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-   Do It Yourself, Boating on a Budget (https://www.offshoreonly.com/forums/do-yourself-boating-budget-249/)
-   -   building a reverse rotation merc 260 (https://www.offshoreonly.com/forums/do-yourself-boating-budget/330634-building-reverse-rotation-merc-260-a.html)

mike tkach 09-13-2015 08:59 AM
Originally Posted by donzi matt (Post 4353546)
I pulled a 327 Chevrolet apart that was reverse rotation and that is exactly how they did it, notches to the rear. The pistons had 4 valve reliefs in them though.
big difference from bbc to sbc.a low compression sbc piston has 4 valve reliefs.

f_inscreenname 09-13-2015 10:43 AM
IMHO the pistons on the small block still should have went in the right way.

SB 09-13-2015 11:40 AM
MT - This thread is about a small block.

donzi matt 09-13-2015 04:19 PM
Originally Posted by f_inscreenname (Post 4354123)
IMHO the pistons on the small block still should have went in the right way.
Why? Wouldn't the offset on the pin be the wrong direction?

f_inscreenname 09-13-2015 08:53 PM
Originally Posted by donzi matt (Post 4354220)
Why? Wouldn't the offset on the pin be the wrong direction?
No. If the piston is this way or that way the rod stays the same. The piston just slides from one side to the other on the piston pin.
Another concern I would have is if the rod is also on backwards or is it normal on the piston which will be backwards. If the rod is on backwards and if you are using a forged crank with radius corners on the crank journals the narrowed rod bearings will grind on the crank. Bottom line is the bearing tabs go outside always.

donzi matt 09-13-2015 08:58 PM
The rods were oriented the usual way in the motor I am discussing. The pistons were on opposite of how they normally are so the offset would reduce the thrust load on the reverse rotation.

mike tkach 09-13-2015 10:12 PM
Originally Posted by SB (Post 4354142)
MT - This thread is about a small block.
well crap.i guess i have bbc on the brain,OOPS.

mike tkach 09-13-2015 10:14 PM
i did not know a sbc has an offset pin in the piston.are you sure about that?

Unlimited jd 09-13-2015 10:17 PM
If the Pistons have 4 valve reliefs they can go either way

mike tkach 09-13-2015 10:26 PM
Originally Posted by Unlimited jd (Post 4354321)
If the Pistons have 4 valve reliefs they can go either way
i have done quite a few that way,i never heard of a sbc with on offset pin bore.


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