I know it's kinda backward, and the risk of bottom end failure is greater due to intermix of antifreeze and oil, but I see these failed HG DOHC candidates frequently and wonder if the 2.2 heads, ecu, intake, header and bits swap would be worthwhile to put a frankenmotor together in it, even leaving the block in place.

Thinks?

 

Thanks.

2.2 is the better choice. The 2.5 is engineered to its max possible output (DOHC) so it is somewhat fragile. The 2.2 is robust and has the ptoential for lots of tinkering.

If you put 2.2 heads on a 2.5 block does it make it a non interference engine as long as heads are from 96 or earlier??

But wont solve the HG issue.

I do not know, but I doubt it. The reduced volume of the 2.2 head apparently increases the CR and HP, requires 91 octane gas. That suggests interference.

 

There are very specific requirements for HG. Many thread on that topic, but apparently the pistons protrude slightly, therefore requiring the 2.5 larger diameter bore headgasket, and a specific thickness, and modification for coolant flow. It also requires a specific Delta cam regrind. There is one writeup I felt confident in following but couldn't find.

Most often this is done by swapping in a 2.5 block into a 2.2 car using 2.2 ecu, intake, exhaust, etc, and there is a track record by others for that. Depends on what is cheapest and best bodywise, and how long I'm willing to wait for boneyard parts to surface.

 

If you put 2.2 heads on a 2.5 block does it make it a non interference engine as long as heads are from 96 or earlier??