Dead spark plugs ?

[sim]

NGK D8EA 1958 sprite 938 Aluminum head from Moss. Point less Distributor from Moss, Coil is 30K . The question is Any idea why the NGk have a short life? I get about 2 years on them less than 2k miles. They go from working to not working in 4 starts about 15 miles. Not black no oil and not white. Just a tan Gray color. last start was a 1 mile hop and they would not restart the engine. Had to rope tow the POS back. I think they did the same thing to me 2 years ago.
Was going up a hill and lost one cylinder due to no spark. The other 3 went off one after the other before the top of the hill. Had enough energy to get over the top. Still need a push home 1/2 mile. I tested for spark at all points from the coil through distributor through wires to plugs. everything tested bad. replaced coil, tested now good. Still no spark at plugs Replaced wires and rotor. Tested spark again. This time I had it all the way to the plug but would not jump the gap. replace plugs and it work fine till the other day.
Thanks
Sim

 

[Jim_Gruber]

Coil polarity wired backwards perhaps. If you changed from positive to negative ground need to swap coil wires around. Car will run with wiring reversed there under a stock setup. Otherwise I'd speculate bad condenser.

 

[aeronca65t]

Jim has some good ideas. Also......

The NGK "8" series is fairly cold. I run them in my race car (although I realize some sources say they are OK for street cars). And your D8EA 12mm plugs are intended for motorcycles which run much higher revs where colder plugs work better.

Personally, I'd run NGK "7" or even "6" plugs (hotter) in a Spridget street car, especially if I was having plug deposit issues.

Also: Do you have the carbs set at the basic setting (jets 12 flats down?). Not set too rich (or even stuck float valve or misadjusted float level).

I know you've said you have good spark but I'll just say that I am a big fan of solid-core wires, even with electronic ignition (and not the carbon filament radio resistor wires that most people use). It's hard to find 7mm solid-core wires, but they fit best.

 

[arfamoe]

I installed these HT cables on my Midget after suffering from misfires and weak spark. If they can keep an aircraft aloft they must be good for an earthbound MG.

https://www.aircraftspruce.ca/catalog/eppages/spkplugwire.php

 

[sim]

Coil polarity wired backwards perhaps. If you changed from positive to negative ground need to swap coil wires around. Car will run with wiring reversed there under a stock setup. Otherwise I'd speculate bad condenser.

Hi
Still positive ground Will check to make sure it not reversed
Thanks

 

[sim]

Jim has some good ideas. Also......

The NGK "8" series is fairly cold. I run them in my race car (although I realize some sources say they are OK for street cars). And your D8EA 12mm plugs are intended for motorcycles which run much higher revs where colder plugs work better.

Personally, I'd run NGK "7" or even "6" plugs (hotter) in a Spridget street car, especially if I was having plug deposit issues.

Also: Do you have the carbs set at the basic setting (jets 12 flats down?). Not set too rich (or even stuck float valve or misadjusted float level).

I know you've said you have good spark but I'll just say that I am a big fan of solid-core wires, even with electronic ignition (and not the carbon filament radio resistor wires that most people use). It's hard to find 7mm solid-core wires, but they fit best.

Carbs setting are good I think float level is ok.
I had solid core wires till I switched to new electronic distributor. Said to switch back to carbon wires. Thinking was solid wires would interfere with the hal sensor in the distributor. If you think this is not the case, I will switch back. Will try a hotter plug
Thanks
Rod

 

[sim]

I installed these HT cables on my Midget after suffering from misfires and weak spark. If they can keep an aircraft aloft they must be good for an earthbound MG.

https://www.aircraftspruce.ca/catalog/eppages/spkplugwire.php

This looks like the ticket for solid wires with ignition shielding braid​

 

[aeronca65t]

The Aircraft Spruce wires above are exactly what I've been running with my Pertronix ignition for over 10 years. No problems.

 

[sim]

The Aircraft Spruce wires above are exactly what I've been running with my Pertronix ignition for over 10 years. No problems.

Thanks that is what I will get
Rod

 

[David_Doan]

Are the"dead" plugs shorted? If you put an ohm meeter from the top connector to ground do you get anything?

Shorted plugs could have killed the rest of your ignition.

 

[sim]

Are the"dead" plugs shorted? If you put an ohm meeter from the top connector to ground do you get anything?

Shorted plugs could have killed the rest of your ignition.

ohm meter has dead batteries. I do have a Ne2 test light and when it is in line with the end of the spark wire and plug I get no glow. If I go directly to ground , I get a glow. I get even a brighter glow if I go from end of coil wire to ground/
Thanks
rod

 

[Deleted member 8987]

ohm meter has dead batteries. I do have a Ne2 test light and when it is in line with the end of the spark wire and plug I get no glow. If I go directly to ground , I get a glow. I get even a brighter glow if I go from end of coil wire to ground/
Thanks
rod

That took twice reading to comprehend.
Coil wire to ground you are reading through the coil secondary, normal.
But to ground?
Or negative (hot) battery?
Ground is the cable that bolts to the chassis/block.
If you read the end of the plug to hot, and get a glow, most likely the porcelain is glazed.
Fuel additives (too much) can do that. No il deposits, so that's not it.
Wrong heat range can cook the porcelain.
Take your old plugs someplace that has a plug blaster, and clean them. Rotate them around to get the blast at all the porcelain.
Blow them out WELL with spray carb cleaner, including threads, then air.
Check gap and try them again.
If it runs, it's plugs.
As said, try a hotter heat range.

