I'm posting this because I think the advice is some of the best I've seen for the 3vze.
After lots of experimenting I agree with everything he says (I do not know for sure about pistons, gaskets and valves yet, but if/when I do these, I will take his advice). His thoughts on headers, plugs, ignition, wires, exhaust, isr, TB, cams, is SPOT ON. it's rare to find one post where all these things are said so well.
taiko

Originally posted on Toyota Nation by SB5walker. on 03-14-2009, 07:32 PM
http://www.toyotanation.com/forum/ar.../t-290134.html


The question was:
Hello All: I have a 1993 4 Runner 3.0 3vze engine i am rebuilding and I am in need of some help. Can anyone tell me if there is any thing to give better performance in regards to cylinder heads and valves? I am needing everyday driving performance, not high performance from this engine. I am sending the heads in to be rebuilt and any help is appreciated. Also to use the MLS head gaskets how much needs milled off of the heads & block to accomidate these gskt's? Does anyone have a recomindation on main & rod Bearing, piston & ring Mfg's.Any tips for rebuild is greatly appreciated as I have been reading forums on this engine and sounds to be very challenging with some of its issues. Thanks again Louie2

The answer:

Milling is required for the mls gaskets not necessarily to remove material but to make sure both head and block surfaces are extremely flat and smooth. The tolerances required are half what graphite gaskets can cope with. But properly-installed mls gaskets are practically bomb-proof, and using them in the 3vze is a very good idea. About the only thing that will kill them is corrosive coolant. Just be sure to use excellent-quality new head bolts.

Acidic coolant is unfortunately easy to arrange. Just leave coolant in longer than two years, or mix it with an incompatible type (including changing from one type to another without THOROUGHLY flushing the old coolant out of everywhere including heater core), mixing coolant with tap water, or using the wrong type (Organic Acid Technology, or "OAT" coolants - like DexCool or Prestone's Extended Life - will corrode the copper/brass/lead radiator and heater core). Any of those mistakes can kill your gaskets.

If you really want to improve matters with the 3vze, install headers, a high flow cat, and a 2 1/4" cat-back system with a high flow muffler. Open up the intake side with an ISR mod (intake silencer removal - search for info on yotatech).

Using headers has the huge benefit of removing the terrible heat-producing stock crossover that causes so many head gaskets to fail on the #6 cyl, plus headers will give you more hp and better gas mileage.

As far as WHICH headers, the LC Engineering ones appear to be the best on the market - very heavy flanges, stainless steel and ceramic coated. They're a bit more but are probably worth it:
http://www.toyotacatalog.net/M1WebGe...0-BD3461454C49

People say very good things about the Doug Thorley headers too, especially the ceramic coated ones. Downey Off-Road makes headers and exhaust too, but people say mixed things about those. Some people point out that the Thorley & Downey headers & collectors appear to be identical, suggesting the same company makes them. They look identical to me, too. So, hm. I notice that the Thorleys come with the Y-tube/collectors for about the same price as just the headers from Downey. Summit Racing sells the Thorley for a big discount.

If you want to get real fancy, you can have your throttle body bored out 3-3.5mm overesize. Downey and LC Engineering will both do that "for a price". To go along with the bored out TB, oversized valves are worth considering - even 1mm can give a noticeable increase in hp. And to take advantage of the oversized valves, a cam can give further increases. For valves and cams, talk with LCE or Ted at engnbldr.com.

Keep the stock ignition system, including wires. The stock denso wires use inductive RFI suppression, which achieves radio noise suppression by tightly coiling the wires, whereas most of the supposedly-great aftermarket wires use resistive RFI suppression - they filter with resistors which degrades the spark voltage - not exactly an improvement. For plugs, you'll probably not do better than the factory spec Denso K16R-U, but the Denso Iridiums look like they would be fun to try - who knows?

For pistons & rings, many people seem to use and like NPR (Nippon Piston Rings) They may be the oem, I'm not sure. ITM parts get a lot of mentions, too. I've heard excellent things about LC Engineering (high end - and expensive) and engnbldr.com (cheaper but most customers seem very happy with quality). Bearings I dunno. I don't have first hand experience with any of the vendors above - and I recommend you try to get reports from people who have used the parts. If no responses here, you might try yotatech - they seem to have a lot of techie threads over there and you'll be likely to hear from folks who have rebuilt 3VZEs and used some of these parts.

