ugh....trying to get syked up for this...looks like a simple enough job, but I don't look forward to taking off the plenium with a the vacuum hoses.

I've looked through several youtube videos and I'm going to try the flip over method where you keep the PS hoses connected.

Here is what I think I need
- valve cover gasket...felpro ok?...got 460k and just need to keep it going
- FIPG...any brand?
- TB gasket
- intake gasket
- PVC valve and gasket

Anything else?

Also, anyone have a good method of keeping track of bolts and nuts?

I'm going to take pics of the vacuum hoses and connections just in case the flip over method doesn't work

 

Take lots of digital pictures before pulling everything apart and also as you proceed.
For nut and bolts organization. two things come to mind: 1) drop nuts and bolts into numbered and labeled zip lock bags at each step...when re-installing grab highest bag number and work backwards, 2) a cardboard template can be drawn and bolt inserted in a small hole at the appropriate location.

 

The leak could have been caused by not following the FSM instructions. Since you're getting sealant, I'm guessing you know the right way to do it.

Personally, I don't see how the "flip over" method could work. The problem is the hose to the PAIR valve. It's about 25mm, pretty short, and isn't about to bend 30°. much less 180°. I just remove the plenum and don't worry about twisting something off. (The power steering hoses are dinky; just note where they go and pull them off. Order doesn't even matter.)

Photos are nice (and digital pictures are free), but nothing beats a simple hand-drawn diagram. The stock vacuum hoses are marked with something like "#2." If not, get out some masking tape. Try to note which hoses go over and which under. It's perfectly obvious when everything is connected, but when you are installing them you will get it wrong. Save the diagram --- you'll use it again!

You shouldn't NEED a throttle body gasket; it doesn't have to come off. Don't forget that you need to drain about a gallon of coolant to disconnect the coolant lines to the TB.

Before you do anything, find the Thermal Vacuum Valve below the plenum by the firewall (trace the line from the vapor canister). At 24 years, it will be very brittle, and the slightest abuse could break off one (or both) of the nipples. Know where it is and be careful.

The reason to use FIPG is because it sets up in about 5 minutes. This is good if you are a professional mechanic, have to get that rig out of the bay in the next half hour, are lightning fast, and never have to reposition anything. Is that you? It's not me. I use plain-ole RTV (I like the blue stuff, but I don't know if there is really a difference). It will take 24 hours to completely set, but you've got the time.

I recommend getting a 1/4" torque wrench (about $12 at HF right now). The torque on the valve cover bolts isn't much (48 in-lbs), you can break them easily, and if too loose it will leak.

I keep track of nuts and bolts by putting them back into the tapped hole once I remove the part. If I have to leave them out (like sending a head to the shop to be cleaned), I just measure them and write the size of the fastener right on my diagram. You can try poking them into a sheet of cardboard, but if anyone bumps into it you'll end up with a few on the floor. Just KNOW the size fastener for each location, and you'll never go wrong.

 

Another thing I do: as I take a hose off I label it #1 and the corresponding connection #1 of a piece of tape...increasing the # as each hose/connection comes apart.

Scope is right on target with his excellent advice.

 

Check Valve clearances while in there. With 460K you just had clearances checked/adjusted at 420K right? Why are the covers leaking so soon?

I would go OEM on the gaskets, I used aftermarket in 2006 when I first pulled mine to fix the leaking, they started leaking again within 5 minutes. switched to Toyota and they are still completely leak free after 10yrs now. I used FIPG in the corners and also I put a bead in the channel in the valve cover itself and pressed the gaskets into it. Mine were leaking over the top of the gasket.

Torque wrench is critical as has been mentioned. In fact I just pulled my drivers side covers to check valve clearances (DID I MENTION CHECK YOUR VALVE CLEARANCES WHILE IN THERE!) and figuring I'm gonna be right back in there I didn't even do a very good job cleaning the surfaces, no fresh FIPG, just stuck the cover right back on there. What I did do was go by the sequence in the book and used the correct torque on the bolts. Guess what....no leaks. 10yr old gasket with virtually no prep work and it resealed, I would bet if I didn't use a torque wrench and correct tightening sequence it would be leaking already.

