What Kind Of Timing Light?

How many of you guys know how to check for a worn or defective camshaft using a timing light?

 

That's a new one on me, I can't imagine how one would be able to tell that with a timing light.

 

Agree with @Oldpappy above.
Not that I would know what to do if I did know but I love learning. I learned here on this site how to adjust timing with a vacuum gauge so, Please enlighten us!

 

Worn lobes on a cam shaft would impact valve lift, and possibly fuel pump actuation but I don't see how it would impact ignition timing.

 

There may be a confusion between a timing light with a vacuum gauge.

You really don't need a vacuum gauge either. You can advance it by ear.
Initial timing with the light.
Bump up the timing till the engine knocks/pings under load, then back it down till it goes away.

Personally, I use vacuum gauges as a diagnostic tool. Low vacuum at idle or a "ticking" needle can be an indicator of other issues.

Back in the 70's they were the rage for monitoring your driving habits as well.

 

Had a lot to do with the oil embargo/energy crisis of the time. Keeping the vacuum "in the green" (high) helps gas milage.

 

Okay, sorry it took me so long. The old timing lights with the thumbwheel and a little meter or the ones with a knob on the back that let you move the strobe back to TDC and then you can read how many degrees of advance you actually have, valve cover off, you zero it on the spark signal, then point it at the exhaust valve and wind it around until you get the strobe right where the valve hits it's maximum lift and record it's position. Then do the same with the intake. On it's own this reading is meaningless, but when you record all of the cylinders and compare you can see what's going on with it, be it wear or faulty cam. You can also check the valve closing but max lift is gonna tell you most everything you are going to need to know anyway. And in the real service world there's just not a lot of need to do this, but that's how you do it.

 

I always knew there had to be a good use for a timing light!

 

If you’ve already got the valve cover off, I’d think it would be easier to just directly measure max lift at each rocker to check for cam wear. That how I’ve checked which lobe(s) is getting wiped.
-Donny

 

Nowadays that is done with a pressure transducer, laptop, and some software without disassembling anything but removing a spark plug. Used to check relative compression. It can be done without the pressure transducer and removing a spark plug as well.