counter rotating engines
 

I know that this is more of a performance site. but I'm presently working on a 34 Searay with inbboard engines. stbd engine is reverse rotation. what is involved with building a reverse rotation engine other than the 2-gear driven reverse ground camshaft and firing order? thanks

Seals.

Do a seach, topic has been covered several times last year:drink:

have delt with this many times..just had to 2 months ago...they now longer do the gear to gear cam setup when they went to the roller cam, they use a special cam w/reverse cut dist gear,reg timing chain, now this is with the genVI engines, have to use the special delco est reverse rotation dist with the upper bearing to take the load...NOTHING else will work !!!! after killer 5-6 dist I know...you should swap the pistons side to side, and use the reverse crank seals, I have not had a issue with the timing cover using the std one, but rear main will leak without the correct one...

Thanks for the info.

im confused,why would crank rotation direction require a different rear main seal?

There are scribe or slanted wick lines on the inner part of the seal. When the crank rotates it pushes the oil back into the engine. I don't know the science behind it but they are different. One is slanted towards the left and one is slanted towards the right.

There are two different front crank seals, directional, and universal. The universal seals are very common and work fine. As others have mentioned the rear seal is direction specific. You can still use the gear to gear timing set and a standard distributor. Bob Madara (RMbuilder) has cores if you want a custom grind, or a roller. You can do reverse rotation GenVI's with factory hydraulic rollers and the timing gears. It requires very minor clearancing in two spots near the timing cover bolt bosses and an aftermarket timing cover. Some of the old flat top pistons were directional and needed to be installed backwards on the reverse rotation engines, the newer small dome styles do not. Other then that they all look the same inside! :drink:

wish they would have stayed with the gear to gear setup....the reverse cut dist setup not a great one from what I've seen..and the rear mains seals have grooves for a specific rotation...never knew about the universal ones...

I always hate when people say this because you ever use the search function on these types of websites its like sifting through a garbage can you can find what you want but cant quite get at it.