<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Andy,</div><div>My best advice is to start at </div><div><a href="https://www.bighealey.co.uk/engines/3000-bottom-end">https://www.bighealey.co.uk/engines/3000-bottom-end</a></div><div><br></div><div>The issue with stock rods is the bolts. Have a look at them. 7/16 x 2.5 inches long. I have recently worked out you can machine Pontiac ones to fit, but I haven't tried them yet. </div><div><br></div><div>A standard crank and rod setup (with forged pistons, aftermarket harmonic balancer, crank & rods lightened and hardened) should be kept to around 6,000rpm. There is a major harmonic at around 6,200 - 6,300</div><div><br></div><div>A modern steel aftermarket crank & rods can be revved to 6,500 - 7,500 all day. Denis Welch pulled 8,500 rpm on Conrod Straight at Bathurst in 1998 in the heat of battle with Peter Hopwood, to retake the race lead. </div><div>You know why it's called Conrod straight? Lots of broken ones.....</div><div><br></div><div>You should also seriously consider the gun drilled cam from DWR. This design is also popular and available for the A series. Cam wear and cam follower wear is the biggest single issue - even in stock road engines - due to the splash, drip and pray oiling system for lobes and gears. </div><div><br></div><div>Here are my specs & Dyno sheets from 1998. <a href="http://www.myaustinhealey.com/dyno_sheet.html">http://www.myaustinhealey.com/dyno_sheet.html</a></div><div><br></div><div>Best</div><div>Chris<br><br></div><div><br>On 8 Jul. 2017, at 12:45 pm, A H List <<a href="mailto:austinhealeyslist@gmail.com">austinhealeyslist@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><span>Question for those who have built race engines, what, if anything is</span><br><span>necessary for survival at higher rpm in the bottom end of a six</span><br><span>cylinder? This is an old race car from the 70s which hasn't run since</span><br><span>then and we are getting it back together after it collapsed a piston</span><br><span>due to detonation.</span><br><span></span><br><span>Previously the bottom end was bone stock apart from Jahns pistons-</span><br><span>which don't appear to be of very good quality. I have gone with</span><br><span>dome-top Ross forged pistons, will keep with stock rods and crank</span><br><span>since it won't be a serious competition car, more of a weekend racer.</span><br><span></span><br><span>I know on the A series BMC engine it is common to strap the centre</span><br><span>main bearing, is this something worth doing on the six? Any pics?</span><br><span></span><br><span>What about camshaft oiling? Most likely will go with a reprofiled</span><br><span>original stick, however if there are known issues with this approach</span><br><span>then I would look at a replacement.</span><br><span></span><br><span>Has anyone experienced a bottom end letting go due to inadequate</span><br><span>strength of the stock crank/rods? What about rod bolts, are they</span><br><span>available as uprated strength?</span><br><span></span><br><span>Flywheel- is the stock lightened manhole cover adequate?</span><br><span></span><br><span>What is a safe redline for the stock parts?</span><br><span></span><br><span>Appreciate any input/experience from the collective wisdom</span><br><span></span><br><span>Andy.</span><br><span>_______________________________________________</span><br><span>Support <a href="http://Team.Net">Team.Net</a> <a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a></span><br><span>Suggested annual donation $12.75</span><br><span>Archive: <a href="http://www.team.net/archive">http://www.team.net/archive</a></span><br><span>Forums: <a href="http://www.team.net/forums">http://www.team.net/forums</a></span><br><span></span><br><span><a href="mailto:Healeys@autox.team.net">Healeys@autox.team.net</a></span><br><span><a href="http://autox.team.net/mailman/listinfo/healeys">http://autox.team.net/mailman/listinfo/healeys</a></span><br><span></span><br><span>Unsubscribe/Manage: <a href="http://autox.team.net/mailman/options/healeys/austin.healey@gmail.com">http://autox.team.net/mailman/options/healeys/austin.healey@gmail.com</a></span><br><span></span><br></div></blockquote></body></html>