vokeyz

Hey all,

So this is a topic that has been discussed in great detail, and I'm not really interested in starting any kind of debate about who "likes" the 3VZ-E, or who has had bad experiences with them in reference to their head gaskets etc.
What I would like to talk about, is how to utilize them as a solid, simple wheeling engine that can stay reliable and be understood to a point that allows quick troubleshooting (easy repair). That's a bit of a tall order to fill but I've read enough threads detailing the weaknesses of the 3VZ-E, and how most of them can be overcome through tactful modification (albeit, some cost considerable ones).
At the end of the day, I've read most all of the feasible engine swap threads and came to the realization that while do-able and pretty cool, why do I need to squeal mud tires in a 4runner? My father-in-law, a long time wheeler and Yota enthusiast, has run a 22 series engine for over 35 years and has long talked about how it's not power that makes a 4x4 go places. Granted, the 22 series engines have had an incredibly long history of being bullet proof sewing machines while the 3VZ-E engines have been generally plagued by their weak head gaskets, funky plenum design and vacuum spaghetti. I understand there is a lot of reasons to swap the the 5VZ-E, namely for improved power and reliability, but I just feel like there's a level of gold not unearthed on these things. Since doing the manual transmission swap, Pair-EGR removal, intake simplification and vacuum deletes, I'm quite taken back by my 4runner now. It drives and runs fantastic (for now). Having had a manual 3VZ-E prior to this one, (same transmission that I swapped from the old one to my latest one), this one makes a noticeable increase in horsepower after a few minor modifications, not to mention my mileage has increased by a couple mpgs at least (probably to do more with the manual transmission than anything else).

So help me figure this out. Will I be spending a ridiculous amount of money making my 3VZ-E "bulletproof" in comparison to "bulletproofing" the most common swap (5VZ-E)?
I have a 3vze with a blown headgasket (out of my other 4runner, sitting on the floor of the shop) that I'm debating doing a fresh rebuild on. I already have head gaskets and new TTY bolts, so it's not like the more basic components are missing, but who has walked down this road? Where did you spend needless cash? For those with a 3.4L, what really changed for you after the swap when the honeymoon was over? And to the guys blowing headgaskets, did any of you delete the crappy crossover design?

Woodmac64

I’m in the same boat as you. I have a ‘91 DLX pickup with the 3VZE and 5 speed with over 310k. I bought it with a suspect motor...bad exhaust valve in cylinder 3, but it runs well! I’ve put over 20k on the truck since purchasing and it’s my DD. I recently bought new parts to redo the clutch as the throw out bearing has squealed on occasion and snagged a set of heads off of a low mileage 4Runner at Pick-N-Pull. I’ve started thinking a rebuild of the bottom end is in order to make this all it can be.

dbittle

Great thread idea. I picked up one that last ran in 2013. I'm doing head gaskets, headers, egr and pair deletes. New fuel pump and filter. Hope to start it this month! Anybody play with degreeing the cams?

COMTB

My .02 since I'm tossing different ideas around as well. I have done a significant amount of maintenance on my 3vz since I bought it 2 years ago and I don't have too many complaints about the motor with the exception of the lack of power. It's a darn tractor in low range and with the 5sp it makes it drive able almost anywhere. My issue is the passes I have to contend with out in CO. Going up most of them I am in third gear, at about 3500 RPM doing between 35-40 mph. Honestly, not a fan. I want to swap in a 5vz and trd SC just to make driving passes bearable at an acceptable speed (like 55? not asking for much here).

I wish these motors could take some modifications to get 50-75HP that wasn't the cost of a motor swap in the end. I believe this is why most people go to the 5vz, for the same price as modifying my 3vz I can have a more reliable, DOHC motor with the option to add an SC in there later on.

I would love to see some dyno numbers before/after mods because I honestly love my little 3vz, especially off-road but it leaves too much to be desired when I really need some power to get somewhere.

vokeyz

That sounds like a good plan. They really do truck along just fine once you deal with the head gaskets. I'm hoping to do a full rebuild of my spare 3vze out of my 93' 4runner with the blown head gaskets.

Thanks, I'm sure that will change how it drives significantly. I found the biggest change was from the EGR+Pair delete, and the original crossover delete (welded my own down pipe that hooked up further down stream). I've never played with the cams, though I know my 3vze is in need of some valve adjustment. I knew at one point in time, people were putting aftermarket camshafts in, but most of them were regrinds, and I'm not aware of actual dyno sheet improvements.

