Hey Yotatech.

I am in the process of bringing some life back to my 1991 Toyota Pickup and wanted to document the process.

I bought it 10 years ago and it's served me well up until recently. I was experiencing a rough low idle caused by low compression in the number 4 cylinder. An exhaust valve had burnt due to zero valve lash. Doing a compression test showed all cylinders excluding 4 at ~170 PSI—cylinder 4 was around 120 PSI. This was back in March 2020 and it's also when the tear down began. Yes, this project has been going for far too long. I've been busy with school and work, but really it's mostly procrastination.

I'm a noob at this stuff so feel free to criticize and/or offer advice! I should have started this thread when I first started tearing into my pickup, but better late than never!


Project begins in March 2020.


Better times.


What a mess.

Finally got it out.

3VZE on the stand


Closeup of cylinder bore.

Another closeup.

Head gasket fire ring looks blown? Maybe previous owner used head gasket sealer?

The problem valve. It's hard to see, but it was fairly worn on the valve face.

Bad valve on the left and good one on the right.


Left bank cylinder head

What a mess. This was almost two years ago. The garage looks much better now.

Heads rebuilt!

Block rebuilt! It took the machine shop over five months to complete. There's some paint overspray that came off with some rubbing alcohol.

Hardware everywhere. I should have been more organized.

Waiting on hardware and various parts. Decided to tackle the A/C that hasn't been working for years.

New evaporator low pressure pipe has an odd bend.

I bent it as close to OEM as I could. Think it's going to cause any trouble?


Desiccant clogged the liquid tube at the expansion valve. Sorry for the leg hair.

New condenser installed. It's still sealed.

The cause of all my A/C troubles.

Expansion valve finally came in.


Ready to place cylinder head on block.

I chased all the head bolt holes. Fortunately, no metal shavings came out with the tap. Now the studs screw in nice and easy.

ARP Head Studs. I went with these just in case I had to tear into the heads again.

Machine shop painted over this coolant passage on the block. Should I sand off the paint? Also, does anyone know if there's a gasket for this or do I have to use gasket maker?

Starter always had issues cranking. Turns out the one plunger contact was worn. The contact kit part#28226-72080.

Contact on the right has really worn down.

Contact kit comparison.

Super worn contact.


Another angle of worn contact.


Using a 14 mm and 15 mm to install the new contact,

Starter all good to go. Anything else I should look at with the starter?

Cleaning liquid tubes with A/C solvent.

All done cleaning.

New dual pressure switch.

It's pretty neat how the dual pressure switch works. As long as the pressure in the liquid tube is within 38 - 384 PSI , the pressure switch will have continuity which feeds a voltage to the A/C Amplifier powering the A/C compressor magnetic clutch.



So that's it so far. Thanks for reading!

 

Wow. I'm impressed with the pictures you took! I wish I had been that diligent on my rebuild. If the heads are still off, there's no better time for long tube headers. They'll slip right into place. Be smarter than I was though, and wrap the passenger side one BEFORE you put it in. Its a lot harder to slide the header in, install and torque the head, bolt down the header and then decide that you should wrap it so it doesn't melt some of the wires and hoses on that side. The only other things I can think of are maybe to rebuild the alternator and put a seal kit in the power steering pump while they're out, and maybe to get the injectors rebuilt just because they're out as well. How do your clutch, pressure plate and throwout bearing look?

 

Hey dbittle! Thanks for the input.

I'd love to do long tube headers, but I live in California and the CARB legal ones are expensive.

I did replace the brushes a few years ago following this tutorial. Are there other wear components that should be replaced?

I did install a new seal kit. I ran into some issues along the way. You can read about it here.

Steering Gearbox taken apart.

Did some decent damage on the valve assembly adjustment nut.

Good idea. Totally forgot about these. Do you know any good rebuild kits? I stumbled upon these from a quick google search.

They clutch disc still has some material left. You can still feel the machining roughness on some parts of the pressure plate.

Replacement clutch kit and flywheel from Luk.

Old Aisin on the left. New Luk on the right.

Aisin pressure plate looks worn, but it never gave me trouble.

