CH 270 Engine rebuild project

[irobertson]

I found a matching pair of counter rotating Crusader CH270s on Kijiji, and they were only 45 minutes from me.
I may be a bit off my rocker, but they are now in my garage waiting to be torn down.
The plan is to build them up nice and fresh, then swap these in place of the existing CH220s in the boat.
Fresh engines with a total bump of at least 100 HP. Wish me luck......

[bud37]

Cool....always loved building engines.....I am envious....good luck with your project ......

[RGrew176]

Good luck with the project. Sounds like the way to go. Rebuild the engines while still using the boat. Then drop in the rebuilt engines and you are ready to go.

Just out of curiosity what are you planning to do with the current engines, rebuild them and keep as backups?

[Viper]

Why 2 counter rotaters,or are you converting one to standard rotation?

[irobertson]

Source of the post Why 2 counter rotaters,or are you converting one to standard rotation?

Possibly my misuse of terminology. One regular and one reverse rotation.

[irobertson]

Source of the post Good luck with the project. Sounds like the way to go. Rebuild the engines while still using the boat. Then drop in the rebuilt engines and you are ready to go.

Just out of curiosity what are you planning to do with the current engines, rebuild them and keep as backups?

I will either sell my CH220s as is, or rebuild them first, then sell them.
Not sure yet.

[mjk1040]

Don't know if you have ever rebuilt a counter rotating engine before, just remember that the rods have to be reversed when installed. Not sure if there are other things that also must be installed in reverse. Please do ur research before tackling this rebuild. I have a couple long blocks if anyone is interested, just want core value. Mike

[tomschauer]

I have never built a counter rotation engine. I would not have known to install the rods needed to be installed backwards. I guess the cam, distributer, oil pump etc. would all be different than the standard rotation gm motor?

[irobertson]

Yes, the wrist pins in the pistons are offset to minimize side forces during the power stroke, since the engine turns the other way, the counter rotating pistons have to go in the other way around. I expect the cam will be different as well. Distributor is the same, just wired in a different order.

[Viper]

Correct; the pistons are installed 180* to standard position, minimizing piston slap. The crank will be the same but the cam is different. The distributor will have a gear with the splines cut in the opposite direction. Both distributors typically rotate in the same direction. Chrysler counter rotating distributors use a thrust collar that is not needed on the standard one. Oil pumps are the same for both rotations. Different main crank seal, grooves are cut in opposite direction. Starter rotates in opposite direction.

One must also consider the transmission. For the most part, transmissions of that vintage were not bi-directional like they are today.