VVT heads on non VVT

[JustenGT8]

Had a quick search but no joy. I'm sure someone has tried this but can't recall the outcome...David?

Apparently the VVT exhaust ports are similar enough that my non VVT turbo manifolds will fit. This makes a head swap to improve top end flow feasible IF the heads actually fit. Has anyone tried this?

I know the inlets are different but i have options there, need to know if the ports will match, water galleries, timing belt length suitable etc etc

 

[Lextreme II]

Justen,

I assume you are talking about VVTi (1uzfe) right? It will work. However, you would also need VVTi pistons, lower and upper intakes, Harness, ECU and few of misc parts. Just imagine you would need block up accessories. Personally I don't think its worth the money and trouble. http://lextreme.com/forums/attachment.php?attachmentid=5019&d=1166627670

 

[cjsupra90]

Are we positive that we would need the VVTi pistons?

Dave looking back at your page that details the differances between the 3uz and 1uz piston, It seems that the 1uz piston would sit .043 lower then the 3uz unless you have a misprint there. its stated that from the top of the ristpin hole to the top of the piston its .917 for the 1uz and .960 for the 3uz.

Second is looking at how deep the recess is for the intake valves on the 1uz, I cant see why flycutting releafs for the exh. valves would be an issue. seems that they are not deep at all on the 3uz units and actual looks to be deeper on the intake for the 1uz then it is for the 3uz.

 

[Lextreme II]

The VVTi combustion chambers were designed differently. If you really want to force it. I would assume it would work but I don't think it would work optimally. However, the intakes and all other accessory parts would be different. Therefore, its still alot of work.. and money too.... Basically you will need every from the block up.

 

[JustenGT8]

I would have to confirm piston clearance but as would be going custom forged i don't see this as much of an issue. Same for inlet mods as i would either ust use the stock VVT ones or go custom. A bit wary of going custom but if i do all this then i'm chasing alot more hp than i currently have so would likely have to do these mods anyway.

ECU etc is no prob, autronic remember

Will only happen if i can find the heads etc at the right price anyways, most likely from a dead engine. Just making sure my ducks will line up if the opportunity arises.

 

[Lextreme II]

Justen,

If you going with custom pistons then it would be a problem at all. Perhaps you can look into 2uzfe heads. They are alot around.... Basically, you would need a complete dead motor. That will reduce headaches and hunting for parts. Perhaps you should contact Cribbj for his VVTi engine.

 

[JustenGT8]

I'm not sure how the 2UZ heads flow though? whereas Ed has flowed the VVT heads and we know they flow better in stock form than even ported non VVT heads.

Than ks for the heads up, i'll drop Cribbj a PM.

 

[LondonBenji]

Justen,

If you going with custom pistons then it would be a problem at all. Perhaps you can look into 2uzfe heads. They are alot around.... Basically, you would need a complete dead motor. That will reduce headaches and hunting for parts. Perhaps you should contact Cribbj for his VVTi engine.

Sorry if this hijacks your thread Justen but we are touching on a question I have been meaning to ask for a while as well.

What in theory would be the best combination of xUZFE engines if you were going to custom everything anyway, ie custome rods, pistons, cams, ecu, exhaust manifolds, inlet plenums, etc?

I mean like you I have read Ed's notes on the VVTi heads flowing better than even ported/polished non-VVTi heads, I wonder if this is true for the 2/3UZFE heads?

The reason I would be interested in using 2uzfe/3uzfe heads is because someone mentioned that you might start cracking 1uzfe heads (VVTi or otherwise) much over the 1200-1500bhp mark and I have heard that cast iron heads (which if I remember correctly 2UZFE heads are or 3UZFE's as well for that matter) are stronger so should be able to take more than 1UZFE heads, I assume because they are aluminium they 'weaker'.

I know MR2 Mk2 boys have a habit of cracking heads and have looked extensively into how to get around the problem. If any of them have input they would be more than welcome

If they are stronger and you could use them on a 1UZFE block would there be any issues with mating cast iron heads on to an aluminium block with the different metals or will the gaskets handle this?

What combination heads/block in theory would give you the most (safe, streetable, friendly) capacity with custom pistons and rods? Isn't the 2UZFE like 4.3L and the 3UZFE 4.7L? Because wouldn't it be a better starting base to making 1000BHP+ from 4.7L (or more if using the 4.7L heads with custom pistons/rods, 5L maybe?) than from the 4.0L 1UZFE standard block/heads?

Sorry for the huge amounts of questions. If anyone can provide information on all of the above I will be eternally greatful

 

[JustenGT8]

Whoaa there Benji, NONE of the UZ heads are cast iron!!!! Toyota haven't made a petrol iron head motor as long as i can remember

I've never heard of any toyota heads cracking and i've been playing with 3SGTEs for nigh on 8 years now. MK II MR2 are known for cracking blocks when making BIG hp as a large number of blocks (GEN III) had a slightly dodgy casting from factory. Could be you misunderstood?

