Honda J35 Valve adjustment, affect idle quality

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I am sure this has been discussed a million times about Hondas in general but, a quick search really didn’t provide anything recently relevant. I have a 2015 Accord V6 with 120,000 miles and really do not know if spending almost $900 at the dealer was the right thing to do for a valve adjustment. The Indy mechanic was not that much cheaper to be honest because I called them too. Normally I would not worry about this because engine runs great, except at idle in gear I can feel the engine vibration through the steering wheel and into the cabin. Common with 4 cyl engines but was not expecting this with the V6. With that said I have changed the motor mounts with oem, cleaned the throttle body, ran Techron through the tank, new plugs, and timing belt was done at 100,000.
I am kind of out of ideas and didn’t know if valve adjustment would affect idle quality at all and if this is something that I could do myself. I am do have mechanical ability and have been inside engines before not never has to adjust valves. What do you all think?
 
I assume this one has VCM, if so it could be it has a bad engine mount(s) again. At 120K the valve adjustment is usually okay.
Edit: Which mount did you change?
 
Who replaced the engine mounts? If they are indeed new OEM, I would think they might be bound up a little. I would try loosening the bolts just enough to allow the mounts to slip a little, then tug the engine back and forth to allow them to settle a bit, then retighten. I have seen them get bound up and cause these minor vibrations when done on an incline such as when the vehicle is on jack stands. Other than that, you could try a valve adjustment, but in my experience I usually find the job only quiets it down a little, with no measurable change in driveability or idle condition at your mileage.
 
Are you saying that you had the dealer do a valve adjustment and now it has an idle vibration? Or are you wondering if you should tackle the job yourself hoping it will fix the idle?

I can't offer any help on this particular model. The only valve adjustment I've done was on a Mopar Slant-six, probably about the easiest engine to do almost anything on. I don't remember anything about the idle, but it did wake up that 145 hp beast at higher RPM.
 
If the valve clearance is too tight, it can adversely affect idle quality. Check the MAP voltage at hot idle, should be under .9.
When it is usually at cold idle, valve clearance increases when the engine gets to operating temp. I mean you cant rule anything out from the armchair but there would have to be a lot of valve recession to get tight enough to idle rough.
 
When it is usually at cold idle, valve clearance increases when the engine gets to operating temp. I mean you cant rule anything out from the armchair but there would have to be a lot of valve recession to get tight enough to idle rough.
I've adjusted some of these where the exhaust valve clearance is probably less than .003". The newer ones don't seem to be as bad as the older ones, but the exhaust valves can get very tight.
 
The J motors are notorious for motor mounts, its a well know problem for these engines. How many of the mounts were replaced? IIRC there are 5, but maybe only 4, and the rear is the most expensive and the most difficult to R&I, the others are easy. I have been out of the business for a long time, but I would say it would cost a grand to replace W/dealer parts at a minimum W/labor.
 
really do not know if spending almost $900 at the dealer was the right thing to do for a valve adjustment.
I've done it on my Saturn Vue Honda V6 and the rear bank is a pain to get to so the intake comes off, but that shouldn't be any where near a 7 hour job. The front bank shouldn't take more than an hour and only if they were way out of spec, would you then decide to do the rear.

if this is something that I could do myself. I am do have mechanical ability and have been inside engines before not never has to adjust valves.
Nothing really complicated you couldn't do in an afternoon or weekend. Just involves sticking feeler gauges under the rocker arms to check clearance.
176Rear bank valve adjustment.JPG
 
I've done it on my Saturn Vue Honda V6 and the rear bank is a pain to get to so the intake comes off, but that shouldn't be any where near a 7 hour job. The front bank shouldn't take more than an hour and only if they were way out of spec, would you then decide to do the rear.
It's about a 4 hr job, book time. Most dealers are over $200/hr now, some are getting close to $300 here.
 
the Indy shop quotes me $560 in labor plus the price of valve cover gaskets. Right there is well over $100 an hour. Dealer was even more expensive. I’m less then an hour from Chicago to it’s not cheap here anymore like southern Indiana
 
Are you saying that you had the dealer do a valve adjustment and now it has an idle vibration? Or are you wondering if you should tackle the job yourself hoping it will fix the idle?

I can't offer any help on this particular model. The only valve adjustment I've done was on a Mopar Slant-six, probably about the easiest engine to do almost anything on. I don't remember anything about the idle, but it did wake up that 145 hp beast at higher RPM.
I didn’t have a valve adjustment done yet. Just called for a couple quotes.
 
My 08 Pilot got adjusted at ~165k. It made a difference and the engine smoothed out a lot. I remember a noticable difference. The mechanic said they were out of tolerance but not terrible. 120k is a little early for valves. I think the manual only specs adjustment at that mileage if they are noisey. Are they noisey?
 
Were the engine mounts that you removed visually damaged/torn/worn/taken a set?

The engine mounts for the Legend have a tightening sequence. I doubt this is the case here (C vs. J engine). I hope Honda redesigned this so that this is sequencing is no longer necessary.

Before tearing into the engine, I'd check the easy (cheap) stuff first.

I struggled with a similar vibration back in 2013 with the Legend. I could feel an intermittent miss by holding my hand close to the tail pipe.

After eliminating ignition, the path led me here:

spreadsheet.jpg
 

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My 08 Pilot got adjusted at ~165k. It made a difference and the engine smoothed out a lot. I remember a noticable difference. The mechanic said they were out of tolerance but not terrible. 120k is a little early for valves. I think the manual only specs adjustment at that mileage if they are noisey. Are they noisey?
Not really to me. I could be used to it all the different noises. The manual does say that 7 years or 105,000 miles scheduled maintenance for timing belt and valve adjustment
 
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