Hi guys... I'm building a 198/2.2 combo for my 74 swinger.. this motor is being built for weekend racing/cruise and potentially autocross maybe down the road. I'm adapting a 5 speed also..any how this motor will routinely be shifted at 5700-6000 rpm. I'm just seeking some expertadvice as to whether it is work the extra time and $$ to balance the rotating assembly.. i'm getting eager.. but i want this thing to last for a little while... thanks for the advice guys Dan

We didn't balance mine and it hasn't scattered yet. It's now on it's third season and has well over 600 passes on it and around 30,000 street miles.

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Official Cookie and Mater Tormentor.

hey Dennis, that sounds like a plan to me, thanks for the help...all the quicker i can get racing.......Dan

I had my '64 bottom end balanced, and I have been very happy with it. Personally, I would spend the extra $150 and do it, but it may be fine without it too. Glad you're making progress over there, Dan.

Lou

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Home of Slant6-powered fun machines since 1988

lou, that sounds like a pretty good price for balancing...i assume no mallory metal was needed?

I would not build a lawn mower (or slant) without balancing it.

Will

The last time I had an engine balanced (my '64 motor) was in 1993, and it was $110, so I assume $150 is closer to reality nowadays. I haven't checked in at least 5 years, so I may be low still.

You never need Mallory metal for a Slant because you don't need to balance the rod/piston assy to the crank bobweights, like on bent 8s. All you need to do is grind off weight to make the crank rotationally balanced, then balance the rods/pistons to each other.

Lou

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Home of Slant6-powered fun machines since 1988

Lou, so no bob weight is used on an inline motor when the crank is balanced? Is it necessary to equalize the big and small ends of the rods? Or does just all six rod/ piston assemblies need to be equal without regard to rod ends? I have a scale to do pistons, but not a rod swing to equalize the rod ends. This sounds great, change rod and/or pistons without crank rebalance.

Cecil

You should equalize big and small ends of the rods, but the crank can be completely independent. Yep, change pistons/rods w/o crank rebalance. This is also how some guys have cut 10+ lbs off their crank weights withouth balance problems.

This is feature of I6 engines, and some other engine geometries (I think V10 and I5 also work this way).

Lou

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Home of Slant6-powered fun machines since 1988

Thanks Lou, I had been thinking how the bob weight was figured since there are no shared journals on a slant. Great, no bob weight! I may go ahead and spring for a rod swing, then I'll only have to have the crank spun.

Cecil

This is exactly what I do, I send the crank (with damper and flywheel / flexplate) out for balance and do the pistons and rods myself "on the kitchen table". I can get the crank alone balanced for $75 to 100.00) depending how close it is.

Truth is the cranks I send out for balance are usually pretty far out of balance and always need some work to bring-in. That is because I take a grinder to it and smooth-off all the ugly burrs, seams and forging "break-away" marks before I send it out for the rebalance work. This cuts down on weight and windage.
DD

I guess I missed out the opportunity to shed crank weight (85 lbs) when I replaced the bearings on my 60 block last month. Next time.

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Cheers!
Al T

Truth is that the first 2 years of SL6 cranks were real heavyweights so yes, you can drop at least 9 lbs by swapping to a 62-67 225 crank. (76 lbs)
If you want to spend time with a grinder and pay for a rebalance, another 1 or 2 lbs can be removed without hurting the structure of the crank.
DD