As for the UZ, the blocks have split here in OZ at around the 800hp mark but have never heard of a head cracking and can't think of a reason why one would??

The 2UZ has an iron block so that would solve the splitting prob but they also only have 2 bolt mains which is a big step backwards in my book.

A quick answer to your i think the late VVTi UZ engine with the early UZ rods is probably the best combo of stock parts for an all round performer.

I think there will be a number of different views on this though as 'best' really depends on your intended use eh

 

[LondonBenji]

Whoaa there Benji, NONE of the UZ heads are cast iron!!!! Toyota haven't made a petrol iron head motor as long as i can remember

Ah, ok I think I've read something wrong somewhere then, my bad

I've never heard of any toyota heads cracking and i've been playing with 3SGTEs for nigh on 8 years now. MK II MR2 are known for cracking blocks when making BIG hp as a large number of blocks (GEN III) had a slightly dodgy casting from factory. Could be you misunderstood?

I could have sworn they were cracking heads but then it was quite a while ago I read all about it on the forum so again, highly likely I have read it wrong again then.

I thought I read by the end of it all they thought it was because of the design of the water channel between cylinders 2 and 3. I thought someone x-ray'd the block or something equally extreme and discovered it might be the cause as to why they were cracking.

As for the UZ, the blocks have split here in OZ at around the 800hp mark but have never heard of a head cracking and can't think of a reason why one would??

Really? How many have cracked? Is it just lucky then that Maajola's block was okay?

The 2UZ has an iron block so that would solve the splitting prob but they also only have 2 bolt mains which is a big step backwards in my book.

Totally agree, I mean I know there have been 4/6 bolt conversions but thats engineering that I really wouldn't want to take on and use in extremely high powered engines (1000bhp+).

A quick answer to your i think the late VVTi UZ engine with the early UZ rods is probably the best combo of stock parts for an all round performer.

But if you are chucking away the rods anyway it doesn't really matter I guess. Does the VVTi block really flow that much better? Would it be easier to obtain 1000bhp or more if it did?

I think there will be a number of different views on this though as 'best' really depends on your intended use eh

Lots and lots and lots of power (if you haven't guessed around 1000bhp+ :tongue2

In a lightweight tubular chassis with 4wd :smoker:

 

[sideshow]

hey what autronic do u have

unless u have the sm4 you cannot do full variable cam timing control

even then its a pain to tune if the tuner doesnt know what to do

 

[JustenGT8]

Sideshow, i have the SM2. I would just use a PWM output IF i used the VVT which i reckon would give a good enough result. More than likely though would go custom non VVT cams.

Benji, only 2 blocks i know of have cracked and another serious drag team that went with a custom CNC alloy block straight off the bat. Quite a few now grout or half grout their blocks but not much good for street use.

and YES the VVT heads do flow that much better than the non VVT...even ported non VVT

 

[sideshow]

well there is vvt and vvti
i think sm2 can only do vvt
from what i have seen only sm4 can do full variable vvti

i might be wrong never really mucked round with vvti engines with aftermarket

i know only afew aftermarket ecus can do vvti

 

[HKS]

Actually I think you getting confused. There is VVTi (Variable Valve Timing or VVT same thing) and the is VVTLi (Variable Valve Timing and Lift)

 

[ed_ma61]

no no no...

vvti is NOT vvt

vvt is a simple step function, vvt-i is fully 3d map variable

vvtl-i is a whole other system

 

[JustenGT8]

Yeah, i thought the UZ was just variable valve timing, not variable lift as well?

Can't see a reason why the SM2 still couldn't do both anyway. The lift shift is just an rpm trigger so that's dead easy. The PWM tables are configurable enough i think to get a passable result but certainly not as good as the new haltech which does VVT very well by all accounts.

Still, with turbo torque VVT isn't high on my priority list so just plain old boring cams would do me fine I just want that extra head flow and redline

 

[LondonBenji]

When you say custom CNC alloy block do you mean they created their own replica block or modified the block in some way?

By grouting do you mean filling the water channels with concrete (or thereabouts)?

 

[JustenGT8]

yup, their own block

and yup again although a bit more hi tec than concrete

 

[KazeSupra]

OK, to bring this back from the dead, can you swap VVT-i heads to a non-VVT block? Someone said yes, but David's compatibility chart says no. If so, does anyone know what you would need to complete the swap? I'm using aftermarket engine management, so I not too worried about the harness, but what other components would I need to use to swap on an older block (besides the complete heads and new pistons)?

 

[KazeSupra]

OK, to bring this back from the dead, can you swap VVT-i heads to a non-VVT block? Someone said yes, but David's compatibility chart says no. If so, does anyone know what you would need to complete the swap? I'm using aftermarket engine management, so I not too worried about the harness, but what other components would I need to use to swap on an older block (besides the complete heads and new pistons)?