Topic: Setting points with an ohm meter

[TwoTired]

If you pay attention to small details you may notice that when using a 12v light to set your static timing that if you are in a dark room(or you turn the lights down) that as the timing mark comes up towards alignment that the 12v light may be glowing a faint orange and then if you keep turning the engine a few more degrees that the 12v light will get to full brightness.

If you pay attention to the small details, and have any understanding of electricity and/or physics you would know that, that a bulb cannot glow at all unless there is current flowing through it.  As the bulb is connected directly to the point terminals, properly closed points should physically shunt (bypass) any current away from a bulb filament.

If the points are defective and only limit current flow, THEN the bulb may faintly glow while they appear to be closed.  But, that would be an indication that the point contacts are dirty or need cleaning/reconditioning.   Unless the meter is capable of of such sensitive measurements, and the test instrument operator is skilled enough to notice these small resistance discrepancies, the meter method will not catch this deficiency, because the voltage it uses to perform the test is much lower than what the points normally experience.  So, the meter method the Honda shop reportedly preferred, was likely employed to avoid doing the proper work of tuning up/reconditioning used points, or cleaning point contacts that still had their preservative grease applied for shelf storage.

One CAN use the bulb method as poorly as using the meter method, if one understands that the bulb will be at full intensity only when all the current passes though it, and the points are truly open, rather than resting on some resistive material, which would make it glow dimly.

I will add, that if points contacts ARE dirty, it increases operating temperature, makes them wear faster (altering their set timing), and shortens their useful lives overall.   All to the benefit of recurring maintenance.  What Honda shop wouldn't enjoy more frequent recurring customers?

[bollingball]

Round 3 Get the beer out Your turn Lucky Nothing out trumps logic.

[grcamna2]

Well, good news. got it done. Started right up but wanted to run at a very high idle with no throttle response... guess its time for a carb synch.

It never hurts to check your centrifugal spark advancer to be sure it's moving smoothly w/ enough lube,that can make the engine idle high also.

where?

Six guns,
     The centrifugal spark advance unit is accessed directly behind the points plate;just remove the entire points plate & the bolt in the center of the crankshaft that holds the advance unit.There are threads here on the forum that will tell you the best way to maintain that very critical piece so you'll get the best performance from your points.

[grcamna2]

Weather it's a light or a buzz box or an ohm meter etc that you use to set static timing and they all will work I'm sure and everyone has their favourite. You should follow up with a timing light to check it and the advance while running, all the above mentioned ways will get you close enough and running in a pinch or on the side of the road.

I agree.Static timing will get you "in the ballpark",but the best way to check the timing is a quality timing light w/ it's own separate power source. 

[bollingball]

I may have missed it with all the fun going on. I have not heard to much about using a dwell meter. I like to use it and I think I get one set closer to the other using it. When I use my dwell meter, I use the 8-cyl. scale and the reading should be 23 to 24.5 degrees the 2-cyl scale is to wide at 92-98deg. or the 4-cyl is ok at 46-49deg. I do make sure I zero it every time plus it has the mirror. Any thoughts? TT or Lucky.
Ken

[TwoTired]

Dwell meters can be quite accurate.  Do realize that the ideal dwell specification for the SOHC4 is 195 degrees.

Dwell meters use a resistor/capacitor charge/discharge time constant for holding a voltage on a d'arsonval meter movement.  These can be calibrated for the point system being used.  But, I don't know of any that are specifically calibrated for the SOHC4. But, you can calibrate nearly any Dwell meter for use with the SOHC4, buy ignoring the maker's markings and using your own.  Most of you are already doing so, actually.

To calibrate, you simply set the points to the book value gap setting, and then note where the needle deflects on the scale.  Mark or note that reading and use it for all future, measurement references.

A more detailed calibration, would involve mounting a degree wheel on the crank, and then adjusting the point gap so that the points are closed for 195 degrees of crank rotation.  Then run the engine, note the meter's deflection point and mark it at 195 degrees.  You just made a dwell meter for an SOHC4.

I have and use dwell meters.  It allows one to set accurate dwell or point gap with point sets that are pitted or have spires.   Personally, I like to set point contacts that are flat as new, making the measured gap pretty accurate.  But, that's the value of a proper point file.

[bollingball]

I did leave some parts out I use a wire type feeler to set a new set of points then see what my meter reads on the scale I like and use that for my dwell setting. That is where I came up with the 22-24.5degs. On my meter it shows up at about 23 degs. on the 8 cyl scale if my memory serves me well.
Ken