I've got a 1995 3.0L V6 M/T 4Runner, 3vze engine, 165K miles, blown headgaskets (#1 & #6), entire top end out of the engine. Here's some things I'm considering doing while everything is apart, with some concerns I've found based on reading and talking to different people. I need some feedback, not just 'I heard this or that', but from those who have actually done the upgrades/mods/maintenance. My goal is to improve the towing capability (low- & mid-range torque), but also keep it fun for driving in the dunes (mid- to high-rpms), while keeping everything cost-conscious. Here we go...

#1 Downey CARB legal Ceramic coated headers
Pros - should improve performance, including at the lower rpm ranges
Cons - A couple of people have reported higher engine bay temps, and problems with stuff melting. Is this common? Seems there are other choices - NWOR & Thorley, but what are the *factual* differences? And it looks as though the NWOR headers are *not* CARB legal - bummer.
Result - I found a fairly good deal on the Downey headers, so I installed them at the same time as the top end. They sound wicked without the exhaust hooked up. One caution if you're gonna do it yourself, Downey supplies a straight copper tube to connect the Reed Valve to the headers, which means the valve will not bolt back onto the intake manifold. I don't know how the factory hose is supposed to stretch far enough to fit back on the valve. We tried bending the tube by hand, but that just really messed it up. Doing it again, I would have bought a new piece of copper tubing, and a professional tubing bender. Luckily, I've been driving it around for a couple of weeks, even towed a camping trailer, and haven't noticed anything getting hot. I wish I had done this upgrade years ago!

#2 Clean & flow test injectors
Sending them off today to RC Engineering, 'dee you en, dun'. That's who Downey uses for their injector and throttle body service.
Result - awesome! No more rough idle after starting, no stumbling. The flow rates were ok on the injectors, but two of them weren't spraying, just dripping. Wish I had done this years ago too.

#3 Surface cylinder heads, valve job, O/S valves
One intake valve is burnt, coincidentally on the same cylinder that would crack the ceramic on the spark plugs. Found out that all the valves are pretty much toast, not sure if it's from the blown head gaskets or poor work of the dealership. The Toyota dealership did a valve job & replaced the timing belt & water pump in Oct 2003 at 133K miles, so I'm thinking all that stuff should have been good for another 100K miles. If your valves are shot, like mine are , consider the oversized (OS) valves. The best source is probably engnbldr.com, but his prices are better if you buy on eBay ($72 on website, $60 on eBay). Cost is going to be around $500 to do everything. Seems a bit high to me, but not a lot of choices around here.
Result - the machine shop did a great job, installing the O/S valves and the reground cams, I am so glad I didn't send them to DOA!

#4 Port & polish heads, intake manifold & plenum extrude hone & port matching
Seems like if you're gonna do it, do it all. However, in talking with Ted & engnbldr.com and others, I will 'gain' 30HP at the mid and top but lose it down low. Is that what others have experienced? Has anyone tried just doing the intake or exhaust, instead of both? Just got prices for extrude honing, roughly $1,400 for the whole intake. Pretty pricey. This would have taken more time and money, and I didn't really want to spend anymore of either for something that might have a negative effect. Doing the cams, valves, and headers seemed enough.

#5 Regrind the cams
Haven't seen any dyno tests, would be interested if there were gains without much loss. I've been hearing a little about weasy2k's cams, but I'd like to learn more.
Result - I did it, and I'm glad I did. The truck runs way cooler, and the cams sound good at idle. Definitely a torque and horsepower increase, just not sure how much. If you ever have the intake manifold off, just go ahead and replace the cams!

#6 Bored throttle body
Cons - expensive, doubts to whether this will truly make a difference? I can wait on this one, but I'd still like to do it in the future.

#7 engnbldr.com grade 10.9 head bolts
Also on the way, just makes sense, better than spending $375 on a bolt kit.

