The part about this engine that has me stumped is the lack of torque down low. This engine is great from about 3,000 to about 4,600rpm. Falls off after 4,600, not so bad because it is only a 2v engine. However, under 3,000 this thing is a dog. I have driven a lot of 2v motors in my days and they usually ahve a healthy low-end punch and then fall off when they get up there.

I read things about the headers for this engine and the biggest improvement being in the 2,000 to 3,500rpm range. This is not a product of free flow but usually a product of restriction. The more restriction the more torque you make, remove the restriction and torque usually goes in favor of hp. In other words it moves the torque curve up in the rpm band.

I would be happy with 150 hp and no breathing above 5,000rpm if I had a wider torque curve.

I think that I may need to introduce a little more swirl in my intake. How?

EB, have you or Tod got anything new on this discussion?

I have a little to add.

After a few mos. with the DOA heads and some testing it appears I have 4 leaking intake valves. my COLD comp numbers are below 80 in 2 cyls,below 60 in the other 2 cyls and over 180 in the last 2? In all 4 of the weak cyls I have air blowing out my intake if I hook my compressor up to the comp tester (minus the check valve) @35psi with the respsctive cyls @TDC. The two 180 cyls are tight as a drum when put to the air test. Im guessing maybe Tim decked the crap out of my virgin cyl heads with his "belt sander resurfacing" method creating an interference motor? The other option is bent valves when he brilliantly shipped them back in a box half full of peanuts sitting side by side unwrapped beating the crap out of each other all the way. I had to have several spots repaired in the gasket surfaces when I got them back due to Tims poor excuse for packing and maybe I missed some potential valve damage?

Im kinda stumped to be honest. As the weather cools down I am having starting troubles and lots of missing at low speeds (800-1100 RPM) until the engine is warm. This is what prompted the compression test and air leakage tests.

I recently drove to portland and picked up a set of real OS valves from EB along with a gasket set. Im going to have my 1k$ POS DOA heads redone by the shop I should have taken them to in the first place. The shop just bought a new machine to cut seats so I will be having 1mm OS valves AND seats installed. I should have the truck ready to go by the end of febuary. Tim said he used a 1mm over sized exh valve in the "Turn Key" rebuild I purchased but upon recieving them and checking them out myself with my digital caliper I found that not to be the case. He just used new OE sized valves not oversized ones (have pics if any one wants to see)

I will be sending my Throttle Body out to be bored for $100 (I will let you all know how this goes)

I will be going through my lower intake manifold much the way I did my upper and porting each runner to uniformity in hopes of seeing gains in the mid range as the upper intake cut/port gave me. I will probably run the truck with the stock AFM for now to get a base line from a dyno I found in town. Im sure the stock AFM will be the last and most restrictive bottle neck in the system. Once I get a good baseline number then I will be adding an SMT 6 so I can do away with the stock AFM meter and probably use one of the supra ones. Once I get the SMT 6 in and properly tuned I will pretty much be at the end of the rope.

Im sure it will run better than it does now and to be completly honest Im fairly happy with it except for the crappy cold starting and idling. I cant wait to see how it runs when Im done. I guess the worst that can happen is a bunch of 3.0 performance stuff is up for sale in the classified section and I swap in a 3.4

The ONLY reason Im not swapping in a 3.4 is because Im fairly certain the 3.0 can make a reasonable amount of power. The only thing I dont like is being the test dummy for the project but I do like the tinkering aspect of it. If it works then I will have some proof for all the nay sayers that a 3.0 can make power. If its still lacking then I guess its time to buy a bender and build an intake manifold from scratch <img src="/forums/images/graemlins/smile.gif" alt="" />

>>>*Just for giggles...Suppose we were to walk the cam lobe centers apart by..say, one to two degrees?

I would just regrind one and try that but the lobe shape sorta defeats it, plus any reduction of base circle creates all sorts of valve train geometry worms...

**Hmmm...Need me a longer valve..by about .030" or so...
**Hmmm...Then we can regrind the cams...


*More lobe spread tends to flatten the bottom end and bring up the torque. Then we could fix that funky valve seat on the exhaust side, which still looks screwy to me.

Just some thoughts, I haven't done the math to see what part runs into another part yet.

Logically a soft bottom end is either valve timing or too much port size...*well, rich and timing will do that, too, but that ain't it....*EB

well just my 2 cents, but i think the MAF/AFM is way to small. HP needs fuel and air. that maf on the 3.0's airbox stinks. lil guy. probly flows about 300cfm. in 1996 most car's came with "LARGE" maf's. for example.. my 89 corvette had a like 550cfm maf when modified. But my brothers LS1 trans am 2001 has this 900 CFM 4" or whatever maf. RPM also has to do with CFM requirements for an engine. look up CFM calculator and play around with it. DOes anyone know how much CFM the stock 3.0 maf flows?

well.. at 100%VE reving to 6500rpm. we'd need to be flowing 350cfm roughly. at 83%VE we only need 250cfm. if someone could find out what cfm the 3.0's maf flows that would do us some good.

[quote]well just my 2 cents, but i think the MAF/AFM is way to small. HP needs fuel and air. that maf on the 3.0's airbox stinks.
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>>>*I agree it is too small, but the engine shows better response at mid to upper RPM typically, than it does at low speeds.

Usually when airflow is less than adequate, an engine will simply run out of air and not increase RPM past a given point. This would seem to suggest that airflow is adequate.

That is why I am curious if cam lobe timing will affect. What I don't know for sure is at what point the electronics begin to resist the change....*EB

Er...uh...which engine are you talking about? The 3VZE as about the broadest flatest torque curve there is . Calling it a curve isnt even right. It climbs drasticaly off idle and remains a gentle rise after that and makes a good bit more torque than it does HP. I believe about 90% of its 180 ft/lbs available torque is available at 1800rpm

Y'all is nuttin butta buncha sillies! Why mess with that huge cast iron ship anchor?? Open the hood on a 3.0L pickup or 4Runner and what do you see?? No where a fella can stick his hands to mess things up! Thats what. Change out the cubed pistons for some cylindrical ones that match the bore and you may just get some usable power. Cams on this engine would be scary as hell, all them shims for adjusting this and thats. Figure out a roller rocker design or computerized valve actuator pusher downer thingy and a 110v pluginable ignition system and I'll break down and get me one. Foe Shu. <img src="/forums/images/graemlins/drunk.gif" alt="" />

~Darin <img src="/forums/images/graemlins/nana.gif" alt="" /> altered states

well i'm gonna do a compression test on my 3.0 here in the next week. i really want a 3.4. now that's an engine.