I have an old 1st gen HKS SSQV BOV that I suspect is getting worn out. I had the thing apart a couple years ago, and it basically looked fine back then.

My question is: if I hook a Mighty vac to the vacuum port, it won't hold vacuum. I can get to 15 in/hg, but then it just leaks down in 2 seconds. Ideally, shouldn't that diaphragm be vacuum tight?

I can hear a slight hissing down inside the valve as it's leaking down.

Thanks,
Al

 

Air leakage past the valve stem is typical due to the clearance required between the stem and guide surfaces. Higher machine precision can minimize this effect and i'm not sure how precise HKS used to machine their components so I couldn't tell you how normal it is. What I can tell you is that most people are going to see this effect on their hardware. Likely most of them will be the cheap knockoff gates as well.

 

Yes, this is an original HKS valve. It's so old, I don't think China existed when it was made!

I was thinking that should be air tight. I have a couple issues going on, and I am looking everything over with a fine tooth comb. I was going to buy a new version of the HKS racing valve since it will fit the existing flange that is welded on, but their new stuff doesn't look too impressive. Sign of the times, I guess.

Al