placing a 2.2 crank in a 2.5 T1....thoughts?

I am building a 2.5 engine and was thinking that I could switch cranks (yes both cranks are CB) when/if I wanted to change to 2.2. Depends if I like the 2.5 in my Sundance
This is not a 2.2 vs 2.5 thread as we have plenty of those!!
I was thinking I need to drop than tranny, switch bearings, change ECU etc but should be able to do this with the engine together in the car. I cannot see an issue with the 2.5 pistons with a 2.2 crank other than I assume the 2.2L are better.
I am looking for an easy backup plan.

I'm pretty sure that 2.5 CB pistons are about a quarter inch shorter than 2.2 CB pistons. You'll have a really low compression ratio.

shorter ? , or is the pin height different ?

I know my 2.5 has a pretty big dish too compared to my TII

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Originally Posted by Dr. Johny Dodge

shorter ? , or is the pin height different ?

I know my 2.5 has a pretty big dish too compared to my TII

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Shorter compression height. The pin is closer to the top of the piston to compensate for the added stroke of the 2.5.

To The OP: You can certainly do this, but your compression ratio will be in the toilet. Plus, with the lower piston height, you are going to lose all squish in the chamber, and probably really screw up the combustion properties of the head.

I personally wouldn't do it. Now, if you were going to put 2.2 pistons in it, along with the crank, then you should be fine...

You might as well pull the engine to do it. Or just build up both a 2.2 and 2.5 short block.

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Originally Posted by ajakeski

I'm pretty sure that 2.5 CB pistons are about a quarter inch shorter than 2.2 CB pistons. You'll have a really low compression ratio.

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Oh, I forgot about that!

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Originally Posted by thedon809

Or just build up both a 2.2 and 2.5 short block.

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Yes that was my original plan A.

I have a still compleate 89 2.2 TII short block , common block that I've been planing to rob the crank from but I'd swap it for just a good steel 2.2 common block crank

it's an old rebult motor with .75 o-s pistons ( unknown brand ??) that's been sitting around for 18 years and would need rebuilt again I'm sure

I want to put the steel crank in my stronger 93 2.5 block so I'd also have an extra 2.5 turbo crank , rods and 3 pistons (should be o-e pistons as it was suposedly a new crate mopar motor )

92-3 blocks are supposed to have thicker main webs and I've noted the "bar" cast onto the rear of the block where the frost plug holes are is much cleaner as cast and definately stouter too

I was planing though to keep the 89's accessory shaft as the 93's would be the newer one akin to the r/t motor era that isn't quite the same steel as the earlier ones seem to be

if any of these odds and ends sound usefull just let me know

lol , you would already know where they are

and I'd have no use for any of the con rods as I have a set of B C rods already

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Originally Posted by Dr. Johny Dodge

if any of these odds and ends sound usefull just let me know

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Thanks for info...I should have enough internal parts for two spare long blocks one 2.2 and one 2.5 but if I don't I will let you know.