Oil mess. Tried cleaning it with degreaser and made it worse. Where do you think it's leaking from? Transmission input shaft seal?

Throwout bearing looks like it needs to go.
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I will have to look up your steering pump/gearbox experience. I didn't mess with mine while I had everything apart. The pump has started to leak though, so I have to go back into it. On the injectors, I sent mine out to get overhauled, but the kit you linked looked like it should be fine. I'm assuming a new rear main seal got put in your engine during the rebuild, so the input seal is an easy call. I live in Alabama, so we don't have emissions inspections and I could do the headers. They truthfully probably didn't do that much for performance, but they let me get rid of the crossover pipe, which was my main goal. Great job on the rebuild!

 

I think I'll get a reseal kit for the pump, too.

I really hate this exhaust pipe. It's so difficult to remove that I said screw it! Whole engine rebuild it is.

Thanks!

 

New expansion valve sensing bulb poorly wrapped with aluminum foil tape.

Cooling unit assembly ready to go back!

New hoses for the A/C compressor.

Cooling unit assembly back in. Maybe I should address that dirty blower motor. Anyone know if you install a filter on these blower motors?

Cooling unit assembly was a pain in the ass to install, but I got it in. You'll most definitely need a helper for this.

A/C compressor partially installed.

A/C system all put together! Time to pull vacuum and test for leaks.

Success! It's held what looks like 29" Hg for over two hours.

Now it's time to tackle the power steering.

 

So I goofed up. I've been working on the power steering pump and did some serious damage to the pump shaft cylinder surface. I was removing the shaft out the front of the housing when it should have been from the rear. The shaft's key ending up gouging a nice chunk of the cylinder surface and the shaft no longer fits in the cylinder. Think this is repairable?

Cleaned up the power steering.

I thought the snap ring was going to be the only grief I'd deal with.

Nasty damage done to the cylinder surface due to hammering the shaft in the wrong direction.

 

How many miles were on the engine that you needed to do a complete rebuild?

 

Sorry for the late reply! I've been busy with school and work and haven't found the time to work on the truck till recently. So the odometer reads 236,300 miles. I'm sure if I had adjusted the valves, the engine may have gone to 250k to 300k miles no problem.

Heads are finally on!

Closeup of the ARP head studs.

Oh boy, I screwed up here. The water bypass pipe that sits between the heads cannot line up with the block stud. This should have been installed before installing the cylinder heads.

The bypass pipe.

So I took a grinder to the bypass pipe bracket.

And voila! All good!

Exhaust studs installed

Getting all the little things installed like the water pump, cam and crank seals, pulleys, etc. I used the AISIN TKT016 timing belt and water pump kit. Also installed the intake plenum.

Cam gears are on. So the cam gears can't be swapped! Make sure the driver side cam gear has the lip on the outside. Otherwise installing the timing belt is going to be a pain.

Timing belt installed. Super easy doing a timing belt job when the engine is out!

Need new oil cooler hoses.

New oil cooler hoses!

Tested all the fuel injectors and replaced its rubber seals. Fuel injectors are good to go!

Unfortunately, the crossover exhaust is going to be reused.

New fan clutch. Went with a BECK/ARNLEY 1300185. The old Aisin didn't seem to have issues, but I wanted to do a little preventive maintenance so I don't have to get back in there. Hopefully, I don't regret it.

Garage is super messy again. I have too many projects going on.

Machine shop forgot to install this oil plug in the block. Got a new one from the dealership. The dealership must be loving me by now.

New OEM O-ring for the dipstick tube. Some odd packaging.

New PCV valve and grommet.

Need to replace this coolant hose going to the throttle body.

I believe this is one of the throttle body coolant hoses.

Engine mostly assembled. Distributor was also lined up according to the servicing manual. It was much easier than I thought it would be.

Rear main seal going in.

LUK LFW196 flywheel installed. Installing the pilot bearing from the LUK 16059 clutch kit. I used a Harbor Freight harmonic balancer pulley tool to install it. Worked great!

Pilot bearing fully seated.

Lining up the clutch disc with the pilot bearing and clutch pressure plate.

