what's the purpose of doing valve adjustment and how often it needed to be done?

I have read about it here and finally get a chance to ask my mechanic yesterday when he was replacing the spark plugs. he told me it is not necessary to do it because most cars manufactured after 2000 are hydraulic ( i dont know what he means by hydraulic) and do not need it.

Any suggestions? Thanks a lot

 

Over time, heat makes the exhaust valves tight.
over time, the intake valves get loose.

perform a valve adjustment to get them back into factory specs.
however, some are noticing that they arent far off from factory specs, thus not really a need to do so.

a mechanic would have a measuring tool or a feeler guide that shows how far off they are.

 

he must be thinking of BMWs with hydraulic lifters.

It's not the same with our J series engines. i would take it somewhere else if he's not even familiar with our engines. He must not work on a lot of V6 hondas. It's also pretty careless to make a blanket assumption for all cars.

 

If you're interested how the valve adjustment is done, Eric The Car Guy on youtube actually went through our car with a step by step process.

Video 1of2

Video 2of2

 

thanks for the info

 

i went to another mechanic ( friend of mine) and he also said that it's normal for Honda engine and not necessary to do the adjustment. so now i am not sure when it will become necessary to do it.

 

manual says it is done with the timing belt job at around 105k.

your friend, he has experience with Honda V6s?

 

armed with this information..... means that a mechanic with a feeler tool can tell you if your shit is getting too tight.

that's when you perform a valve adjustment.
when it's out of spec!!!!

you dont want your shit too tight

 

Getting the valves adjusted every 100K or so is more of an insurance plan for your engine. Your car is upwards of $5K right now, are you really going to be frugal over 100-200 dollars for the adjustment to ruin a $5K+ car right now? I know I wouldn't!

 

You have two main types of traditional lifters/valvetrains. Hydraulic and solid. For some reason Honda has stuck with a solid valvetrain while the rest of the world began going hydraulic 30+ years ago. It has it's advantages in very high rpm applications, my fathers GN that spins over. 9,000rpm uses a solid cam. 7,000 rpm can easily be done with a hydraulic valvetrain.

But back to the how and why. A hydraulic setup uses a lifter or bucket in the valvetrain to take up the slack. The lifter or bucket is somewhere between the cam lobe and valve stem. It pumps up with oil pressure to take just the right amount if clearance out of the system to be at zero clearance. It compensates for wear over time so valve adjustments are not necessary.

Solid cams or solid valvetrains have to be adjusted because there's nothing there to take up the slack as things wear. As the exhaust side tightens, a hydraulic setup doesn't pump up as much to keep clearance the same as new. As the intake side gets looser, the hydraulics pump up more to keep clearances the same as new.

What wears? On the exhaust side the exhaust valve seat is the biggest contributor, called seat recession. The exhaust valve sits deeper in the head or closes farther than it did when new. This causes less clearance between the valve stem and the rocker and rocker to cam. Clearances become tighter because the valve stem is sticking out farther. It's these tight clearances that hurt things. They make no noise but they lead to a burned exhaust valve which usually shows up as a misfire and the heads have to be removed to replace them. The exhaust valves cool themselves when they close fully and transfer heat into the valve seat which is carried away into the head and into the coolant. Not closing all the way causes them to over heat which is what happens when clearances are too tight.

Intake valves usually get too loose over time and get noisy. This is more of an annoyance but doesn't significantly hurt power or reliability. It's from a stack up of valvetrain wear, cam, rocker arm (all 3 wear points), and even the valve stem itself.

Noise is not an accurate way of determining valve adjustment necessity. The intakes will let you know when they need to be adjusted but the exhausts will burn a valve without ever making a noise.

 

my TL has around 85k miles. so would you guys recommend to be proactive and get it check out/adjust now or wait until 105k service?

only reason i want to do it now is the noise my mechanic pointed out when i did the spark plugs replacement (@83k)

 

"It depends" is the only real answer. A lot of the clearance change happens early on in the engines life so the difference in 85k and 105k might not be much.

The noise isn't a problem unless it bothers you. You're not going to lose power or mpg or hurt anything. The big unknown is the exhaust valves since they usually get tighter and make no noise yet they are the ones that will cause the expensive problems. You don't hear of too many TLs with burned exhaust valves. I did mine at 113,000 miles and I think I had one sort of tight one, I would have to go back and read what I found. I probably could have gotten another 100k out of it. You can also use intake manifold vacuum as a rough indicator of whether it needs a valve adjustment.

If the noise bothers you it's definitely not a bad idea. If you're doing it yourself it's practically free. If you're getting it done by a friend or you're in good with your mechanic you might get a deal since a lot of them likely won't have to be adjusted, just checked.

Whatever you do, make sure it sits for 24hrs without being started. I get home from work at 5pm and get back in the car at 4:30am. I've popped the hood in the morning after sitting almost 12hrs twice now and the engine is usually 20 degrees warmer than anywhere else in the garage and if the external temps are like that you can bet there's even more heat still trapped in the heads. Be careful of the mechanic that has you drop the car off in the morning and has it ready for you by the same afternoon.

 

usually people get it done when they're engine is idling a little noisy it only will make things a little quieter possibly a little bit smoother ride...

 

I did my valve adjustment at 74k miles and only one of the valves was slightly loose, and not by much. Keep in mind, when I drive, its very spirited driving and has a decent amount of mods on it. Only reason I did mine was to give me peace of mind before the turbo went on.

I wouldnt recommend you doing one til at least 125k or more.

 

I first adjusted the vales around 100k. Its been another 120k and nothing has needed to be adjusted further. However, I still check.

 

My engine is definitely noisy, 140k miles, I feel like I could do it myself but would probably rather pay if it can be done for around $300.

 

At 190K, I think I'm due no matter what. Right?
.
.

 

I did my first adjustment because I had a tick. Most of the valves required adjustment. When I checked a few months ago everything was still within the tolerance.

If you haven't had anything look might as well see where it stands.

 

That's exactly what normally happens. Most of the wear is done early on. Once you adjust the valves the first time you might be able to go twice as long the next time.