TheSamba.com :: View topic - UPDATED: Need help help finding a NOS part.

Sat May 23, 2009 11:44 am

best thread on the samba in a while! I have a box full of these valves, been saving em whenever I see em to try and find two good ones for my motors, now I know how to test/rebuild em.

Sat May 23, 2009 11:59 am

save them, even the bad ones. If we can get replacement diaphrams at a reasonable price we might be able to rebuild them and sell them. I'll let the community know what the rough estimate is on the diaphrams. I am guessing 250 to 1000 minimum. I just wish the old ones had screws holding the top on instead of glue. Maybe Mann Hummel will get back to us too.

Sat May 23, 2009 12:15 pm

last thought - am still an looking for a NOS one if someone comes across one and wants to make some money.

Flame trap - Fiat used to use a spiral wound metal piece that acted as a flame trap between the airfilter and the crankcase. They would gum up if not cleaned. Neither of these valves acts as a flame trap well and one might consider inserting a stainless flame trap into the vacuum line leading to this although it would have to be cleaned periodically like the Fiat ones.

I can't honestly say that some of the VW bus fires and sudden oil seal failures might not be caused by the lack of a flame / backfire trap in this line. It might even be worth just inserting a real PCV valve in the line as a backfire suppressor.

Mon May 25, 2009 11:09 am

The valve on the left in the pictures is for a south american vw, not a vanagon. I tried to get a hold of one of those thinking they were newer hence more reliable, but they seem to be NLA at the mexican parts places too. It looks like we will be rebuilding these. sgkent I will get pictures to you soon of the vanagon setup. Hopefully I will get picts taken today. I think it would be easy to fabricate some clips to hold the valves together so inspecting and replacing the diaphragm in the future will be easy.

Mon May 25, 2009 5:39 pm

Here is what it looks like on the vanagon.

My measurements are:

Diameter is 2.5",

Outlet inner diameter is .5"

Outlet outer diameter is .77"

It would be possible to make a billet version of one of these that is rebuildable. What would people be willing to pay?

Let us know on the vanagon forum if you find a source for the diaphragms.

Thu May 28, 2009 1:19 pm

Any of these work http://www.thesamba.com/vw/classifieds/detail.php?id=781866

Thu May 28, 2009 9:32 pm

Any chance this might be modified to work??

http://store.europarts-sd.com/index.asp?PageAction=VIEWPROD&ProdID=1496

Thu May 28, 2009 9:36 pm

SGKent, did you measure the diameter of the diaphragms when you had them out? If so, what were the measurements? Have you heard back from the diaphragm manufacturer?

Thu May 28, 2009 9:48 pm

there is a grommet that goes into the stamped valve cover on the older water-cooled vw's. the breather valve then goes into that. i wonder what the diameter is.

i'll pick one up at work tomorrow and check.

does anyone know what grommet i'm referring to?

Thu May 28, 2009 9:50 pm

Similar to this???

http://store.europarts-sd.com/index.asp?PageAction=VIEWPROD&ProdID=1505

Fri May 29, 2009 6:47 am

that's the one.

Fri May 29, 2009 11:32 am

just a thought, aren't the old automatic 1700 pcv vavle seperate from teh breather, to clear the smog pump? I just parted out one, there was no valve, just a black top w/ a big opening. I don't know any more than that about them, but maybe thier design can be mimcked?

Sun May 31, 2009 9:12 am

I found this on a motorcycle forum about repairing a bad diaphragm. I am going to attempt it and see if it works sometime this week.

http://www.kawasakimotorcycle.org/forum/vintage-mo...works.html

The more I look at the efi system the more I realize the PCV on these things is really important for MPG. The fuel pressure regulator operates on vacuum and that can't operate at maximum efficiency if the PCV isn't keeping the vacuum regulated from the crank case. I imagine most of us are not able to see the MPG that we sometimes see people getting because of parts like the PCV not being in correct operation. If it wasn't important for it to be a diaphragm operated valve VW would not have done it in the first place.

Sun May 31, 2009 9:51 am

German Supply has the 80-83 units s used. The design could be adapted to the Bus chimney, I suppose. From SGKent's pictures, what is the other breather from? Must've missed it.

Sun May 31, 2009 10:05 am

I have not heard back from Mann Hummel re making the whole device however I did get a reply from Dow Corning. The info they sent was really nothing more than contacts so I need to make some calls to see what the parts might cost. I am thinking that even if we just had replacement diaphrams then we could at least rebuild the old ones until new ones became available. Someone out there should be able to make molds from the plastic parts and make them in aluminum or plastic. Here is the reply from Dow Corning:

Quote:

Steve:

So you need the preformed part right, made out of oil resistant silicone rubber?

Is so, please use the following list to help get the parts made for you:

Automotive Parts -
BRC, Cherabusco, IN; ph 260-693-2171
FNOK, Tillsonburg, Ontario, Canada; ph 519-842-6451
QSR, Twinsburg, OH; ph 330-425-8472
Lexington, Vienna, OH; ph 330-856-1121
Federal Mogul; Skokie, IL; ph 847-674-7700

Thank you for your interest in DOW CORNING products and services.

Pete
Assembly Products Liaison and Facilitator

Sun May 31, 2009 10:32 am

Quote: SGKent, did you measure the diameter of the diaphragms when you had them out? If so, what were the measurements? Have you heard back from the diaphragm manufacturer?

about 2.5 inches. The one in the valve to the left was flat and could be reproduced from sheet viton or silicone rubber while the one on the right (1975 - 1979) had curves and pre-formed structure.

If we cannot produce all styles then we need a master one that has adapters for each engine style. I think that would be do-able. I would add a backfire / flame trap as well.

Sun May 31, 2009 10:37 am

One other thing. In reading on the rubber parts - DO NOT use carb cleaner or GumOut on them etc. The silicone rubber cannot resist these items. It will swell with exposure to Acetone or MEK but the carb cleaner and GumOut eats them right up according to acticles. I used some hot water and soap then ammonia to clean the one diaphram and it came cleaner. One can tell it is somewhat deteriorated from use however so I am sure every 75-79 FI bus needs a new one regardless.

Sun May 31, 2009 12:32 pm

You could always hook the crankcase breather to say the vacuum port with a Tee at the AAR valve and have a restriction in it like Ray says. Plug the large hose at the S boot.
As long as you have a "pull" on the crankcase to evacuate the gases you won't blow out all the seals.

Sun May 31, 2009 9:06 pm

The fuel pressure regulator is connected to the vacuum. The restrictor would work as a band-aid but in the end the system is set up with a diaphragm system so the vacuum is not as effected by the crankcase pressure part of the time. In the end the fuel pressure regulator and the rest of the L-jet setup would be affected by the restrictor setup. I think it is worth the effort to find a way to fix this be it rebuilding them or getting a new part made.

Mon Jun 01, 2009 6:58 am

SGKent wrote: One other thing. In reading on the rubber parts - DO NOT use carb cleaner or GumOut on them etc. The silicone rubber cannot resist these items. It will swell with exposure to Acetone or MEK but the carb cleaner and GumOut eats them right up according to acticles. I used some hot water and soap then ammonia to clean the one diaphram and it came cleaner. One can tell it is somewhat deteriorated from use however so I am sure every 75-79 FI bus needs a new one regardless.

SGKent, MEK and acetone should not hurt silicone. But...chlorinated solvents will. Slight surface swelling is normal and temporaily wwith silicone. Spray them...and let them dry and they should be fine.

Berrymans works fine on these. Gumout does not. Ray