Have fun! I love building motors. Reminds me of making models as a kid, only these are the real fun models that actually start when you finish building them!*

 

That one post sums up what it took me 10 years to learn about the 3.0.

 

yep, tons of 3vze wisdom in there. still, it takes a lot of experimenting to learn where the truths are...
having tried alternatives, I can see how true this post is. He's so right about the headers, peace of mind for cylinder #6 and much better performance. I followed this advice re: exhaust, 2 1/4" is the sweet spot for sure on this engine. His thoughts on ignition couldn't be truer.
Keep the stock ignition system, including wires. The stock denso wires use inductive RFI suppression, which achieves radio noise suppression by tightly coiling the wires, whereas most of the supposedly-great aftermarket wires use resistive RFI suppression - they filter with resistors which degrades the spark voltage - not exactly an improvement. For plugs, you'll probably not do better than the factory spec Denso K16R-U,

I have tried Jacob's ignition, V-power and Iridium plugs, different gaps, NGK wires, and I just got fully back to stock after that misadventure. The stock plugs with a new OEM cap and rotor, and stock wires, is giving me fantastic performance. My stumble is gone and it's running beautifully, the plugs are pre-gapped from the dealership, don't touch 'em, just install is my opinion.

 

I would add that there are a couple of shops that can flowbench the 3vze heads and make significant improvements in their flow--a main issue with the heads--to make the 3.0 an enjoyable engine. That said, it's a lot easier to swap in a 3.4 or other engine...

 

Excellent Info, thanks!!!

 

I love my 3vze because I believe in it's potential.

I do disagree on the issue of stock spark plug wires vs. after market wires.

No reason to run RFI supressive(high-resistance) wires unless you like to listen to the radio. Gotta go with the solid core for least resistance(most spark to the plug) and longest life.

 

didn't take me long to figure out that the 3 slow was not pos motor

i get 550 to tank and i walk on all the 22r's around here and have more power then the 3.4's

once i get my cam's in she will be done


now the question is will i slap on Eaton or mill the out of my head and block to up the comp ratio ??????? and go for full out Na power


ps don't bother porting your thottle body that's just waste money it's pretty big all ready

 

I understand your point from a physics point of view Mudhippy, you are right I have no doubt. In my experience, I was running ngk iridiums with ngk wires. I also ran jacobs wires with vpower plugs. Both the Jacobs and NGK wires were expensive aftermarket wires. I have to say, that I am running so much better now with stock plugs and wires.
This is just my personal experience so I'm no knocking your opinion at all, I'm just sayin'

 

hey nashman did you do o/s valves w/any machining work? you are right on the t/b upgrade, did not do much. Cams will be great for you, I love my weasy2k cams.

 

SB5walker knows his stuff. He has many other pearls of wisdom over there...

 

as for valve's no i am not opening up the motor tell i have to

but if the valve were afford ab able yes indeed i would slap them in

looks like you can run up 2 plus mill in these motor's

and 2 valve motor's they are easer to port then 4 or 5 valve motor much more simple

i have yet to look but i wounder if some makes hi comp piston


and i have plans to make new intake manifold as well since the stock one is junk and may end up runing 1uzfe thottle body

 

wow. I just learned so much. Well I already knew a few things but wow, this is great!

 

I cant wait to get my truck back on the road. i just got headers, cams, and 2 1/4 exhaust and im just waiting on some new rod-ends to get here. i think after this i might get the aluminum rad from LCE with the spal fan(or maybe just a Taurus fan, depends on cfm's) and get my alt rewound. i cant wait lol

 

I got the solid core wires(ultra-low resistence, but NO RFI sheilding), but other than that the ignition system is stock(parts wise). Truth is I only bought them wires because the were cheaper than a new stock set, or I'd have stock ones on there now, that and my rig has no radio to listen to period.

 

most folks (like me) dont want to spend all that Time/sweat/money on HEADERS for the 3vze and re welding exhaust pipes when considering the $ difference in 3.4 swap.

I feel that another less "exhausting" approach can be to put a hood vent with a fan that pulls the cold air off the back of the motor. ive seen a few goods threads on it somewhere out there, i think big mike on 4x4 wire.. anyways, it reduced temp substantially, especially when moving slow.

our engines have such little space back there that some air flow to get that heat out can only be good...and cheap & easy.

im going for this mod as soon as I can find some sweet high flow home theater fans for cheap on ebay.

 

usefull info..

 

Yes, He really knows his 3.0 & is always very helpful too. He's on this board as well.