I probably will...in the spring. So, when i advance the timing to 5 deg or so BTDC, do I then go back and reset the idle to 500 RPM?

Yes, whatever you normally idle it at.

BTW, I recall now ... back in the olden days they figured octane level two different ways. One was with a lab test, referred to as the "research" method, and the other was with a specified test engine, referred to as the "mechanical" method. Current octane figures are an average of these methods. On today's pumps you'll usually see a note to the effect that that the octane number is being calculated by Octane=R+M divided by 2.

Right, so my question relates to the assumption that our cars were meant to run on 80 octane so that with regular fuel now at 87 octane we should be able to take advantage by advancing the timing without damaging the engine long term. That assumption is only correct if there was no significant change in the way octane ratings were assigned back in 1950 vs. today. I think I need to do a little reading on the internet. Or, there may be one of our seniors out there who would remember.

It would certainly be interesting to know exactly the difference, if any, from the calculations in earlier times.

In the meantime, you could consider the empirical evidence of the many Hudsons currently running around with moderately advanced timing, better performance and no negative percussions.

Yes, I'll definitely check that out. Of course, all that has to wait until I find a replacement muffler for the one I blew up yesterday. I think the local parts store has them cuz this muffler is only 2 years old, and i think i got it a NAPA.

BTW - anybody ever set their points with a dwell meter? I always thought that using a feeler gauge is just to get you close but dwell was the right way to get the fine adjustment. Any experience?

Since it's dwell that you really want to be correct, I prefer to use the dwell meter. It's the easier way to check the dwell, and it keeps potentially oily feeler gauge blades away from the points! There's a bit of a problem finding a meter that will work on 6v, but there are some that do, or are independent of an outside power source.

Number on my recently purchased NAPA muffler for the '51 is 840691. Perfect fit and original appearance.

Funny you should mention that because i have a Heathkit Dwell Tachometer that has instructions for both 6 and 12 volt, positive or negative ground, but when i hook it up the way it shows, red lead to the screw on the coil that is connected to the distributor and black lead to the screw on the coil connected to the ignition switch, the dwell reads 27 degrees, not 36, as it should. Since the tach settings work just fine, I'm wondering if it's just a bad meter.

Oh, and thanks for the NAPA part number. I'm going to call them tomorrow.

Michael,

The dwell meter might be sensitive to polarity. The instructions may have assumed that ground is negative like all the 12 volt cars, instead of the positive ground that Hudson and some of the other 6 volt cars used.

Try connecting it the other way.

Per

Per, the way he said he connected it was for positive ground. Red lead to the distributor (which grounds the points when they're closed).

Michael, you're not looking at the scale for an 8-cylinder engine are you?

Michael, re: the figure of 5 degrees I tossed out in my post earlier, take that number with a grain of salt. To be honest, I've forgotten exactly where 5 degrees would fall on the flywheel marks. Maybe someone who has a flywheel can tell us where 5 degrees is, compared to the factory stated limit of 1/2" of advance on the flywheel marks (Darned if I know why they put that in terms of distance rather than degrees!)

One thing I experienced once when I accidentally set the advance too far on my Hornet ... I had set out on a trip, and soon found that when I was decelerating, the thing had a surging behavior, especially at the lower speeds. Fixed it by getting the 7/16" wrench out and reducing the advance a little.

Hi all - as for the operation of the dwell meter, the instructions are very clear on how to hook it up for either positive or negative ground cars; as i mentioned above, the correct hook-up is red (+) lead to the primary side of the coil connected to the distributor and the black (-) lead to the primary side of the coil connected to the ignition switch. Also, there is only one Dwell selection, but multiple scales on the meter. I was reading the one for 6 cylinders, so I think I was using the meter correctly. That means i'm still not sure why it reads 27 degrees.

This may be a dumb question, but ... why do you think it's reading incorrectly as opposed to the points being out of adjustment?

Ah, the great Daytona Trip !!! That is a great story Ric !

[quote="Fred Pinder" post=7961]Yes, Very common. The wire going to the points often has the insulation worn. When the vacuum advance moves the breaker plate is shorts out. Exploded a muffler on my way to Daytona beach in 1965. Loud trip. Little friction tape cured the short so I was able to complete the trip.

"Ric"

Excellent article on distributor advance in Nov. issue Hemmings Classic Car. Plotting advance curves vs. rpm; why advance; ping; etc.

Hi Park - great question. I haven't tried adjusting the points to obtain 36 degrees lately. I just set the points to 0.020 with a feeler gauge and observed a reading of 27 degrees. My recollection of past attempts is that I was able to adjust the points to obtain a reading of 36, but that the gap was barely over 0.002 - 0.003".