I've never been to CO but up here across the border in Alberta, I can share in your displeasure of long hill pulls. I live in the foothills and have quite a few hills I used to absolutely dread. I will say that with the EGR+Pair delete, crossover modification, and intake simplification, I have much more success doing long hill pulls around here. I can keep at a steady 50mph up most hills, in either 4th or 5th depending on the incline. Generally speaking, I don't get passed as much anymore. There's obvious advantages with the 5vze, namely stock power and power modifications being more accessible, but I find when push comes to shove having driven a stock 5vze in a 3rd gen 4runner the power is (by my crude butt-dyno) negligible when it's stock. I was intially sold on the idea of the 5vze until I started to do research on the cost of power mods for the 5vze. Even if you reliably get an additional 30-50hp, the cost to get there to me wasn't justifiable. Then again, it all depends what you're going for. Long term plans for my 4runner is to be an offroad machine, not so much a daily driver. So offroad, the additional horsepower isn't needed so much as wanted. I am considering getting a dynochart done for my current truck as it stands and then going forwards with a few changes and seeing where I can actually get to. On wikipedia, I read the 3VZ-E is stock with (crank horsepower) 150hp, and the 5vze in the 4runner puts out (crank) 183hp. Reliable modification could probably land you at 210hp, depending on tunes, power additives and corresponding exhaust/intake/ignition modifications. To me, to gain 50-60 hp for that cost just doesn't quite land but many, many have done this before and said it was worth it for them!

RJR

Something not quite right here. At 3500 rpm, you should be doing about 35 mph in 2nd gear, assuming stock gearing and tires. 3500 rpm should give you nearly 50 mph in 3rd. Plus, you can run that engine at 4000 rpm all day uphill, so there's really no need to be below 55 mph going up those passes. I do it all the time.

COMTB

Was rounding, sorry. It's around 40-45, but definitely NOT 50. Running 31x10.5x15's. as far as I can tell it's stock gearing (4.56's with a G254 axle code on the door) but I haven't pulled a third to count the teeth. Man I burn a f* ton of oil if I do 4k up the hillls, compression tested across all 6 cylinders at 155-160 PSI at 49XX ft above sea level (Fort Collins) cold, in December. I went back through it twice with the same results because I didn't believe them. I've gone through 99% of the maintenance at this point including replacing that cracked timing belt that was causing my timing to fluctuate. I honestly don't know what's up with the motor as I feel like it should be giving me a bit more but I also don't want to blow it before I can get a 5vz on a stand and ready to drop in.

RJR

Well, math is math. If you're not reading close to 47-50 mph at 3500 rpm, either your tach or speedometer is off. The two are absolutely related by gear ratios and tire diameter - there's no wiggle room. 10.5x31x15 with a 4.56 ratio is bone stock and should give you exactly the numbers I quoted.

Your compression numbers seem pretty high for 5000 feet. I live in Loveland and I've never seen higher than about 135 psi, on any engine I've tested. But, if they're even across the cylinders, that's more important than the actual number. Auto parts store compression gauges probably have their own inaccuracies, as well.

The oil consumption is interesting - mine doesn't change when working it that hard.

None of that changes the fact that more power would indeed be nice. Every time I drive my '94 up into the mountains to go offroading, while I'm on the highway going up the passes I think "Damn, I sure wish I was in my '06 with the V8". Then when I get on the trail, I think "Damn, I'm glad I'm in this high clearance short wheel base '94 with super low gears and a locker." You pays your money and takes your choice.:-)

scope103

Are you sure? The OEM bolts are not Torque-to-Yield, and while I don't know all parts manufacturers, I don't know of anyone who even purports to make TTY head bolts for the 3VZE.

Toyota specs a two-step process to torque the head bolts, but that doesn't make them TTY. TTY bolts can't be reused, and Toyota has a TSB saying that reuse of the head bolts is perfectly okay.

Yeah, I've heard lots of the gossip about how the 3VZE has shortcomings. With few exceptions, it's all just wrong. But you should make your own choices.

COMTB

I'm closing on a place in Loveland next week!

Man I was really impressed by the compression, mid December last year. All my other vehicles (subarus/jeeps) were all below 140 when testing them. I did use an autozone compression tester so it most likely was off but it was pretty much the same across all 6 wich the exception of 1 cylinder being a bit higher (within 5-7 PSI).

So I can guarantee this truck was not maintained very well before I bought it. I found this out after getting into it a bit but it replaced my 1989 XJ as a daily so I really didn't care because it's comfortable and Toyota. But this motor makes me miss the inline 6 4.0.

It needs the OPG replaced because it does leak slightly still and I think my VCG job had some quality control issues (woops) so there's two spots that could be causing my oil consumption issues but it doesn't make sense it's only when i have it under load at high RPM. I have issues throwing tons of time into a motor I really want to replace. That's my response to the OP as well, while it's a good motor it's still SOHC and early EFI which doesn't leave a ton of room for improvement when the next version of the motor is so drastically different and had a factory SC that could be slapped on. With that being said, I would love to see someone bring this puppy to it's full potential.

now that I hijacked this thread....sorry OP

superex87

Couple of things,

Your higher than normal oil consumption running up long/ big hills - Could be worn oil rings but unlikely unless you can see the smoke coming out of the exhaust. The culprit is probably the rear main seal and the moon shaped plugs on the back of the cylinder heads. Both areas would leak more than normal on a uphill climb.

IMO the biggest power restriction and over all running performance is hindered by the antiquated EFI computer system. The EFI on these was designed in the 80's and never saw any real updates until the 5VZ came along. If you were to use a stand alone engine management system utilizing modern sensors you could greatly improve the 3vz. For example our engines do not have any way to tell the current altitude to the computer. The only real feed back the computer sees is from a narrow band oxygen sensor. Not the most accurate way to determine how the engine is performing. If you used a mass air flow and or manifold pressure sensors you could really dial in the tune and make it run really good. Take notice that all newer engine use a crank sensor coupled with a cam sensor to determine injector pulse timing and ignition timing. This is due to the slop that old distributor engine had between the crank and the distributor. Take off your distributor cap and wiggle the rotor back and forth. In a perfect world there would be zero play for precision timing.

Most physical limitations of the 3vz are the poor exhaust crossover design and the limited air flow through the heads. The air flow of the heads is not a big deal from a reliability stand point but from a power point it is. I believe all so the head bolts are a little on the weak side and can stretch under boost.

This engine will always suffer in the sense that you have to upgrade all of it to really see any real improvements. For example if you put headers on it you will not notice much performance increase due to the limitations of the computer. The good news is most of these limitations can be over come with knowledge and determination. I personally want to megasquirt my 3vz using a crank trigger wheel, keep the stock distributor (it will be a dumb distributor and simply distribute the spark) use a matching boush igniter and matching coil, use manifold air pressure to determine engine load (coupled with the tps) add headers with a wide band o2 and see what the 3vz can do.

vokeyz

Interesting, I’ve never read that TSB (not that I frequent those bulletins very often, but I was under the impression it was TTY. But if it isn’t, then it alarms me a little bit as I’ve read conflicting information. If you had a link to the TSB I would appreciate the read.

generally speaking, they’re not the best gaskets. Fel-Pro tends to work fine for most things but in the case of a head gasket, I do have my worries. It’s a bit of job to do, to have it blow 15,000 miles down the road. Or sooner. I’ve found since driving it for a bit, the coolant is now steady. Which indicates the white film on the oil cap was from Seafoam (via gas tank) and that the head gasket most likely is not gone, which is a relief.

My ideal head gasket job would be done with the MLS gaskets and ARP head studs that LC engineering sells among other performance distributors. And I would venture to work the heads a bit, like a port and polish.

vokeyz

This is what I’m finding via research as well. I have a dream of Utilizing the 6 cylinder engine management system that LC Engineering created that can be used for both the 3VZE and 5VZE. The advantage of starting with this major upgrade in conjunction with headers would be a much greater degree of control over engine tuning, which could really take the 3VZE to a new degree of performance. However, at 2000$, you gotta really wanna dive deep haha.

scope103

I'm pretty sure the TSB is #EG00298, but the link I had to it now goes nowhere. If you have another source for TSBs, I'd appreciate a copy.

The Toyota head bolts are tightened with Torque-Angle. Modern TTY bolts are also tightened using the Torque-Angle method, but the reverse is not true (just because you use torque-angle to tighten a bolt, doesn't necessarily mean it's Torque-to-Yield). You're not the first to be confused. https://www.onallcylinders.com/2016/...gle-fastening/

COMTB

Interesting about the oil consumption on hills, I am pretty sure my rear main is leaking (not a ton) but enough because I see oil down on the oil pan and not too much coming from the top around the VCG's (even around back). I'll have to look a little deeper at some point.

At 2k I'm well on my way to a 5vz swap which makes it really tough to throw more than that into this motor. if i'm dumping that much money into a motor I would be preferable to DOHC and the factory SC. I would absolutely love to see one of these little motors put down some acceptable power numbers while maintaining reliability. I don't plan on selling/scrapping the motor when (if) I end up swapping it so I am very interested to see what someone, with more knowledge than I have, can do with modern technology on this motor. I have read lots of talk about "toyota used to race this and got XXX power out of it" which always led me to believe it was possible but reliability and cost were always the limiting factors in my mind considering most of their parts were all custom built.

