timing light question

[vash]

i have been shopping for a new timing light. dropped my old beater awhile back. my car occasionally pings, when i get on the gas. may as well get a new timing light.

the ones with a digital read-out on the light....so does this mean that you dont even need to search for the tick marks on the pulley? or do you calibrate it at TDC, and then you can advance it without looking at the pulley. i barely knew how to use my old one, the digital read out gives me questions.

cliff

[Early_S_Man]

Cliff,

You still have to use the Z1 or TDC mark on the pulley, but you can ignore the 5° ATDC, 30° BTDC, & 35 ° BTDC marks ...

[Jubbie]

From what I have seen, I think the digital reads out things like, rpm
Point dwell, Advance setting, and voltage.

You still have to line up a mark with the flashing light. But, the rpm readout may be helpful to make sure that you do it at the right rpm. The advance, if it works like the knob on the back of my light, will advance when the timing light flashes. You can use this if you only have a advance mark on your pully and don't want to time it at full rpm.

[911pcars]

Pardon me for not assuming too much as I was unclear of your understanding.

First, the strobe light indicates when #1 cylinder fires (assuming you have it clamped over #1 spark plug wire). With the engine ON, pointing the timing light will "freeze" the corresponding TDC and advance marks on the pulley and engine (crankcase split).

A basic timing light merely indicates when the spark occurs relative to the engine mark (ID the marks then determine if the marks line up or not). A digital or analog readout (if started from zero), will provide the number of degrees the spark occurs before, at or after TDC by using the control knob to "zero-align" the appropriate marks at any engine speed. Basic ignition timing is set at idle speed. Rotate the distributor housing clockwise or cc to change when the spark occurs.

Sorry if I over-simplified the process, but I think that covers it for some.

Sherwood

[vash]

perfect assumption! ( i dont know much)

thanks guys. (no one lets you read the instructions prior to buying.)

[randywebb]

A shop owner told me that you couldn't time a 911 engine with a regular timing light -- that only a special light could time the engine at 6,000 rpm...

This guy is often pretty bogus -- so, what do you think?

[Early_S_Man]

Pure BS, Randy! I did it for years with plain Craftsman/KAL/Actron timing light!

Cliff,

Here is a recent thread with extensive discussion of timing lights and dwell/tachs:

Dwell meter timing light suggestions

You CAN read the PDF manual of the KAL/Actron [SunPro] timing light [same model as the Craftsman I have] ...

http://www.actron.com/publish/2004/06/07/pdf_english_16182.pdf

[randywebb]

Thx Warren - that's what I figured. It's the only shop in town, unfortunately...

[cbeers]

Cliff,

I have a light you can use anytime if you want to avoid buying one for now


-Chris

[B D]

The lights with digital readouts are the best. You can accurately set your idle with the RPM readout and set the timing at 6000 with out looking through the rear window to the dash.

Randy the mechanic may be referring to the fact the VDO tachs in our cars are not that exact and many are way off. I have a recently rebuilt tach from NHS and it is off slightly even. The best way to set exact timing and idle is with a digital readout. You can also use nothing at all and just set the timing by ear if you know what you’re doing and have good hearing, but not recommended.

[randywebb]

Thx B D - however i know that mechanic too well... it was pure BS, designed to prevent people from working on their own cars.