Pings with more than 10 degrees advance

P

Plainsman30

Member
Hi All,

We did a partial rebuild on my motor after the first rebuild failed due to scored pistons.

I found that it pings at road speed if I give it more than 5 to 10 degrees advance as measured by a timing light. It has a new 5.5 head and a “touring grind” cam. It is bored .80 over with stock type pistons and has a stock carb and distributor.

At the present time, I have the initial timing set at 20 degrees retard, and it does cause a nice show idle, but it will still idle at 25 to 30 degrees retard.

I have checked the following:
- top dead center (TDC) mark was located on front pully according to when timing pin drops into dimple on timing gear.
- I can see the piston come to TDC with an inspection scope exactly when the pin drops into the dimple on the timing gear.
-The points are adjusted correctly.
- I am running premium gas, and the carb mixture setting doesn’t seem to make any difference on pinging.

The motor is still a little tight yet, but it runs nice and has good power and speed.

I wonder what could be causing this and whether or not I should worry.
 
Appears over 200 million ways were offered thus far on how to time a Model A.

If you try this simple test, it may answer your simple "pinging" questions.

1. Remove (4) plugs to allow engine to turn easily with a crank.

2. Electrically connect No. 1 spark plug (the one adjacent to your radiator), to your distributor.

3. Turn switch "ON"; retard spark handle all the way up; and rotate engine with hand crank.

4. When timing pin slips in, no. 1 piston at TDC, at that very moment, no 1 spark pug should fire.

Let us know what you find.
 
Mr. Chauvin,
I will try your method in the morning, but unless I am missing something, I think I am doing about the same thing with the timing light.
 
Somehow, some Model A owners get confused with the different 1,999,999 other timing methods suggested heretofore using timing lights, Nu-Rex devices, Dial Indicators, Test Lamps, Radar, Rotor Settings, Cat-Scans, MRI's, and PAP Smear machines, etc. etc.

With the "simple" test described in #3 above, you should be able to drink (2) bottles of cheap whiskey, put on a dark welding helmet, and at midnight on April Fool's Day, conduct this simple test to verify if your timing is "accurate".

If not, it will not be because of the wrong brand of whiskey, or a poor fitting welding helmet, or the day of the month.

Hope this helps someone remember how to check "accurate" timing ...... the hangover is just a bonus.
 
H. L. Chauvin said:
Somehow, some Model A owners get confused with the different 1,999,999 other timing methods suggested heretofore using timing lights, Nu-Rex devices, Dial Indicators, Test Lamps, Radar, Rotor Settings, Cat-Scans, MRI's, and PAP Smear machines, etc. etc.

With the "simple" test described in #3 above, you should be able to drink (2) bottles of cheap whiskey, put on a dark welding helmet, and at midnight on April Fool's Day, conduct this simple test to verify if your timing is "accurate".

If not, it will not be because of the wrong brand of whiskey, or a poor fitting welding helmet, or the day of the month.

Hope this helps someone remember how to check "accurate" timing ...... the hangover is just a bonus.
Click to expand...

We live in a complicated world. Our minds are being "rewired" to expect things to be complicated. Just a look around and you realize what I'm saying is true. Cars have computer networks to do things like turning on the lights.

I use the A to unwind and place myself back to a simpler time. A tail light bulb and some wire lying around along with some practice, is virtually all the test equipment you need for the A.
 
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Hi Mike,

In your question, like so many similar Forum questions : "I wonder what could be causing this and whether or not I should worry."

"Pinging" with advanced timing? Most already know it means the fuel mixture is being ignited before the piston reaches the top of the stroke at the piston's top dead center (TDC).


So here you have a soft Babbitt bearing pushing a piston upwards .... and right before it tops out at TDC, the piston is hit with the brute force of combustion.

Never mentioned is ....... this is similar to a 300 pound Gorilla hitting the top of the pistons with a hammer ...... and just one (1) never asked question is ... at just 1,500 RPM's:

How many Gorilla hammer licks can the soft Model A Babbitt bearing withstand before it is crushed like a fresh fragile crispy ice cream cone sandwiched between the top of a wood piling and a heavy steel pile driven hammer?

Advanced timing, even without hearing "pinging" can shorten Model A Babbitt bearing life.

Some may forget about effects of hearing Model A advanced timing "pinging" ...... but let's hope they will never forget about the 300 pound Gorilla with the hammer and/or the fresh fragile crispy ice cream cone under the pile driven hammer.
 
Hi Mike,

And something else ...... it never hurts for any of us ask what we sometimes think are "basic" questions ....even with the best of the best ..... I know a Model A engine re-builder who told me about 15 years ago that he totally dismantled a Mode A engine three (3) times trying to find a noise ..... he found the noise when he removed the fan belt ..... the fan was slightly loose on the fan shaft and rattling.

None of us will ever know everything .........
 
I know my High Compression Head -Antique Engine Rebuilder in Skokie recommends advancing no more than 28 degrees. I get pings if advance is lower than 8:30 o clock, but I can easily go 65 mph and the engine has performed extremely well for 10,000 miles.
 
Per #14, most find that just about "anything" is possible "after" even a minor restoration of a Model A or Model B.

As late as the 1950's Sears Roebuck in every state was offering Model A and B engine rebuilding services. Can anyone imagine how many "extra" parts, including reproduction parts one could find in a Sears engine rebuilding shop.

If anyone really enjoys "surprises", just buy a restored or an un-restored Model A.
 
I'm wondering if maybe the timing gear is one tooth out. Not too hard to pull the timing gear cover and check it.
 
Looked at an engine I have on a stand with the head and pan off this morning. With #1 piston at TDC on compression stroke I can see the timing pin directly over the cam gear dimple. Seems to me the only possible answer is the distributor cam is off. I set my timing per the red book and check with a timing light (non adjustable). I have a Nurex scale and TDC notch filed in the pulley. Full up on the spark lever is 0 deg and each notch is about 5 deg. My range is 0 - 40deg.
Hugh
 
Plainsman30 said:
Hi All,



At the present time, I have the initial timing set at 20 degrees retard, and it does cause a nice show idle, but it will still idle at 25 to 30 degrees retard.
Click to expand...


:confused:

I don't believe the engine would run at an actual 20 degrees retarded. My guess is that you actually have it timed slightly advanced and that when you think you are at 10 degrees advanced you are actually 30+.
 
Dick Steinkamp said:
:confused:

I don't believe the engine would run at an actual 20 degrees retarded. My guess is that you actually have it timed slightly advanced and that when you think you are at 10 degrees advanced you are actually 30+.
Click to expand...

I agree.

If timing is as stated then:

Most likely the engine has a Model B timing cover, which sets the static timing at 19 degrees before top dead center.

So when you advance the lever from full retard to full advance ... you get 59 degrees total advance .... WAY too much!! Engine will buck at idle and ping "like a banshi".

Look at timing pin that you use to set timing ... there is a bolt on the cover each side of the pin.

is the pin closer to the upper bolt?

If so then it is a B cover and needs to be replaced with an A cover.
 
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