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Re: Crankshaft Balancing?
Posted: March 8th, 2008, 3:35 am
by John
The 7 mains position us for a pretty secure crankshaft, consider a v8 arrangement is with 5 main bearings. We just don't have a design that provides dampening for that cam. As the rpm increases, lubrication is getting to the edge of adequacy, with higher lift cams, stronger springs on our valves, the forces on the mounting design become a serious challenge. The straight cut howler gears we used to replace the timing chain set allowed them more vertical end play without breaking the chains. There was other methods used to bring the Rambler/AMC I6's into a higher rpm range, but all are hellish expensive. The Indy car photo I use is Barney's old 600+ Horsepower I6 199 Rambler. Most things have been done before, There is usually a reason we quit doing things.
John
Re: Crankshaft Balancing?
Posted: March 10th, 2008, 7:06 pm
by Jeep-Power
I had my rotating assebly (crank, rods, pistons) balanced by a reputable engine builder. To me it s worth the peace of mind.
Re: Crankshaft Balancing?
Posted: March 10th, 2008, 7:57 pm
by 1bolt
it seems to be very much not an optional thing for engine builders who are after best performance. I haven't done it before but my next build I think will involve knife edging/stream lining the 4 counter weight crank, and smoothing the rods. Maybe with Cryo treatment and/or shot peening. I think when you're going to modify the rotating assembly it's probably more critical.
I remembered what Lee had said about the Crank, is involves the oil holes in the crank when trying to turn it above 5500 RPM's not being adequate to oil the mains he said he makes a cross drilled crank to solve that problem.
So Like I was saying it wasn't really meant to spin much past 5000 RPM's