d240zx2 Posted October 23, 2007 Share #1 Posted October 23, 2007 My old '70 was built back when Datsun was using 5 counterweight crankshafts. They're good and solid....up to a point. That point being about 7500 rpms. Then they pull the amoeba trick and become a two-piece crankshaft.After this problem was discovered, it was corrected by installation of 7 counterweight cranks. Problem solved....go for 8 grand or higher.Question: What modifications to the block are required to install a 7-CW crank in lieu of the 5-CW OEM crank? Any other parts or pieces that need to be changed? Link to comment Share on other sites More sharing options...
Phred Posted October 23, 2007 Share #2 Posted October 23, 2007 Wow, I've been building engines since those first came into the states, and I've only seen one, and it wasn't in an engine. I thought they had all been broken or replaced. I remember reading the BRE cars broke their eary cranks, before the later style was available. I believe the later cranks are a direct replacement fit. Phred Link to comment Share on other sites More sharing options...
d240zx2 Posted October 23, 2007 Author Share #3 Posted October 23, 2007 Thanks, Phred.I'll check with Nissan to see if the 7-CW cranks are available still. Link to comment Share on other sites More sharing options...
e_racer1999 Posted October 23, 2007 Share #4 Posted October 23, 2007 hahaha... amoeba trick.... Link to comment Share on other sites More sharing options...
Patcon
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