smile

My car just got a valve adjustment done yesterday. The car has 45K mi on it. Since I bought it used, I have no records of what the previous owner did to it. Anyway, the shop said that the valves were too tight, so they loosened them back to the stock spec. After picking up the car, I noticed that the idle is smoother and a bit louder. My first initial test-drive suggested the following: 1) the engine tone was changed a bit. Perhaps, the sound had a sharper tone than it used to be. <Tell me if I am wrong though. Tighter valves = less noise? Loosen valves = more noise?> 2) the power seemed to be a tiny bit stronger and much smoother.

This morning I noticed that the car is making some strange and rattling noises that weren

Gernby

Who did the valve adjustment? I'll bet the mechanic adjusted the wrong clearances. Some Honda heads are supposed to have the clearances measured between the cam lobe and rocker, while others are supposed to be measured between the valve spring retainer and adjuster screw. All of my previous Hondas were of the 1st type, but the S2000 is of the 2nd type. I made this mistake myself the first time I adjusted my valves on the S2000, and I had similar results as you.

BTW, something else that backs up my theory is that the mechanic said they were all too tight. If you measure the clearance between the cam lobe and roller rocker, the clearances are much smaller than they are between the retainer and adjuster screw. For example, the clearance spec for an intake valve clearance is .008-.010" between the retainer and adjuster screw. If the valve clearance is within this range, then the clearance between the cam lobe and roller rocker will be about .006". I think he measured the .006" clearance, and adjusted it to .008". This means that your actual clearance is now about .013".

SanMarinoCpe

Was the car cooled off before measuring/adjusting? I like to have the car sit over-night before adjusting valves or at least 3-4 hrs to cool before work.

marcucci

To answer your other question, "tight" valves are quiet. "Loose" ones tick. Some tick is normal on all Hondas running stock clearances. The noise you are hearing off-idle is probably just the clatter from the valve clearance. Whether or not they were set right is another story...

hondaS2001

gernby and sanmarino are all over this. It could be either what gernby said, or what sanmarino said, or even a combination of both. They need to do it on a cold engine otherwise the valves will be tighter if the engine is warm, and then if they measured between the cam lobe and the rocker, it will lead them to believe they are too tight.

smile

gernby -- The shop that did my valve adjustment is very knowledgable and have worked on all of my cars without any problem.

Questions -- will there be a problem if I continue to drive as is? If I go to a dyno this weekend, will I put the engine at risk since the valves are possibly misadjusted?

hondaS2001

If they were too tight you would stand a chance to do damage, too loose and they are just noisy from what I understand. Unless of course they are CONSIDERABLY loose.

smile

yes, the car was cooled off before they made the adjustment.

smile

hondaS2001 - thanks for your help.

Billman250

You could ask them nicely if they checked the clearance in the right spot. I've done valve adjustments on about 10 different S2000s. Out of 160 valves, I've never found a single valve to be tight. When initially checked, the intakes usually range between .009-.014, and the exhaust range between .011 and .015. I go with .008 for the intakes and .010 for exhaust.