When it quits, do you have any spark at all at the plug wire end?
Phillips screwdriver inserted into boot held 1/4" from ground while someone cranks it will tell you.
For troubleshooting purposes, good information to have.
You have spark, your ignition is probably functional.
Clean the plugs and they work, try another heat range.

Lots of folks seen to like that brand, I never, ever use them.
I use Champions wherever on Brit cars and Fords.
Never, ever had any issues.
What brand and hat range does the manual call out, specifically?

Dave

 

[sim]

That took twice reading to comprehend.
Coil wire to ground you are reading through the coil secondary, normal.
But to ground?
Or negative (hot) battery?
Ground is the cable that bolts to the chassis/block.
If you read the end of the plug to hot, and get a glow, most likely the porcelain is glazed.
Fuel additives (too much) can do that. No il deposits, so that's not it.
Wrong heat range can cook the porcelain.
Take your old plugs someplace that has a plug blaster, and clean them. Rotate them around to get the blast at all the porcelain.
Blow them out WELL with spray carb cleaner, including threads, then air.
Check gap and try them again.
If it runs, it's plugs.
As said, try a hotter heat range.

When it quits, do you have any spark at all at the plug wire end?
Phillips screwdriver inserted into boot held 1/4" from ground while someone cranks it will tell you.
For troubleshooting purposes, good information to have.
You have spark, your ignition is probably functional.
Clean the plugs and they work, try another heat range.

Lots of folks seen to like that brand, I never, ever use them.
I use Champions wherever on Brit cars and Fords.
Never, ever had any issues.
What brand and hat range does the manual call out, specifically?

Dave

Hi Dave
coil is not to ground. But I am not sure I have the + side to the + terminal. When i installed the coil, I think I did it correctly. the wire from the ignition should be - neg and that should go to the neg post on the coil. the other wire goes to the Distributor. The Dist interrupts the flow through the coil and coil puts out the high V. I get good HV at the end of spark wire but nothing through the plug. I could have glazed porcelain and i should go a little hotter. The plan is to go to aircraft wire that has a shield and new plugs.
Thanks
Sim

 

[Deleted member 8987]

If you've got good spark at the ends of the wires, new wires will give you....good spark.
How far does the spark jump?
Still thinking wrong heat range or additive issues.
I say additives as in the old US car restoration biz, I saw a LOT of that.
Every so often, add whatever additive was in vogue that week, never run it enough to really use all the petrol....made a mess of fuel pump valving, carb needle valves, gum on valve stems.

Nobody know how much StaBil is too much, either.

Dave

 

[sim]

If you've got good spark at the ends of the wires, new wires will give you....good spark.
How far does the spark jump?
Still thinking wrong heat range or additive issues.
I say additives as in the old US car restoration biz, I saw a LOT of that.
Every so often, add whatever additive was in vogue that week, never run it enough to really use all the petrol....made a mess of fuel pump valving, carb needle valves, gum on valve stems.

Nobody know how much StaBil is too much, either.

Dave

No Additives. i drive the car daily but they are short hops. hotter plugs should help Not sure on the jump I use a test light. If it is bright orange then a really good spark. Lighter not so good. It is brighter at the end of the coil wire than at the end of the spark wire.
Here is a picture of my test light
https://www.youtube.com/watch?v=NBD9x3UIHww

 

[HealeyRick]

Those plugs seem pretty cold to me, too. Mild street 948s generally run pretty well on NGK BP6ES plugs. It would be a cheap test to give a set of them a try. If that doesn't work, I'd be looking to see if there's something in your distributor that's not giving out enough juice.

 

[sim]

Those plugs seem pretty cold to me, too. Mild street 948s generally run pretty well on NGK BP6ES plugs. It would be a cheap test to give a set of them a try. If that doesn't work, I'd be looking to see if there's something in your distributor that's not giving out enough juice.

I am running the aluminum Head from moss. That was the plug they suggested. Will go hotter and see what happens
Thanks
Rod

 

[HealeyRick]

I am running the aluminum Head from moss. That was the plug they suggested. Will go hotter and see what happens
Thanks
Rod

Maybe it would be a good idea to give Moss a call and see what they'd suggest. I'm running the BP6ES on a 948 cc with a 12G295 iron head and have no problems. Maybe the Ali head has some different requirements. The phone call is free.

 

[sim]

Maybe it would be a good idea to give Moss a call and see what they'd suggest. I'm running the BP6ES on a 948 cc with a 12G295 iron head and have no problems. Maybe the Ali head has some different requirements. The phone call is free.

I am running what they suggest for the Al head. I bought the plugs from them. But do they really know what they are doing.
they never suggested running shield copper core wires.

 

[nomad]

Can you fit a set of points and a condenser? Just as a test. Could be just a weak spark from the pertronix.