Pressure plate installed, but not quite aligned. This will cause me grief later when mating the engine to transmission.

Damn it! I asked my dad to get me spark plugs from the auto parts store. He comes back these. I asked him to get NGKs or Denso, but I guess the parts people convinced him to get these? The spark gap was too large by 0.010". I regapped them to roughly 0.032". Oh well, we'll see how they go.

Engine going in!

Another view of engine going.

Engine finally in the next day! Hooray! My dad and I were having a hell of time lining up the engine and transmission. Turned out the clutch disc wasn't centered with the pressure plate. Had to pull the engine out and properly reinstall the clutch disc and pressure plate.

Now the new nightmare. Getting all these vacuum lines, coolant hoses, electrical, etc. connected.

Almost there.

So when pulling out the engine the first time around, I forgot to remove the clutch hydraulic lines mounted to the engine. I ended up destroying the metal tubing going to the slave cylinder and the rubber hose.

Dealership wants over $50 for this clutch hydraulic hose!

Fortunately, this brake line hose part#77664 from Autozone did the job. It only costs about $12 too.

Surprisingly, the metal tube was only $18 at the dealership. Toyota part#31482-35250

Old stretched out tube to the right, new tube and slaver cylinder to the left.

Anyone know how this wire harness is supposed to be routed? It seems to go towards the transmission. It's touching the exhaust header and has a bracket further down the line, but I'm not sure where it attaches to.

Intake manifold ready to be worked on.

Another headache. This short hose with an inner diameter of about 5/8" that goes to the air injection system has cracked. Dealership wants to $22 for it! Anyone recommend an alternative? my local parts store don't have rubber hoses this large.

Welp, that's the update! More to come!

 

Just pay the money. That's a molded hose, so you'll never be able to get the correct bend in off-the-reel 5/8" hose.

FWIW, my favorite online dealer (Lakeland) says the part is discontinued. But McGeorge claims to have it, for only $14.67 https://toyotaparts.mcgeorgetoyota.c...o-1-1734165040 (though shipping would easily make up the difference to your brick-and-mortar dealer.)

 

That’s the battery cable harness. On my ‘91 it’s attached to the wheel well here.

 

Thorough, meticulous work. You'll have it running like new soon!!

 

Hopefully! I've taken too long on this project and forgotten where a lot of things go. Now I'm paying for it by not being more organized from the beginning.

Thanks! Didn't realize there was a clip for the wire harness there. Are those two large hoses the A/C lines? Also, any way you can get a pic of the harness further down the line? There's a plastic and metal bracket there and I have no idea where it's supposed to go.


Where does this plastic part mount to?


Underside view of plastic/metal bracket.


Damn! Wish they had free shipping. It will cost about $10 to ship it here. Honestly, not bad because I still have to special order this part from my dealer for $21.96 w/o tax and then pick it up. Probably worth going with Lakeland if I do a bigger order.

Forgot to mention, I had to adjust most of the cylinder head valves as they were out spec despite the machine shop work. Both intake and exhaust valves were around 0.006"—0.007". Spec:

3VZE Valve Clearance Specification

I went to the junkyard and pulled a whole set of 3VZE valve shims and ground them down to meet valve spec. I pretty much did it like this: I ground down the bucket facing side of the shim and constantly measured it with a micrometer when grinding. Valve shim thickness variance were 0.001" or less. I know I'll get a lot of flak for this, but if it doesn't work out, I'll swap the old shims back in.

I chose 0.009" for intake clearances and 0.011" for the exhaust clearances. It's a nice middle ground—not too loose and not too tight. (Honestly, I would have gone for the greater clearance, but it took like 10 minutes to grind a single shim.)

 

You're doing a lot of great work here.

I've found this site to have really good deals on OEM Toyota parts; https://www.toyotapartsdeal.com/

It's probably a 20% discount on basically everything. That said, the shipping cost can sometimes eat into whatever you would be saving, so it's best to order in bundles.

Also, you should consider Napa as an alternative. They have a line called Altrom, which is generally Made In Japan, but pretty much never China . It's a great deal for hoses, gaskets, etc.

