MTL_4runner

Hey Guys,

I have been doing some work on the beast lately and when I was under the hood today it seemed like the valvetrain was ticking more than I remember when it was new (been a while since I put my ear right up there). Now I know that the valves are solid and use shims to adjust them, but the car seems to be lacking a bit of power so I was thinking maybe the increased valve clearances might be robbing me of some power. Has anyone adjusted their own valves on this motor and do they recommend doing it? Did it make any difference?

I did call the stealer about this and they just told me it was not necessary and very costly to do (yeah thanks....I kinda figured it would be idiots....don't know why I even bother asking them anything.....totally worthless in my opinion) I don't trust em as far as I can toss the service manager so let's hear what you guys think.

1WiCkEd_RuNNer

Well I have had many a toyotas with the 4 banger and the V-6. The 4 needs to have the valves adjusted and the V-6 does not. Believe it or not the valve train is hydraulic in nature. There for the shims only keep the proper distance. The only time the valve train should be adjusted is when the heads are done. I dont know what kind of air system you have but simply cleaning the air filter regains alot of lost power! Sounds wierd but it works with me. You might want to try and use a fuel injector cleaner. BG44K from a dealer normally, is the best I have found. It really works. It cost about $20, but you will see a dramatic difference in one tank of gas. We actually need more info. But what I have given you should work some. Good luck!!!!!

rimpainter.com

There was a thread going about this last week I think.

Do you know what TDC is? Do you have the FSM? Are you comfortable with feeler gauges, torque specs, and working in tight places? Do you have access to decent tools? If you said yes to all those things, then you could do a valve adjustment.

Power "gains" through valve adjustments are not going to be huge. A valve adjustment will smooth out the engine through the power band and "increase" throttle response, not much more.

I would get the FSM and review the procedure, then decide. But that's just me.

MTL_4runner

I am sure I can do the job but I am curious if anyone else has done it too and if it made any difference for them?

I just changed the air fliter, cleaned the throttle body and did the deckplate mod......got some huge gains with the latter but I am looking for everything she's got and to make sure it continues to run like new. Doesn't sound like a common thing people are doing to their trucks in terms of maintenance.

rimpainter.com

Here is the thread I was talking about. Scroll down and you will find some info on the 3.4.

Its quite an involved procedure. I sure wont be doing it any time soon.

MTL_4runner

I just don't really want to do it unless I will see any difference and it seems like I won't see much. It is a ton of work so unless I do a teardown or a rebuild I think I will stay away for now and use the old saying.........
"if it ain't broke don't fix it"

Thanks for the link too!

Gadget

The valve train on the 5Vz engine is not hydraulic. It uses solid lifters that are not self-adjusting.

If the valves need to be adjusted, then they need to be adjusted. For anyone to tell you over the phone that your valves do not need to be adjusted doing you a real disservice and that is completely irresponsible and reckless on their part.

I think the maintenance book recommends the valves be checked every 15 or 30,000 miles. The quick check is to listen for ticking and check for a rough idle. The proper way is to pull the cam covers and physically check the lash with a feeler gauge. It is easy to check with a feeler gauge, and yes they are a pain to adjust.

If the lash is greater then spec it will tick and there will be accelerated wear on the cam lobes and the rest of the valve train. This however is better then the lash being to small or non-existent. If there is no lash that means the valves are not closing all the way and can leak combustion gasses between the valve and seat. This can over heat the valve and destroy it. Ever hear of "burnt valves"?

Remember, to much lash is better then not enough. You can hear too much, you can't hear if you do not have enough. A quick test for the more serious of the two is a compression check. You can do a standard compression check and if any cylinder is to low, then do a follow up cylinder leak down test. If it shows air escaping through the valves you had better adjust them fast before you need an overhaul.

Still the best way to know for sure is to physically check the lash with a feeler gauge. If you find that they are out of spec and need adjusting, the easy way is to do the adjustment in conjunction with a timing belt change. With the timing belt off you can easily remove the cams over the valves that need adjustment and you will not need the special adjusting tools that don't work well at all.

The procedure is to check the lash and record the lash that is out of spec. Then remove the existing shim and mic it. Then you look up the lash and the existing shim size in the chart in the FSM and it will tell you what shim to reinstall.

Shims are available from Partznet.com for about $8 a shim. The last time I adjusted mine I needed two out of 24. It runs fantastic and there is no ticking in my engine.

So, lets review. Whoever told you over the phone that you do not need to adjust your valves is a complete ass since his did not check your truck. Chances are you do not need to make any adjustments, but the only way to know for sure is to physically check the lash. If you are concerned, pull the cam covers and check the lash and then you don't have to worry anymore.

That guy that told you over the phone that you do not need to adjust the valves, is he going to pay for your engine overhaul if he is wrong or are you going to get stuck with that?

Gadget

www.GadgetOnline.com

MTL_4runner

Thanks Gadget....I knew you'd come through for me!!!
I knew that guy was an idiot I have yet to find a stealer worth a darn!

Sadly, I just did the timing belt myself but didn't think to do it at the same time ....oh well. The valves are really just ticking a little bit, but being the perfectionist I am, I wanted it to purrr and have all the power just like new. The idle is still very smooth and it really just ticks worse at startup, but when the engine warms up it becomes far more faint (as you would expect it to.....warm engine = reduced valve lash). When you pull the shims I would asume they have wear on just one side (cam lobe side). Can you just flip them over or was there enuf cam wear to need new ones? Is there something preventing them from being flipped and used again?


I also wish I had a bore scope so I could see what the valves look like (ie if they have heavy carbon buildup or not). If they did have buildup then at that point I might pull the heads and clean the valves too. You got any tricks for cleaning the valves without pulling the heads? Did yours need cleaning?

Gadget

You are not going to find any measurable wear on the adjusting shims. They are not going to change size from wear unless something is really, really wrong. Fliping them over does nothing for you as the thickness does not change.

In normal operation the lash on the exhaust valves would normally get smaller as the seats wear from errosion from the exhaust gas and pounding of the exhaust valves. That is not good and if you run out of lash they do not close properly and you get brunt valves.

The intake valves will normally increase lash over time form build up of carbon and other crud on the backs of the intake valves. Increased lash can cause an aduable tick.

The best thing going right now that I know of is the Motor Vac Carbon Depletion service. It is a machine that is hooked up to your fuel line and provides a special chemical that you engine is idled on for an hour or so. This cleans the injectors, cleans carbon from the backs of the intake valves and cleans carbon from the combustion chamber. It restores new car performance and it called the Viagra for engines. I have used it myself on my own cars and there is a very noticable increase in performance when this is doen. A clean engine runs better. You really should look into having this done.

However I doubt it will make much difference at all on your valve tick.

Just get yourself a FSM and pull the cam covers and physically check the lash and see what you have. You may find that all is well.

Gadget

www.GadgetOnline.com

MTL_4runner

Cool.....thanks for the advice!

How much did the Motor Vac Carbon Depletion service cost you?
Is there a way to locate places that can do it for you?

keisur

they told me the same thing. the guys here advised to get it done.