ATX4Runner

Great thread. I'm cross-posting from this thread, as this seems to be a better place for this discussion.

I'm a first time wrencher and long time DIYer, and I've had a lot of fun (for the most part) tinkering on my 2nd Gen 1995 4Runner 3vze manual 4WD with 195k miles.

Work history documented below. What next? I'm itching to upgrade the suspension, maybe bolt on some headers and replace the cat & muffler? Intake mods seem easy and inexpensive, but I have read mixed reviews on whether there is any benefit. Should I delete the EGR or wait until something breaks? It's running pretty great right now, but now I have the itch to wrench. Being quarantined due to COVID-19 is intensifying this itch.

My goals are to increase performance (power and MPG), keep this thing running for another 200k miles, and keep it "stock+" (close to original but enhanced). It's a daily driver. I don't have any offroad aspirations.

July 2019

• New alternator
• New battery
• New rear brake drums
• New master cylinder
• New water pump
• New timing belt
• New clutch slave cylinder
• Fixed surf window switch
• New fuel filter
• New radiator fan shroud

August 2019

• New windshield
• New thermostat
• New JVC stereo receiver with microphone and Bluetooth
• New Rockford Fosgate front dash speakers
• New Denso plugs
• New NGK performance plug wires
• New Denso OEM rotor
• New Denso OEM distributor cap
• New reverse light switch
• New front blinkers
• Lubed surf window and sunroof joints
• New Aisin door lock actuator in passenger door
• New Toyota OEM power radio antenna
• New upper air intake hose
• Cleaned valves

September 2019

• Changed transmission fluid with Redline MT90
• New Denso oxygen sensors
• Cleaned EGR system and replaced gaskets
• New power steering idle air control valve
• Changed power steering fluid
• New shifter knob

October 2019

• New coolant temp sensor
• New Toyota OEM thermostat
• New Weathertech cargo liner

November 2019

• Head gasket rebuild
• Resurfaced heads
• New knock sensor & wiring harness

December 2019

• New front bumper
• New taillight and rear blinker bulbs

January 2020

• New Toyota OEM shifter bushing and seat collar
• New Denso OEM throttle position sensor

March 2020

• Changed fluid in front & rear differentials and transfer case. Valvoline 75w90
• New battery
• New Toyota OEM battery harness

Upcoming projects planned:

• Replace o rings on oil cooler (nasty leak).
• Remove the tach cluster and clean the contacts, tighten everything up (I'm getting the irregular tach jumping likely caused by a bad connection in the cluster).
• Moog rear coil springs & spacers (getting a little butt sag and the ride is a little rough).
• Replace missing skid plate.
• Clean up the engine bay without frying anything.

Thanks guys.

coopster

Mr Scope - you might recall another post just recently, with this discussion. I had already got new head bolts from Yota1 Performance, so its now moot for me.
Last fall I had fetched as much from the TIS as I could locate, for a 99 5vz (my donor). So I thought I'd go look for that bulletin you mention.

Now look at this. W. T. H. I'll upload the pdf.

I think Toyota is probably as confused as (a Large International Oil Services Company - name withheld).

dbittle

When I replaced my head gaskets, I decided to use my torque wrench to tighten them , just to see. I torqued them up in 10 ft lbs increments until I had the correct turn to angle end point. They stretched like taffy over the last quarter turn. It was a bit unnerving. I threw the bolt thread diameter and such into a torque calculator we have at work and yield is something like 65 ft lbs for a reasonable strength steel.

davidmc36

Just finished head gaskets. Funny I did not sense any stretch. Took nearly my strength on a 28 inch bar sitting braced in the engine compartment for the last 90 degrees. Any manual I got from here just says replace if damaged.
Wish I had time and money to do something with it. The strange thing though......my number 1 was the one that started shooting steam. The number 6 was looking quite poor though.
Should last me many years though with occasional 100-200km per week use. Just a toy.

dbittle

As always, your mileage may vary. Here's what I did.

I had the torque wrench idea between tightening the first head up and the second one. The first one I did with the regular breaker bar and didn't notice anything unusual. On the second head, I set the initial torque per the recommended procedure, put the dab of paint on all the heads as we all do, and started working my way around the bolts; first to 40 lbs-ft, then to 50, then to 60, then to 70 (my recollection is that I reached final angle before hitting 70). From the amount of turn it took to hit the successive levels, I'm pretty certain there was yielding going on. In the event that I ever have to go in there, I personally plan to not re-use the head bolts.