1 tuff z Posted May 15, 2011 Share Posted May 15, 2011 looking good dc, keep us posted. dp Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 15, 2011 Share Posted May 15, 2011 If the pin is moving in the rod, you got issues. Everybody who saw our engine said "I've never seen a press-fit pin do that before! With the cost of the block prep, adding buttons 'just in case' was what we decided to do. We did NOT do a traditional pin button like you would on a floater. These do NOT contact the cylinder walls. They are an "insurance policy" should they move again. We couldn't determine why they moved, and the small-end was still at-spec (as were the piston pin bores...requiring normal heat and a press to get them back out!) They moved to where they were with the engine running, and then stayed there once the contacted the cylinder walls (in the process scoring them 0.080"!!!) We have not had a pin move yet since, and the 2L is capable of, and has run over 2500 rpms higher than the L28. The decision was made to put them in on the L20A because suitable blocks are few and far between--they are stock 1998CC's, and overboring is not possibly without a corresponding destroke on the crank... Meaning you got a matched crank and block that can't go anywhere else. With the new block we have on the new L20A, it's a standard/standard setup, not 0.020 overbore and destroked crank with undersized bearings. Unless you are doing...ahhhh...10,000 rpms+ for 5 or 6 miles at a time with pressed pins I don't think you will need them. No, it's not a typo. Quote Link to comment Share on other sites More sharing options...
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