Every month or so, my '88 GT (73,000 miles) begins to run a tad poorer. Fuel mileage drops, idle degrades. That's when I know it's time to de-oxidize my distributor cap. White/green fuzz builds up enough inside (on the terminals) to mitigate the spark, apparently. So I keep a number of spares cleaned and ready to swap.

Question: I always got the copper terminal "premium" caps from NAPA or Car Quest (they appear to be the same manufacturer). Are there ones on the market (even GM) that will NOT need to be cleaned of oxides? I don't ever remember having this problem with anything but Fieros... and I go 'WAY back!

And yes, the screen is clean.

Accel is the best. I tried a bunch of different ones and the Accel lasts the longest. I had an MSD 6A box on my last Fiero and that thing would burn through all the other caps in no time but the Accel could take it for a lot longer. On the Fiero i have now, i just have an MSD coil but the Accel still is the best choice. They aren't pretty to look at but they sure work the best.

You can get them at Murrays (sp?), sometimes Pep Boys, and Auto Zone. If all those fail you can always get them through Summit Racing. Part# 8133 for any parts store and ACC-8133 for Summit.

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Activities Director N.I.F.E.

www.fierofocus.com

You know what? It sounds like you are having moisture inside your cap. Some caps have gone so far as put a vent in them to solve this. It allows the moisture to escape when the engine warms up. Try drilling a hole in your cap, what have you got to loose.

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Concrete Cruiser, 1986 GT, low & lean

quote Originally posted by fuzz: You know what? It sounds like you are having moisture inside your cap. Some caps have gone so far as put a vent in them to solve this. It allows the moisture to escape when the engine warms up. Try drilling a hole in your cap, what have you got to loose.

The distributor's base plate already has 2 screened vent holes in it. Perhaps they are blocked.

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Fiero Fiesta - August 1, 2004 - Calgary, Alberta <--- click this LINK

3.4L S/C 87 GT www.fierosound.com
2002/2003/2003 World of Wheels Winner &
Multiple IASCA Stereo Award Winner

Are you pressure washing your engine bay? If you get moisture sitting on the engine it will vapoize and make it's way into the the cap as everything heats and cools... might be a case where the aluminumn terminal caps like the OE style A/C Delco would work better?

Hey... aluminumn is lighter than brass... probably worth 5 hp if you put a sticker on with it ;-)

Like someone else said... check the screens, if plugged might want to try blowing them clear with compressed air and a wire brush. First thought would be carb or brake cleaner... but your cap might blow off/up when you go to start it.

hi the brass posts seem to be better ..try this post has some parts numbers.other dist post.

I agree. I'm using a Bosch cap with the brass.

Arn

One thing I've learned is, stay away from the caps that have the spring loaded center posts. The caps with the solid center contact post transmit volts better and allow less moisture in the cap. I had a Neihoff cap-rotor set and this was the case. Humid days the car wouldn't start. I didn't think it was the cap and rotor since they were new. After looking at the design, I realized how bad it was and went to the other solid center contact and I have not had the same problem.
As far as preventing moisture from getting to the distributor, use die-electric grease round the sealing edges of the cap. Also make sure you have plug wires that seal around the terminal posts on the cap and use die-electric grease there too. I have MSD plugs, and they seal real nice. ACCEL plugs don't. The only way to stop any moisture from getting in is to make the distributor air tight, and I dont think that's going to happen. But you can make it more air tight and lessen the problem.
Also some corrosion might be due to the reaction of ambiant gasses, metal and electricity.

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Rick D

86GT
84COUP

http://www.fierodriver.zymdragon.com

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