DISA 0 Ring

Here is another good thread for you about the Disa Valve O-ring replacement DIY by Bimmerfiver:
http://forums.bimmerforums.com/forum...1#post23179709

Originally Posted by Bazza-Aus

Technically, there is no O-Ring on the M54 DISA units... and that's why there is not one shown on the realoem diagrams. The sealing is done via a built-in "lip" on the base of the unit that mimics an o-ring. Yes, you can gouge out the old sealing to uncover the grove that a normal o-ring can be fitted into, but you have to wonder why BMW made it the way they did, why it's rectangular, and the original seal is moulded and "glued" into place.

Also, and a big assumption here - the reason the DISA units may not have a traditional o-ring fitted, is, what might happen when it wears, or is mis-fitted, and gets sucked down the intake manifold and into the motor?

Putting an o-ring onto an old worn unit might be a bit of a risk perhaps.

So, there is no DISA O-ring to replace on a M54 E39 530i?
What's the consensus then? Don't try to add one?

Funny how this Ebay guy is selling it for the E39.
http://www.ebay.com/itm/BMW-E39-530i.../260679616897?

...

So, there is no DISA O-ring to replace on a M54 E39 530i?
What's the consensus then? Don't try to add one?

The M54 DISA valve's seal is molded into the O-ring groove. I believe this was a cost saving decision, since they were already molding in the silicone seals for the flapper valve and frame work. The stock molded seal can be carefully scraped out with a narrow flat blade screwdriver. Once that is done a -139 silicone O-ring is a perfect fit. The ring is totally captive in the groove and could never get sucked in anywhere. I would absolutely suggest doing this if you have a DISA seal vacuum leak.

Thats good info about the 0 ring--I've made gaskets to fit and have worked well for me but thats a lot of trouble to go to.Any ideas on where to find a 139 0 ring?

Thats good info about the 0 ring--I've made gaskets to fit and have worked well for me but thats a lot of trouble to go to.Any ideas on where to find a 139 0 ring?

It's not that much trouble, it takes about 5 minutes to scrape out the old gasket. You just have to be careful not to scratch or gouge the o-ring groove.

http://www.mcmaster.com/#o-rings/=fi9hkf

For some reason it won't let me link to the actual page of the correct o-ring. You need to select dash 139, then silicone on the selection page of this link.

This is the correct McMaster part number - 9396K78

Originally Posted by BikesStillRule

The M54 DISA valve's seal is molded into the O-ring groove. I believe this was a cost saving decision, since they were already molding in the silicone seals for the flapper valve and frame work. The stock molded seal can be carefully scraped out with a narrow flat blade screwdriver. Once that is done a -139 silicone O-ring is a perfect fit. The ring is totally captive in the groove and could never get sucked in anywhere. I would absolutely suggest doing this if you have a DISA seal vacuum leak.

Ok, I'm going to leave mine alone, since there's no problem yet, but this is good to know.
Is this o-ring good then? It's the same one he's selling for the E46 M52.
http://www.ebay.com/itm/BMW-E39-530i...#ht_503wt_1396

Ok, I'm going to leave mine alone, since there's no problem yet, but this is good to know.
Is this o-ring good then? It's the same one he's selling for the E46 M52.

If it's the thread I'm thinking of, than it's the same size but different material. I think he's suggesting a Viton rather than a silicone material. Viton is better at resisting the effects of exposure to fuel and oil, and silicone is better at maintaining it's shape and tension in a static sealing application. Either would work OK, but since there is very little fuel and oil exposure in this application, I would prefer (as did BMW) using silicone.

.

For those that may be interested:

M52tu and M54 DISA housing o-rings are now on the website and both are available in 3 different compounds.

Thanks,

Gary

M54 Viton DISA O-rings can also be had here: OringsAndMore.com has them for $4.25 shipped and you get FIVE!

The other 3 can be resold for $2/ea to the next guy in the thread.

We have them on the site as a convenience for people that may be purchasing multiple items or who just want to patronize us for whatever reason. We currently purchase them at retail in lots of 50 and we have to pay someone to enter them into the system and ship them out. I think we make about 3 bucks each on them after postage just to cover our time in processing. As time goes on if there is enough demand we will look at finding a wholesale source and hopefully then we will be shipping enough volume of products that or shipping system will be more refined and cost effective.