#8 Knock sensor and wire
Seems like the wire is gonna be a problem, some debate as to whether the knock sensor really ever 'fails'. The 'electrical tape' used to wrap up the pigtail had come partially off, exposing wires, so I went ahead and bought a new wire, Toyota part number 82219-35010. Just do it. For a $10 part, you don't want to have to tear the intake manifold off again.

#9 High flow cat, flowmaster muffler
Downey recommended 2.5", so that's what I'd like to stick with. And I've had a Flowmaster on for 6 years, love the unique V8ish sound, so I'm sticking with it. Another member here, A64ID, really did his homework, and lists information on the different choices in headers, exhaust sizes, catalytic converters, and mufflers. The info is based on the 22RE offerings, but it's interesting that Downey uses Magnaflow cats and mufflers, and they do recommend the 2.5" all the way through. Magnaflow part # 94006 for the universal fit 3-way cat, used for the 90-95 4Runner. Not sure which Magnaflow part number for the muffler matches up with Downey's.
Result - The Magnaflow cat was finally delivered, but we didn't wait for it to connect the exhaust. My bro-in-law, who is a much better mechanic, and way better welder than me, fabricated a header-to-stock cat exhaust using stuff from Kragen's, an old chop saw, and a Harbor Flake flux-core 110V welder. Look for the picture down below. All I have to say is it works, and it doesn't leak.

#10 Oil pump
To my knowledge, I've never had it replaced and I'm the original owner. Can I tell if it's going bad, or is it just as easy to replace it?

#11 Starter
Thanks to Morhpine on this one. It is impossible to remove the starter on this model without lowering/loosening the front 4WD components. I had to repair mine in place a few years back. Nows the time to check it out, which I will tomorrow.

#12 Clean and check pistons
Look for obvious damage to the head of the pistons, scoring of the cylinder walls, try your hand at cleaning the piston heads, like ChickenLover. He used 'some type of brillow pad from Walmart' on a Dremel. I have the Dremel, have to get the brillo.

#13 Replace freeze plugs
Old rusted freeze plugs do no good, so some brass ones would be much better. I have minimal rust on this truck, but our winters do get cold, so I need to check this out.
Anything else I'm missing? Besides cleaning, cleaning, cleaning?
Result - they looked fine, so I left them alone.

#14 Replace water pump/timing belt kit
Mine only has 30,000 miles on it since I had all the work done (almost $2K at the dealer!), and it all had just started to wear out at 130,000 miles. So I'm still debating whether or not to just do it, even though everything should be perfectly good.
Result - had some temp problems when we first got it going, so I replaced the water pump, which actually looked and felt fine. Then I figured out that we didn't add enough coolant to begin with, oh well.

To round things out, I have a custom airbag suspension in the rear (awesome!), 31x10.5 BFG A/Ts, no other suspension mods, K&N air filter. It would be cool to put 33's on it, but if I do, I'd like to do the T100 front shaft swap with the lengthened IFS and coilover shocks in front, for a true long-travel suspension. Total Chaos had the first, but I'm not sure if they are the best, as Downey and Camburg have something similar. Has anybody swapped out the rear axle with the T100 also?

 

sounds like you got it covered.

 

welcome to yotatech.... sounds good too me

 

From someone who's done all that and more - DON'T DO IT!
You are polishing the turd, it'll never give you the performance benifits you spend. Take all that money and put it in a savings account towards a swap.

Take what you have and do the minimum you can to get it running, that's a valve job, new timing set, knock sensor pigtail and gaskets. Put it back together and drive it.

DO NOT waste your money on 3VZE performance upgrades. The bang for the buck just isn't there - too many bottlenecks in the 3VZE's design to get power.

That's my 2 cents and I've been down this path.

