2uzfe heads on 1uzfe block

[dass]

Hi all,
I am currently building a spare engine for my TT1uzfe 6speed track car, it seems that most would like shim under bucket set-up ,COP,Short runner inlet manifold (custom).So I have a pair on 2uzfe heads coming from Dave.Does anyone see any disadvantage of using the 2uzfe heads on a 1uzfe block ,like poor ports smaller stem etc. Any coments would be a help.

 

[cribbj]

Dass, many have reckoned the 2UZ heads ought to flow better than the 1UZ, which strikes me as odd since the 2UZ is a truck motor, and the 1UZ was standard fare for Lexus' "sports" car. So you'd think the 2UZ would have tiny ports and would be set up for torque, but apparently it's not the case.

It'll be interesting to see how this works out for you, and since I've recently gone through a shim under bucket conversion with one 1UZ, I can see now that it probably would have been easier & cheaper to use different heads, if they just bolt up, and there's no cam drive issues, etc.

Since the 2UZ has 94mm cylinder bores and the 1UZ has only 87.5, are you anticipating any sealing or combustion issues? Which head gaskets are you going to use?

 

[dass]

I am hoping that the the head gasket sealing area will work with the small Dia. bores. I have used the late factory MLS gasket and 1/2 head studs on the current engine and had no sealing problems (600 RWHP).Will use the same combo.

 

[JBrady]

Some concerns:

Larger bore 2uz heads will overlap the smaller bore 1uz creating an unwanted dead zone that will not have good combustion properties.

Chamber size is likely larger due to the 2uz having both lower compression along with larger displacement. Using larger chambers with a smaller displacement will lower the compression even more.

Now, the benefits are a better designed head and intake manifold along with SUB buckets.

Some careful measuring may allow you to surface cut the heads. This could be very helpful in two ways. It may shrink the bore size of the chamber as the head is surfaced. This could partially or totally correct the bore mismatch. It would reduce the chamber raising compression.

If this works you would want to also make sure the intake ports still have a good match to the intake manifold and port grind as necessary.

 

[dass]

When the heads turn up , will have to measure the combustion chamber volume and dia. After doing a search on the 2uzfe /1uzfe combo, it appears to have been discussed but never tried. One thing I didn't think of was combustion area design with a low comp.piston. Any thoughts.

 

[Pro]

i'm considering going the other way - 1UZFE heads on a 2UZFE block using 2UZFE gaskets.

the 2UZ pistons are low comp anyway, aren't they? the relief in the piston crown is quite large...

 

[cyberdiamond]

I would be concerned about both the combustion chamber size and the piston crown shape affecting squish (and detonation resistance).

What intake are you planning to use?

 

[Zuffen]

He'd have to use 1UZ or custom make something.

 

[SuperRunner]

I have some 2UZ heads on the way for my 1UZ block, so I will be doing something similar.

I will flow test the heads too to see how much better they are.

Couple things to remember. The 1UZFE was designed for fuel economy, not performance. The 2UZ was built with more performance in mind and the cost of fuel economy. Only thing that concerns me is the match up of the combustion. You would mill the head, but then you might need some custom adjustable cam gears since the angles will be off slightly.

Anybody know the duration of the cams. I definatly want to get some custom cams. 270hp and 315 ft lbs? At that torque, a better cam profile would easily yield 350hp on pretty much cams/tune alone.