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Turn a 2RZ into a 3RZ?

40K views 29 replies 23 participants last post by  Enola Gaia 
#1 ·
The 2RZ and 3RZ engines are almost identical. What are the differences? Is the only difference between the two in the bottom-end components (pistons, connecting rods, and crankshaft)? Is the 3RZ block physically larger? If I were to take my 2RZ apart, and replace the pistons, connecting rods, and crankshaft with 3RZ components, what else would I have to do to turn my 2RZ into a 3RZ? ECU? Are the heads swapable? Are the engine mounts the same? Does the 3RZ use the same drivetrain as the 2RZ (7.5")? Any downsides to this operation?

If I could find a cheap, complete, older 3RZ engine (with the EGR system and Distributor like my old 2RZ) and 3RZ ECU, could I swap my 2RZ head (with street-grind cams) onto the 3RZ, and then drop the 3RZ into my tacoma? Would my Hotshot Tri-Y header fit the 3RZ? What other issues would I need to address (fuel delivery)?

I'm always full of questions, I appreciate the answers! Thanx in advance!
 
#3 ·
I dont have my haynes manual next to me but I believe the differences between the 2RZ and 3RZ is the crank, cams and ECU programming. everything else is the same, pistons, rods, valves and head.
 
#5 ·
The 2.4 and 2.7 share the same piston bore size, but the 2.7 has a longer stroke to gain the extra 0.3 liter of engine displacement. To upgrade from 2.4 to 2.7 you would need at least the crankshaft. Depending on the design by Toyota, pistons and connecting rods might also be required. If the 2.4 head was retained, then the compression ratio will be increased due to the larger volume to air space inside the cylinder. This would be good for a naturally aspirated engine, but not good for a supercharged and turboed engine. They perform better with a lower compression ratio than stock, not higher. I think it would be much easier to just drop in a complete 2.7 instead of just swapping the internals. There would also be a much shorter downtime compared to tearing up your current 2.4. Just my 2 cents. Nice topic.
 
#6 ·
The 3RZ is also equipped with two balance shafts, that the 2RZ doesn't have in its block. but the only real advantages to the 3RZ anyway are about 8 to 10 hp and about 20 lb-ft of torque. Its basicly a stroked and modified 2rz, but is it worth it in the end for what you'll have to put into it?i don't think it is, cause i stomp the crap out some local 2.7 tacos on a regular basis. but yea if u wanted to you could swap the head or swap camshafts, and i beleive the header will work too. thats about all i know, hope i helped.
 
#7 ·
yea... 20 foot lbs of torque..PSssst! who needs it?

the 2.7 pulls VERY well at low-rpms... it makes it's torque lower than the 2.4 in the RPM range, along with a lot of what was mentioned above.. the only reason you might "pull" 2.7's is that this motor was made to pull the heavier 4x4/Prerunners, not a light-weight mini... so for it to be in a 2wd min would be very awesome... i think there is a guy on this board who has a 2.7 turbo in his mini and is quite impressed with it... i think the 2.7 is worth it over the 2.4 any day, only if it's a quick easy swap....
 
#8 ·
So If I did swap for a 3RZ crankshaft, I could retain my 2RZ head, and with the streetgrind cams I'd raise the compression even more! Thanx for the info! Does anyone know if I'll need a 3RZ ECU? Or will my stock 2RZ ECU adjust? Any concerns about increased vibration and excessive wear on the engine mounts? What and where are the balance shafts located on / in a 3RZ? Do you think I should add them if possible? Thanx for all of the responses guys, I want to do some serious engine work next summer!
 
#9 ·
i agree with some these guys 2rz is like the 305 in chevy & the 3rz is the 350. So like in them [censored] heavy chevy's some of these parts will interchange. E.L protypes has stroker kit for the 2.4L and don't the 3rz. This makes me think that all there doing is using the connecting rods and pistons out of a 3rz. Which like other guy said you would have serous compression. Which means lower gears a bit and you'll fly out of the whole.
 
#10 ·
I was thinking of getting a supercharger for my Taco, but I didn't want to supercharge my engine without a complete workover. Then I got to thinking of just dropping in a new engine since it'd come with a warranty. And then I got to thinking and asked around--the price difference between a new 2.4L and 2.7L wasn't that great... So, dropping a new supercharged 2.7L into my truck sounds pretty good. Plus, my 2wd weighs less than a 4x4 or PreRunner which should translate into more power goodies for the buck.

