Why are valve adjustments important?

I've read in a couple threads around here that valve adjustments are important every 60-90k. I've got a used Tacoma that I just got this summer that just hit 90k, and I was wondering if I should get this work done. However, I was hoping to get a better explanation of what it is, why it's needed, how it's done, and if it's needed on other cars too? I've also got a Subaru with 200k miles and have never gotten this type of service work done before...

Thanks for your help in advance!

 

Valve adjustment is important becuase it will ensure that the valves are opening and closing at the right time in the cycle of the engine. It will alsomlet you see the state of the cams and springs in the engine. With valves way out of adjustment, you are going to be down on power and mileage.

Some cars need it more than others. And more modern cars tend to need it less often. Check out the frequency that old ducatis needed a valve adjustment, every 8k miles.

Check for a factory service manual or a repair manual for how to check, or find a shop that will do it. Shouldnt be too much on a 4 cylinder.

 

A tightly adjusted valve will become a burned valve, and a noisy valve is a happy valve (albeit not altogether desirable).

 

Right around $1000 at the dealer. It takes about 8 hours to do from what I have read. For someone who has never done it before.

 

>>Right around $1000 at the dealer. It takes about 8 hours to do from what I have read. For someone who has never done it before.<<

$1000? WOW! On a 4-cylinder? Double-wow!

Maybe you should look around at an independent shop for somebody who has done at least 20 valve adjustments on a 2.7L engine and see what he says and charges.

About 8 hours for the job? It took me about 4 hours to adjust the valves, but that was 25 years ago when I had a 2.7L engine. Nowadays it takes me 2 hours just to get started on just about anything .

 

The dealer near me wanted $800 to adjust. My local Toyota mechanic did it for $500.

I sure miss the 22R on my old rig, which didn't have the bucket/shim type valve train. All you needed was a screwdriver and a metric wrench to adjust the valves.

 

The dealer in my town said right around $1000. I have no doubt it can be done for less. I don't know if it actually takes 8 hours or not. That was my assumption from hearing what you have to do to get the job done. I have no doubt it would take someone who has never done it all day long. You're also right about it taking 2 hours just to get started. Age has a whole lot to do with how long something takes. That's for sure.

 

The bucket and shim type is very, very durable though. It's a trade off for having valves that, for the most part stay in adjustment for a very long time. Ferrari uses a similar arrangement. Theirs is slightly more durable than the 2.7 though. I forget what the difference is but they are very close by design.

 

Ferrari uses bucket over shim I believe. The bucket tends to keep the shim stable above 8000 rpm, but you have to dig deeper into the cylinder head to get the job done. Now back to the Tacoma, the every 60k mile recommended valve clearance check/adjustment for 2rz/3rz is not really that bad when you consider all the fun stuff you can do while you are in there: new valve cover gasket, PCV valve, clean throttle butterfly and IAC, and maybe even some new plugs. This is a moderate level DIY project though, but there is serious $ savings if you are up to it.

I forgot to mention the logistical problem with this project. After you remove all of the air intake hardware and valve cover, you have to measure the valve clearance. If any of the valve clearances are out of spec., you then have to remove and measure the thickness of the associated shim. Next you have to order the shim(s) you need to correct all the out of spec. measurements. In the worst case this requires the truck to be out of service for almost a week.

And another thing. If you take this on and have to order shims, spend some money and get an assortment that takes care of the tendency of the valves to get tighter over time. The 30% off list price on-line ordering deal works out to about $7 per shim. So for about 15% of what you will save doing this yourself, you can make it real easy next time.

Don't forget special tools, other parts, and a few you-tube video watching sessions!!

 

I believe that is what I read about the Ferrari now that you posted it. As far as the valves on the 2.7 wearing tighter? I have a friend that was a Toyota mechanic for 25 years. He says they wear loose. The dealer I go to from time to time also says the exact same thing. The service manager there who I have found to be honest and very knowledgeable tells me that Toyota says, "If they aren't making noise, they are fine.". However, the service manager did say that a valve getting tighter isn't impossible which is why I'll probably fork over the dough in the not-to-distant future and have them check my valves. What they charge is cheap insurance in my book when you look into the expense of having to pay someone to fix a burnt valve. You're explanation of what it takes to do the job doesn't jive with my Taco being my only form of transportation right now. Not only that, for decades I always had a shop to work in but that isn't the case anymore. I've got 150,000 on mine right now. I'll probably have someone check the valves towards the end of next year.

 

TRVLR500
I think you have the right approach. If you cannot afford the down time, take it to the shop. The clearances need to be checked cold so the shop will probably want to keep it overnight.

I had always heard that the valves wear tight and that matches what I measured on my 2RZ. I would like to understand this better though. With other engines that use adjustable eccentric followers, I have measured both tighter and looser.

Is it common for the Service Adviser to go against the Toyota recommended service intervals? This valve adjustment question comes up quite often and it seems more common for owners to skip having the work done. Maybe Toyota is too conservative.

Please let us know what your mechanic finds.