TheSamba.com :: View topic - Set timing with dwell-tech and strobe

Sat Nov 19, 2011 10:26 am

I'm having trouble setting up the dewll-tech and strobe to do my timing. When I have the dwell-tech meter and the strobe positive clamps connected to the positive post on the coil, them both grounded to the lid hinge and the strobe pickup clamp attached to plug wire one, the car wont start. If I only ground one of them the car starts but I get a shock when I press the lever on the carb to give it gas. Also, the strobe wasn't working even at idle. What am I doing wrong? Thanks.

Sat Nov 19, 2011 10:33 am

Dwell meter-Green to points side of coil, black to ground(engine block).

Timing light-Black to ground, red to power( choke wire will work fine), inductive lead to #1 plug wire.

Remember to multiply the 8 cyl. scale by 2 on that meter.

Sat Nov 19, 2011 10:41 am

I don't know if that hinge is the greatest location for a ground.

Sat Nov 19, 2011 11:52 am

I get "bit" while using my timing light too. The last time I checked the timing I pulled on a pair of latex gloves to keep insulated.

Sat Nov 19, 2011 11:58 am

Willhelm wrote: I get "bit" while using my timing light too. The last time I checked the timing I pulled on a pair of latex gloves to keep insulated.

Whoa!

You can solder a wire to the housing of the light or just connect it to one of the housing screws, then use an alligator clip on the other end attached to the engine case to eliminate the zaps.

Sat Nov 19, 2011 12:10 pm

Thanks Jim. I'll keep that in mind. The gloves are pretty simple though, I have a box of 'em for the really grimy jobs. (by the way, in agreement about tapping into positive pressure and having the chips evacuate up the flutes, from another thread )

Sat Nov 19, 2011 1:08 pm

I just ground to one of the tin screws, never had a problem.

Sat Nov 19, 2011 2:02 pm

69 Jim wrote: Dwell meter-Green to points side of coil, black to ground(engine block).

Timing light-Black to ground, red to power( choke wire will work fine), inductive lead to #1 plug wire.

Remember to multiply the 8 cyl. scale by 2 on that meter.

the choke side appears to be the other side of the coil, is that right?

Sat Nov 19, 2011 2:49 pm

topofsteel wrote: 69 Jim wrote: Dwell meter-Green to points side of coil, black to ground(engine block).

Timing light-Black to ground, red to power( choke wire will work fine), inductive lead to #1 plug wire.

Remember to multiply the 8 cyl. scale by 2 on that meter.

the choke side appears to be the other side of the coil, is that right?

Yes. If the car doesn't have a tach installed, then the only circuit on the negative side of the coil is the points. Everything else is ran off of the positive side, such as choke, cutoff solenoid, reverse lights. Any of those points are good positive sources for testing purposes. Be careful though, that circuit is NOT fused. A short to ground there can be a real mess. Many of us have added an inline fuse in the trunk. Something to think about. Good luck.

Sun Nov 20, 2011 9:24 am

Willhelm wrote: Thanks Jim. I'll keep that in mind. The gloves are pretty simple though, I have a box of 'em for the really grimy jobs. (by the way, in agreement about tapping into positive pressure and having the chips evacuate up the flutes, from another thread )

8)

Sun Nov 20, 2011 9:51 am

Be sure you are not trying to draw too much current from the coil positive terminal. I reached a point where I could no longer use the coil as a power source... it would prevent the coil from sparking when I pulled the timing light trigger and the engine would just die.

If you have an alternator, you can use the B+ stud where the heavy gauge wire connects. This is connected to the battery positive terminal so can provide all the current you need for the timing light, or other testing items.
If you have a generator, you can clamp a battery jumper cable to the battery and run it to the rear of the car while you are testing. You can power all your test equipment from that.

I have always found the distributor cap clamps are a good ground, as well as the bumper brackets (if you can reach them). If your alt/gen strap bolt is accessible it will work too.

Sun Nov 20, 2011 11:28 am

ashman40 wrote: Be sure you are not trying to draw too much current from the coil positive terminal. I reached a point where I could no longer use the coil as a power source...

What caused the change where it could no longer be used as a source?

Sun Nov 20, 2011 11:40 am

You have something wrong with your timing light in order for it to become hot.

