Failure #2 of MSD distributor cap on FE ???

[edwhite7]

You mean like this.

I couldn't get the car to start, when I pulled the cap this is what I found. This cap is less than 500 miles old. MSD 8594 dist with MSD 6AL box and blaster coil.
The cap is vented, tomorrow I will cut a window in the side of the cap so that I can see what is going on. I have a feeling that the rotor may be lower than the cap. I think I will look elsewhere for a distributor. My last distributor looked like this after two years.

MSD said it was from ozone and an unvented cap. I replaced it wth a new distributor and a vented cap and yes the new one is rusting also but the cap failed first. Search the MSD forums for rust, you might be surprised at what you find. MSD solution, drill some holes in the cap and pull the distributor, press the gear off the shaft and clean it. Apply some dielectric grease and drill a new hole for the gear retaining pin. The new hole does limit how many times you can do this.

[decooney]

I tried the Borg Warner aftermarket cap, and with more research found multiple instances where people are indicating the problems occur with these MSD caps for two primary reasons.

1. Tab on rotor not bent up and not aligned properly; arching. Degrading center carbon terminal (as confirmed here on CC too)
2. Corrosion, dampness, rust, and evidence of deterioration inside of cap (ion gas, etc.)


One issue I have with using one of the stock Chevy replacement caps from Kragen or Parts America or other places is the springs don't seem to have quite the same amount of tension as the MSD cap does. They work, but seems like they should be a tad more snug on the disributor. Since I use the older style male wire setup, not the HEI terminal type, so if my cap goes bad I can use a standard Chevy cap in a crunch from any local parts store. So, I'll keep my BW cap as a spare and try the new MSD one.

So, just for the heck of it I just ordered one of the NEW "MSD Extra Duty Distributor Caps" with (reportedly) improved terminals and lots of obvious vent holes in it. Look at the picture, there are large 1/4" diameter holes in the top of the cap and all they way around the cap. That's quite a bit of venting, i'll give it a shot and compare use/corrosion over time to see if it's any better or not.

Distributor Cap, Alkyd, MSD Chevy V8 Distributor Vented (8438)
Footnote: Quote: "MSD Extra Duty Distributor Caps are designed with performance in mind and are molded from high quality, voltage insulating material and use low resistance terminals", unquote. For Ford FE 332-428.
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Link: http://www.shopatron.com/product/pro...=MSD8438/424.0

You can get it for less at Summit, but this link was right off of the MSD website for information reference.

[edwhite7]

Maybe MSD could redesign the rotor to give it some airfoil. Then it could suck fresh air in through the bottom vents and blow it out the top . I have had a lot of problems with rusting and carbon button failures. The MSD solution of providing vent holes seems like one designed for the lab and not really for the general market. I sure hope you don't get caught in the rain, the FE tends to lead with the distributor. I used the same MSD 6al box and blaster coil with my Mallory distributor and never had any problem. I got talked into the MSD pro billet and I will be switching back when my new MSD cap fails.

[decooney]

Yeah, it's more of an experiment on root cause analysis at this point.... I tend to latch on to these things and won't let go until I've proven to myself in a repeated scenario what the final results are; even after I know the answer - still more validation. I'll run this setup for a year, and if it fails, the MSD distributor will go on eBay for highest bidder and I'll try my friends trick of using a stock Ford Duraspark disbributor and wiring in the MSD. He's not had a single distributor unit or distributor cap fail on him to date over the last 10 years when hooked to the MSD 6AL boxes. Plus, it looks more original anyhow. Some of these super-duper-billet-hyper-extreme-performance parts can be a little over rated at times. We'll see.