DISA Valve kit

[nebilex]

Originally Posted by Ricky Bobby

Does the GAS kit not come with a flush mount titanium bolt anymore and they switched to something with a rounded head up top? Nice work, been a couple years but mine went in a bit different I think.

I got the kit from my local euro imports place.. The kit was $40.

[Ricky Bobby]

Ahhh that explains it

[TiminIndy]

I had my DISA valve off today because I was replacing my lower intake boot. I cleaned up and inspected the DISA and it was in pretty good shape. Appears to be the original, and the car has 116K mi on the odometer. No damage to the flap at all, it stays open, and when I manually close it, it pops right back to open when I let go. I saw a vacuum test on one of the DIY videos, where you close the flap, then hold a finger over the hole, and see if it stays closed until you release your finger. I tried this and it moves towards open about 1/4", then holds there until I release my finger from the hole. I assume this is indicative of a slight leak in one of the diaphragms, but I'm not sure. The car runs fine and there are no codes, so I guess there is no immediate need to replace it. I thought about the rebuild kit, but it doesn't have anything for the diaphragms, so I don't know that it's necessary at this point.

At a minimum, I would like to replace the O-Ring, but realoem.com doesn't show a part number for that. A bunch of O-rings from ebay come up when you do a Google search, but I don't know who to trust there. Does anyone have any suggestions for an O-ring source?

[80stech]

The Ebay one in a bag for $2 works well. It is #140 o-ring and makes for a bit of a tight fit. #139 is a bit easier to install.

[TiminIndy]

Originally Posted by 80stech

The Ebay one in a bag for $2 works well. It is #140 o-ring and makes for a bit of a tight fit. #139 is a bit easier to install.

There are so many different sellers on ebay for the O-ring.

I guess I will go with this guy; he has 2,100 transactions, 100% approval:

https://www.ebay.com/itm/BMW-DISA-Va...5R9qO2&vxp=mtr

BMW DISA Valve Fluorosilicone O-ring Replacement M54 Engine

Our Fluorosilicone O-ring is a military spec, aerospace grade product Excellent temperature extreme and compression set properties, plus excellent resistance to fuel and oil.

This is the "Mother of all O-rings" for reliability!

[Fifty150hs]

Originally Posted by TiminIndy

I had my DISA valve off today because I was replacing my lower intake boot. I cleaned up and inspected the DISA and it was in pretty good shape. Appears to be the original, and the car has 116K mi on the odometer. No damage to the flap at all, it stays open, and when I manually close it, it pops right back to open when I let go. I saw a vacuum test on one of the DIY videos, where you close the flap, then hold a finger over the hole, and see if it stays closed until you release your finger. I tried this and it moves towards open about 1/4", then holds there until I release my finger from the hole. I assume this is indicative of a slight leak in one of the diaphragms, but I'm not sure. The car runs fine and there are no codes, so I guess there is no immediate need to replace it. I thought about the rebuild kit, but it doesn't have anything for the diaphragms, so I don't know that it's necessary at this point.

At a minimum, I would like to replace the O-Ring, but realoem.com doesn't show a part number for that. A bunch of O-rings from ebay come up when you do a Google search, but I don't know who to trust there. Does anyone have any suggestions for an O-ring source?

The YOutube video I found before replacing my DISA valve flap and pin with a bolt showed that the flap doesn't stay fully closed. It moves about a quarter turn and stops. Then opens fully when you take your thumb off the diaphragm inlet. So this seems to be normal.

[TiminIndy]

I was going to order that fluorosilicone O-ring, then found this seller with one that is supposed to be Dupont Viton:

https://www.ebay.com/itm/172971081031

I figured, if Viton is good enough for my OFHG, it's good enough for the DISA.

Then I looked further and realized that Viton (FKM) temp range only goes down to -15°F.
Range: -26°C (-15°F) to +205°/230°C (+400°/440°F)

fluorosilicone (FVMQ) is good down to -100°F.
Range: -73°C (-100°F) to +177°C (+350°F)

I guess 15 below is about as cold as it ever gets around here and that is pretty rare. Worst case scenario is a little vacuum leak on a very cold start, but I will probably be more concerned with frozen CCV sludge at those temps!

(some may remember that the failure for the space shuttle Challenger was due to failure of a Dupont Viton O-ring caused by freezing weather the night before the launch)

[80stech]

If you go with the #140 there is a little bit of extra rubber which makes it harder to install but maybe is a good thing at colder temps. I run both the #140 and #139 in two different vehicles and they have seen -30's and have had no problem. That being said I think I would like to try the flourosilicon next time.

[TiminIndy]

Originally Posted by 80stech

If you go with the #140 there is a little bit of extra rubber which makes it harder to install but maybe is a good thing at colder temps. I run both the #140 and #139 in two different vehicles and they have seen -30's and have had no problem. That being said I think I would like to try the flourosilicon next time.

I asked both sellers if they were #139 or #140. First one never answered and the second one didn't know, but is sure it is the right one...

[bcredliner]

At 116K on the DISA valve I would just replace it. It's an inexpensive part.