One thing I didn't notice on the other site is the flourosilicone o-rings which are the best way to go if you don't mind spending twice as much for them. Just an aside, of the dozen or so that we have sold so far, it's been 90% silicone, 10% flourosilicone and 0% Viton.

Thanks,

Gary

Since the DISA o-ring source on Ebay is gone, so I start looking for new supplier for my bimmer.

I found this guy is selling again on other site.

http://www.kusoz.com/forum/f8/%5Bfs%...eplcement-305/

same price and free shipping.

Originally Posted by chemgigi

Since the DISA o-ring source on Ebay is gone, so I start looking for new supplier for my bimmer.

I found this guy is selling again on other site.

http://www.kusoz.com/forum/f8/%5Bfs%...eplcement-305/

same price and free shipping.

You're better off getting it from Gary@germanautosolutions.
He's a sponsor, and helps out the community with improved designed parts.
I would not post links for shady sellers. Gary has the O-rings in 3 different flavors

You're better off getting it from Gary@germanautosolutions.
He's a sponsor, and helps out the community with improved designed parts.
I would not post links for shady sellers. Gary has the O-rings in 3 different flavors

Thanks Doru.

Just an FYI - If the picture on the listing is of the actual o-ring he's selling, it is definitely not correct. That o-ring in the picture is at least twice the diameter of the correct one.

same price and free shipping.

His price is $11.95 shipped, our is $5.65 shipped.

Gary

Originally Posted by gary@germanautosolutions

The stock molded seal can be carefully scraped out with a narrow flat blade screwdriver. Once that is done a -139 silicone O-ring is a perfect fit.

I was hoping 'that' would answer the 'size' question I've had since the start of this thread!
However, these two stated o-ring sources (apparently) differ in stated size:

Oringsandmore size:
- 2-1/4 ID x 2-7/16 OD x 3/32 CS (<== "cs" is apparently the thickness)

McMaster-Carr size:
- AS568A Dash No. 139: Width: 3/32" Fractional (0.103" Actual),
- Fractional size: 2 3/16" ID, 2 3/8" OD
- Actual inch size: 2.175" ID, 2.381" OD

Originally Posted by gary@germanautosolutions

McMaster part number - 9396K78

I 'think' this is the o-ring set you're referring to, right?

Originally Posted by Wayne's World

M54 Viton DISA O-rings can also be had here: OringsAndMore.com has them for $4.25 shipped and you get FIVE!

This is the set referred to, I think:

Originally Posted by gary@germanautosolutions

flourosilicone o-rings ... are the best way to go ... we have sold so far... 90% silicone, 10% flourosilicone and 0% Viton... Viton is better at resisting the effects of exposure to fuel and oil, and silicone is better at maintaining it's shape and tension in a static sealing application. Either would work OK, but since there is very little fuel and oil exposure in this application, I would prefer (as did BMW) using silicone.

Just for the record, I guess 'that' answers the long-standing question I had over what material to use:
a) flourosilicone (best for resistance oil)
b) silicone (better for maintaining shape)
c) viton (good)

I'll contribute here too with my experience on replacing my DISA o-ring.

I pulled the DISA on my m54 a little while ago to check for wear as I'm at 66k miles. I didn't want to put it back with a disturbed o-ring as that would be prone to leaking. I was involved in a thread on bimmerforums with some o-ring experimentation and bought a pack of ten #140 viton o-rings from Small Parts through Amazon. I paid around $13 for a pack of 10 including shipping, and then sold a bunch of them to forum members to $2 shipped as I only needed one. The nice thing about Small Parts through Amazon is that they offer free shipping with Prime.

But about the o-ring. A #140 is a very snug fit with the relatively hard viton material. I chose Viton because it's always the material of choice when dealing with fuels and oil and I use it exclusively in motorcycle carburetor overhauls. I chose a material I'm familiar with instead of fluorosilicone. Plus at even a low mileage my DISA came out quite dirty and was covered in an oil film, which Viton would be resistant to. That wasn't too surprising as I bought the car with a CCV that had been replaced by the previous owner, so there was oil consumption at some point.

