onehunglow

Is it really important to balance a .030 over engine? I'm mean were talking barely anything added! on a street engine that"s built to be abused, to last long enough to get another one worth balancing built. that's a few hundred $ that can be used some other place. I was just planning to have the clean up the crank and press the new pistons, but my shop is dead set on the balance...

Quick Ranger

iTrader: (2)

Unless the pistons are the same weight, It will need to be balanced. The new pistons are gonna be heavier, I'm sure.

Taxman20

iTrader: (11)

Anytime I change anything in the rotating assy I have it balanced.

madmike9396

iTrader: (29)

It's worth the extra $ imo

Deeohgie69

iTrader: (3)

That extra two or three hundred is worth it imo. You already have that much in it, just do it right so you didn't waste all that money to just have problems later.

onehunglow

yeah its getting done next. I'll order the arp rod bolts, the flexplate and underdrive crank pulley next week and get things in order to go.

Thanks for the help.

zraffz

iTrader: (1)

Don't forget it will cost around $150-200 to have the big ends of the rod honed .002" and you'll need special rod bearings (clevite makes them for a stock crank and a cut crank in .010" increments).

onehunglow

I'm not under standing why they need to hone the big ends out on the rods. feel me in on this because it was never mentioned when the machine shop explained what they're going to do. the rods were never descussed except magging them for cracks and standard balancing of weighing each one and making them idenical in weight over all and to both ends. $200 is the top of all the machine work to balance this thing, and $7 a piston to press them, and the bearings are extra.

zraffz

iTrader: (1)

If you are switching the rod bolts out for ARP bolts (which have a stronger clamping force and will distort the cap) you need to hone the rods. Anybody who says otherwise hasn't measured the big end for out of roundness.

onehunglow

Ok, yeah I've heard of this. Im not sure if it's something they do as procedure, or extra. I will be sure to bring it up. Thanks for bringing this to my attention.

madmike9396

iTrader: (29)

My motor has ARP rod bolts. Nothing was honed.

onehunglow

Do you think it matters on the type of bolt? I thought arp had 2 diffrent bolts for these. The wave lock type and the standard bolt type shank .

madmike9396

iTrader: (29)

Mine has the standard bolt style. I really don't see a issue as long as the bolts are torqued to the right spec.

madmike9396

iTrader: (29)

If it was a worn out engine I could see. But since it will be fresh shouldn't be a issue. But I'd look into it more if concerned

Mine is a ls6 Block bored to 3.920. Arp rod bolts. All new bearings,factory crank,factory rods,Speed pro Pistons. Balanced.
Got around 3k miles on mine so far without any issues. