For anyone that has driven, worked on, or even had a 3vze die under their right foot heres your chance to post what went wrong and vent. So what parts died on ya? (Im doing this survey to try to figure out exactly what the weak links are before my rebuild.)

Rod
Rod bearings
Main bearings
Crank
Pistons
Rings
Headgasket (hahahaha)
Valves
Cams
Main Webs (though I doubt it looking at the main cap(s)...lol

To avoid flaming Im not going to talk about what Im planning on doing with the 3vze, save building it so that it will have a STOUT bottom end...

 

Ive only had to replace : cam seals and valve cover gaskets, water pump, timing belts, and a starter! Ive got an early 88 so I think Im OK on the head gasket issues! 153,000 miles and counting!

 

only the cap and rotor, plug wires and plugs... Oh ya there was that time that the tranny line (factory clamp) came off while wheeling.... No major problems with the 3vze but I only have abot 100000km on it.....

 

I was driving to work down the freeway when all-of-a sudden it started missing very bad. I pulled over and found 2 plug wires came disconnected from the cap. Plugged them back in and it runs like a dream. I have not figured out how they came un-plugged.

 

Well the only part on your list that has failed me in 12 years is the headgasket.

I have heard from EB that the valves tend to get burned.

Here is a quote from EB from this link: http://www.4x4wire.com/forums/showfl...5&o=14&fpart=1

">>>*Morning!

*I just spotted this thread. Le' and I are getting ready to wander off for a short few days of sanity recovery, so I thought I would chime in.

I have been looking at the 3VZE, and the more I look the more I wonder why?

The design is odd, the airflow is inefficient, the engine is heavy and hard to get to to even work on. I was looking for a reason for it burning valves from time to time on #5 & #6, and my heat gun showed some spooky looking exhaust gas temps. Every time we see the exhaust manifolds they are warped beyong belief.

Restrictions. No doubt. So looking at the heads, they are easy to free up. I realized instantly that the engine needed a bit larger valves, so I went and had some made. That turned out to be cheaper and better than buying stock ones.

All one needs to do is pull an exhaust valve out and look at the seat and port. What were they thinking? I looks like they cast the head, then decided to use a smaller valve afterwards. My best guess was they built the engine, then realized it had more RPM potential than they wanted, so they took the easy route to choke the thing off..it couldn't have been for improved mileage, that doesn't work. Efficency is what improves mileage.

For a long time we were seeing these mostly for head gasket/valve problems (heat, not the gaskets...), now we are starting to see the engine more and more as they get older in the fleet. Rebuild kit prices plummeted this last year so that helps, suddenly it is in a typical budget to rebuild one.

So far, larger valves combined with port changes and a better exhaust seems to add a nice 30-35 H/P easily. The short block just needs to be snug. Adding a cam is a can of worms, the upper end valve train dictates lots of changes. I even thought of having the valves made .030" longer to leave room to regrind and add lift/duration but it hit me quickly that this would restrict the cam choice to fit the valve.

Besides, the factory got very close to correct on the stock cam design for what my opinion is worth, when the goal is to just drive. I do see that some folks are offering cam setups, way ahead of me there. Fine if in the budget but the amount of work didn't look worth it to me. I will bet that soon some suppliers will be offering new stock base circle cams for these.

So like all engines, she responds to airflow. Free up the intake and exhaust, bit of port and valve improvement, and I see a nice 20% plus gain in there.

So far Tod has only done a half dozen or so but it seems to work real nice, I agree with Tim over at DOA. There is 20-30 easy ponies in there, much more gets you reaching deep in the jeans for the hardearned......*EB"

 

I agree with mt goat on this. The article hits it right on the head. The valves are a little weak. Engine is a work horse. 251,000 miles and she still runs strong. I was driving on only 5 cylinders and could still go wheelin' with only a slight degree of hesitation. The second day after I changed the spark plugs, I blew out a spark plug - Store tech said a defective spark plug and if I found it caused any engine damage "Bosch" would cover it. Engine is fine - from where the plug blew out. Doing 70 on the freeway with only 5 cylinders and then this happened, I still made it home safely with only 4 cylinders. I tell you the 3vze takes a lot of crap here and I think she's a work horse. Forget the engine swaps...rebuild it!.

Crappy pic of my blown plug with only 50 miles on it at the most:

 

Blew the headgasket at 106k. That's about it.

 

The 3.0 is a good durable engine, now, with that being said here are the issues that I've come across working as a Toyota Technician.
1. We all know about the HG issues, mostly effecting 91> years
2. The engine just can't breathe enough air to get the proper HP out of it.
3. The x-over is a mis-engineered nightmare, it robs more power that anything.
4. The valves are too small
5. The injectoes are too small
6. This engine was in production for exactly 71/2 years, it's a shame really, Toyota knew about all the problems with it, when Toyota finds a problem they correct it with a service campaign and the next production year it's fixed, Why not the 3.0? It was allowed to go for 7 1/2 years!
7. #6 exhaust valve burns up because it can't get a breath of fresh air there because of the restricted x-over.
8. I can't complain, I got almost 300,000 original miles out of mone before the HG started to leak and I rebuilt her.
9. The pcv valve is a PITA to change.
10. I love the 3.0, it's one of my favorite engines by Toyota, there not bad to work on, It's definetly a workhorse and she'll crank em out mile after mile.
Good luck on your Rebuild!

 

good to know this is comming from a tech, not a shade tree mechanic

so after 91, HG problems were less frequent?

got any remidies for this problem?

your talking about the crossover pipe on the exhaust right? I heard that it was deisgned to help scavange the exhasut. guess sometimes you over engineer stuff

both intake and exhuast? what size do you think would make the motor breath better?

know of any replacements that work better? are the injectors at 100% duty cycle? if so at what RPM? Also what is the pressure at the injectors? sometimes bumping up the pressure will give you a better/wider spray pattern on a close to maxed out injector

that's dumb, toyota sucks on that point. did the camry have the same problems? I know it's a pretty close relative to the 3.0L

this is why I was asking if you were refering to the x-over as the crossover pipe on the exhuast side. what do you mean by fresh air? I'm thinking that you mean that exhuast gases are always passing over the valve instead of a normal pulsing hot/cold cycle, correct? wouldnt there be the same type of problem on log style turbo manifolds?

nice, it's amazing what proper maitnence would do... care to explain your personal maitnence plan?

do you have a exploded parts diagram of the PCV valve? I got in a tiffle/argument with a friend on where/what the PCV valve is last night, so now i'm a bit confused

I can't believe this, I fell like working on my old BMW's is like working on a 1969 no smog chevelle! there is no room to work on this stupid truck compaired ot my other cars! I feel like every nut or bolt is designed to only be removed by the tiny asian hand that put it in in the first place!

not intended twards me, but I'm doing close to the same thing, so thanks!

 

rings on my 89, main bearings on my buddys 91

 

oh yeah, forgot my answer to the origional post.

while i've owned the truck:
very severe rod knock, will not turn more than 3,000rpm

before I owned it:
at least 2 head gaskets
#6 exhuast valve replaced

 

My '90 Runner burned #6 exhaust valve at 145K. Sold it at 185K, the 3.0 was still running great.

 

CON ROD and HG.

I have a 91 the is getting sent to the scrapper, it had 3 HGs in less than 2 years. ISO 3v eng the mach shop kept messing up the heads last HG required brand new heads. Final blow to truck was the #1 con rod disappearing, we can not even find enough pieces to come colse to getting the exact break point or correct length. I view the con rod failure as related to the HG and head failures. When the con rod went I was head up 10% grade at 120Kph
(@65-70MPH) had to drive another 75Km at 30Kph (@20 -25 MPH) to get to any type of service area. When I did stop the entire cat and as much of the down pipe as I could see was glowing red. The tear down revealed: The crank is out of balance and scored, the oil pump gears got hot enough to be deformed and blued, and I still can not figure out what allowed oil in to the cooling system, but there was no notable anti freeze in the oil pan and no detected smell of burning anti freeze, although the oil in the pan was burned very badly. Lucky the whole thing did not burst in to flame. I can not think of the U.S. built engine that would have taken abuse and still run, YES it was running when I pulled it into the shop to tear it apart and figure out what happed. I will swear by and at the 3vz motor. It is not the most power motor available and there are some things that could have been designed better and it is a ROYAL PITA to work on in the truck but it is a good strong engine.
The 4 runner is heavy and not a race car You want a high hp 4X$ then buy one not the 4 runner, you want a good truck for DD that can also take you off the path and bring you back get a TOY with a 3vz.

Dragon

 

Just figured Id bring this to the top.... I have a TON of valve train noise (sounds like a train wreck actually)

dragon - I believe the same as you - this motor is stout. Reading through the TFSM it said that the block can be bored to .050" over!! That makes me feel very very good when Im thinking about having her bored 0.030" over.


Im trying to gauge if a Japanese imported forged crank for 800 and change is worth it. After reading about the connecting rod failures Im definately getting the forged connecting rods! LOL

TTT and the survey continues...

 

I love my 3.0. But the weakest part? Probably me when I work on it.

 

I've got 180,000 on my 1995 and I've never had a headgasket problem. I have done the following though:
3 Timing belts
1 water pump
1 power steering pump
2 radiators
2 sets of belts and hoses
2 sets of cap, rotor, wires
A whole bunch of spark plugs and oil changes.

I keep thinking I'll do something to the heads when the headgasket goes, but she just keeps running fine.

 

Mine has been great. I did just rebuild the thing, but that was because of a cold start injecter that wont shut off, which caused my engine to run rich, which caused my cat to clog, which caused my #6 exhaust valve to burn out, which caused my oil preassure to drop, which caused a main bearing or two to deteriorate. The happened over a drive accross Texas and back and for many miles before that and a few after. If I would have taken notice to my loss of power as being a problem with the catalitic converter, I would have been able to fix it without having anything broken down/machined/rebuilt. Also, noticing about the cold start injector not turning off would have saved me from having to notice the bad cat. All in all I have been very impressed with how long it held up with these bad things. I probably put close to 20,000 on it with the failing cat before it finaly gave in. If taken care of this engine is a serious workhorse. Sure, a little weak, but it gets the job done and keeps on getting it done.

As for Bumpin' Yota... Did you ever have oil in the thing? I have never seen so many internal problems on one of these engines. It's like you dogged it with no oil for quite some time. You must have just got a crappy block. That is a long list....

I would like to solve the breathing problem, though. I just makes for a more efficient engine. Since I opened the air box it made a good amount of difference in engine response. I would like to do the valves, headers, and exhaust just for the reason of letting the thing breath. Not so much for the gained HP. I would like my engine to be able to perform as long as possible and that will increase it's life.

 

Oh god no, my 3vze has never had any of those problems... *knocking on wood* That list was the long list of things that ive heard of people having problems with. My stock engine has gone a full 258,000 at current....I think she'll reach 300k before I actually need a rebuild.

 

Burned a valve at 185,000, put a Jasper in with Downey headers, and runs good except for a really loud injector(?). Plan on a injector rebuild as soon as it warms up.

 

Whew! That makes me a little more secure....
You do that yourself? If not there is a guy that does it for cheap will flow test results and all new seals and screens for only like $12 per injector. I used him and was happy with the professional work and cost. I don't have the link here at home, but if you PM me I will look it up at work for ya.