Set timing without timing light

[VE8EV]

Did the tuneup this weekend on my 1975 OMC 235. A buddy was supposed to drop by with his timing light but didn't show. After installing the new ignition parts I set the dwell with a multimeter that reads duty cycle (V8 duty cycle = dwell / 45) and then manually rotated the engine to the 10 degrees BTDC mark. With the multimeter measuring continuity between the points lead and ground I adjusted the distributor until the points were just barely opening. It seemed to run fine on the water but my question is was that good enough? Would a timing light be more or less accurate?

 

[Howard Sterndrive]

Re: Set timing without timing light

you need a timing light.

 

[HT32BSX115]

Re: Set timing without timing light

Did the tuneup this weekend on my 1975 OMC 235. A buddy was supposed to drop by with his timing light but didn't show. After installing the new ignition parts I set the dwell with a multimeter that reads duty cycle (V8 duty cycle = dwell / 45) and then manually rotated the engine to the 10 degrees BTDC mark. With the multimeter measuring continuity between the points lead and ground I adjusted the distributor until the points were just barely opening. It seemed to run fine on the water but my question is was that good enough? Would a timing light be more or less accurate?

That's a good way to destroy the engine. In the best case, you could run retarded and just not get good power and maybe run a little hot.

In the worst case, you would run (TOO) advanced and have a detonation event and destroy the engine. o o o -- o --

you need a timing light.

You need a timing light.

73/Rick

 

[Boomyal]

Re: Set timing without timing light

You can do it without a timing lite but you would, at least need a test light and you need to be able to find your timing mark on the damper (for example 6? btdc).

Crank your damper around until the pointer is on that mark (do it with a socket) Make sure the rotor is pointed near the #1 plug contact. The rotor will go around once for each two rotations of the damper.

Loosen you distributor hold down clamp. Attach your test light to the coil negative and park the probe tip in a good ground. Turn on the ignition key. You need to know which way your distributor rotor turns when running. Rotate the distributor backward from it's running direction then slowly rotate it forward. As soon as the test light lights up, STOP and tighten down your distributor clamp. You will now be about as close as you can get on the prescribed timing.

 

[VE8EV]

Re: Set timing without timing light

You can do it without a timing lite but you would, at least need a test light and you need to be able to find your timing mark on the damper (for example 6? btdc).

Crank your damper around until the pointer is on that mark (do it with a socket) Make sure the rotor is pointed near the #1 plug contact. The rotor will go around once for each two rotations of the damper.

Loosen you distributor hold down clamp. Attach your test light to the coil negative and park the probe tip in a good ground. Turn on the ignition key. You need to know which way your distributor rotor turns when running. Rotate the distributor backward from it's running direction then slowly rotate it forward. As soon as the test light lights up, STOP and tighten down your distributor clamp. You will now be about as close as you can get on the prescribed timing.

Yup, that's pretty much exactly what I did except I used the ohmeter to watch for the points opening instead of a test light. Will try to find a timing light to verify this weekend.

Thanks

 

[bruceb58]

Re: Set timing without timing light

Don't run it until you get a timing light and a real dwell meter.

 

[VE8EV]

Re: Set timing without timing light

Don't run it until you get a timing light and a real dwell meter.

No magic in a dwell meter, dwell is duty cycle. I'm not worried about the timing either, I'm sure it is inside of a degree or so (plus or minus) which would be within the tolerances of the damper markings and the little pointer. I already had it out and it ran great, I was just curious if this method would be more or less accurate than a timing light and a Mark I eyeball. Guess I'll find out when I can get my hands on a timing light.

Cheers!

 

[Boomyal]

Re: Set timing without timing light

Don't run it until you get a timing light and a real dwell meter.

I say, don't run it until you get rid of those points and get a Pertronix ignitor! :laugh:

 

[VE8EV]

Re: Set timing without timing light

I say, don't run it until you get rid of those points and get a Pertronix ignitor! :laugh:

:lol:

 

[bruceb58]

Re: Set timing without timing light

I say, don't run it until you get rid of those points and get a Pertronix ignitor! :laugh:

Not me. Stay with the points.

 

[VE8EV]

Re: Set timing without timing light

Not me. Stay with the points.

Points forever! No C-tow in this neck of the woods. Search and Rescue won't even start wondering where you went for at least 48 hours and I hate rowing...

 

[Boomyal]

Re: Set timing without timing light

Not me. Stay with the points.

Oh bruceb, I thought you were more progressive than that!

 

[bruceb58]

Re: Set timing without timing light

Oh bruceb, I thought you were more progressive than that!

Only when it provides a benefit.

I would use the money instead and apply it to a Voyager distributor if the engine is a chevy.

 

[VE8EV]

Re: Set timing without timing light

Well, the jury is in. I got a timing light this weekend and the timing was bang on.

Tip: Before you start the engine, find the timing marks and use a black marker at the proper setting. Much easier to see with the timing light than the faint numbers stamped on the damper.