so the previous owner of my 4Runner never adjusted the valves in the 180k that he had it. not long after i got it, it began to run badly and i had a flashing check engine light. anyway, the compression test came back zero and after pulling the head off, this is what one of the exhaust valves looked like









nice huh?

 

ouch, thats horable. time for OS valves and a lil port n polish!

 

You don't hear much about doing valve adjustments on these engines. I need to re-visit the maintenance interval for this.

 

yep. valves have already been done, cleaned up the head, everything is back together and it is running like new!

 

valve adjustments are as critical for the 3rz/2rz motors as much as it is for the 3.0's. Do it every 60k

 

nice to here that proly runs a lil better.

 

like a rocket compared to before

 

That valve is obviously burnt crispy. Did the machine shop give you any indication whether that valve was stuck open or if the other valves were out of adjustment. Usually burnt valves are sticking valves, valves that don't seat properly or valves that are to tight. Anyway, I bet it runs alot better.

 

Ha the valve looks like a mushroom.

 

This is a 4 banger thing only, right? The 3.4 is hydraulically adjusted, correct?

 

No. The 3.0 & 3.4 use shims for valve clearance adjustment.

 

So I need my valves adjusted how often? And how do I do this?

 

I had to get my valves adjusted at one point (I have the 3.4L), only because it started to sound like a diesel. From what I heard, these engines don't need valve adjustments as regular maintenance (cost me about $400 to get mine done) - if your engine in knocking, then yeah, get it done... no problems since (this was about 3 years ago).

 

I have 98k, and I should be good as long as I keep everything else well maintained then.

If I get some knocking I'll pull off the head and see how they look.

 

I've been searching for a valve adjustment DIY, nothing yet. I'm curious to see the shim type and how the adjusters on the 3.4 work. I did the valves on my Prelude no problem, I'm hoping the 4Runner uses the same tool. Shims scare me though, the Honda doesn't use them, and I hate using them on my motorcycle engines as they're a pain to manage and odds are you never have the size you need.

 

What the h@11 ate that valve? That looks like severe overheating to me. Did that come from #6? Not adjusting the valves will lead to zero clearance and no compression. Toyota has failed us again with the use of specialized shims. Something the average guy can not deal with thus a guaranteed trip to the stealership and lots of money to reset the valve clearances. Now, if the design team had put a tapered screw on those shim pods, valve adjustments would be simple for any person with some skills. But no and the 3.0 adjustment disease continues into the 3.4 and beyond. Yes, one can argue that the design is simple and very reliable. If you got lots of money, no need to complain.

Rant over.....

 

the valve was not closing all the way. it was still moving, but never fully contacted the head so it couldn't transfer the heat off the valve. and yes, it does run much better. when it was idling, it felt like i had a huge v8 it something but i had the power of a 3 cylinder....which i did. now i can actually keep up with my friends 3.4L

i have the 3RZ 4cyl. it was on the #1

 

These valves do not have typical adjusters like the 22re's. They are shim and bucket. The only way to adjust them is to use a special tool the pushes down the bucket and another tool that goes around the cam and holds the bucket down enough for you to get the shim out. Or you can measure clearences and remove the cams. You need to measure what clearence it has before you do anything that way you know what shim to get for it. The shims only come in .002 increments. The 3.4's I wouldnt worry as much about but the 4cyls I would as well as the 3.0's There isnt any toyota motor that has valves that adjust themsleves

 

Here's one that I recently repaired. Same engine as yours. Certainly not as bad as yours, but bad enough to show 100 psi difference in compression compared to the other three cylinders.



I really didn't think that the valve adjustment was that big of a deal. I measured all the valves before teardown, (all ex valves were too tight) so after it was disassembled, and I was able to measure the existing shims, the chart in the FSM made choosing new shims easy. This was my buddies truck that he intended to sell, so I just lapped two new exhaust valves into the existing seats on #1. If it was my truck I would have replaced them all, but that is neither here nor there. I did end up having to make an extra trip to the dealer because I had to try to guess what shims would be appropriate for the two new ex valves. I got one of them right and one was off, so that was really the only hang up.

 

Damn, that looks bad!

I just had some help from my grandpa, and he mesured my valve clearance while i was replacing the valve cover gaskets and they all were in spec. So i guess it had been adjusted not too long ago, the PO took good care of it.