My '97 is paid off (as of this month). To get a new truck with its warranty (and new-car woes) would require that I take on MORE monthly payments. So, for 1/3 the price of a new truck, I can get a fully warranted supercharged heart transplant in my beloved Taco.

Hmmm...
 
#12 ·
... i think there is a guy on this board who has a 2.7 turbo in his mini and is quite impressed with it...
that would be jerry and the reasion he went to the 2.7ltr was he blew his 2.4ltr

so it would have cost him about the same both ways, so why not go with the 2.7?

but if there is nothing wrong with the 2.4ltr, why spend a thousand to get 8 more HP?

you could spend less then 1/4 of the price and it would be the HP as a stock 2.7ltr
 
#13 ·
... i think there is a guy on this board who has a 2.7 turbo in his mini and is quite impressed with it...
that would be jerry and the reasion he went to the 2.7ltr was he blew his 2.4ltr

so it would have cost him about the same both ways, so why not go with the 2.7?

but if there is nothing wrong with the 2.4ltr, why spend a thousand to get 8 more HP?

you could spend less then 1/4 of the price and it would be the HP as a stock 2.7ltr
Look at the date, It wasnt jerry, that was about a year ago
 
#14 ·
... i think there is a guy on this board who has a 2.7 turbo in his mini and is quite impressed with it...
that would be jerry and the reasion he went to the 2.7ltr was he blew his 2.4ltr

so it would have cost him about the same both ways, so why not go with the 2.7?

but if there is nothing wrong with the 2.4ltr, why spend a thousand to get 8 more HP?

you could spend less then 1/4 of the price and it would be the HP as a stock 2.7ltr

Turbo357 has had a turbo 3rz in his truck for a while...

as far as power difference is concerned, the 3rz definately has a bit more pep... bout 20 horse power I think. it also has balance shafts for reduced vibration (unlike the 2rz).

In regards to EL Prototypes' stroker kit, I'm fairly certain that it is just a 3rz crankshaft & rods.

If I can find a cheap 3rz engine, I'll bite.
 
#17 ·
It's doable. Yes your head will work, you will need to get injectors off a 3rz because the 2rz are only 260 or 270 something cc whereas the 3rz has 308cc injectors (according to calculations made from a toyota factory manual on flow rate checks).

Without the two balance shafts which isn't in the 2rz but IS in the 3rz you will get a whole lot of vibration from the motor. Especially at idle.

The only differences are the camshafts, crankshaft, pistons and rods otherwise. And of course the ECU programming.

Andrew
 
#19 ·
I know this thread is REALLY REALLY old, Does anyone know for sure that you can put a 2rz head on a 3rz block? My 2rz is making some odd noises, and since I have a spare motor I was going to start building a back up.

If I could run a 2rz head on a 3rz block, Could I still run my 2rz ecu since it already has all the 2rz stuff in it. (ie 2rz inj) What problems am I looking at? In most of my reading, people have said that the 2rz and 3rz heads are the same.
 
#25 ·
Yeah, the head is exactly the same on the 2rz and 3rz. The 3rz block is taller by 3/4". If you look at the dipstick tube either engine you will see 2 different bolt holes. One is used on the 3rz, and the other on the 2rz. The block height differs by the distance between the centerline of both holes. The blocks are different and the crank, rods, and pistons are in no way interchangeable between engines. Don't even try. I have done major research on this subject.
 
#26 ·
Yeah, the head is exactly the same on the 2rz and 3rz. The 3rz block is taller by 3/4". If you look at the dipstick tube either engine you will see 2 different bolt holes. One is used on the 3rz, and the other on the 2rz. The block height differs by the distance between the centerline of both holes. The blocks are different and the crank, rods, and pistons are in no way interchangeable between engines. Don't even try. I have done major research on this subject.

Maybe you can answer another question for me. I plan to build a 3rz to replace my 2rz. I am going to reuse my current 2rz head. That means 2rz intake, TB, Injectors, cams... Everything. I figure I will need a 3rz timing set.

1. Are the cams the same between the motors? will there be any special parts I need to run a 3rz timing set on 2rz cams?

2. Will my ECU throw a code now that there is going to be more air in the motor? (longer stroke pulls in more air)

3. Will the ECU be able to feed enough fuel to the engine threw 2rz injectors.


Maybe im over thinking this, I dont mind sourcing a 3rz computer and injectors, but would rather save the money. :)
 
#30 ·
Clues, please ...

(1) What are the details on the Taco itself (year / transmission / 4X4 or PreRunner)
(2) Just so we're clear - you're transplanting a 2RZ into your Taco to replace a 3RZ - right?
 
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