changed plugs now poping

diyforever

Junior Member
1930 Model A.
Well, decided to change from Motorcraft T10s to Champion W18. WHY? It was next thing on list. Gap them to .035. Engine starts but now pops like a pop corn popper. I attach pic off old plugs. Black but not oily.
Should I narrow the gap to .030?
 

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I'll try to explain. While engine is running, it idles but the engine makes popping noises. Not present with old plugs. I do the following;
1 - pull timing lever down all the way and seems to reduce the popping. But still happens.
2 - opened GAV slightly and improves a little more but still present.
Didn't have to do 1 and 2 above with old plugs.
 
Is it popping out the carb, exhaust, or is it a compression leak from a loose plug. Did you install gaskets under each plug, are you running modern wires and possibly crossed one... Is it misfiring????? Cracked plug...drop something down the hole.... Why not put 3X's on your list??
Just some creative guesses....but I have a feeling it will be none of these
 
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Well, I started it up and out of garage so that I could check for leaks. Then it heated up and overflowed thru the overflow tube. Lots of rusty looking liquid. So, will have to diagnose the cooling system and correct as first priority then attack the popping.
BTW....car has old type wires. 99.99999 sure nothing fell in spark plug holes...:rolleyes: yep on 3x plugs and maybe put Motorcraft back in.
Theoretically speaking. .. is there a plausible explanation on installing new plugs and popping?
 
I share the opinion of others that you did something more than just changed plugs or it was not running properly in the first place. Wayne
 
Hi diy,

Popping could really be a coincidence rooted in another problem that just happened at the time plugs were changed.

Reporting lots of rusty looking liquid like shocking news sounds suspicious ...... then your being shocked with the engine heating up sounds even more suspicious ...... several unmentioned problems thus far may cause popping ....... a little more history may help ........... like ......... how long has this car been sitting with no maintenance?

What is on the remainder of your "check list"?
 
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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.
 
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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.

Technician in a can ,, this is 2016
 
Hi A31,

"Marvel Oil starts in 1923."

Also ........ Air Conditioning was invented in 1923.

Then .............. TV was invented in 1927.

Maybe our vintage neighbors never learned about Marvel Oil or had Air Conditioning in their cars and houses because Marvel & A/C never placed ads on TV back then ....... and/or ....... ?????????????????
 
Mr. Foster,

Per your #15, so few today know this about Kerosene ..... for removing thick, sticky Model A valve varnish, Kerosene makes Marvel Mystery oil look about as effective as spraying valve stems with watermelon juice.

Kerosene was also extensively used in vintage engineer field tests to distinguish between asphalt and coal tar content in bitumen surfaced highways and flat membrane roofs.

My Dad sold Kerosene for 15 cents a gallon when gasoline was 20 cents a gallon. Old folks used to refer to Kerosene as "Insurance Oil" and "Coal Oil" ..... (positive reasons for said nomenclature) .... many kept Kerosene in a small bottle in their medicine cabinets ..... before screen doors and windows, "immediately" stopped horrible mosquito bite itching where extremely difficult to reach and scratch ...... or even where it was easy to scratch ..... appears nothing else works like Kerosene for mosquito bite itching, cleaning Model A valve stems, and bitumen tests .... and please don't tell anybody about mosquito bites ..... we may "all" get sued for practicing medicine without an M.D. degree & a medical license.
 
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