 

The headers kill low end torque but gain horse power at the top end. It depends on how fast you want to turn your engine and where you want horse power or torque.
As far as the cams go, if you get re-ground cams, you can't find thick enough shims. So the only other option is to find longer valves. I don't know if anybody makes them or not.
Napa has head bolts, they are about $70 for an engine set.
You can also remove the starter by taking the compressor off or unbolting the compressor and bracket. Jack up the engine, remove the motor mount, and take it out through that way. But that is with a 3 inch body lift.

 

I was worried that it was TMI for my first post. I'm anxious to get everything back together, but at the same time I want to explore all my options before it's too late - 'cause once it's back together, I don't plan on *voluntarily* doing the HGs again.

I plan to keep my 4Runner for as long as it lasts, 'til its completely rusted out and broken down. So I was hoping that there's things I can do to make it more enjoyable 'til that happens.

MonsterMaxx - I've been reading what you've gone through, and it makes me sick to think what happened to you, and how close I came to sending my heads off for Tim's port and polish and getting his head stud kit. Maybe after I get this engine back together, I'll have more courage to do the 3.4 swap.

It's just hard when there's the people who have done the such-n-such and they're really happy, and others who've done it and wished they hadn't wasted the money. I'm still inclined to go with the exhaust headers and cams, since it will be about $1k - $1500. Then again, if I'm gonna do a swap, I might as well go with the new 1GR-FE 4.0L V6!

 

Headers - From what I read and the research I did , if you live in California and you plan to be *legal* Downey is our only option. Engine bay temps and melting is a concern. If you aren't carefull you can melt your battery cables and some of the plastic tiedowns that are OEM n the engine bay. Take your time reconnecting everything on the passenger side.

Replace the battery if it's about time. Maybe an Optima redtop! Doing the cables with everything else why not.

Another thing you can do with the top end out since you will have more room is to replace the freeze plugs.

Otherwise it looks like a good "checklist" for those of us who planning on keeping our 3vze.

 

Why in god's name would you use OEM TTY headbolts from napa?!? There is better for cheaper; engine builder's grade 10.9 Headbolts are 1/2 the cost and are reusable. The oem jobbies and the nappa oem like jobbies are not...

Cams maybe so but thats why you have a thin shim to move the oem shims up. Take it from someone who has aftermarket cams that are 100x better than the junk OEM cams.

 

You forgot one thing - the oversized valves that engine builder uses. Those + headers + PNP = 30 rwhp.

 

I'm starting to rethink the whole 'keep the low-end torque' idea. When I'm pulling something, especially over a steep hill we have here, my RPMs always stay above 3000. I usually have the take the hill in 4th, then drop down to 3rd, even if I'm just carrying passengers. For this engine, and please, correct me if I'm wrong, low-end would be 1,000-2,500, mid-range would be 2,500-4,000, and the high-end would be *anything* above 4,000.

All this got me thinking, with this engine normally aspirated, what would be the absolute maximum HP and torque it could achieve? Meaning, perfect conditions, 100% volumetric effiecienty, based on displacement. Anybody tried to figure this one out?

Morhine - good reminder on the freeze plugs. Mine look good, but I'll add that to the list.
Bumpin - gotta add the OS valves. I need to talk to the machinist to see how much/how long it will take.

 

do the valves and the cams before any other mod. Those are the weakest links to this engine... btw there are dynographs for weasy2k's cams on here. He has a site www.s2stuning.com, not sure if its still up but those are the cams Id go with. (Or should I say DID go with! )

As far as theoretically best possible hp is going to depend on a LOT of variables. Assuming:

1. 100% VE
2. 85*F intake temp
3. Sea Level
4. 0% humidity
5. oem 181ci displacement with a 5800rpm redline.

The 3vze should only sweep through 21.89lbs/min of air. That equates out to approximately 215hp or so. Any more than that and you will need F/I. And anyone claiming a 225hp NA 3vze *cough*DOA*cough* should get a solid snap kick to the balls...aside from being a crook...

Kinad makes me think, hmmm 26-27lbs/min of air from a huffer wont be so bad...lol

 

Site is still down, and I'm trying to find out how much/how long to do the cams. I tried the Wayback Machine to see if I could find the dyno graph, but no such luck.

