Engine Popping Sound

[Geo.T]

I am experiencing frequent “popping” sounds on my ‘30 A the same as described in Mr. Chauvin’s response to another earlier inquiry as shown below: My timing checks OK.
My questions are:
1. I presume that Marvel Mystery Oil would be preferable to Liquid Wrench?
2. How much Marvel Mystery Oil should be added to each spark plug hole”?
3. Do I rotate the pistons to then force the MMO to the valves head area?
Thank you in advance.
George

Originally Posted by H. L. Chauvin
Hi diy,

From miles away, and not being able to see or hear your "popping", this sounds like this could be a typical Model A that did not run for extended periods in a long time.

If so, with this possible condition, the volatile components of the oil lubrication at the valve stems & valve guides evaporated and left a sticky varnish material such that the valves are sticking, & moving up and down slowly; hence valves could be out of time causing delayed combustion "outside" of combustion chambers which one can readily hear & sounds like "popping".

As stated, (again if this is the case), moving the spark lever up & down changes ignition timing slightly, affecting engine "popping"; however, ignition timing changes are not enough to correct delayed valve timing, "and popping".

This "popping" caused by sticky valves was as common as a common cold in our area where old vintage tractors were not used in off-season-periods ...... sounded like a 12 gauge dove hunt in a farmer's back yard.

Before Liquid Wrench, Marvel Oil, & other "Mechanics in a Can", we all soaked our valves for 24 hours with Kerosene poured in each spark plug hole ....... this was the vintage miracle cure that worked 100% of the time to dissolve the varnish, set the valves free, and made our neighbors quit staring at our "popping" war zone.

But remember, ............. just one possibility.

[Patrick L.]

You may not be getting responses because of some confusion. I'm certainly confused.

So,
How does the engine run?
What kind of popping ?
Where is the popping ?
We need info.

[Geo.T]

Engine runs OK, particularly when the carb gas valve is opened further. The popping sound seems to emanate from the manifold area. Sounds like mini "backfires". In particular, when I first start up the popping sounds are almost constant, one every 2 to 3 seconds. Moving the timing lever makes some, but little difference.
I was also wondering if the problem could be due to a non-firing defective spark plug with the raw fuel mixture being exhausted to the hot exhaust manifold and igniting there??
Thank you for your interest.
George

[Big hammer]

Listen to the exhaust, is the popping coming from there? Listen at the carburetor inlet popping coming from there? Either way 4oz of MMO to 10 gal gas will free up sticking valves! Opening the GAV 3/4 - 1 turn for cold starts, and after its warmed up closing the GAV to about 1/4 open. After the MMO installed in the gas tank, go for a nice long drive, Enjoy! the ride :-)

[Chuck Sea/Tac]

You either have a manifold/vacuum leak, or are starving for fuel(lean).

[Patrick L.]

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1. compression test
2. when running spray starting fluid/ether along the intake gasket area. If the engine sound/running changes then there is a leak.
3. you have spark plug wires ? Not strips ?

[Geo.T]

I have the original strips