Franklin 165 Autolite Spark Plugs?
- Thread starter dtreid
- Start date
I started to look into this shielded plug series awhile back. They might be just fine.
This is what I have found so far from combing the forums. They were designed for mil vehicles like a 4 by 4 I called my ride overseas decades ago. They are resistor types. That means they are not likely to erode to non-functional in 25 hours like the formerly approved C10S plug. The price is right. ( about 6 - 9 dollars) at O'reilly's ) The 2243, 2245, 2247 are a cold to hot heat ranged series. The 2243 is coldest.
There is also a slightly different series 2242, 2244, 2246. The difference is a full inside ceramic sleeve to the top of the plug. Some of the military vehicles for which the 1st series mentioned were originally intended can't use these plugs due to the differences. Which series would work best and accommodate an ordinary shielded aircraft spark lead, I don't know.
Well, I had very good luck with BG 707SR's. But if these could be a good replacement, I'll quit looking for more, unless they are bargains.
This is what I have found so far from combing the forums. They were designed for mil vehicles like a 4 by 4 I called my ride overseas decades ago. They are resistor types. That means they are not likely to erode to non-functional in 25 hours like the formerly approved C10S plug. The price is right. ( about 6 - 9 dollars) at O'reilly's ) The 2243, 2245, 2247 are a cold to hot heat ranged series. The 2243 is coldest.
There is also a slightly different series 2242, 2244, 2246. The difference is a full inside ceramic sleeve to the top of the plug. Some of the military vehicles for which the 1st series mentioned were originally intended can't use these plugs due to the differences. Which series would work best and accommodate an ordinary shielded aircraft spark lead, I don't know.
Well, I had very good luck with BG 707SR's. But if these could be a good replacement, I'll quit looking for more, unless they are bargains.
twheel47
New member
For whatever it's worth to you, the Type Certificate Data Sheet (TCDS) for the Franklin engines, E-238, specify what plugs are allowed. The FAA take is that if it's not listed, it's not allowed on a certificated engine, hence certificated aircraft. There is some wiggle room because the TCDS is no longer updated by way of "direct replacement" and "superceded part" plugs if the manufacturer's data shows another plug meets the specification. Case in point is the Champion REJ38 that is the correct plug but didn't exist when the TCDS was put out. Still, a jerk (in the FAA?) could be a bother even if he's not ultimate correct.
The 150 HP can use:
AC A-44, SA-43, SA-47
Autolite A-4, A48, A4SA, BG RB613S
Champion 78S, AJ-66, REJ-38, C10S-4, J-43
The 165 HP can use:
AC A-44, SA-43, SA-47
Autolite A-4, A4S, A48A,
Champion 78S, AJ-66, C10S-4, S10S-4, REJ-38
Other than those, it "isn't legal" and an IA is either in deep poo or is headed there if they sign off an annual (and get caught).
Blue side up
Scott
P.S. Hope I didn't miss any other legal plugs that have happened along.
The 150 HP can use:
AC A-44, SA-43, SA-47
Autolite A-4, A48, A4SA, BG RB613S
Champion 78S, AJ-66, REJ-38, C10S-4, J-43
The 165 HP can use:
AC A-44, SA-43, SA-47
Autolite A-4, A4S, A48A,
Champion 78S, AJ-66, C10S-4, S10S-4, REJ-38
Other than those, it "isn't legal" and an IA is either in deep poo or is headed there if they sign off an annual (and get caught).
Blue side up
Scott
P.S. Hope I didn't miss any other legal plugs that have happened along.
Larry Lowenkron
New member
or..."They weren't in there when I did the annual".
Larry Lowenkron
New member
Larry, what do you mean by "later day list"?
LL
LL
Yeah, the resistor is very important to keep the electrodes from eroding.*
Larry Wheelock, over on the Stinson forum had exactly the same experience as me with C10s/ BG707 spark plugs. :
http://www.stinsonclub.org/newBB3/viewtopic.php?f=5&t=703
He quoted the same short 25 hours with the C10S that I have mentioned for years.
SO, because the FAA can't find their ass with either hand to include excellent plugs that perform very well in the TCDS, we have to act like criminals and switch plugs for annuals.
Maybe, the good guys at Small Aircraft Directorate should be made aware of this dumb stuff that, in this case, has been going on for over 50 years .
ron
* When the spark occurs, a very short arc in the amp range will follow if the lead capacitance unloads across the gap without a resistor to limit current. The resistor also lengthens the spark duration, which is good. A common application of the spark/arc phenomenon is TIG welders that use a spark to start the arc.
Larry Wheelock, over on the Stinson forum had exactly the same experience as me with C10s/ BG707 spark plugs. :
http://www.stinsonclub.org/newBB3/viewtopic.php?f=5&t=703
He quoted the same short 25 hours with the C10S that I have mentioned for years.
SO, because the FAA can't find their ass with either hand to include excellent plugs that perform very well in the TCDS, we have to act like criminals and switch plugs for annuals.
Maybe, the good guys at Small Aircraft Directorate should be made aware of this dumb stuff that, in this case, has been going on for over 50 years .
ron
* When the spark occurs, a very short arc in the amp range will follow if the lead capacitance unloads across the gap without a resistor to limit current. The resistor also lengthens the spark duration, which is good. A common application of the spark/arc phenomenon is TIG welders that use a spark to start the arc.
blimpy
New member
ok... L/C/R resonance or time constant if you prefer.. and the R is important in the discharge time
and maybe wave shape.
