Jim brings up a really good point. The balancer/damper should have been rebuilt or replaced as part of any basic overhaul.

A mechanic's vacuum gauge connected to manifold will tell the tale on your general setup. A healthy stock engine in good tune should pull about 20" steady needle hand at Sea level. "Slow" or late (retarded) ignition timing, poor compression, valve lash too tight, misadjusted carburetion, exhaust restriction, they are a very good yet inexpensive diagnostic tool.

Tedster and '57 Rancherojim, the engine is a 256 cid and I suspect that the dampner has been properly installed inasmuch as the   engine was balanced.  It is still 6 volt and I confirmed from the repair manual that the initial timing is 3 degrees BTDC.  The manual also describes various distributor tests that would have been done with various shop test equipment back in the day (which I don't have).  However, I do have a vacuum gage and can check that reading.  Assuming the vacuum is adequate, how can I test to see if the dizzy is advancing properly?  Valves were adjusted about 1,000 miles ago.  Teapot carb has been rebuilt and adjusted and seems to be working well.  Have not checked compression yet but it seems that the timing issue needs to be corrected first.

Just wondering if you disconnected the vacuum line to the distributor before setting the initial advance?

Your engine has (I think) what's called a Load-o-Matic style distributor, so there is no mechanical advance whatsoever, engine ignition advance is derived solely through engine vacuum from two different sources, "venturi vacuum" being one of them. I have no idea how to check this, I'll look in my manuals and see if there is something that can be performed without special or proprietary test gear.

Still, now that I think about it, the testing with a conventional distributor is simply to spool up the RPM and watch where the ignition advance ends up at. I'd think it would be very similar with the LOM distributor. You'll need a tach and a timing light.

One bit to keep in mind though, don't take anything for granted when troubleshooting. A compression test is not a bad idea for a couple different reasons.

One is there's a recorded baseline for future reference. Verifying or checking for true TDC (using a piston stop tool) you know for certain whether the timing marks on the damper are accurate or not. If the balancer/damper was not renewed as part of the overhaul, a new one needs to be fitted. Basically what I'm getting at is you can't make any assumptions, don't guess, measure. Low engine or venturi vacuum would cause big trouble with a LOM, because all of the advance is derived from there.

LOM timing is 3 degrees STD and 6 degrees AUTO factory tune. Curb idle has to be at spec to set initial timing..

To check timing advance, watch whether the marks on the balancer advance when reving the engine. This will only give an indication as to whether the advance system is functioning. You would need either a DIST MACHINE or TACH and timing tape to verify the correct timing advance curve whether OEM or modified.

Take verifying #1 TDC as the first step to heart. Beyond that is just guessing/assuming.

____________________________

If you still have the original Load-a-Matic distributor, the diaphram may be bad,
not allowing the correct advance.
Just a thought
Jim

Kahuna and Tedster, more diagnostics today and find that there is NO vacuum at the carb vacuum advance port, let alone at the dist.  Rather than take the teapot apart again to see if there is a blockage to that vacuum port, I will re-route the vacuum line from a manifold location using a tee block and then retest for advance.  Yikes!

If you connect a loadamatic distributor to intake vacuum it will go to full advance immediately. They only need about 3 in vacuum for max advance may damage an old diaphragm if you hit it with
15 to 20 inches of vacuum. Get a hand operated vacuum pump to check your distributor advance. If you get no vacuum from the carb when you rev it a bit the carb is at fault. Not too familiar with a 54 Tpot if it has a spark control valve you can change it other than that it may have to come back apart.

Along with what Sandbird mentions, unless your vacuum guage reads real low, you might not see a reading, especially at idle and just above. It’s a very weak signal, more in the manometer range than an automotive vacuum guage.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Miker and Sandbird, thanks for your replies. . . .  Just came back from from NAPA with the same info on low vacuum, so I will not hook up to the manifold and will recheck my gauge to see if it reads low enough - probably not.  The teapot does have a spark control valve and I will look further at the repair manual for clues. . . . . . . . . .