After weighing my new K-1 H-Beam rods,the lightest to heaviest is a difference of 5 grams. Should that be a concern when having the rotating assembly balanced? My friend from Ohio says NO...but,my machinist seems to think it should be balanced with the balancer(externally) Who's right? I didn't think 5 grams was enough to worry about...since they have to be equalized anyway! School me on this,"Engine Masters"!

I get them closer than 1 gram
EDIT
since its a external balance balancer ...yes it should
be balanced with it

[since its a external balance balancer ...yes it should
be balanced with it

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Cast Crank?

Externally balanced?? Cast Crank motor? Anyways......trust Shawn.

trust Shawn.

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100%

Questions done!...I DO trust Shawn!..and his judgement on what to do!

My K1 rods (6.535 x 2.20) were within +- 0.5 gram as delivered. Thanks Dan at Performance Only for the rods and 4.15 K1 crank...

You're getting confused by two different situations.

When the assembly is balanced your machinist will weigh everything and correct any differences. But a small difference in rod or piston weight is not the reason to balance with harmonic damper and flywheel.
The reason to balance with the entire rotating assembly is because it gives better results, closer to "perfect".
This is true even for an internally balanced engine. Sounds to me that your machinist is pretty good and trying to do a good job for you.

R.

Post deleted by mr_340

Thanks for the info,dogdays! I just thought a 5 gram difference was pretty substancial..especially when I see some companies guaranteeing +/- 1 gram in a set of "matched" rods.I got a VERY GOOD price on them,from a VERY RESPECTED engine builder in Ohio! I'm thinking,to a GOOD machinist..which I know Sean is,it should be no big deal! If using the Fluidamper gives it a more precise balance,I'm all for it! BTW...it is a FORGED factory crank..so it's an internally balanced engine from the factory.

Randy, like Steff and Raff have said, trust Shawn.

Randy

I had to get two replacement Eagle H beams to make a set again. I gave them the numbers off the weight card but the rods I got were 10 grams heavier on the big end than the old ones. I bought these things about 12 years ago so returning them wasn't an option and if you've ever seen these rods you know you really can't take anyweight off them. My machinist suggested to just add the 10 grams to the bob weight on one journal and install those two rods on the same journal. He says he's done it before without a problem and everything balances OK. So that's what I did.

Hey..just saw that "pretty" motor on Friday..when I dropped off my Diamond pistons,that have to be sent out for a .005 coating on the skirts! Apparently,when the motor was rebuilt 6 yrs. ago,a torque plate was not used,and Shawn measured the cylinders up to 4.361-.362..on a .040 over-bore...and without a plate bolted up. He said once the plate was installed,and torqued to spec...the cylinders would measure even bigger! So...I have 2 options...bore it out,and replace my GOOD pistons,or bore and hone to 4.365...and coat the piston skirts,which I opted for. He said he's had excellent results using this method! Sounds good to me!

Thanks for the insight,John! I'm sure Shawn knows what he's doing...and will balance everything properly! I will have a discussion with him about using the balancer,as well! He's been building HIGH HORSEPOWER motors for years...with EXCELLENT results!