New Engine block with updated cooling jackets and bored out?

For those of you with experience replacing head gaskets or engines in the Gen 3. What are your thoughts on if there was a "NEW" block available for purchase that has updated cooling jackets and additional cooling features found on the later model 1.8L motors? Versus buying a used JDM or simply replacing the head gasket, do you think having a block that's been improved to eliminate the current cooling issues would be an ideal part to install versus replacing the motor with a motor that will eventually have the same issues? Would you think cooling features should be the only change or should the new block be bored out for additional displacement to a number we've tested to confirm works in the Prius without any ECU modifications? The thought is, if someone has to replace pistons might as well make some gains... right? Or just, additional colling and strengthening the walls in a manner of which if you want to bore it out your self you can, unlike the current block you are limited to how much bore you can do? I had the block analyzed too determine the max bore for safety given the thin walls.

Any feedback is appreciated, the process to wire EDM the block kicks off soon and then it will be scanned and then ready to have the first new block manufactured and tested. I'm wanting any feedback as to have the most optimal new block produced.

 

on this thought, for the retrofit Gen 4 to Gen 3, there would be more unknowns(in the sense that if issues after install, we wouldn't know if cylinder spacing or others you mentioned are causing issue A. Wanting to make a change, test the block then make another change and test the next version of the block in a different vehicle is the plan) IMO then say starting with a Gen 3 block and modifying to replicate the improvements on the Gen 4. From the folks I've been working with who have taken the various Gen 4 blocks apart, we are best to start with a Gen 3 and modify from there. Even just the differences in the early year Gen 4 to the later, the changes in internal engine beauty are vastly different. This is why our 2017 has a low coolant and similar issues as my Gen 3 PIP. Where as the 2022 models wouldnt have the same issues as our 2017.

that's when my brain goes, well, why not take the new Gen 5 motor I'm installing in my Gen 3... actually its the motor from a UX250 but same thing... it's not a true 2.0L, but the differences in displacement should work with all Gen 3 Prius ECU's without modification. so taking the M20 and its block into the measurements and such although being a different motor family we could see where X, Y, and Z differences in the new motors can be easily applied to the Gen 3 block with the theory no more cooling issues or bad head gaskets.

for me, I dont see why take the easy route and install rebuilt even if using new pistons if the same cooling issues are present. I'd like to think a little extra work for piece of mind knowing routine oil changes and the motor I installed will outlive the vehicle makes me warmies inside of me feel good!

edit: for me, the main thing is no cooling issues and some performance gains that do not impact MPG. The other theory we have is, improving performance how it's planned will provide MPG gains but.. wishful thinking right now.

 

lost me there, can you elaborate?

 

.

 

for me, its worthwhile just in the sense that I know I can hammer on the pedal going up a 4x4 trail and not have to monitor my temps as vigorously as I do now... having to pull off to the side of a trail to let my car cool off... never again! I just figured all the work, maybe others would be interested or could share what they think should be done to improve on the motor...plus... do you know how many Gen 3 vehicles need head gaskets replaced? heh.. heck how many are buying rebuilt engines... the number is staggering!

 

This is why the wire edm to block, then 3D scan to implement certain later year Gen 4 motors cooling features!

 

Trying to finish the AWD portion of this build now. Went with the 2.0l M2A-FXS and once running will pick this back up.
The plan, put a 1.8 in my Gen2 with this new block I'm building.