Platinum plugs and gap

[Jay Laifman]

I know this is a subject that has been brought up many times before. I understand that platinum plugs are often put down for the older cars because additional oil causes fouling issues.

I have a 73.5 911T with the CIS injection. On the Pelican site, it specially identifies the 73.5 and identifies a specific Bosch platinum plug for it. Pelican does not seem to identify this plug for any other cars. Admittedly, I ordered a set of the plugs and did not focus on the fact that they are platinum. I've always used copper in there.

Now that I have them, I'm thinking of using them for this round.

My question is about the gap. The gap is wider than what the factory calls for. I went to the Bosch site to see what it says about the gap. It says the gaps are pre-set for the application and therefore they don't have to be adjusted. But, really? This plug is specifically for the 73.5 911T??

Assuming Bosch is wrong on this one. Is the gap size the same regardless of the brand and style of plug? I have seen the posts on why wider gaps help on cold starting and some fouling (though of course I also saw a post that said the exact opposite).

This is not one of the double or quad tip plugs. Just a single tip.

[Jerry L]

Jay, in general the platinum plugs are running a wider gap from say the Supers as the tiny + electrode in the plug will allow a similar volt input jump a wider gap and in theory give you a better flame propagation. I would trust the Bosch settings and give them a shot. I have used them in early cars as well a iridium and other things to tinker with, in the end I see no big advantage or disadvantage other than price. I have used platinum in a over carbed motor to come up to temp faster and reduce low end fouling.

Regards

[Jay Laifman]

For what it's worth, I just spoke to Bosch. The techincal support guy who called me back said that yes, they are all pregapped at a specific point - but if that's not the correct point, they should be regapped. He said it is a common misnomer that pregapped means for every application. He said it is ususally in the center of the range of gaps for that plug. He did say that some of their multi point plugs cannot be changed. As to a wider gap, he said to gap it at whatever the factor called for originally.

That said, I'm the first to not trust a salesman or claimed tech guy who is reading from a pre-scripted answer. But, this guy seemed to know his stuff.

[RSTarga]

If you have the stock CD ignition I'd go for the wider gap of the 2. If that is Porsche spec or how the plugs came.
I always thought that only the E and S used Platinum plugs although the newer Bosch Platinum look nothing like the original ones. NGK or Nippondenso iridium plugs look more like the originals. I think the S used a W265P21 and the E a W235P21, the T must have been in the 200 range whatever that translates to now.
For a T I'd probably prefer a copper NGK.

[Jay Laifman]

Yeah, on hindsight, I have always used the copper, and I probably will in the future. This only came up because I ordered the specifically noted plugs from Pelican for the 73.5 T, and when they came I found they were platinum. They were not expensive, and I could just get the copper plugs. But, I figured that since I had them, might as well use them and see if I notice any difference. Thanks for the thoughts.

[ESully]

Jay,
Please give an update when you have some mileage on them. A lot of posts on Pelican say to stick with the NGK copper, but I have always wondered if there is a difference.