Is platinum OK??

[81 SC Ray]

Hi,

I discovered that the previous owner put Bosch Platinum spark plugs in my stock 1981 SC. The manual calls for standard copper plugs. Is there any problem with using the platinum plug??

Thanks.
Ray

[billybek]

My SC came with those in it as well.
Changed out to Bosch copper plugs and it ran better.

[kach22i]

If those are the 4-ground Electrode type, they suck.

NGK or Bosch solid copper is conventional wisdom.

[81 SC Ray]

They are not the four ground type - they have the single electrode.

[Gogar]

+1 If you have them out and you're looking at them, then spend $10 and put in some Bosch or NGK copper plugs. I think the Bosch is WR5DC and NGK is BP7ES

[island911]

I think that the platinum's are designed more for longevity (while using as little of the expensive electrode material as possible) whereas the old-school type of plug give a bigger better spark, but need to be re-gapped/replaced more often.

[81 SC Ray]

I have new correct plugs, I just could not get to plug number 6. I got the tool on it, I just could not get enough leverage with all the other stuff in the way. I have to get creative!! Like everything with the 911 - you have to be patient and learn to do a lot by feel!!!

[Trackrash]

What Bosh platinum? They make four types of "platinum".

My experience is with "platinum plus", the type that has the one tapered thin electrode. They suck and should not be used in an aircooled motor. The tip runs hot and encourages pre-ignition.

[kach22i]

FYI: a couple people in this old thread thought iridium was good.

No first hand experience myself.

iridium spark plugs

[81 SC Ray]

Gordon,

That is what I had --- I say had --- I just changed all the plugs to the factory recommended Bosch plugs. I have no idea why the previous owner, or his mechanic would put those plugs in.

Thanks for your help.

Ray