2.2 to 2.5 engine rebuild
 

I am rebuilding a 2.2 using 2.7 cylinders/pistons. THis car will be a street daily driver. THis is what I have so far ... please give feedback:
1. Original 2.2 crank and rods and hopefully case.
2. Nikasil 2.7 cylinders and RS domed pistons.
3. Port / polish heads
4. Solex cams
5. Several mods as listed in Dempsey's text

Questions: What are risks with case mods and how to avert problems? WHat will be eventual compression and can I increase easily without additional piston purchase? Must I purchase some JE's? Any feedback appreciated.

Why not spend another $350 and get the 70.4mm crank and rods, and have a 2.7?

Compression will be low; in the 7.5:1 realm using the 66mm crank. The only way to remedy this is to order JE pistons in the CR of your choice. You could probably sell the new Mahle pistons for a decent enough price to make it a wash.

I'm doing the same conversion. The reason for not swapping cranks is to get an 8,000 redline, in my case. That redline does require a few extra mods, like stiffer valve springs. I'm using a GE80 cam and 10.5 compression ratio, twin plugs. Make sure you have a case that is appropriate - either an early aluminum case that has been bored, or a later 7R case.
I think that the higher compression ratio will be key in preserving torque in the lower rev ranges. First time I do something like this, though, and I'm still at least a month away from driving.

Michel Richard

C-
I'm doing the exact same build. I bought JEs, but if you have good RS pistons, I'd just do a 2.7 so that you end up with a decent compression ratio. Either way, I'd think about buying a 7R case. That's what I did. After realizing how much it would cost to enlarge the 2.2 spigots and install piston squirters, and realizing how cheap 7R cases were, it was an easy choice. The extra strength of the 7R case is a bonus. My 2.2 case sits on a shelf, in case there is ever a need for a "numbers matching" car.
-Scott