If I had to do it again I would have still gone with the viton material but tried a #139 oring. The #140 was very snug and I had to use the two mounting bolts to pull it into place, even with it lubricated with clean oil. On the plus side it will not be leaking.

I still have two o-rings left. If anyone's interested just PM me. I'm not trying to make money on these things.

Originally Posted by waehrik

If I had to do it again I would have still gone with the viton material but tried a #139 oring. The #140 was very snug

I'm researching all the o-rings we can buy, ahead of time, for this thread:
-> E39 (1997 - 2003) > Let's create a list of o-rings (by size & by part number) to buy when ordering parts

Q1: For the M54, did we come to a consensus that the Viton flourosilicone #139 o-ring was the way to go?

Also, may I ask, what about Formed In Place Gasket (FIPG) material?

Q2: Do you think 3M FIPG Gasket silicone would work for the DIZA valve O-ring?

Originally Posted by waehrik

I'll contribute here too with my experience on replacing my DISA o-ring.

I pulled the DISA on my m54 a little while ago to check for wear as I'm at 66k miles. I didn't want to put it back with a disturbed o-ring as that would be prone to leaking. I was involved in a thread on bimmerforums with some o-ring experimentation and bought a pack of ten #140 viton o-rings from Small Parts through Amazon. I paid around $13 for a pack of 10 including shipping, and then sold a bunch of them to forum members to $2 shipped as I only needed one. The nice thing about Small Parts through Amazon is that they offer free shipping with Prime.

But about the o-ring. A #140 is a very snug fit with the relatively hard viton material. I chose Viton because it's always the material of choice when dealing with fuels and oil and I use it exclusively in motorcycle carburetor overhauls. I chose a material I'm familiar with instead of fluorosilicone. Plus at even a low mileage my DISA came out quite dirty and was covered in an oil film, which Viton would be resistant to. That wasn't too surprising as I bought the car with a CCV that had been replaced by the previous owner, so there was oil consumption at some point.

If I had to do it again I would have still gone with the viton material but tried a #139 oring. The #140 was very snug and I had to use the two mounting bolts to pull it into place, even with it lubricated with clean oil. On the plus side it will not be leaking.

I still have two o-rings left. If anyone's interested just PM me. I'm not trying to make money on these things.

how about post a link to Amazon ?

Originally Posted by bluebee

I'm researching all the o-rings we can buy, ahead of time, for this thread:
-> E39 (1997 - 2003) > Let's create a list of o-rings (by size & by part number) to buy when ordering parts

Q1: For the M54, did we come to a consensus that the Viton flourosilicone #139 o-ring was the way to go?

Also, may I ask, what about Formed In Place Gasket (FIPG) material?

Q2: Do you think 3M FIPG Gasket silicone would work for the DIZA valve O-ring?

1. What does Gary at German Solutions recommend...?

2. I would NOT use ANY sealant on the Disa Valve O-ring.

[QUOTE=bluebee;7329597]

Also, may I ask, what about Formed In Place Gasket (FIPG) material?

Originally Posted by champaign777

how about post a link to Amazon ?

The Amazon item does not look to be available any longer but the link for reference is here. It also includes all dimensions for any interested parties. Keep in mind I would still recommend a 139 size o-ring instead as a 140 was a very tight fit due to the slightly too large (imo) outside diameter. This could be mitigated using a different material since Viton has the highest durometer of all the available solutions.

Bluebee, from my engineering experience I would strongly advise against the use of a formed in place gasket / RTV solution in place or even in addition to the o-ring. That solution may be acceptable for a press seal such as an intake manifold or oil pan. In those cases the seal is between two horizontal planes with pressure applied from the bolts. The DISA valve seal is completely different. The three bolts simply hold the valve in place while the o-ring sits on a groove in the valve which in turn deforms slightly to fit into a hole in the intake manifold. The seal is maintained through the elastic deformation of the o-ring which exerts a pressure against both the valve and manifold.
If a formed in place gasket were used I would be highly suspect of its continued sealing capability. These gaskets do not typically expand significantly under curing and would not exert the same pressure to maintain the seal. Numerous heat cycles and vibration may also loosen it since the formed in place gasket relies on adhesion to the surfaces unlike an o-ring which should not adhere (and should be lubricated so as to avoid stiction). If the formed gasket were to come loose it would cause issues not only with the engine as it passes through but with the O2 sensor as it likely contains silicone which is a big no no for the intake tract.
That's probably a longer explanation than anyone but Bluebee cared to read, but since she asked...!

