stupid q: can you go back to 2.2 from 2.4 P&Cs?

Was always wondering if you can go back to 2.2 if an engine has been set up with 2.4 p&cs? Is there a certain piston size the engine can handle up to before it needs to be bored out?

Apologies if this is an obvious question- I'm not mechanically inclined when it comes to engine-innards...yet :)

Zero issues. Both motors used the same valve angle, so as long as you are doing apples to apples 'S' to 'S', 'E' to 'E', etc., no issues. Going from a lower CR to higher CR combo will require a little more diligence on valve clearance, but again, no real issues.

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Originally Posted by Kaleid

Was always wondering if you can go back to 2.2 if an engine has been set up with 2.4 p&cs? Is there a certain piston size the engine can handle up to before it needs to be bored out?

Apologies if this is an obvious question- I'm not mechanically inclined when it comes to engine-innards...yet :)

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The short answer is that 2.2 & 2.4 litre engines share the same bore size and cylinders. Only the piston pin heights are different due to the stroke change.

Worn 84mm Biral cylinders can be safely bored to 85mm and use a custom piston.

Another stupid one....how much lose or increease on the compression ratio ??

All things being equal, going from crank to crank, you lose ~1 full point of CR going from 70.4mm to 66mm.