Crankshaft Compatibility

Tristan Eiland

Tristan Eiland

Greenie N00B Member
Does anyone know if I can use a 2.3 crankshaft with a 2.5 block? For example, I am looking at this crank and I want to use a 2.5 block from the 2014+ models. My long-term goal is 5-600hp so I want to build the motor right the first time and not worry about slipping timing when I start to get into higher hp.
 
don't. also you're not going to get that power reliably on a 2.5L block. 2.5 is good to get your car on the road cheap that's it. this has all been covered recently in multiple threads please start looking through them. for example a few threads below there's this one https://mazdaspeeds.org/index.php?threads/engine-build-foundation.16325/

here's another one
https://mazdaspeeds.org/index.php?threads/mzr-2-5-disi-swap-internals-question.16095/

I've seen your two recent threads please start searching these took me seconds to scroll through for you. there's plenty more
 
The "build foundation" thread is not a good representation to the OP question. That thread in particular was focused on engine block strengths and nothing to do with internals. The only useful info about block strengths was simple observations of what everyone else has built and that being MSR. The attributes to any of the MSR, duratec, ecoboost family type blocks and their strength capabilities are still not openly known. Im finding that any of the families engine blocks are more than capable of 600hp. The internals strengths and capabilities are most definitely known and need aftermarket upgrades to withstand any serious power handling
 
Blak2012 said:
The "build foundation" thread is not a good representation to the OP question. That thread in particular was focused on engine block strengths and nothing to do with internals. The only useful info about block strengths was simple observations of what everyone else has built and that being MSR. The attributes to any of the MSR, duratec, ecoboost family type blocks and their strength capabilities are still not openly known. Im finding that any of the families engine blocks are more than capable of 600hp. The internals strengths and capabilities are most definitely known and need aftermarket upgrades to withstand any serious power handling
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disagree it's an example of threads relatating to the 2.5 block which OP wants to use. sure it may not have the 2.3 crank in the 2.5 question.

first thread I linked addresses some of the costs, which leaves me back to the sentiment of: not worth it
 
Worth it or not, simply answering with the least possible info (like such info found on FB) should NOT be what a forum is about. Detailed info is seeked and shut down by lame simple undescribed info. Being more detailed with a response might look like this to the OP question....

Yes, from what knowledge ive gained, a 2.3l crankshaft can be used in a 2.5l block with corresponding rod lengths and pistons for desire zero deck. Im unsure of 2.5l engine block strengths do to lack of experience and web based knowledge. But in my experience, a long rod/stroke ratio is favored in performance and horsepower production especially forced induced.
 
thank you for that I am aware how I could have written it. you can get off your high horse. you also could have simply answered the question like you did so eloquently but rather you did not. so let's drop this and move on
 
First post. Sorry to revive an old thread but I have the same question. It's been a few months so maybe the community has gleaned some more info on this topic? I'm picking up a speed tomorrow with rod knock so I am considering my options between a full rebuild, 2.5 swap or some frankenmotor combo using the forged 2.3 crank in a 2.5 block. I understand costs may equal out in the end, but I would like to know whether it can be done so I can make the best decision. End goal is a dailyable 320-350whp but my budget to get it on the road can't exceed $2000-2500 for whichever option. I'm not including upgrades in that figure btw. Purely get it back to reliably operational. While laying the groundwork for future power of course. Lmk if any of this makes sense. I've been awake too long. Thanks in advance
 
For for a daily driver in the 320-350 range all you need is a bone stock 2.3. Go get one from the junkyard for pennies.

You aren't going to frankenstein build something for cheap that will handle 600 HP in the future. Get back on the road cheap, then save up and do a proper build...Half-assing it will see you building motor after motor trying to get it where you want it, and you're gonna wind up buying the good shit eventually anyways to get there.
 
Enki said:
For for a daily driver in the 320-350 range all you need is a bone stock 2.3. Go get one from the junkyard for pennies.

You aren't going to frankenstein build something for cheap that will handle 600 HP in the future. Get back on the road cheap, then save up and do a proper build...Half-assing it will see you building motor after motor trying to get it where you want it, and you're gonna wind up buying the good shit eventually anyways to get there.
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So is the consensus still that the 2.5 bottom end is only good for getting back on the road cheaply and not a permanent/buildable solution? It seems like the room is split on the topic. Some swear by it, others seem to view it as blasphemy lol
 
I personally wouldn't do it, but what I do nobody else will do either so...bit moot.
 
So what does getting a knocking disi back on the road "cheaply" entail if sticking with the 2.3? Polish the crank get new bearings, call it a day and send it? Soon to be previous owner said they replaced the timing components (I'll ask him more about that when I get to the car later) then it started knocking a week later so he parked it.
 
Not sure. I only ever built one engine and that didn't turn out so great lol
 
Easter Bunny said:
Can't say without disassembling
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unfortunately this is the answer here. each engines failure is unique, some may only need a bearing, some may need rods, pistons, bearings or more and now we're talking about a much bigger rebuild.

In my mind the 2.5 "cheap" option isn't cheap rather it's an additional cost to eventually just rebuilding a 2.3
 
Awafrican said:
unfortunately this is the answer here. each engines failure is unique, some may only need a bearing, some may need rods, pistons, bearings or more and now we're talking about a much bigger rebuild.

In my mind the 2.5 "cheap" option isn't cheap rather it's an additional cost to eventually just rebuilding a 2.3
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Word. Well I picked up the car and it's def knocking like the police lol. I decided to say fuggit and plan for a full bottom end rebuild. Tear down, have a machine shop do their things then forged everything going forward. I'll probably start my own post about that when the funds come thru and I can start. Any advice would be appreciated
 
If you have the ability tear the engine down to a bare block before taking to the machine shop so you can inspect it for damage, like the cylinder walls/sleeve to ensure they’re still usable. If it is good then next I would have the machine shop see if you can use 87.75mm pistons instead of going straight to 88mm. If you need to rebuild in the future then you can go to the 88mm if that makes sense. Let the machine shop check bearing clearances before you buy any. Figure out what clutch/flywheel you’re going to use and give the flywheel to the machine shop to balance with the rotating assembly.
 
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