Valve Adjustment Yes/No?

[N-Wing]

I have a 92 with 106k on it. Basically its mint. I got it from a former prime member. I'm running Royal Purple Synthetic at the advice of a prime member. The car still is making a pretty pronouced tapping type noise. I've seen information here that this is somewhat characteristic of the engine. So my question is, would anyone suggest I get the valve adjustment maintenance done? I'm sure it wouldn't hurt but it a bit pricey. The engine is pretty smooth for the most part, although I do have some vibration at idle (I plan to try the loosen the engine mount and re-tighten trick I read about on another posting). I'm interested in thoughts.

Thanks

 

[Jin1976]

http://www.nsxprime.com/FAQ/Maintenance/valves.htm

 

[drew]

The job is easy to do and doesn't take much in the way of tools. You can buy a cheap Acura tool on amazon for few bucks.

I'm not a mechanic: just a software guy.

At some point an adjustment has to be made. If the valves are tapping loudly, I wouldn't be so worried. You're just getting sloppy performance.

If it is not tapping "enough" that is more cause for concern. It is common for a valve to recede over time as it pounds away on the valve seat in the head. This can cause low contact time with the valve against the valve seat head, and not able to dissipate the heat. This causes the valve to heat up and burn itself out. You won't know this has happened until the engine starts missing and your compression has sunk.

You are asking "how much is too much"? Well, nobody knows, each engine is different. You will have to check it and see. The NSX doesn't require much maintenance as it is, so I'm not sure why you are worried about the cost.

The book calls for 15K then 30K (depending on model year). I've done mine at 30K and found only one [maybe two] out of minor adjustment. I would suspect that 60K is really pushing your luck though.

However, you only need one burned valve to cause yourself many thousands in damage repair. You won't be able to pass smog either.

Bottom line: if you are worried about cost...do it yourself. It is an easy job.

Drew

 

[nsxtasy]

I would ask the previous owner when all of the various scheduled maintenance procedures were performed (and, if he doesn't know, if he can tell you which dealer or mechanic did them, so you can ask them). If you can't find out when they were performed, then I would do ALL of them now (and start keeping records so you know when everything was last done).

The recommended maintenance schedule specifies valve adjustment every 15K miles or 1 year, whichever comes first (I would do this one based just on miles, not time), and a bunch of fluid and filter changes every 30K miles or 2 years, whichever comes first (most of which I would do based on either miles OR time). If the cooling system hoses have never been replaced, I would do those too.

I just had a bunch of maintenance done on my NSX. The valve adjustment cost $350 for 3.5 hours of labor, plus $53 for head gaskets. Which is not pricy at all, IMO (a lot less than changing the timing belt, for example - and yours better have been done by now, with 106K miles on it). If you have the mechanical ability and enjoy working on your cars and have a place to do the work and all the tools, then feel free to DIY.

 

[N-Wing]

Thanks for all your comments. I started reading through the FAQ's, as usual I'm embarassed to not have checked. The cost I was quoted was $450 plus. I would be more than willing to do it myself. Is that procedure spiked out in the maintenance manual? I'll finish reading through the FAQ's in case its there. I have a good number of records but I don't recall seeing a valve adjustment. I'll call my dealership and see if they see it in theirs. Thanks, Mike.

 

[Tom239]

I would be more than willing to do it myself. Is that procedure spiked out in the maintenance manual?

See http://www.danoland.com/nsxgarage/valve/valve_clearance.htm
and http://www.blazen.com/mike/nsxmanual/page.php?page=128

 

[sjones]

I had mine adjusted with my 90K service and they were a little noisy when the car was cold. I'm anal about maintenance so i went back to have them done again at 105K and again at 120K but the dealership tech listened to them and told me they were fine. Can they be diagnosed just by listening to them?

 

[drew]

Can they be diagnosed just by listening to them?

I think you are confusing "diagnosis" with "normal sounding"....my guess is that "Your valves sound normal."

**
What is the sound of one hand clapping???

The danger problem is not clacking valves, but the QUIET ones.

How do you hear that?

**

To answer your question: Sure, this is possible. You would need a precision transducer, input from the CAS and a recording device you could listen to and analyze these sounds.

You would have to compare them against a "normal database" and determine if your valve sounds exhibit similar characteristics to a well tuned engine.

A lot of work to replace a simple very accurate feeler gauge, especially for a single occurrence.

Though a well financed factory effort could probably turn this into real product that would be extremely useful and economical to use.

Heck, they could just integrate this into the on-board electronics....the more I think about it: this really should be made into a product. You could do a quick audit of the health of an engine from day one and be notified of any gradual changes and/or degradation in performance.

**

You can also diagnose a lot (by eye) with a sensitive vacuum gauge to see if there are any variations in the cylinders. Poor valve adjustments will show up quick.

Drew

 

[N-Wing]

TOM239, excellent files. I really appreciate those. I'm reasonably technical and with those I think I'm good. I double checked my pricing. The dealer wants $510 for the valve adjustment. Its just seemed to steep. If I get confused I will pay it in either case. Thanks everyone, good comments. :smile: