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I'm kind of at my wits end here guys and need some help.
I've got a Tial Q series 50mm BOV and its continuously stuck closed.
The diaphragm is perfect, the shaft and guide are perfect and the correct spring for the vacuum level is installed.
The o-ring is continuously getting stuck against the housing to the point it won't open at all and I'm experiencing compressor surge.
I've pulled it apart four or five times and lubed everything up, tried a little oil on the o-ring, some dielectric grease and for a bit its okay and works as it should but as soon as the car sits for a few weeks its stuck closed again.
Any help or insight would be greatly appreciated.
Thanks.
And have you tested this with a vacuum source to see if it opens and operates correctly off car ?
Hey Stevie, I don't have the ability to test off the car but after I've pulled it apart and lubed it, it works fine.
I can actuate the throttle and it visibly opens and closes, I go for a drive and I can hear it clearly.
Come back a few days/week later and compressor surge is all I hear.
When I take it apart it takes considerable pressure to unseat the o-ring so something is definitely not right.
I purchased this used and I'm sure its been an issue from day one I just never knew until recently.
Man I hope not, it has a serial number under the Tial mark.
Okay so lets suppose its a knock off and I need a new one, currently looking at a XS Power, Tial and Turbosmart.
Suggestions?
Again...pictures would speak a thousand words as to what the problem is you're describing and what is sticking.
Not sure how to send a picture of a sticking o-ring...
If flip the BOV over on the ground and place the handle of a hammer on the piston and lean on it, it will pop open abruptly, that's how stuck it gets after sitting.
I just cant picture why there would be an o-ring on the seat ?
Or is this different to a round rubber o-ring you're describing ? Is the o-ring on the seat, the valve, other ? Is it the correct size of o-ring ?
Ah I see what you're getting at.
The piston has groove in it for the o-ring and the housing has a bevel cut into it for receiving the o-ring creating the seal.
I've tried to get the o-ring out and its not happening, I don't know how its in there but it ain't coming out lol.
I've attached an image of the piston, you can see the o-ring on the right side.
Ahh, so it's more of a piston style setup rather than a valve ?
And when it sticks, is the o-ring visibly swollen or anything ? Are you spraying meth before the BOV ? or near it ?
Precisely, the o-ring looks totally normal, not misshapen or swollen with oil.
I've worked with hydraulics for some years so I'm pretty good at gauging an o-rings condition but at the same time this isn't hydraulics lol.
No meth, just pump 93.
Its really weird, I can't get over how stuck it gets, even 12 lbs. won't knock it loose.
If I rev the throttle in neutral after I've lubed it I can see the valve actuate so its got the correct spring right? Its the color Tial recommends for my vacuum level too.
I've reached out to Tial as well so if they respond I'll report back.
I guess I'm looking for a magic bullet or lube for this stupid thing, or maybe I'll just buy a turbosmart valve, do they have a piston too?
Such things should not need any sort of regular maintenance like lube though.
Could you maybe try enlarging the hole it fits in a little ? Does it feel nice and smooth ?
Maybe a honing tool or something
I totally agree and perhaps it is a knockoff, I'll get a photo of it today.
When I reassemble it it feels nice and smooth, for some reason when it sits the o-ring just gets stuck.
I've gotta figure something out because I'm not pulling this apart before every drive.
What about a new unit, turbosmart or the like, any recommendations?
Here's a picture of the BOV and it was stuck again...
I pulled it apart again and examined the piston to make sure there no weird burrs or anything binding the piston.
I reassemble it without the spring and it slides perfectly.
So I broke it down again and flipped the o-ring on the piston over as it looked kinda flattened so we'll see if that does it.
Well good news guys, flipping the o-Rings seems to have fixed it.
The car has been sitting since the 4th since I've been out of town so I went for a drive today.
Upon throttle tip in I heard a bit of compressor surge but then the valve opened.
It makes me wonder if its still a bit tight, would cutting a couple coils out be a good idea since boost holds it closed anyways right?
Tial makes different springs depending on your vacuum the engine makes. Its on there website. I had to change mine when i went to a fairly large cam to make everything work like i wanted.
03-02-2018, 12:40 PM
Tial Q Series 50mm BOV Sticking Shut 
