Is there any parts interchangeability between the SOHC and DOHC motors?
“Putting DOHC pistons in an SOHC engine has been done. The two engines have essentially the same block and crank except for the PCV system in the ’95 SOHCs. DOHC pistons raise the compression a little less than half a point. The DOHC engine actually has slightly less compression than the SOHC because it has 54cc of combustion chamber volume. The SOHC has about 48cc. Thats why the DOHC uses slightly domed pistons, to get the compression almost all the way back up. If you are planning on putting a DOHC head on the SOHC block even after you change the pistons, you’d better plan on getting a DOHC donor motor for the project. Otherwise, it’ll get real expensive quickly. You’ll need the manifolds, throttle body, sensors, some timing belt drive components, and wiring harness to get it running. You’ll also need a DOHC computer to get the right fuel and spark. SOHCs and DOHCs will run with the wrong computer, just not that well. The fuel and spark tables are totally different because the engine
“Putting DOHC pistons in an SOHC engine has been done. The two engines have essentially the same block and crank except for the PCV system in the ’95 SOHCs. DOHC pistons raise the compression a little less than half a point. The DOHC engine actually has slightly less compression than the SOHC because it has 54cc of combustion chamber volume. The SOHC has about 48cc. Thats why the DOHC uses slightly domed pistons, to get the compression almost all the way back up. If you are planning on putting a DOHC head on the SOHC block even after you change the pistons, you’d better plan on getting a DOHC donor motor for the project. Otherwise, it’ll get real expensive quickly. You’ll need the manifolds, throttle body, sensors, some timing belt drive components, and wiring harness to get it running. You’ll also need a DOHC computer to get the right fuel and spark. SOHCs and DOHCs will run with the wrong computer, just not that well.
