C-2 Spark Plugs

[Donald M.]

What would the group reccommend for a '67 327/300 street driven car OTHER THAN AC? I am especially intersted in platinum plugs or even multiple electrodes. I am not having any fouling problems, just want a smoother engine, plug-wise.Thanx!
Don

[mike cobine]

Re: C-2 Spark Plugs

Why not the AC? Some people have good luck with Champions, I've never had luck with them. But I usually run a heat range hotter. A 45 instead of the specified 44. And an extended plug like a 45S will work well.

Not the answer for the platium plugs, but maybe some help to you anyway.

[Joe L.]

Re: C-2 Spark Plugs

Don------

I have tried numerous different brand of spark plugs and never found any that would run better than Champions in a Chevrolet V-8, both small block and big block. I have used Champions exclusively for years.

However, there is a lot of new spark plug technology that's come on the market in the last 10+ years. I'd be ready to experiment with some of these to see if they'll do better than Champions.

[Jack H.]

Re: C-2 Spark Plugs

If you have a set of factory stock reproduction plug wires, I'd start there for a smoother running engine. Turn off the lights in the garage some night, fire the engine and look/watch. I'll bet you see random arcing from the plug wires...

[mike cobine]

Re: C-2 Spark Plugs

Don, listen to Jack. Most ignition problems I've ever had I traced back to bad wires and/or corroded cap and rotor. I've pulled plugs out that were coated almost solid out of engines, and found often little improvement with new plugs. Change the rotor and cap or the wires and the car comes alive.

[Duke W.]

Re: C-2 Spark Plugs

C-2s were originally equipped with non-resistor plugs. Circa '69 resistor plugs were installed - perhaps to meet new, sticter EMI requirments, but they dissipate some spark energy.

Few non-resistor plugs are available, nowadays, and mulitple electodes are heat sinks that can quench an insipient flame. They are a marketing gimmick except on a few engines that are designed to use them.

Too bad AC no longer offers the non-resistor AC 45 as that was the best normal driving plug to use in any small block, however both NGK and Denso make equivalents, the B4 and W-14U, respectively.

If you suffer from "brand xenophobia" consider that all new Corvettes ship out of Bowling Green with Denso spark plugs.

With unleaded fuel and reasonable fuel mixture and oil control, these plugs should have a service life of 15-30K miles, and with a good cleaning every 15K miles they may be good for 60K. Unless you are racking up high annual mileage, the longer life characteristics of some platinum (not all are "long life" type) plugs may be of little value, and all that I know of are resistor type.

Duke

[John H.]

Re: C-2 Spark Plugs

Duke -

In the near future, ALL GM products will ship with Denso plugs - GM just dropped the contract with AC-Delco/Delphi for spark plugs.

[Jack H.]

A sad commentary on American competitiveness! *NM*

[Joe L.]

Re: C-2 Spark Plugs

John-----

I think that they pretty much had to do that or would have had to do it very soon. I believe that DELPHI is going to be exiting the spark plug manufacturing business. If not, then they're definitely going to be exiting the spark plug manufacturing business in the US. I believe that Denso has many US manufacturing operations. So, it may be that the Denso plugs to be used by GM will actually be of US manufacture. For at least the last several years, I think that AC spark plugs have been manufactured in Mexico.

What surprises me with the GM move to Denso is that they don't have Denso manufacture them with the "AC" or "AC-Delco" branding. Those brands belong to GM. Most of the parts sold under those brands are not manufactured by GM and, instead, are manufactured by outside suppliers to GM. In fact, DELPHI was one of those suppliers. I would think that Denso would pick up where DELPHI left off.

[Patrick H.]

Re: C-2 Spark Plugs

I'd bet that GM didn't want to spend the extra $0.03 per plug to have them with "their" AC brand on them.

Really.

Patrick

[John H.]

Re: C-2 Spark Plugs

GM's first usage of Denso parts was the starter on the Northstar engine; the starter on that engine is buried down in the valley between the cylinder banks, sealed in there underneath the intake manifold, requiring major disassembly to access, and Cadillac chose not to take a chance on a Delco starter in that location for reliability reasons. Caused a huge ruckus in the Olds Engineering garage when they built the first Aurora prototypes, got the engines from Cadillac, and the UAW mechanics found out they had Japanese starters.

[Donald M.]

Would That Now Be "AC DENSO"? *NM*

[Philip C.]

I dont think you could get it to run any

smoother by changing plug brand alone. I use extended tip plugs because thats the advice I got from the tuner guys. But if its running smooth but your looking to stand a nickel on the intake then thats a different story. Phil 8063