And I'm all out of o-rings now, so please save yourself the PM before asking

Originally Posted by waehrik

The Amazon item does not look to be available any longer but the link for reference is here.
It also includes all dimensions for any interested parties.
Keep in mind I would still recommend a 139 size o-ring instead as a 140 was a very tight fit due to the slightly too large (imo) outside diameter.
This could be mitigated using a different material since Viton has the highest durometer of all the available solutions.

Bluebee, from my engineering experience I would strongly advise against the use of a formed in place gasket / RTV solution in place or even in addition to the o-ring.
That solution may be acceptable for a press seal such as an intake manifold or oil pan. In those cases the seal is between two horizontal planes with pressure applied from the bolts.
The DISA valve seal is completely different. The three bolts simply hold the valve in place while the o-ring sits on a groove in the valve which in turn deforms slightly to fit into a hole in the intake manifold.

The seal is maintained through the elastic deformation of the o-ring which exerts a pressure against both the valve and manifold.
If a formed in place gasket were used I would be highly suspect of its continued sealing capability.
These gaskets do not typically expand significantly under curing and would not exert the same pressure to maintain the seal.
Numerous heat cycles and vibration may also loosen it since the formed in place gasket relies on adhesion to the surfaces unlike an o-ring which should not adhere (and should be lubricated so as to avoid stiction).
If the formed gasket were to come loose it would cause issues not only with the engine as it passes through but with the O2 sensor as it likely contains silicone which is a big no no for the intake tract.
That's probably a longer explanation than anyone but Bluebee cared to read, but since she asked...!

And I'm all out of o-rings now, so please save yourself the PM before asking

Thank you for the information Sir...!
Link to the 139 Vitron O-rings:
139 Viton O-Ring, 75A Durometer, Black, 2-3/16" ID, 2-3/8" OD, 3/32" Width (Pack of 25)
http://www.amazon.com/dp/B000FN0YPS/ref=biss_dp_t_asn

Thanks!
Jason

Thanks Jason

Originally Posted by waehrik

I would still recommend a 139 size o-ring instead as a 140 was a very tight fit due to the slightly too large (imo) outside diameter. This could be mitigated using a different material since Viton has the highest durometer of all the available solutions.

This is EXCELLENT information for those of us who have not had the need just yet.

Originally Posted by waehrik

I would strongly advise against the use of a formed in place gasket / RTV solution in place or even in addition to the o-ring.

Now you tell me!

Originally Posted by Jason5driver

Link to the 139 Vitron O-rings:
139 Viton O-Ring, 75A Durometer, Black, 2-3/16" ID, 2-3/8" OD, 3/32" Width (Pack of 25)
http://www.amazon.com/dp/B000FN0YPS/ref=biss_dp_t_asn

Here's a screenshot, since links are ephemeral but pictures are forever.

See also:
- Where to get a proper DISA valve repair kit (1) & how some jury-rig 'repair' a rattling DISA unit (1) (2) (3) & how the DISA valve operates (0) (1) (2) (3) (4) & how to test DISA operation (0) (1) (2) (3) (4) & a simple DIY to install an M54 DISA (1) & a nice DISA autopsy (1) (2) & a great DISA group buy (1) & how the disa valve o-ring fails (1) (2) & how it can reputedly cause all sorts of cold-engine rough idle problems (1) (2) & where to get just the DISA valve o-ring (1) & why you want to check the DISA at 100K miles or whenever the airbox is removed (1) (2) & why the DIfferenzierte SAuganlage ("Differential Air Intake") valve flap breaks (1), sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) & a well documented example of how a broken DISA flap can ruin your engine (1) & yet another seemingly complex set of misfire codes reputedly traced to a broken DISA valve (1)

EDIT:
Here is a thread where there is a before & after picture of the o-ring put in place: