2.5T VVT Hub/Adjuster Inner O-ring size

[- Pete -]

I have been taking down some measurements for these & the space they occupy.

I'm curious if anyone is interested or has anything to contribute to this relatively un-discussed topic?

I'm referring to the one pictured below.

s-l1600.jpg

I'm troubleshooting an oil leak & thus far have replaced the crank seal, oil pump seals & was about to finish it off with VVT o-rings & cam seals. Then, after I installed the one eBay sellers "Volvo VVT o-rings" I realized they were NOT sized appropriately. In fact, the material seems the same, but size-wise when torquing down the center bolt the o-ring actually got cut in half circumferentially.

I have a couple feelers out to other sellers who offer these seals with contingencies on them providing the ID, OD, and cross-sectional width of the o-rings.


I do realize that, allegedly, the hubs themselves can leak oil regardless of the condition of the plug sealing ring, the inner o-ring, etc.
I'd just as soon take a shot at it with o-rings before committing to a $600 set of hubs.

[abscate]

I’ve got a hub from a 1999 exhaust, but I think P2 hubs are different?

I’ll dig up part numbers.

Are yours growling or just leaking?

On edit...crap, I don’t even remember making this measurement but I did

viewtopic.php?f=1&t=89395

[cn90]

That GREEN O-ring: when it leaks, it leaks INTERNALLY.

You need to review this thread where we discussed the VVT anatomy in detail:
https://volvoforums.com/forum/volvo-xc9 ... 251/page2/

The problem with Volvo VVT:
- When the O-ring is bad, oil leaks INSIDE, so no advance or retard of the cams.
- The gearing mechanism is worn, the TB walks in and out.

If you get some 160K out of the factory VVT, it is good, I know it is expensive, but just get new VVTs ($250/each) and move on.
People have tried to rebuild the VVTs with no success.
Treat them like your car tires, they wear and need to be replaced.

[- Pete -]

These are not mic measurements, I just took them with a caliper. I took at least 3 measurements of each & then took the average, so should be pretty close. If you're feeling brave & want to find your own o-rings, here ya go.

OD VVT hub groove which o-ring sits in - 48.44mm (this would correlate to the OD of the o-ring)
OD of the cam end - 44.94mm (this would correlate to the ID of the o-ring)
ID VVT hub bore that slides over cam end - 45.14mm
I did not take a measurement for the width of the groove.

Not surprisingly, nobody I contacted would divulge their o-ring size.
The seller I purchased mine from did confirm that the o-rings I was sent were in fact the wrong size.
I will measure the correct o-rings he sends me when they arrive & get some measurements.

That GREEN O-ring: when it leaks, it leaks INTERNALLY.

You need to review this thread where we discussed the VVT anatomy in detail:
https://volvoforums.com/forum/volvo-xc9 ... 251/page2/

The problem with Volvo VVT:
- When the O-ring is bad, oil leaks INSIDE, so no advance or retard of the cams.
- The gearing mechanism is worn, the TB walks in and out.

If you get some 160K out of the factory VVT, it is good, I know it is expensive, but just get new VVTs ($250/each) and move on.
People have tried to rebuild the VVTs with no success.
Treat them like your car tires, they wear and need to be replaced.

CN90, thanks for your input, here & all over the various discussion boards. I have read every single VVT thread google-able (except the o-ring size thread Steve posted, thanks for that) including the one you linked. In fact I spent considerable time reading that thread & all the links in it several times before I even posted this thread.

I am replacing the exhaust hub. It's axial deviation is what I would call excessive & it's pretty rough feeling in it's action.
Based on the buildup on the inner face of both intake & exhaust sprockets I do believe that both exhaust & intake inner o-rings were leaking.

I don't really see where else the hubs could leak oil from if the inner o-ring, plug o-ring & cam seal are all new & done correctly. The oil leak is my main concern. Restored VVT function would just be a bonus. While I'd like to keep my old exhaust VVT hub as a spare, I'm going to have a hard time resisting the urge to take it apart so I can see how it works. If I do that, which is pretty likely, I can post some pictures.

[cn90]

In a perfect world:
- New VVT bc not only O-ring but the gearing mechanism is gone by 150K etc.
- New Cam Seals (Volvo or Corteco).
And you move on...

The reason you got oil leak is that: even you have new cam seals, the old VVT walks in and out (axial play), causing oil leak.
At factory, the axial play is very very small for new VVT.
Once worn out, it can walk in and out 2-3 mm, causing leak.

[abscate]

The seller I purchased mine from did confirm that the o-rings I was sent were in fact the wrong size.

Not surprisingly, nobody I contacted would divulge their o-ring size.

What is up with that behaviour?

I get that you don’t want to “ give up “ the size so people can source them but you will get more bees with honey than vinegar.

When I see someone who sells an o ring and then documents the size to match my parts in hand, I buy!

Since we are going to document the size here anyway, his gig is up

[- Pete -]

Here’s a nice chart my one military aircraft mechanic friend shared with me. He said they reference this chart & others like it for material type/exposure/environmental temperature all the time.

B695DF0D-6B6D-497B-8EB2-245D285C62D0.jpeg

Edit: forgot reference

https://www.gen-aircraft-hardware.com/t ... name=oring
(blue links at bottom)


CN90 - you’re killing me here. And actually my wife will be doing the same pretty soon as well!

A huge box 5’ tall from IPD came yesterday while I was working & I could just feel the hairy eyeball when I got home. At least the box with the VVT’s will be small & innocent looking in comparison.

You seem to have a pretty firm handle on how these hubs work, have you had one apart around the interval at which you say the mechanism is shot by? In no way am I asking that because I’m doubting you. I just tend to keep my “plow deep” & have a hard time just accepting answers at face value. Like when a parent tells a child “because I said so..”

I reluctantly ordered both intake & exhaust, as you said was necessary. 280k I spose isn’t horrible. This $100 cam/crank seal job is going over budget.

Like I said, my exhaust hub is pretty coarse feeing, almost like you can feel tiny air bubbles passing though the passages in the cam & the hub itself. Feels gritty, and I can hear the air in it. So that one I’d be ok with dismantling for photos on MVS. The intake one still feels pretty good, I need to measure how much it runs out from the face of the cam.

I’ve read that new ones can have as much as ~1mm axial play, is that correct?


Abscate - yeah that mentality is a turn off for sure. I should have the correct o-rings tomorrow so I’ll put one in the intake hub & post some
ID & cross sectional measurements. Between that & the chart above people should be able to source their own o-rings.

[cn90]

Yeah,

The VVT cutaway anatomy is in the thread below, courtesy of jimmy57.
Your can see the gearing mechanisms.
After millions of cycles of advance/retard, the gearing mechanism is loose.

PS: The BMW Vanos system is actually better engineered.
The Volvo VVT system is an offspring of the P80 timing belt system.


viewtopic.php?t=81207

[cn90]

Yeah,

Don't worry.
Philosophically, we agree to buy new tires when old ones are worn.
We have a hard time paying for $250 VVT bc we think this lasts forever.
I am the same way, but sometimes you have to get new parts (or good junk yard parts) to make it work...