Jerry

Tue Nov 22, 2011 12:24 am

69 Jim wrote: ashman40 wrote: Be sure you are not trying to draw too much current from the coil positive terminal. I reached a point where I could no longer use the coil as a power source...

What caused the change where it could no longer be used as a source?

:?:

Tue Nov 22, 2011 4:50 am

topofsteel wrote: I'm having trouble setting up the dewll-tech and strobe to do my timing. When I have the dwell-tech meter and the strobe positive clamps connected to the positive post on the coil,

Ok, stop. As 69 Jim said, the power wire for the timing gun and the green wire for the tach/dwell meter do NOT hook to the same spot.

But I don't think that's the only problem. The photo isn't high enough resolution to see where the coil wires are, but it looks like you have the red clip for the timing light on the right side of the coil and the green clip for the tach/dwell somewhere near the carburetor?

In my car, looking at the coil in the engine, the LEFT side is the positive side, and the right side (nearer the carburetor) is the negative side. Is your car reversed?

In any case, the wire that supplies power from the car plugs into one side, which is the POSITIVE side of the coil. The wire to the carburetor solenoid, and the wire to the choke should also plug in in the same spot (and the red wire to the electronic ignition if you have that). This is where the red clip for the timing light goes.

The ONLY connection to the negative terminal of the coil should be the green wire that goes to the distributor (unless you have a tachometer pickup). This is where the green tach/dwell clip goes.

If you're hooking stuff up and the car doesn't start, unhook it IMMEDIATELY. You're probably shorting out the wiring and are in danger of melting something. Also, if normally grounded parts of the engine are shocking you, then somethings very wrong and you've wired something wrong.

Hope this helps.

Craig Steffen

Tue Nov 22, 2011 12:44 pm

69 Jim wrote: What caused the change where it could no longer be used as a source?
30-years of age in the black ignition wire that powers the coil. Maybe some carbon build up in the ignition switch contacts too. :(
I would wager that most original Beetles made before 1980 are in a similar situation. If you measure the voltage at the battery and compare it with the voltage at the fuse box and then the coil... what difference in voltage will you find?

I ended up installing a relay to power all the engine compartment items. At idle I now get 14v at the coil. More input voltage = more output voltage! :D

Tue Nov 22, 2011 1:08 pm

[quote="ashman40"] 69 Jim wrote: ashman40 wrote: What caused the change where it could no longer be used as a source?
30-years of age in the black ignition wire that powers the coil. Maybe some carbon build up in the ignition switch contacts too. :(
I would wager that most original Beetles made before 1980 are in a similar situation. If you measure the voltage at the battery and compare it with the voltage at the fuse box and then the coil... what difference in voltage will you find?

I ended up installing a relay to power all the engine compartment items. At idle I now get 14v at the coil. More input voltage = more output voltage! :D

Makes sense, excellent upgrade. 8)

Tue Nov 22, 2011 1:21 pm

ashman40 wrote:
30-years of age in the black ignition wire that powers the coil. Maybe some carbon build up in the ignition switch contacts too. :(

Yes, but that's not the original poster's problem.

His engine runs. It's just when he hooks up the tach/dwell meter and the timing light, the engine doesn't run, which as likely as not means he's hooked something up wrong and shorted the coil.

The picture clearly shows the positive for the timing light looked up to the GROUND side of the coil, so there are hook-up problems competely independent of whatever voltage is getting to the engine compartment.

Craig Steffen

Tue Nov 22, 2011 2:42 pm

Do yourself a favor and hook up the red or green clamp of the dwell meter to the "1" or "-" side of the coil. Put the black or ground on a known good ground.

Some people hook up the timing light to the coil, but I still hook it up to a set of jumper cables attached to the battery. Never an issue.

Tue Nov 22, 2011 10:53 pm

gevmage wrote: Yes, but that's not the original poster's problem.

His engine runs. It's just when he hooks up the tach/dwell meter and the timing light, the engine doesn't run...
Same thing happened to my engine.
In my case the voltage at the coil (+) was only in the 10v range due to the old wires.
When I hooked up the timing light it "stole" current away from the coil and the coil stopped sparking. It would actually flash once or twice, but then it would stop flashing and the engine would die. Maybe its the other way... it would steal current from the coil so it would no longer spark which would kill the engine.

IIRC, the voltage at the coil (+) while the timing light was ON was less than 10v.