Now that's some real homework! So that means a bone stock 3VZE is only working at 70% of max capacity. So how reasonable is it to expect to get up to 190 HP? Not sure what you mean by 'huffer', but anybody try an electric turbo(super?)chager?

Just got off the phone with *the* tech at Extrude Hone in Paramount, CA, and the cost for doing the intake and heads is $1,400. Maybe I'll just stick with a little porting and polishing for now.

 

VE's on normally aspirated engines aren't going to exceed about 85% or so at specific places on the curve of manifold pressure and RPM.

Extrude hone for $1400? That's nutty... I'm sure you could have something fabricated for less.. Even so, be sure that it's the manifold that's the limiting factor before spending your $$$ there.

An electric supercharger can work in theory, but the power required to drive one is huge and they'd be a temporary solution at best due to the required amperage draw. The stuff you see on ebay is JUNK, typically made from air flow systems for marine applications.

Theres an interesting thread over on pirate about a home-brew turbo setup for the 3.0 that seems to be successful and has good A/F ratio:
http://www.pirate4x4.com/forum/showthread.php?t=532878

 

Dcg9381 hit the nail on the head, on average the VE is going to be about 80% or so, however the VE changes vs the RPM. For my little calcuation I assumed 100% VE at 5800rpm. In reality the VE would be about 65-70 in that high of an rpm if I were to take a stab in the dark.

Personally I think the 3vze can hit 190hp NA...

The dyno graphs are here on yotatech btw.

 

You may already have these other parts on your list during your repair, but I'll mention them anyway (I am also in the middle of this headgasket job).

waterpump
front main seal
tensioner
radiator hoses
other misc. small coolant hoses
thermostat

I opted not to replace the knock sensor. I am replacing the wire though. The tape on mine was quite crispy too. I talked to the dealership while I was ordering the wire, and he said they don't replace the knock sensor itself as standard practice. I've rebuilt several engines, mainly 22R/RE's, but I have never had a knock sensor go bad (including on any engines I didn't rebuild).

I am not doing any mods in my repair. I am just replacing what's needed and not looking for more power. I blew $3000 into rebuilding and upgrading my '90 4Runner 22RE, and while it helped, it is not money I will spend again.

 

I'm still debating the water pump and timing belt parts, as mine only have 30K miles. However, when I blew the HG, I also blew out the solder joint at the top of the radiator. The compression must have gone into the cooling system, and put too much pressure into it. Seems like the water pump might have been affected too.

I'm looking through my diagrams, and I don't see a front main seal for the 3vze. Do you have more of a description?

So basically I *could* end up with and engine with about the same performance as a stock 3.4l, and I don't need an engine lift and $5000. I'll go with that! I searched for the pics, seems like they're missing from the threads, prob' 'cause sea2sky is down. Bummer.

The local machine shop wants $500 to install the O/S valves I'm providing, do a valve job on the heads, mill the deck (they were warped, not beyond repair tho), install the new cams (when I can find Weasy2k , and get everything adjusted. Sound about right?

 

Well, I got everything back together, and I only had 4 extra bolts! But that was only because the Downer header requires slight relocation of the reed valve. As far as upgrades go, I did the oversized valves and head bolts from engnbldr, the reground camshafts from weasy2k, the Downey headers, and I'm going to have the Magnaflow hi-flow cat installed before the next big trip.

Overall, it was money well spent, it improved performance, the engine runs much cooler, and it sounds great. The only real problem I encountered was not putting enough coolant in the engine before I started it up the first time. I should have looked at the specs, which calls for 11 quarts, almost three gallons, but I only put about 2 gallons in it the first time. It may look full when pouring coolant into the radiator, but until it actually starts to overflow and stops 'burping', there's not enough.

I've updated the orginal post with more info, but here's some pics for you're enjoyment!