Hi guys, I just had to bring this thread back up to ask stupid questions about a current issue I have over running aluminum rods in a high revving dirt modified circle track engine.
I just aquired a very nice used SBC Hines balanced 355 rotating assembly including Eagle 3.48 steel crank, SRP high dome slugs, and real nice looking 5.7 aluminum rods. I don't know what brand they are but they sure look like very high dollar pieces. This nearly brand new assembly came out of a drag engine that the owner claims he only made a half dozen passes and now wants a bigger badder 434 instead.
I started putting my shortblock together yesterday when a very experienced circle track racing partner came over and saw what I was doing. He loudly and adamantly protested that under no circumstances should I ever run aluminum rods in a circle track race engine. When asked why he claims that aluminum rods are too soft and stretch at cycling high revs, causing pistons to hit the small chamber heads I run (World Products Sportsman II 64cc).
Is he correct...? I was planning on running this up to about 8000 rpm on a mechanical roller cam, on rough dirt tracks, and I wanted to take some of the 'shock' out of my rotating assembly. I would 'clay' the valve to piston dome clearance as usual to make sure I have plenty of stretch room. The block deck height is still at stock 9.025 I believe...? I could run a thicker head gasket if needed.
Please give me the Good, the Bad and the Ugly about aluminum rod use on other than drag engines...?
Thanks, Jim