I just got my Scat rods in the mail. They are floating I-beams. I was just wondering if it would hurt anything to polish the beams. Just the casting flash from the parting line. On one hand the rotating assymbly has to be balanced anyways so how could it hurt anything? On the other, there isn't much of a balancing pad, and it might end up costing an extra $75 to balance cause I wen't and screwed up the rod weight. Should I just leave it alone?

You coulda bought them already milled and polished.

me,
Leave them alone. You will not accomplish anything other than getting a lot of grinding dust in your lungs. The Scat rods are almost perfectly balanced and are plenty strong just the way they are. If you are not going to exceed the HP and rpm ratings of the rods, they will be fine. If you are going to exceed it, you should have purchased a better rod :rolleyes:

I was just thinking less reciprocating weight = more power. The stronger factor was just a bonus hehe. If it's only going to amount to 1/2 a hp I won't do it.

Better keep reading the M.E. books ... rod weight does not affect horsepower. It does affect acceleration, but not peak HP. And thats from someone who took his M.E. classes over 30 years ago :D

I haven't gotten to the "real" engineering class's yet as you can see. I just can't see why turning more weight won't rob power!? I'm sure less weight will help the engine spool up faster which will make you accelerate quicker, unless you wan't to store energy in the flywheel for launch, but I don't need that.

Originally posted by 19Nova72:
I haven't gotten to the "real" engineering class's yet as you can see. I just can't see why turning more weight won't rob power!? I'm sure less weight will help the engine spool up faster which will make you accelerate quicker, unless you wan't to store energy in the flywheel for launch, but I don't need that. =

If you do a step or steady state dyno test you will see that the weight of parts doesn't effect HP but,,, (always a but) your reasoning is correct, in an acceleration test you will see a perceived increase in HP in corrected numbers because of the inertia of the parts.
You will also see slight differences in corrected power when going from say a 300RPM/ sec. to a 600RPM/ sec test which is one reason you need to be sure all your tests are controlled pretty good when changing things.
This should translate to a small improvement in "power" on the track.
Actually not HP but more acceleration as you are using the same HP to "accelerate" the lighter parts so,, the car should accelerate faster. :confused:

This brings up a very good point about those balancing pads on the rod cap. Some of those things are huge but it seems that even a small one would put a lot of strain on the bearings causing excelerated wear over a long period of time.
Is there something to this or am i way off.

think of it this wasy: if the bob weight is about 1800 grams and you take 10 grams off each rod what is the percentage change involved?

gspan: those balance pads may actually serve to strengthen the rod cap. they don't cause bearing wear.

Tom

Scat rods are probably shot peened. Grinding on them will remove this. If you do it, you should have them shot peened again.

30 yrs ago at the Tulsa dragstrip....I had a history teacher that tried the 60lb flywheel deal, in hopes of keeping the rpms up between shifts,,,well, it worked great for the launch,but the rpms wouldnt come back down quick enuff so he could shift it.

I'm not to familiar with balancing an enigine, but 10/1,800= approximately 6/10th's of 1 percent. Not much. So if you take 10 grams off the rod do you have to take 10 grams off the bob weight also? Is the bob wieght supposed to wieght the same amount as the rod/piston/rings/bearings/bolts/oil or what?

Originally posted by gspan1830:
This brings up a very good point about those balancing pads on the rod cap. Some of those things are huge but it seems that even a small one would put a lot of strain on the bearings causing excelerated wear over a long period of time.
Is there something to this or am i way off. On stock rods, the pad on the top of the rod is the one that it pays to remove if you want to remove somethng.
Any weight you can remove from the reciprocating end without sacrificing needed strength is a good thing.
Scat rods as with most aftermarket rods don't have all this extra unnecessary meterial.
===

Originally posted by 19Nova72:
I'm not to familiar with balancing an enigine, but 10/1,800= approximately 6/10th's of 1 percent. Not much. So if you take 10 grams off the rod do you have to take 10 grams off the bob weight also? Is the bob wieght supposed to wieght the same amount as the rod/piston/rings/bearings/bolts/oil or what? Not exactly.
The formula for a V8 is 100% rotating & 50% reciprocating

The formula I did to calculate it on my balance sheet is:
=(2*(PISTON & PIN'+ROD UPPER+LOCKS+RINGS)*FACTOR)+(2*ROD LOWER)+(2*INSERTS)+OIL
The usual factor is 50% except for some high rpm stuff where I use 52%
I use 5 gms for oil, some people use more, some less & some none.