 

It's alive!!
Finally got it running, but I haven't driven it yet. It took a couple of cranks to get it started, but it idled smooth right after.

But..

I ran into a hiccup when setting ignition timing. I had let the engine warm up to operating temperature and the engine began to run terrible then stalled. As I restarted it, I noticed the temp gauge was at max so I shut it down. Huge idiot moment! Hopefully no damage was done. I let the engine cool overnight and went to bed to feeling like a real dingus.

Today, I began diagnosing the overheating issue. I pulled the thermostat and boiled it in water and it proved to be in working order. No blockage in the radiator and the coolant that came out looked clean. I realized when I pulled the thermostat, only a little over a gallon of coolant came out which seems very low for this truck. So I reinstall the thermostat and hoses, jack up the front of the truck and pour coolant into the radiator. It took over two gallons of coolant this time. I started the engine and cranked up the heater and then I added more coolant to the radiator. No more overheating. So the cause of the overheat was air in the cooling system. I hope those ARP head studs kept things from warping, but only time will tell. So far the engine has been idling fine and there doesn't appear to be loss of coolant. I also did a relative compression test with my uScope and all cylinders seem to be at the same compression.

Relative compression test looks good. Had trouble with the ammeter scaling the waveform, but no obvious issues with compression.


Also, got the A/C working. Got it pretty cool, but I feel it could be cooler. I added roughly 600 - 700 grams of R134a and had a low pressure reading of 35 PSI and a high of 250 PSI @1,500 RPM Ambient temp = 90 ℉. Should I add more refrigerant?

All that's left to do is reinstall the steering components, flush the power steering fluid and reattach the front grille and skid plate.



New hardware for the intake manifold. New accessory belts. No rhyme or reason why I went this brand.

Got that $22 hose for the air injection system.

New upper radiator hose.

I used about 6 quarts of this break-in oil. I'll change it out around 400 miles.

This is the vacuum line for the power steering. I believe it's an idle up circuit which increases engine RPM when using the power steering. Not pictured is the replacement hose I got from Autozone for $2.

Intake manifold installed.

Trying to figure out the best way to route the starter cables.

Doesn't look right..

I finally got it somewhat figured out. I forgot to take a picture of it though. So far

What a rat's nest. All vacuum lines are back together hopefully correct.

EGR pipe is awfully close to that A/C line.

I bent the A/C line just a bit to clear it of the EGR pipe. Should I wrap the pipe or lines?

Exhaust is connected. Took me a while to figure out where that exhaust bracket mounts. It mounts to the transmission ya dingus!

Accessory belts installed.

Spark plug wires, cooling fan, radiator shroud and radiator installed.

Here's a controversial one. I used universal coolant instead of Toyota Red. It's ethylene glycol—that's what the manual calls for.

Put a beefy ground strap to assist the starter because the original sucked. It was super thin gauge compared to the starter power cable. Now the starter cranks right up.

Truck was overheating so I tested the thermostat.

And it opened just fine. So what gives?

Turned out there was too much air in the cooling system because I did not burp it properly. Here, I am lifting the front end high to allow the air to burp. Make sure to properly burp your cooling system!

Charged up the A/C system with roughly 600-700 grams of R134a.

Here are the gauge readings after using two cans (340 g each) of R134a. Ambient temperature was 90 F and engine was fully warmed up running at 1,500 RPM. Air was pretty cool coming out of the vents, but I think I can get it cooler with a bit more refrigerant.


Thank you! I have tried using them before, but they cancelled my order without notifying me. Seems like it's a common issue according to Google reviews.

 

Missed this last update somehow. Anyway Scope mentioned McGeorge; I have bought a lot of stuff from them. I think shipping is very reasonable especially if I get several items.

ONe thing about them, if an item is wrong or discontinued, they will email me rather than just cancel the order. And I reply with a different question and get answers real quick. Great Customer Service.

Are you all back together yet?

 

Hey coopster! Sorry for the late response.

It's been running great! I have about 400 miles on it and need to do the first oil change. A/C works fantastic! The check engine light is on though—code 71 which pertains to the EGR system. Now to diagnose that..

CEL Code 71 EGR

Here's some videos!