I have a '00 Honda accord EX V6 and had a valve cover leak. I decided to replace the plugs and adjust the valves since the car has 196k miles on it and I don't know when they were last checked. Before adjustment the valves were damn quiet. Upon inspection the intake valves were slightly loose and the exhaust were tight to the point where there was almost no clearance. All valves were adjusted within spec and while in TDC for the corresponding valves being adjusted.

I should mention that the car ran damn good with may a slight hiccup here and there at idle and I mean very very small. After the adjustment the car for sure ran smoother and felt great but sounded like a diesel truck!

I've since adjusted the valves 3 more times. Currently the intake valves are within spec and I have the exhaust below spec but not as tight as they originally were but my very slight hiccup has returned and I'm still getting to much valvetrain noise when slightly accelerating.

What could be going on here??? I'm gonna give it another shot this upcoming and confirm that my TDC is for sure actually TDC so as to rule out that I am adjusting under a non TDC condition. Any ideas or direction would be appreciated.

 

Did you adjust the valves when the engine was cold(below 100°F)?

Did you use straight or angled feeler gauges?
Straight feeler gauges are a bit harder to adjust with and give you a false sense of correct clearance as the straight feelers will get jammed in the valvetrain and surrounding structure.
Angled feelers allow a more precise adjustment, there is more room without getting jammed into the valvetrain, all you really have to do is tighten the adjuster until the feeler 'stands up', a great visual indicator. Once it is snug enough the feeler no longer moves up, back off til it starts to droop and then snug it again to feel. I prefer a slight drag where when held perpendicular there is little to no resistance but slightly angled up/down the feeler is really tight. Makes for easy adjustment.

If the oil is in need of changing the mechanical lifters will let you know, you will hear the ticka-tacka of the rockers.

The sputtering you were feeling was most likely a misfire. As the engine wears the exhaust valve seats and valve faces erode, this is why the exhaust valves were tighter than the intakes. With little or no clearance the valve will hang open, this will cause a loss of cylinder pressure and a misfire. Lack of Fuel, Lack of Air, Lack of Spark, and Lack of Compression are causes for misfires.

J series engines are nice, just peak through the window and you know which cylinder to adjust. #3, go to cylinder #3 and adjust both intake/exhaust.

 

you always use the lower end of the allowed valve clearance range so that as it wears it slighly opens up and is still in the top end range of the valve clearance allowance

you adjust so that the gauge you're using fits, and the next bigger one does not fit, then use a torque wrench to torque it down TO SPEC, and you must recheck the clearance cause it loves to move when you torque it down

 

Very nice tip on the feeler gauges! I'll be using that for sure.

To answer some questions I used straight gauges that I bent and also used them off of the set so it was easier to maneuver. All adjustments have been done on the motor either dead cold or under 100 degrees checked with my IR thermometer.

I'm going to give it a shot again this weekend and use your tips on the feeler gauges to confirm it wasn't me. I don't own a set of go-nogo gauges so when I did it I just made sure the gauge just out of spec would not fit to confirm I was at least close.

I just have this feeling that I am adjusting the valves at the wrong part of the stroke ever so slightly that my numbers are off causing it to be larger. Next time I am going to align the marks and confirm that I am at true TDC for that piston and cam timing to make sure something isn't just slightly off. The problem is I just can't think how that is even possible since I am using the cam sprocket and marks to line up as my TDC method. I would think that even if the timing belt could be stretched so far that it was slightly off form the cams that the cam sprocket timing would be correct for at least one head correct? Maybe the head near the fire wall could be the one that is slightly off causing me to adjust 1-2-3 at the wrong interval of the stroke?

 

Fool-proof way to confirm piston position, with valve cover removed: remove spark plug and insert a small plastic rod ~1/4" diameter X ~18" length through the spark plug hole to the piston top. Roll the crank a little bit each way to confirm cylinder is completely at the bottom. Then make a mark that corresponds with the top edge of the spark plug tube.
You will know, at a glance and beyond question, the position of each cylinder as you adjust valves.

 

Look at the cams, the rockers should be on the base circle of the cam, with no lift.
What might be happening is there could be a stack of clearances, or maybe even low oil pressure.
Intake valve side usually does not get tight, if yours were tight then there may be additional wear on the shafts/rockers that may be throwing the geometry and clearances off when the rockers are in motion.

If you adjust the valves until the bent style feeler gauges are 'standing up'...
Intake:
0.20-0.24 mm (0.008-0.009 in.)
Exhaust:
0.28-0.32 mm (0.011-0.013 in.)
Then you have adjusted them correctly.

If you are feeling curious, drive the car normally, park it to work on, give it 30mins to cool down a bit, then remove the valve cover near the radiator and check clearances when everything is hot.
If something is goofy hte clearances will be the same or more. If they are tighter than the cold spec then you know you adjusted them correctly. You can also play with the clearances(with the engine cold) and tighten them up to the next smaller size feeler below the spec and see if that gets the rockers quieter. Just to cheat it a bit and see if that is indeed what you are hearing.

 

I am for sure interested in a taking a closer look into what is going on when I pull it apart this weekend. I suspect my valves are getting looser with heat because when I start it cold after the adjustment the valvetrain is very quiet but when I reach operating temp the tap develops. The ticking is never there at idle and appears to show itself with slight acceleration mostly around the 2k rpm mark.

