Beetle Spark Plug Life

[No More Landy]

My Beetle has been running quite well for some time, but all of a Sardine, from one day to the next run's like a pig.

Thought it was a blockage in the carb so I stripped and fully cleaned but found no smoking gun.

She shakes quite badly, so it sounds like not firing on all cylinders.

Have all new plug leads, new coil, condenser and points and plugs not that much mileage but at least 1 year old.

Took out two plugs and measured the resistance with a multimeter between the end and the body and found one att 8 Mega Ohm and the other at 0,379 Mega Ohm. The one with high resistance seemed to have soot on the end showing it was firing but the other was clean as if not.

This is the second time that I have a dead plug after relatively low mileage, that is why I changed all the above bits.

Any ideas from the experts.

Thanks guys

[Haans]

Mornin t'you kind Sire,. It seems that all the engine "ghurus" have gone into hibernation already !!!

but,... we've had a similar issue on a bay mostly no 3 cylinder,... now I'm no expert but ,...
is it a specific cylinder,. or random ?
check compression ? if not random
swop plug leads around and see if the "dead" plug follows a lead ??
valve adjustment settings etc ??
this is just to get your mind in gear to start eliminating some issues to get to the bottom.
with the bay we went with a plug hotter in the range,...purely because the distances we travel was mostly less than 8 km per trip,.... yes it did help in our situation.
and yes the motor was fairly tired as well !
hope this trigger some brain waves !! good luck
regards Haans

[No More Landy]

Changed all 4 plugs yesterday for new and she runs so sweet again.

Tested all old plugs on my multimeter and there was only 1 that was good. Remaining 3 had resistance which is no good.

Sent from my SM-A546E using Tapatalk

[AlanH]

What make were the old plugs and new?
I have heard to stay away from a certain brand but cannot remember which. I was also recommended a brand and would need to check as I bought a set to keep in the bus for spare.

[Tony Z]

the fault could lie in anything from the condensor being wrong to leaking rings
I've only had one plug die on me in the last 10 years and I am using my vehicles fairly often.
I did however kill 4 when I decided to open my plug gap from 0.6mm to 1mm to test my fancy MSD 5220 ignition system. The spark wasnt big enough to handle those gaps and I killed the plugs in under 100km.
I've also had someone come to me with issues of fowling plugs regularly and if he puts in new plugs, the car runs well for 20 min then doesnt hardly runs anymore - that turned out to be leaking needle valves in the carbs.

If you dont have any obvious faults in your system and EVERYTHING is working as it should, then I'd reset the plug gaps to 0.5mm (make it 0.1mm smaller than its supposed to be).
Also ensure that your point gap it correct and your timing is right.

[No More Landy]

What make were the old plugs and new?
I have heard to stay away from a certain brand but cannot remember which. I was also recommended a brand and would need to check as I bought a set to keep in the bus for spare.

NGK

Sent from my SM-A326B using Tapatalk

[Pine]

I've had the best success with Champion N7YC plugs

[No More Landy]

Drove her today for 30km and at one point had a miss fire again for a short time but it went away.
Let's see how long they last

Sent from my SM-A326B using Tapatalk

[No More Landy]

Just a thought from an older colleague who suggested that because I have those softer floppy plug leads instead of traditional copper core leads that the carbon type are no good for the plugs.
Any truth to this?
She is still running well so far


Sent from my iPhone using Tapatalk

[sean]

Just a thought from an older colleague who suggested that because I have those softer floppy plug leads instead of traditional copper core leads that the carbon type are no good for the plugs.
Any truth to this?
She is still running well so far


Sent from my iPhone using Tapatalk

I don’t believe so. Both work just fine. I’ve got many cars running Bougicords for years with no issues.

[No More Landy]

Just a thought from an older colleague who suggested that because I have those softer floppy plug leads instead of traditional copper core leads that the carbon type are no good for the plugs.
Any truth to this?
She is still running well so far


Sent from my iPhone using Tapatalk

I don’t believe so. Both work just fine. I’ve got many cars running Bougicords for years with no issues.

Thanks. Maybe just a bad batch of plugs

Sent from my SM-A546E using Tapatalk

[John Alves]

I had similar issues with plugs dying on me, turned out, my mixture was a little too rich

[Tony Z]

wrong mixture and/or wrong temperature range will foul out spark plugs.
They need to get into the "self cleaning" temperature for them to operate properly.

[No More Landy]

They not at all fouled, only just died/down to earth

Sent from my SM-A546E using Tapatalk

[Tony Z]

from
https://www.ngk.com.au/technical_info/o ... mperature/

The operating temperature of a spark plug varies between 450-870°C. At 450°C the spark plug reaches its self cleaning temperature; this means that carbon deposits which are produced during combustion are actively burnt off the insulator nose. When too many carbon deposits accumulate along the insulator nose carbon fouling occurs and engine misfire may occur. If the temperature of a spark plug exceeds 870°C overheating may occur leading to spark plug and possible engine damage.