This would explain why the AC non-resistor types on the list are 7 or 8 bucks each at Fresno
Considering the fact that is almost impossible to change the plugs on cyl #6 without pulling the
cowling... I think I will pass. If they last 25 hours.. what are hours 23 and 24 like ? !
:shock:
and maybe wave shape.
This would explain why the AC non-resistor types on the list are 7 or 8 bucks each at Fresno
Considering the fact that is almost impossible to change the plugs on cyl #6 without pulling the
cowling... I think I will pass. If they last 25 hours.. what are hours 23 and 24 like ? !
:shock:
blimpy
New member
autolite 2245 and similar:
legalities aside for the length of this comment anyway;
Heat Range is Really Important in Aircooled Engines.
Go one step too hot and you can burn a hole through the top of a piston in a heartbeat !
Without some Reliable way to match heat range.. I wouldn't EVER put some dingwad
spark plug in any aircooled engine more valuable than a trash picked lawn mower ( and probably not then).
Seriously, who is going to use a rare-ish $10,000 engine as a test bed for a $3 dollar spark plug,
and then go fly behind it ? !!
I guess maybe flying a VW conversion, somebody did this if they wanted shielded ignition...
but golly gee whillikers Slim.
Now maybe there IS some reputable cross-over chart for these military dual fuel wonder plugs.
So Dan.. in his Experimental Cruisair can test them for us !
No wait.. we need Dan !
Next plan ? :shock:
legalities aside for the length of this comment anyway;
Heat Range is Really Important in Aircooled Engines.
Go one step too hot and you can burn a hole through the top of a piston in a heartbeat !
Without some Reliable way to match heat range.. I wouldn't EVER put some dingwad
spark plug in any aircooled engine more valuable than a trash picked lawn mower ( and probably not then).
Seriously, who is going to use a rare-ish $10,000 engine as a test bed for a $3 dollar spark plug,
and then go fly behind it ? !!
I guess maybe flying a VW conversion, somebody did this if they wanted shielded ignition...
but golly gee whillikers Slim.
Now maybe there IS some reputable cross-over chart for these military dual fuel wonder plugs.
So Dan.. in his Experimental Cruisair can test them for us !
No wait.. we need Dan !
Next plan ? :shock:
Dan Cullman
New member
Dan is 10,000 miles away in the steaming jungles of Southeast Asia. WIFI in the swamp!
The sparkplug forum has been chewed on for years and every year we have new owner/operators in for the experience.
Here's my short and simple list of suggestions:
Work with an AP/IA that you can tolerate and is knowledgeable and tolerant of the old and obsolete aircraft and engines.
The type data certificate sheets are not updated very often on old equipment.
Many of the sparkplugs listed are not available, unshielded nor desirable today.
Many sparkplugs like the BG707SR which have a good reputation were approved in later Franklins, especially helicopter Franklins.
I find the AC 47 series very inexpensive and long lived and available on the internet.
I think the C10S is getting a bad rap on the recent forum. No they don't last as long as the REJ38, but, I have always considered them good for 100-125 hours. I haven't had them fail like some later REM40E plugs.....just wear out.
Get together with the guy who signs your annual. Come to an understanding about what he wants in a spark plug.
Dan
The sparkplug forum has been chewed on for years and every year we have new owner/operators in for the experience.
Here's my short and simple list of suggestions:
Work with an AP/IA that you can tolerate and is knowledgeable and tolerant of the old and obsolete aircraft and engines.
The type data certificate sheets are not updated very often on old equipment.
Many of the sparkplugs listed are not available, unshielded nor desirable today.
Many sparkplugs like the BG707SR which have a good reputation were approved in later Franklins, especially helicopter Franklins.
I find the AC 47 series very inexpensive and long lived and available on the internet.
I think the C10S is getting a bad rap on the recent forum. No they don't last as long as the REJ38, but, I have always considered them good for 100-125 hours. I haven't had them fail like some later REM40E plugs.....just wear out.
Get together with the guy who signs your annual. Come to an understanding about what he wants in a spark plug.
Dan
blimpy
New member
thanks Dan C. always a breath of fresh air.
My REJ's have reached " half life" or beyond.
Always missing the BG's when they show up.
I will look for the AC's.
If we were in experimental land.. and were willing to use unshielded plugs,
there is a wealth of 14mm options for aircooled motorcycle and auto applications.
Not to mention electronic ignitions with actual advance curves !
Been some interesting articles in the last year concerning the improvement in power and efficiency
that comes with these modern ignition systems.
Mix that with a simple single point fuel injector system... and life might start to make sense
even at $6 a gallon.
Not holding breath.
My REJ's have reached " half life" or beyond.
Always missing the BG's when they show up.
I will look for the AC's.
If we were in experimental land.. and were willing to use unshielded plugs,
there is a wealth of 14mm options for aircooled motorcycle and auto applications.
Not to mention electronic ignitions with actual advance curves !
Been some interesting articles in the last year concerning the improvement in power and efficiency
that comes with these modern ignition systems.
Mix that with a simple single point fuel injector system... and life might start to make sense
even at $6 a gallon.
Not holding breath.