Why do 1UZ heads suck soo bad, what can we do.

[SuperRunner]

I know this has been somewhat discussed before, but I wanted to know if there has been any progress on getting better flow, and what needs to be done to achieve this. So that is what this thread is for:

After doing a little research on the 1UZ head, it seems to me that this is the biggest problem about the 1UZ engine. I have been working a bit lately with the 2JZ heads, and they flow way better than the 1UZ

Stock 2JZ heads get about 90cfm at .10" of lift, and 180cfm at .30" of lift, where as the 1UZ only gets 51cfm/120cfm respectivly.

With some mild port work, is there any way to get even close to these numbers? I have a ported 2JZ head that I have been able to get 210cfm at .30" utilizing stock valves, which are basically the same size. I think it is rediculous how bad these heads flow...what were they thinking?

 

[Anaema]

i have no idea what they where thinking. but a total port and polish job would do a 1UZ head alot of good. the casting burs are still there, and that doesnt help airflow, the valve guides poke into the bowl with some thick reinforcing that can be ground away, and the valves are too small. oh, and the cams arent great for power either. high overlap and some big lift should solve that problem though.

so basically, you can port the heads, extrude hone them, try on some bigger valves, and throw in a bigger cam. you can also try to find some way to raise or keep the air velocity while still making huge airflow numbers.

 

[Zuffen]

The heads do exactly what they were designed to do.

They have small ports to keep airspeed up and help enhance torque. The 1UZ was designed to drag around the LS400 which is no lightweight and at the same time the 1UZ isn't exactly of large capacity.

The ports are not designed to flow heaps of air for performance use. Combine this with low valve angles and you won't get them to flow too much.

I believe Kelfords in NZ have done some welding in the bowl area and porting combined with bigger valves and achieved some good results. Not cheap but no horsepower is.

The real answer would be to find an alternative head to graft onto the block.

 

[UZZ30-Québec]

1st of all, you're comparing a GE head to a FE Head.

Those old FE heads are designed to provide good fuel economy and maximise torque output for the engine in low revolutions.

120CFM is not that bad for a 4 liter 6200RPM revving engine. 120CFM * 8 = 960CFM. Those heads can achieve good power N/A, unless you want 600BHP and revs it 10 000RPM

But for this, i'd recommend you a 3UZ, lightweight crank, lightweight rod, lightweight pistons, better flowing heads.

So i do thing the stock 1UZ head is a good head, not good to make a nascar engine, but very good for people who wants to achieve high horsepower with stock heads.

Don't forget that in about every american engines, they changes the stock heads for higher flow heads. now, you have a stock aluminum head already, with good valves (not awesome but good) and good flow (still not awesome but good). Never forget you have a stock OEM engine with a NON GE head. the JZ are considered as High performance engines, not the UZ (according to toyota)

 

[SuperRunner]

Yeah, this totally sucks. I will try to get the same flow numbers as a stock GE head, as anything less than 600RWHP is childs play, and should be easy to do with some improved flow numbers, or I will just have to go with an expensive 3UZ which I really don't want to do because they are more $$$ and harder to get.

 

[Lextreme II]

3UZ heads are not direct bolt on unless you have all the 3UZ heads and intakes.

 

[capn]

I am just doing a little port matching and deshrouding the area around the valves and see what I get, I am not shooting for gobs of torque here just enough to make a NA really fun.

here is some pics of my port matching, nothing extreme but every little bit helps.

 

[bango]

What tool/tools are you using to do that with?

 

[Lextreme II]

Nice work capn and thanks for the photos. I have been tracking your Rx7 swap.... nice gooing....

 

[capn]

What tool/tools are you using to do that with?

Just a really good and sharp carbide bit to take out the metal and little sanding drums to smooth it out, and I am just using a little dremel tool.

Nice work capn and thanks for the photos. I have been tracking your Rx7 swap.... nice gooing....

Thanks man

 

[SuperRunner]

I use a few different tools. I have 4 different air die grinders all connected with a lightweight vinyl hose. These vinyl hoses then go to a 4 way manifold each with its own pressure regulator so I can keep a nice slow constant speed. At first I had the valves at the grinder, but found that I was always hitting them and changing my speed. I also keep the line pressure from the compressor at 90 psi, that way, as the compressor tank pressure changes from 120-110, my output is not effected.

On each of these "small" 4 die grinders, I have several bits. I keep an large carbide to really do some hogging out of the ports quickly, then I keep 2 different smaller carbides, one that is tapered and another with an egg shape head. On the 4th, I have my cartriage roll mandrel. The cartriage rolls I can easily switch out so I can change from regular to taper, or to different grit. I usually stick to the 80 grit on the intake, and on the exhaust I will use a 120 grit after th 80 grit, and then I have a scotch brite mandrel so I can polish them to a nice smooth polished finish.

This method of using 4 die grinders really helps speed things up. I hate having to change out the bits, and the vinyl hose really helps keep the weight of the grinder down. When you spend 20+ hours on a head, you don't want to be holding something heavy for very long.

 

[SuperRunner]

here is an 80 grit finish on an intake.

 

[capn]

here is an 80 grit finish on an intake.

Have you flow benched those heads in comparison with a stock 1UZ head?

 

[SuperRunner]

This is a 2JZGE head. I have flowed 240 CFM with .40" of lift at 28". It flows 90 cfm at .10" of lift.

 

[SuperRunner]

has anybody been succesfull in using the 2JZ intake valves? I am curious to see if this was able to work with a regrind.

 

[plman]

Check some flow numbers I put on a thread about porting heads, this was a GS400 98 heads, factory before and street ported

 

[1UZX83]

there are many 1uz with stock heads putting out over 400kw, in one case a blown 1uz with standard heads is producing 964kw at the crank which is a testimont to how well they can support power.

 

[4000GT]

This is a 2JZGE head. I have flowed 240 CFM with .40" of lift at 28". It flows 90 cfm at .10" of lift.

In the intake side? My mate just flowed over 300 on his Saw the flow sheet today actually. He has mad porting skills and LOTS of hours to do it.

 

[Jaco]

Hi Speedrunner.

Your flow comparason is very interesting. Ive read somware that n good port job on the 1uz heads hield a 19% increace in flow. wich in theory can bring the flow up to 143cfm. which is still bad.
My question is how does it compare to a sb ford v8? say the 302w?
Have you done flow tests on these?

 

[plman]

1UZFE heads

Maybe a little better understanding. A 78% flow increase, producing 112.5 HP per liter on factory cams. Air Technologies stated they were excellent heads for flow and can go much higher increase if wanted.