VANOS replacement success, car runs great....except....

[tommycat1313]

So this is mostly an effort to determine the cause of a change in aural greatness.

The VANOS in my 95 went bad, evidenced by the usual loss of low end umph, noisy knock from the top end, etc. It ended up being the VANOS solenoid actually but I replaced the whole mess anyway. Also replaced sec. timing chain, tensioner, guides, etc.

I timed everything up precisely as before, slipped the new VANOS on (very first tooth, yes. Not my first rodeo). Rotated the engine, no worries. TDC all around and verified. Buttoned everything back up and cranked it, and it runs perfectly. It idles perfectly. Took it out for a spin and it accelerates like a tactical nuke, and that lost torque is now back. No CEL. In essence, I got my baby back.

But, there is a problem (isn't there always?). Though it is running perfectly....it doesn't SOUND the same. That sonorous growl is now a tame, clinical purr, the growl only reappearing when the VANOS advances the intake cam for that brief bit in the rev uptake. It's absolutely working tho, you can feel it.

It used to spit and pop a little when down shifting which is now almost completely gone.

I got my monster back but it sounds defanged a little....or is it just me....I donno.

Thoughts on possible reasons?

-TC

[tommycat1313]

Examining the old VANOS answered my question. It wasn't retracting all the way and therefore never fully retarding the intake cam, even at idle. I guess I just became accustomed to the sound over time and the way it sounds now is the way it is SUPPOSED to sound. When I was a kid my bicycle sounded cool with a playing card in the spokes but I guess that wasn't factory spec either. *SIGH* Oh well.

FWIW - replacing the VANOS is extremely easy and well worth it. I think they tend to fail gradually and you just don't notice what is missing until you get it all back in one lump sum.

-TC

[LockDots]

That makes me wonder if the backfire sounds (pops upon decelerating in gear) are a sign of a failing VANOS.

[tommycat1313]

That makes me wonder if the backfire sounds (pops upon decelerating in gear) are a sign of a failing VANOS.

I think that is a possible sign of a jammed one, yes.

I was originally thinking maybe the previous owner had set the static intake timing a few degrees beyond TDC and clocked the intake gear a tooth clockwise (which it was), and when I put everything back to factory spec I maybe screwed up what he was trying to do. But now that I see the old VANOS, I think he just got the cam clocking wrong.

--TC