You need to check your valve clearances, its very easy to check the clearances. Just pull the 6 spark plugs so its easier to turn the crank, 19MM on the crank nut I believe, turn the crank clockwise until the cam you're going to check is nose up and stick a feeler gauge in there. The thickest one that will fit with a slight drag is your clearance. Don't go crazy trying to shove the next size up in there if it won't go. Once you feel slight drag that's it.

Checking is the easy part....if you find some that are out of spec then that's a little tougher to do but must be done. You can worry about that if/when you find any. I made 2 tools to do it, 1 to push the valve down and 1 to hold the bucket down for shim removal. Took me all of 30 mins to make the tools and probably works better than the SST style based on reviews I've read from ppl who used it.

Start a new thread when you find tight valves and need advice on how to change the shims.

 

wow...thanks for the all the input!.....a lot of stuff I didn't think of

David
I always thought the valves were non-adjusting....I don't remember every having it done

 

My owners manual says every 60K on the valve clearance check. If it's never been done I can't see how it has made it 460K miles?

I just checked my drivers side bank and found 5 of 6 were under min clearance, I'm at 178K. I have a feeling mine may have never been checked....or maybe at 60K, but for sure not at 120K or they wouldn't be as bad as they are now.

Neglect them and you end up like me with a dead cylinder because of a burnt exhaust valve. Clearances in these engines get less and less over time until you have no clearance left and then the valves don't close (seat).....valves don't seat = burnt valves = no compression = now you get to pull the heads like I'm about to do!

When I replaced my valve cover gaskets in 2006 I didn't know how to check the valves, didn't really understand the importance of checking and adjusting them either. So I just didn't do it, now I have do have the heads done....I had the covers off in 2006....if I had checked the clearances back then I bet my truck would be fine now. But I didn't. Now 10 yrs on and being the owner of a few older Japanese motorcycles I full understand the importance of having the valves set correctly!

Check your valve clearances while you're in there.....like I said, it really is easy to check the clearances once the valve covers are off. All you need to check them is a set of feeler gauges you can get from any auto parts store for $10 or so. Plus a new set of spark plugs, might as well change them once you pull them out.

Turn the crank clockwise until the cam lobe on the one you're going to check is nose up. (pointy end up) then stick a feeler gauge between the cam lobe and the valve bucket/shim. Make a chart and record the measurements on intake and exhaust for each cylinder. Done. The min - max clearance is on a sticker on the hood, mines upper left when the hood is open.

If/when you find some that need adjustment that's when it gets a bit more tricky. Like I said, just report back and someone should give you a hand changing out the shims. It's not hard at all either if you can make a few simple tools. You need a claw looking tool, looks like captain hook's hook. That goes around the cam and pushes the valve down, then you need a second tool that wedges between the cam and valve bucket to keep the valve open. Take out the hook and pop out the shim.

Once you get into it you'll see what you need. But I'll post some picks of the tools I used if you're interested.

You can buy a tool that does the same thing, but reviews are mixed. Probably user error and nothing wrong with the tool actually. But it only took me a few minutes to make the tools so I just made them.


Check the reviews for a lot of pics showing how the tool is used.

 

I have the commercial valve adjusting tool mentioned by dr1553. Like dr1553, I make a lot of tools, but for $30 I would (and did) just buy this one. It will take you about 15 minutes to do the first shim, and about 30 seconds each from then on.

DON'T try to remove a shim without an equivalent tool; shop-made or store-bought. That way lies madness.

Someone on eBay is selling these shims. There are about 25 different sizes, but because of the tolerance on the clearance you don't need the exact size. If he's selling a shim you can use, you will save a boat load of money getting them from him. ($12 delivered for 4-same-size, vs. $20+ each at the dealer)

 

From what I understand there is a very short hose that runs vertically under the rear of the plenum, is that the PAIR hose? And is it as hard to get back on as it sounds like it would be?

