The making of a 200HP 2.6L 4ZE1

[isuzu Specialities]

This will be high performance 2.6 L number 6.

Machining of all engine components are performed by myself except for the engine block. I do not have a operational milling machine at this time. The block work was outsource to a local machine shop that I've been using for years.

The displacement of the engine is almost 3L
Engine will be running on the stock I-Tec ECM
Custom tuned by myself using the software I developed.

Polish imported heads and custom-made camshaft or just some of the goodies going into this monster.

Stay tuned.....

[Halden]

I've often wondered how hard these engines can be pushed. It will be really interesting to see...

[isuzu Specialities]

Without replacing connecting rods, crankshafts & redesigning the oiling system right about 300HP-ish is max.
With turbos, rods, pistons oiling system, EFI systems, ignition systems all reworked 450HP is the highest I have seen. All of the 4ze1 variant engines max out at around that number too. The problem is to achieve 450HP is very costly. Re-powering the vehicle with a NorthStar V8 will provide more power at 1/2 the cost.

[Halden]

Without replacing connecting rods, crankshafts & redesigning the oiling system right about 300HP-ish is max.
With turbos, rods, pistons oiling system, EFI systems, ignition systems all reworked 450HP is the highest I have seen. All of the 4ze1 variant engines max out at around that number too. The problem is to achieve 450HP is very costly. Re-powering the vehicle with a NorthStar V8 will provide more power at 1/2 the cost.

Seems like it could be fun to spice one of these engines up. I don't know that I'd ever want to go crazy high on power, but if I ever jump in the gasser game it could be fun.

What do you do for the head gasket issues? Studs? Run cooler?

[isuzu Specialities]

I am convinced these engines don't have head gasket issues. I've built over 50 of these engines and not one has had a problem. None of my own 2.6 engine that are original have had a head gasket issues.

I'm convinced the horror stories you & I have heard are created by the owner of the vehicle. Not fallowing Isuzu maintenance schedule that includes checking head bolts, Cooling systems not maintained, driving for a year with misfire & CEL on, improper head gasket installation are major contributing factors. The absolute #1 reason for premature head gasket failure is disabling the EGR system. People falsely believe EGR is only there for emissions, Simply not true.

All the 2.6L engines I built I warranty for 30k miles & 3 years. I know the owner will not check the head bolt torque which is required maintenance on this engine. As a precaution I have changed the torque sequence & torque valve of the head bolts. I use a bolt conditioning process when installing the head bolts.

[Halden]

I'm convinced the horror stories you & I have heard are created by the owner of the vehicle. Not fallowing Isuzu maintenance schedule that includes checking head bolts,

It could very well be that perhaps they don't. It is a standard practice after replacement/rebuild to torque again. To combat this many people/shops just go a little over on the torque. But I see nothing about Isuzu recommending this regularly, at least for the 2.3 in 86-87 literature. Maybe that changed?

[isuzu Specialities]

It's in a TSB released in 1987(?) about checking the head bolts torque at the first 5,000 miles. I'll see if I can find it.

[isuzu Specialities]

Making a engine to produce more power isn't about adding fuel or RPM. It's about increasing the engines ability to draw more air into & out of the cylinders. With out more oxygen you can't burn more fuel.

Part of this process is new valve & seats. The air must enter the cylinder without turbulence. Nothing can slow down the air speed as it flows into the cylinder. The shape of the valve seat play a big part in this. The vale must also open & close fast. The air takes time to move into the cylinder & the valve is only open for a few micro seconds.

When high performance aftermarket parts don't exist for this or any other engine. You simply must make them yourself.

[isuzu Specialities]

[isuzu Specialities]

[Halden]

I'd be really curious to see how much efficiency is increased with this.

[isuzu Specialities]

The biggest limiting factor about this engine is its sheer size. It's a very large displacement 4-cylinder that doesn't have balance shafts. The more power this engine creates the lower the redline needs to be to prevent it from vibrating itself to death. My research and calculations indicate 267-ish HP is achievable fairly easily. Increasing power above this 267-ish mark requires more funds than it's worth.
This is engine #4 & each engine is a little different than the previous versions. So I am still gathering efficiently data.
In development now is a 250HP version that will use quad side draft SU type Zennith carburetors.

[JoeIsuzu]

Increasing power above this 267-ish mark requires more funds than it's worth.

Diminishing returns. In fact, it seems to me that a 4.3 upgrade would generally make more sense than spending good money trying to make a 4 banger into something it's not. But I'm biased. I hated the 2.6L when I had my Amigo.

Am I wrong?

Jack

[isuzu Specialities]

Increasing power above this 267-ish mark requires more funds than it's worth.

Diminishing returns. In fact, it seems to me that a 4.3 upgrade would generally make more sense than spending good money trying to make a 4 banger into something it's not. But I'm biased. I hated the 2.6L when I had my Amigo.

Am I wrong?

Jack

I have developed this performance modification of this engine to be affordable.
The beauty of this engine is it requires no fancy race companies' expensive high-performance parts. The pistons, fuel injectors & valves are stock OEM parts barrowed form an unalike manufactures. All other parts are simply modified original parts you already own.
In the end it only cost about 2000 over a standard rebuilt 2.6L engine.
In the end the customer is getting a fully rebuilt engine with a warranty. most importantly nothing else on the vehicle is touched.

The V6 option can be done for about 1/2 the cost of this. The problem is you have to cut up your vehicles electrical system, make the exhaust, & fuel, system work too on top of fabrication. Not a big deal for some.. But to some it is. What you have in the end is a 25-year-old used engine with terrible throttle body injection or carburetor. The other problem with the V6 re-power is state laws. 15 states do not allow a non-alike engine repowers, so for some a V6 isn't even an opinion.

The 4ZE1 originally was designed from a inline 6-cylinder made many years before it. The design was modified into a V8 and 100 prototypes were tested around the world. Then 1973 fuel crisis forced it to become a 4-cylinder. I have Identified 6 variants of this 4ze1 engine. No different than Isuzu's 3.2L V6, this 4ZE1 engine is the lowest HP version of them all. Most variants are right around 158HP. There are 2 turbo variants rated at 205HP in stock form. I am not turning this engine into something it's not. I am simply restoring it to what it once was.

[JoeIsuzu]

My brief ownership experience with the 4ZE1 left me with an unfavorable impression. I may have bought the last NOS EGR pipe in the country, and it ended up with the classic blown head gasket. If I'd been game for another project, and if it had been 4wd, I might have considered a 4JG2-T swap, or even a 4.3 swap. But as I said, it left me with an unfavorable opinion of the 4ZE1.

Jack