as to be indiscernible to the naked eye. Using a dial indicator and a continuity light or buzzbox is the only way to get the timing spot on to recommended specs. If you are looking for a good buzzbox, try Morris Magnetos. I purchased mine there online several years ago...reasonably priced and works great. It actually emits a loud continuous beep when the points open so your eyes can always remain on the dial indicator. I've timed numerous different snowmobile engines this way. Some will require you to hold the advance mechanism...but this is usually not terribly difficult if you are patient and careful. It's always easiest if you can do it with the engine out of the sled. I personally have never found it necessary to use a timing light afterwards...but if you're unsure of your work it's a good way to recheck it.   

[2muchfun]

Points=buzz box,dial indicator/flywheel marks
CDI=timing light  and if you have carb or motor issue,you'll never get it timed right

[73 Cat guy]

AND... you only advance the timing advance when using the dial indicator, NOT when using the timing marks RIGHT ?

[ColorMeGone]

Don't forget your edge gap.

[73 Cat guy]

Don't forget your edge gap.

Regarding edge gap, does this ever change ? what would cause it to ? I noticed the range given in spec's, that it is quite a wide range.

[2muchfun]

Don't forget your edge gap.

Regarding edge gap, does this ever change ? what would cause it to ? I noticed the range given in spec's, that it is quite a wide range.

Yes edge gap is pretty well taken care,Timing is more critical. As far as advancing the cam with the use of a dial indicator not necessarily.Some engine manufactures time there engine differently and you should go by there procedures and specification. They will tell you what to do with the cam. From what I know generally if it is less than .100 BTDC that is a retard measurement   More than a .100 BTDC would be advanced cam generally. Again get the specification and go by them.  Also set the point gap to specification mag side First then time engine mag side, then time PTO side by varying point gap.  Some engine manufactures give you both static and running specification and mark the flywheel with such,so try to get the information.  I like the static timing procedure so I don't have to hold the cam in advance position.

[FRAIDY CAT]

I like to set up the dial indicator once. I mark the flywheel with the min/max spec and am done with it. Factory marks get a bad rep around here but they work just fine for general use, Racing is a whole different ball game.

[Ski of Plenty]

I like to set up the dial indicator once. I mark the flywheel with the min/max spec and am done with it. Factory marks get a bad rep around here but they work just fine for general use, Racing is a whole different ball game.

On a JLO/Cuyuna...I prefer to sweat the details. Just sayin...

[2muchfun]

Yes general use is one thing. Racing is another,but I will still use the indicator for both cylinders.  Again gap the mag side points first then use the dial indicator to set the stater to the mag side.  Then set points to the preferred BTDC measurement for the PTO side.