Simple question about setting timing

Maybe I'm stupid or missing something obvious, but are you all relying on the stock RPM gauge while setting the timing, or do you hook up another gauge?
I haven't set the timing in any other way than by feel and my ears, because I deemed the stock gauge as non-reliable and didn't have any other gauge to hook up.
My engine runs fine, but it couldn't hurt to check it with the timing-light.
 
Gransin said:
Maybe I'm stupid or missing something obvious, but are you all relying on the stock RPM gauge while setting the timing, or do you hook up another gauge?
I haven't set the timing in any other way than by feel and my ears, because I deemed the stock gauge as non-reliable and didn't have any other gauge to hook up.
My engine runs fine, but it couldn't hurt to check it with the timing-light.
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My digital, adjustable timing strobe light indicates RPM in digital format. I think this is likely more accurate than the tach in the gauge cluster, but I haven't compared them directly.
 
You need a digital tach and a dwell meter to do this properly.

You will never know if the ignition points are set close to the dwell spec if you set them with a feeler gauge...and each 1 degree change in dwell will change the initial timing by one degree.

So first, set your ignition points with a dwell meter. This is a trial and error iterative process, but take your time and get it close to spec.

Next using the digital tach, set your idle to 1700 RPM (at this time you may want to take a look at the tach in the dash and see what it is reading).

Now set the timing using the process outlined by Stevehose and deQuincey in this thread.

If your car is the only one you will ever set dwell and timing on, and then only every couple of years, it would be good if you could borrow or rent the tach/dwell meter and the timing light.
 
Gransin said:
relying on the stock RPM gauge
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my digital timing light has an rpm readout that seems very accurate. There is substantial disagreement at lower rpm (10% or more). I do not rely on the BMW gauge. My SnapOn timing light cost $25
via craigslist, so despite not using it often I didnt mind buying it. It does get lent out to friends a fair bit, along with an AFR gauge.
 
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Great, thanks all!
I have two timing lights but none with a RPM readout, and I didn't even know they existed, but that certainly makes this process much easier.
I'll buy one just because I like buying tools :D
 
I also have a digital tach in the timing light, also critical for setting mixture, at 950 rpm my dash gauge reads about 100 more.
 
deQuincey said:
yes timing lights use to have that feature

look at this guy

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Very skillful. Once while doing that in an E3, my fingertips brushed against the spinning fan blade tips. No harm but sure scared the bejesus outnof me.

Why didn’t BMW use a shroud like American and Italian cars of that era? It would’ve improved the effectiveness of the fan and made it safer for dopes like me.
 
bfeng said:
Very skillful. Once while doing that in an E3, my fingertips brushed against the spinning fan blade tips. No harm but sure scared the bejesus outnof me.

Why didn’t BMW use a shroud like American and Italian cars of that era? It would’ve improved the effectiveness of the fan and made it safer for dopes like me.
Click to expand...

look carefully, there is a shroud installed in the car
but it makes little difference as to finger protection
regards
 
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