 

The PAIR valve is at the back of the passenger side, over the valve cover. Its molded hose goes up and then turns in to horizontal. For me, the hard part is getting it off, not back on. The secret is to use a hot-air gun (or a hair dryer). Warming up old hoses makes them much easier to flex and remove, and reduces the risk of cracking them. (True for all size hoses, but especially the larger ones.) A hot air gun can get hot enough to do real damage, so I keep my finger on the hose while gently heating it.

 

Appreciate all the inputs, guys!
I have some seepage around the "U" shaped interface i front (will post pix later). Had been like that since after the rebuild, but James E of The Truck Shop says, it's normal and is "the nature of the beast". Also around cover bolt gaskets. The latter look brittle and are cracking so I'll replace soon. However, I'd like to see if I could also do better on the "U" interface.

Alfred,
Are u still in Sun Diego? I'm currently a bum and wud be glad to help and learn, if u could use an extra set of hands.

 

David/Scope,

I'm buying the valve adjusting tool....any links to videos for valve adj on the 3.o...also, any links to the ebay seller for the shims?

 

I haven't looked for any vids for valve adjustment.....what do you want to see? It's really pretty easy if you have the right tools. Download the '93 service manual from here in the stickys at the top of the page....

https://www.yotatech.com/forums/f116.../#post52271630

This version is really nice! Opens in adobe and is really easy to navigate and is searchable....just awesome! There are a few differences between the 91 and 93 I've seen in the manual (distributor, timing belt tensioner) but the valve clearance and adjustment is the same.

Oh ya....you're gonna need a micrometer or at least some dial calipers to measure the existing shims thickness. But only if you find any out of spec, then you need to know what thickness shim is currently installed so you can figure out what thickness you need to install to bring clearance back into spec. The shims are supposed to have a number on them but on most of mine it had worn away or was just barely legible.

The service manual has a chart to figure out what size you need based on the installed shim and clearance. It's hard to read, easier to just do the math yourself. The available shims and their thicknesses are listed in the manual. Roughly in 2 thou steps. So if you're clearance is 2 thou under spec you need at least 1 size thinner (to increase clearance by 2 thou), but could go 2 sizes thinner to get more to the middle or loose side of spec for more miles until they will need adjusting again.

In general it looks like on these engines the clearances lessen over time. I have no idea if this is always the case, but it appears to be the case on mine. So I would rather be on the loose end of spec, but still in spec.

 

After repair summary -

- Valves were within specs so no adjustments needed
- I took a lot of pics but did not label hoses. I WOULD label hoses next time esp vacuum
- all PS fuel injector connectors were broken. I zipped tied them back on
- At 450+k most of the plastic was brittle and cracked easily. I had to use gorilla tape and zip ties every where.

After I got it all put together, everything seemed to be running fine. It idles correctly and I have gained seat of the pants power that I felt missing...ie freeyway onramps.

however, there is a low speed intermittent problem sputtering ie parking lot or from stop light. I'm going to ask about this in another thread.

Thanks for everyone's help!

 

Hmmm. Yes, it is worth reading the advice you are given. Now you know.

 

yeah...I did a big head slap after not listening to you....I would add the heat gun advice helped too and I will definitely use it next time.

 

Hey David,
You mentioned a a shim tool you made to pull the shims on your truck. I'm getting ready to pull my intake and valve covers for the oil leak from the back right corner. As you mentioned it's a good time to check/adjust valves. I'm good at improvising and after searching unsuccessfully for the OEM Toyota tool, I was interested in a little help from you on what you used to fabricate the set.
Thanks for any help.
John

 

When I type "Toyota Valve A" in my browser, google suggests "Toyota Valve Adjustment Tool." Which brings me quickly to

Is sure looks exactly like the one I own. I've never seen one that claimed to be manufactured by Toyota (if that's what you mean by OEM).

As I said above, I make a lot of tools, but for $30 this is one I'd just buy.