12V coil on a 6V system?

HelmetHead · HelmetHead's Garage

A buddy and I are trying to diagnose a rough running motor in his 356c. The car has a 6volt battery and charging system however I noticed last night that it's got a big sticker on the coil which states 12Volt (looks like a VW bosch blue coil). I read up on this and it seems to be common when converting a 6volt system to 12volts by replacing the points/condenser to 12volt along with the charging system but again, I believe this system is still 6volts

What symptoms would a 12V coil on a 6V system exhibit...it runs fine at low RPM but when we get above 3K with a load it sputters something awful.

callard · 07-09-2013, 09:24 AM

Could also be a bad condenser.

id10t · 07-11-2013, 04:35 AM

A 6v coil should still be available... I'd swap it out and see if that fixes it.

304065 · 07-25-2013, 05:51 PM

Quote:

Originally Posted by HelmetHead

A buddy and I are trying to diagnose a rough running motor in his 356c. The car has a 6volt battery and charging system however I noticed last night that it's got a big sticker on the coil which states 12Volt (looks like a VW bosch blue coil). I read up on this and it seems to be common when converting a 6volt system to 12volts by replacing the points/condenser to 12volt along with the charging system but again, I believe this system is still 6volts

What symptoms would a 12V coil on a 6V system exhibit...it runs fine at low RPM but when we get above 3K with a load it sputters something awful.

You lack the requisite ignition energy to fire the plugs. Change to 6v coil.

HelmetHead · HelmetHead's Garage

Quote:

Originally Posted by 304065

You lack the requisite ignition energy to fire the plugs. Change to 6v coil.

Thank you all for your input. As suggested I put a 6v coil on it a couple of days ago and presto...she runs like a top.
I can see where the 6v input into a 12v coil would fall flat when demand and rpm increases, what I haven't yet determined is the who, when and why a 12v coil on this car.