I'm just scratching my head on this one. My suspicion is that I am not adjusting the valves on the base circle of the cam but can't for the life of me figure out that is possible with I am using the cam sprocket to determine base circle. This time I am going to confirm my piston to valve timing is correct as well as watch the rocker to make sure it is at the base and compare it to all the marks to confirm I am in fact adjusting at the correct time. The car was nice and quiet with that ever so slight hiccup at idle before I made any adjustments so I can only assume I am the cause of this problem.

Oh and if I was checking my valves (prior to my touching them) at the base circle before adjusting my intake valves were loose and the exhaust valves were tight with no play.

 

Update:

First off I'd like to thank Mad Mike for the fantastic tip. I wasn't off by much but your feeler gauge tip was fantastic and much much easier to get consistent accurate results.

I have my intake valves adjusted to the factory spec of .20 mm and my exhaust is down much lower than what is called for but open more than I encountered when I made my first adjustments. When first adjusting there was no play at all. Now I have them around .15 mm. The vehicle isn't as quiet as it was prior but the clatter is better and once driving and reaching operating temp almost disappears.

Thoughts on why mine need to be adjusted low under spec for quiet operation? Do you think it is possible the back of the valves have carbon build up causing the valve to not seat ever so slightly?

 

It is nice when the tool does the work for you.
Keep an eye on those adjustments. You don't want to burn and exhaust valve with too tight of an adjustment. Intake has fuel spray to cool it, exhaust relys on transferring heat from the valve to head(valve seat) when it is fully seated close.
There could be a few reasons for the 'strange' spec.

• You are just so used to the too-tight(sewing machine) spec that the engine now(even with correct gap) is so much louder compared to when it was out of spec.
• Worn components/shafts are now wearing/loading in different surfaces on the parts, and you can hear the two surfaces breaking in together which may be louder for the next ~500 or so miles.
• Worn components again, but this could be from a worn shoe on a non roller rocker or a worn roller on the roller tip, shafts/rockers worn out and they are not simply rotating on the shaft but sliding as well. Had a rocker wear out on a Mazda years ago(shaft type) couldn't figure out why it was louder than the rest til I pulled the rocker off the shaft. It had an oblong hole, this allowed the rocker to slide while rotating, which caused a clacking/creaking noise as it slipped fore/aft rather than just rotating. Funny thing is it wasn't until after I had visually seen the damage I could hear what the rocker was doing. Creaking as it slid on the shaft. Which moved both the contact points of the rocker on the lifting side(valve) and the lifted side(cam).
• Your imagination/sensitive to the sound/frequency has you hearing all the noises the engine makes.

With fuel injected cars, there is not as much carbon fouling on the valves as you would in the past. Now if you feel like that might be an issue you can always pickup some SeaFoam and mosquito fog the neighborhood and see if the engine is quieter after the fact. Valves can stick if there is excess varnish on the valve stems. A good indication is seeing how much buildup or browning of the internal components has occured from lack of oil changes. Again SeaFoam in the oil will aid in removing buildup on internal components.

 

Thanks for the insight Mike. This is certainly an interesting and frustrating thing happening here. But I see it as a chance to learn something new. I am certainly more familiar with pushrod motors and know less about overhead cam motors.

Right now I'd say you are dead on with the sewing machine analogy. I only have peak times of noise now that sound like a sewing machine and I feel is a correct and expectable amount of valve train noise. I'm going to look further into what you are saying about the rockers and wear since I don't have much experience with their mechanics.

Going forward I am happy with the results but am going to try and figure out why I have to adjust the exhaust side down so low. Next step will be a little seafoam in the oil and some in the vacuum and see what happens. It sure seems like they must not be returning all the way up if I have to adjust so low for quiet operation.

The oil on this car has been changed every 3k-5k by myself. We have owned the car since it had 50k and now has 190k on the clock. Under the valve covers I couldn't ask for a cleaner result.

As for how the car is idling now? I'd say there is still something not quite right like there was before I did the adjustment. Just a very slight hiccup and maybe a tiny slight extended start if it is cold. This cleared up when I adjusted it how to .30 on the exhaust but was terrible sounding like a diesel truck. Not sewing machine but clack clack clack but only when driving. Quiet as a mouse if idling.

 

Similar Issue, I think - My 2001 Accord V6 turned over 200,000 miles recently and started a valve train noise at idle and acceleration. However the noise would disappear momentarily during acceleration if the driver let off the gas and reappear as the gas pedal was stepped on again - somewhat of a "tick tick tick" type sound. I did the Seafoam process before changing my oil in the fall hoping that would've helped - no luck. This spring I took it to a local repair shop to have the spark plugs changed (personally that rear bank is not fun) and also asked them to investigate the valve noise issue. They called and mentioned that the valves are not hydraulic and need to be adjusted manually. I said okay. They did the valve adjustment and the valve noise is now louder than before. Rather concerned I took the car back. Using a stethoscope they thought the noise was coming from the front cylinder bank. They redid the valve adjustment on that cylinder head. The noise is still there and hasn't lessened after more than 1000 miles of use. I believe I now the correct tools. Should I attempt to check the valve adjustment on the rear cylinder bank? Any tips or things to look for would be helpful. Thanks!

 

why not do the same but with the piston at the top of the stroke? Why the bottom?