I saw damian's posting in regards to making metal check valves outta some parts from mcmastercarr. I think it's a good idea, but they seem pretty long requiring some vacuum tube routing to avoid kinks...

I came across some similar check valves make by Anver.

The difference seems to be that while the mcmastercarr parts have male NPT ends, the Anver parts have female which could mean a shorter check valve.

What do you guys think?

Thanks!

 

Those would probably work, but the temperature ratings are a little lower than I'd like.

I know some people were using check valves that go to the fuel system of a model airplane back in the day. Matter of fact -

http://www.perrypumps.com/prod03.htm

Check out the first product listed. I actually had one at one point - I bought something from someone who sold those check valves, and he threw in a free one. They're VERY nice and tiny, but the nipples are a little on the small side and you'd have to do a tad bit of engineering to make them fit snugly on the hose. But, they're temp rated, and don't mind gas and oil.

Dale

 

Does anybody know what the specs are on the OEM check valves, specifically what their cracking pressure is?

Thanks!

 

Just call Pettit. They have some that are allot like the stock ones but they sell them for a fraction of the price. Cam uses them on about everything. I ordered 4 and have them on my car and they work perfectly and I didn't have to re-invent the wheel finding them. I am sure Pettit makes a profit on them.. BUT every time I call them I get good sound advice on the phone. That takes time for them and I am willing to pay for that level of expertise.

 

Pettit's are $19 a pop, for not all that much more ($26 from Malloy) you can get the OEM Mazda parts. I'm actually going to try a couple of different ones and give them all a try.

 

That's funny. I got them for $12. Must be they like me more! LOL

 

OK I've assembled a small check valve collection. The only one that I'm lacking is the HELP ones that you can pick up at a local auto parts store. In any case from left to right here's what I plan on testing. The two stainless steel ones are from a company called SMC. The smaller one is their CV Series, the larger is a 110. I'll probably not end up using the CV as they have higher cracking pressure (2psi) compared to the 110 (1psi). Both have Viton seals. If anyone wants to try out the CVs, let me know, I've got 4 of them. The next two are the plastic OEM check valves (the smaller ones are from under the UIM, while the larger ones you can get to without removing the UIM). I checked all 4 originals with a Mityvac. 2 were leaking in the checked direction and all were pretty hard to blow through in the unchecked direction. The black and white one is the Pettit "aftermarket" one that Michael Fregoe recommended. I bought 2. They're pretty hard to blow through in the unchecked direction, don't know if that makes a difference. And finally the one at the very end (semi-translucent) is a Polypropylene/Viton check valve from Ark-Plas. It takes by far the least pressure to blow through the unchecked direction and holds 15psi pressure fine in the checked position. Plan on testing them over the next couple of months to see which ones hold up the best.

 

Man, that's awesome! I've Googled a number of times on check valves, but finding small ones is pretty tricky.

I think it would also be interesting to test the car with each different check valve to see what's the best characteristics - do you want a low cracking pressure or not, etc. The big test of course will be TIME - see how well they hold up over the years.

I also plan on finding the perfect check valves for my upcoming FD, so I'll likely do some testing as well when the time comes .

Thanks!
Dale

 

Man, you did some major research on this! Nice work. The SMC 110 looks like the nicest of the bunch, IMO. I did my hose job and used the mcmaster check valves. I didn't have any trouble with kinking hoses, but I did have to be careful about how I routed them.

Sonny

 

Do you have the part number for these check valves? Also, how well did they fit?

 

I had two of the HELP! ones fail on me after ~10K miles. You could blow through in both directions after the failure.

I found some at McMaster-Carr that seemed promising, but I never tried them. Viton diaphragm, PVDF body. "For extreme external applications requiring superior chemical and abrasion resistance. Maximum temperature is 250° F." The part number is 47245K32.

-Max

 

I have 4 of the Pettit white ones on my car and have had zero problems since installing them 5K miles ago. I'll keep the forum posted if they fail. I am sure they hold up well or Cam would not insist on using them when he does a rebuild/engine install in shop. Time will tell.

 

Don't have the part number handy, I got them by going through the RFQ process on their website. They sent the samples for free. In terms of fit, the barbs are the same OD as the stock check valves, the barbs are a tiny bit shorter, and the 4mm Bakers Precision silicon vacuum hose fit snuggly.

 

What size barb did you order?

 

1/8"

 

Thanks for the links and barb sizes, I highly appreciate it! I'll let you know how well they hold up in a few months.=P