Spark advance range

Brambleworth

Brambleworth

Junior Member
Still trying to figure out my overheating issue, checking timing since my mechanic put a rebuilt distributor in this winter. Last year I set up timing marks as per FS ignitions method. So after using a timing light today, it looks like up on the lever is equal to 28 degrees retarded and full down is 8 degrees advanced at a high idle. Would this setup overheat while driving fully advanced?
 
If those numbers are real then your motor is severely retarded, and will overheat like crazy.
You want about zero degrees full up, and whatever you can get full down which should usually be about 28-30 degrees advanced.

It is so retarded I am surprised it will even start up.

There are numerous threads here about how to adjust timing correctly, a search should reveal them. It all starts with correct use of the timing pin.
 
tbirdtbird said:
If those numbers are real then your motor is severely retarded, and will overheat like crazy.
You want about zero degrees full up, and whatever you can get full down which should usually be about 28-30 degrees advanced.

It is so retarded I am surprised it will even start up.

There are numerous threads here about how to adjust timing correctly, a search should reveal them. It all starts with correct use of the timing pin.
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Yes, I concur 110% with TBird. I bet that thing is a 'slug' to drive with only 8 degrees of advance! :o
 
Retimed to zero with lever up and that gave close to 28 with the lever down, ran much better. Rex a co gauge is reading about 195 but not boiling over anymore. What is normal operating temperature at the radiator neck?
 
Brambleworth said:
Retimed to zero with lever up and that gave close to 28 with the lever down, ran much better. Rex a co gauge is reading about 195 but not boiling over anymore. What is normal operating temperature at the radiator neck?
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The key is "not boiling over" in that the extra heat is a good thing in combustion efficiency and keeping the oil additives working. It is only when excessive heat (boiling over) is a bad thing. Go drive and enjoy now.
 
Did it run this hot before the new distributor? What is the condition of the radiator? Your new timing will make a big difference but ambient outside temps will play a big factor. If it is running better but the gauge shows 195 today what is the outside temp? I would not rely on that gauge too much. We tested 4 of those gauges and got 4 different readings on the same pot of boiling water.
 
When it is 100 degrees outside and while driving over hills, my Tudor never goes over 140 degrees. Has an original radiator in it.
 
Last year the temperature was never an issue, the Motometer would usually read in the bottom third of the scale, but I know these are not terribly accurate. The Rex-A-Co was reading very close to the temp that was shown on the laser pyrometer at the upper hose neck. The radiator is a flat tube style non-pressurized, I flushed it several times and very little dirt came out. I am thinking about filling with white vinegar for a few weeks. I might install a Brassworks pressurized unit I bought last year if I continue to overheat this weekend. I assume my spark advance range is OK now running from TDC with lever up to about 28 degrees of advance with lever down.
 
In the early days, car manufacturers recommended using caustic soda to successfully clean radiators & interiors of cast iron engine blocks -- extremely dangerous chemical when one is not extremely knowledgeable & careful for use of same -- can cause severe skin burns, loss of sight if splashed in eyes, plus ruin a good Model A paint job.

Years ago, had an original Model A radiator, (28 years old or so at that time), that overheated to about 210 degrees that I cleaned & subsequently used for years -- about 10% of the old radiator tubes were cut, pinched, & soldered -- fins on front looked like somebody shot at a pheasant, missed, & hit the front of the radiator which experienced only gravel roads -- this particular radiator when looking through the top, looked like the former owner greased the water pump every month with a full tube of axle grease -- the cure suggested by many at that time was to empty half a box of "**** & Span", fill with water, & run it for a couple of days -- then flush with clear water whereby the water did come out looking like jet black sewer water -- next, add remaining half of "**** & Span", fill with water & run for a couple of days -- flush again with clear warer -- both times, lots & lots of soap suds -- Model A radiator opening appeared to resemble the mouth of a dog with a severe case of rabies, foaming at the mouth, which was splashing on the windshield while running down the highway -- but afterwards, the coolant temperature came down to 180 degrees when measure with a commercial laboratory thermometer.

Probably will not work in all radiator cleaning cases to clean radiators, but worked for me. Still have the car & this show piece radiator.
 
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Brambleworth, Full advance on a Model A is actually only 20 degrees. Later engines, like a small block Chevy V8, can run at 34 to 36 degrees full advance. I would guess that the Model A requires less advance because it does not turn high rpm's.
Mike
 
The Model A service bulletins show an ignition advance range of 20 degrees but that is distributor degrees. The specified range is 40 degrees of advance at the crankshaft . When most people talk about ignition advance they refer to crankshaft degrees not distributor degrees. The range of advance will vary with the width of the slot in the distributor body and the width of the advance arm on the upper distributor plate.
 
i think i read .... 5* retard at full retard ... 35* at full advance . i would bump the 20* up to 30* ............. steve
 
just about any motor ever made needs about 30* advance plus/minus, and nowadays we all speak in terms of crankshaft degrees

The actual best way to time a motor (granted this way cannot always be done) is to continue to advance it in steps until it pings under load, then back off until the pinging just stops. This is what racers do. Of course you have to know what you are listening for
 
I don't use a timing light. Degrees on the model A mean NOTHING to me. I set mine as advanced as it will go without starter kickback. I align the trailing edge of the rotor tip with the number one contact in the cap body with NO clockwise backlash. This is as advanced as ithe timing will go without starter kickback when cranking. Any clockwise backlash will result in a slugish hot running engine. Those with the so called modern points will need to tweek the timing so as to find a happy medium. Also, if you aren't getting full advance at the upper plate, you will still be running retarded no matter where the rotor tip is set. It is best to always check and set points gap, then check for full movement,retard and advance in the rear window of the cap body. With the two tooth,30-31 steering , it may be necessary to loosen and rotate the steering column tube for full advance and retard.
 
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I found this thread by searching for spark advance/retard. I am running hot at 185* water temp without a thermostat and 190* with a 160* thermostat. How can I tell if I have 20* timing range at distrib other than the window in the distrib body? I am using modern point kit. 7 tooth steering column.

I also use Les Andrews method of timing (two clicks down turns on the test light)

Bill G
 
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