What part of the stock solenoids actually fails?
 

Anyone ever cut one open to see?

How does the heat affect them exactly?

Dave

I have cut a bad one open, but didn't find anything conclusive. I think the culprit is the rubber seals in the solenoid vulcanize and don't seal properly. It's a magnetic winding that moves the solenoid back and forth.

Dale

There are three main failure points of the stock solenoids. The first is the nipples. They become hard and brittle, and are prone to cracking and breaking (especially when servicing the vacuum lines). The second (as Dale pointed out) is the internal rubber seal. When these fail, you get air leaks. The third is the actual solenoid operator. This is the electrical coil that, when energized, causes the seal to engage/disengage. This is a very common failure and often hard to diagnose. Often, the operator can fail intermittently and at high temperatures. In other words, it works fine when you test it on the bench, but when the solenoid is up to engine operating temps, it fails. This is due to the internal coating on the operator disintegrating over time.

I'm currently testing a new aftermarket solenoid setup that will hopefully cure most (if not all) the concerns with the stock solenoids.

-Rob

Have not disected one yet. Historic info:

1) known to pass bench test cold, but fail bench test when 150-200F.
2) known to pass bench test cold, and not work properly installed and under pressure/vacuum load.

I had occasional lower boost, somewhat related to track events. New TCA and CCA solenoids and problem stopped.

You're right. I forgot to mention that. Failing under load is typcally due to the rubber seal failing, but in some cases it can also be attributed to a bad operator. Hopefully, this info will help some people. Keep in mind that just because you tested it on the bench cold, doesn't mean that it works at operational capacity.

Also, just as an FYI the TCA (pressure) is one of the most commonly failed solenoids that cause turbo problems. I have had so many of these go bad, I lost count.

-Rob

Rob, please share your aftermarket solenoid setup.

I was thinking about using the Mercedes solenoids. . .

:-) neil


Mercedes pn# 001 540 86 97, WorldPac pn# O4045-70190

http://img.eautopartscatalog.com/live/O404570190OES.JPG

Neil, the mercedes solenoids look like they would possibly work, but I would be afraid that the internals are similar to the stock FD ones (rubber seals, non-molded coil, etc). I would have to look at them and examine the internals to be sure (just like I did for the stockers).

I posted a thread with some preliminary information in it. I'm not done testing, but I'll have an update fairly soon. Here's the thread:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/custom-replacement-solenoid-system-404243/

-Rob

What kind of problems have you had so far with your system? I need basically all new solenoids because i'm doing a vacuum hose job and keep breaking the plastic ends off of them. If you get it working fairly soon, i'll pay for another prototype the same day they work. I've already broken over $300 worth of the factory solenoids. Post with updates on how it turns out.

-David

David, razor blades are your friend. It also helps to cut each hose in half before removing it from the nipples.

Unfortunately, finding a drop-in replacement quickly will take some luck. Malloy Mazda is still your best bet at $53/ea on average.

Dave

Zero problems with the solenoid system so far. It works flawlessly. Unfortunately, I spun a main bearing in my engine recently (obviously completely unrelated to the solenoids, but annoying nontheless), so that has delayed my testing by a little bit. If you are interested, I can easily build more setups that are nearly identical to my prototype. The only problem is that I currently can't guarantee their longevity, just due to the fact that they are still in the Beta phase, and I haven't tested them long enough.

-Rob

Who manufacters the solenoids you're using?

The operators are manufactured by Peter Paul electronics. They do a lot of stuff for the automotive world, so they were a pretty knowledgable source of information for me.