<html><head></head><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:16px"><div>OK, you guys have me sufficiently scared to finish putting this stock 100-4 engine together only to have it grenade the crank somewhere down the road. Probably when I am at the furthest point from home. <br></div><div dir="ltr">Mike MacLean<br></div><div id="yui_3_16_0_ym19_1_1483491855193_37853"><span></span></div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: times new roman, new york, times, serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Tuesday, January 3, 2017 3:16 PM, Bob Spidell <bspidell@comcast.net> wrote:<br></font></div> <blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; margin-top: 5px; padding-left: 5px;"> <br><br> <div class="y_msg_container"><br clear="none">Very useful info, as always. Was wondering how much 'de-stroking' the <br clear="none">engine--shorter piston/rod thows--would help? Of course, you'd need to <br clear="none">source yet another type of crankshaft, conrods, etc..<br clear="none"><br clear="none">Bob<br clear="none"><br clear="none"><div class="yqt8699657624" id="yqtfd30306"><br clear="none">On 1/3/2017 1:23 PM, Austin Healeys List wrote:<br clear="none">> Thanks for the interesting breakfast read Michael.<br clear="none">><br clear="none">> You don't mention much about vibration dampers, particularly tuned vs<br clear="none">> non-tuned. The factory rubber-bonded style damper only works correctly<br clear="none">> on the engine it came off as it can only damp one specific frequency.<br clear="none">> There are a host of aftermarket designs that use viscous fluid or<br clear="none">> 'rattler' pucks to achieve damping at any frequency and regardless of<br clear="none">> engine type. I believe guys are even making them to go on the flywheel<br clear="none">> to damp vibes at both ends. For a relatively simple piece of<br clear="none">> engineering, their prices seem to be based on "it is still cheaper<br clear="none">> than a blown up engine".<br clear="none">><br clear="none">> Another thing that doesn't get much mention and is a direct result of<br clear="none">> crankshaft torsional flex is timing scatter. The vibrations find their<br clear="none">> way through the cam chain and into the distributor where they react<br clear="none">> with the flyweights and other parts so the timing, and equally<br clear="none">> importantly the dwell can vary wildly at high rpm. I heard that some<br clear="none">> Chrysler V engines with the distributor at the back will explode the<br clear="none">> flyweights if fitted with a gear drive cam since the chain dampens out<br clear="none">> a fair amount of vibration. The BMC six cylinder timing marks will<br clear="none">> scatter around an inch or so at high speed, more when suddenly closing<br clear="none">> the throttle as this is where the most crankshaft stress occurs.<br clear="none">><br clear="none">> Andy.<br clear="none">><br clear="none">> On 1/4/17, Michael Salter <<a shape="rect" ymailto="mailto:michaelsalter@gmail.com" href="mailto:michaelsalter@gmail.com">michaelsalter@gmail.com</a>> wrote:<br clear="none">>> New post on my blog about Austin Healey 100 crankshafts...<br clear="none">>> <<a shape="rect" href="http://www.netbug.net/blogmichael/2017/01/03/austin-healey-100-crank-failures/" target="_blank">http://www.netbug.net/blogmichael/2017/01/03/austin-healey-100-crank-failures/</a>><br clear="none">>><br clear="none">>> M<br clear="none">>> ichael S<br clear="none">>> BN1 #174<br clear="none">>><br clear="none"><br clear="none">_______________________________________________<br clear="none">Support Team.Net <a shape="rect" href="http://www.team.net/donate.html" target="_blank">http://www.team.net/donate.html</a><br clear="none">Suggested annual donation $12.75<br clear="none">Archive: <a shape="rect" href="http://www.team.net/archive" target="_blank">http://www.team.net/archive</a><br clear="none">Forums: <a shape="rect" href="http://www.team.net/forums" target="_blank">http://www.team.net/forums</a><br clear="none"><br clear="none"><a shape="rect" ymailto="mailto:Healeys@autox.team.net" href="mailto:Healeys@autox.team.net">Healeys@autox.team.net</a><br clear="none"><a shape="rect" href="http://autox.team.net/mailman/listinfo/healeys" target="_blank">http://autox.team.net/mailman/listinfo/healeys</a><br clear="none"><br clear="none">Unsubscribe/Manage: <a shape="rect" href="http://autox.team.net/mailman/options/healeys/rrengineer.mike@att.net" target="_blank">http://autox.team.net/mailman/options/healeys/rrengineer.mike@att.net</a><br clear="none"><br clear="none"></div><br><br></div> </blockquote> </div> </div> </div></div></body></html>