Toddimus

Hi,

Just a quick question for those of you who have bought distributor caps for a 964 or 993 lately...

Do yours have an internal distributor post that looks like this?


If you have previously installed your cap and they look like this, you've got a problem. Either you installed it wrong or your distributor bearings need some help. But what if you just opened the box and your contacts have scoring like that? Will it matter?

The vendor who just sold me mine, said he'd replace the ones I just bought, but all of his distributor cap stock has the same grooves. It sounds like the lathe at the Bosch factory in Spain is our of whack. The two that I just bought have EXACTLY the same grooves. The whole batch is apparently like this! Unfortunately, this seems to me a very plausible explanation.

Pretty sad that Bosch doesn't have better quality control! Especially since these caps have an MSRP of around $100!!!! Think of the profit margin on that part!!! Not that any of us would actually pay that much for one, but even for half of that, it's pretty surprising. Just curious if you have seen any like this, or if you think they'll give me any trouble.

Having been a physics major in college, I should already know the answer, but I'm not certain.

so here's my conjecture...

There surely is an arc of electricity inside the distributor between the rotor and the inside contacts of the cap. Anybody who has looked for a vacuum leak on an older car with a can of brake or carburetor cleaner has found that there's an ignition source near the distributor. You know who you are. You probably left the chuck key in the drill press or lathe too. I must confess, I've been there.

... NOW WHERE'S THAT FIRE EXTINGUISHER????!!.....

The spark will jump the shortest or lowest dielectric constant path (i.e. easiest path) It doesn't really matter if there's grooves in the cap contacts so long as the high points of the grooves are the same distance to the rotor as are the other contacts. This is the same premise that says multiple grounding tabs on a spark plug are superfluous. The spark always, always, ALWAYS jumps the shortest gap.

Now, erosion of the high points might prematurely induce a larger gap on the tab (with grooves already in it) since there's less material to erode away. This would potentially reduce spark at the actual spark plug that leads from this distributor cap contact. Do any folks have a theory on this? Will it matter?

Am I crazy? Should I look for new caps or should I shut up and smile with my new caps and spark plugs? I'll remove as much sheet metal as it takes to get to all 12 plugs. I'm fearless. How hard can it be? I've got caps, rotors, plugs, all filters, Delvac gear oil, dist. belt, and a clean blue mechanic's jumpsuit. What could be better?

TomF

It appears that the when they turned the cap, it was slightly off-center, hence the deep grooves on one or more of the contacts. I would not be happy with this on my car, as I have seen how little it takes to end up with a bad spark. I would get the dealer to supply you with new caps.

Toddimus

Tom,

Thanks for the reply. I've had a good email exchange with the vendor and he says all of the caps he has in stock have the same grooves so he doesn't have anything better for replacement. He did offer to give me my money back, and also noted that there's a 1 year warranty on the part. Great, responsive customer service. And no, it wasn't a vendor with the name of a bird.

I'm just curious if anybody else has seen caps like this from the factory. Bueller? Bueller?

Royalcarrera

Thank you, I received my two new distributor caps yesterday and did not think of examine them that close.
WOW, Looking for the grooving which both have, one cap had some bad cracks! you cannot be to ****. Thank again. Royal
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JasonAndreas

Not in a set purchased just after the first of the year. One thing I would be curious about is where the vendor sourced the caps? Last summer I was at a talk given by the regional manager of Bosch's aftermarket division and he mentioned that they were manufacturing in China and a few other countries but not importing those products into the USA. The parts were not up to standard in terms of expected usage lifetime or initial quality and that was reflected in the cost ($35USD retail MAF sensor) . So I wonder if internet vendors are sourcing (or their distributors) are buying this stuff or if Bosch USA Aftermarket is now selling this crap? What you might want to try is to send an email with your photo to Jeff@Sunset asking him to look for similar problems on the parts they have in stock. He has been extremely helpful when I've had questions that no other vendor could/would help with, including ordering a part that he knew (I made it perfectly clear that) I had no interest in buying but had questions about.

AOW162435

I picked up a set of caps a few months ago from Sunset and had no issues. I did remember inspecting the caps and saw nothing like this.

Andreas

Toddimus

I don't know why I missed these replies?? Thanks JasonAndreas and Andreas! I'll shoot Jeff an email. For what it's worth, the parts have "Made in Spain" on the boxes. I'm reluctant to divulge the vendor because he has been very helpful and offered to give me my money back. I don't want to tarnish his business with some bad press. He just got a bad batch of caps and can't replace mine with better ones.

Cheers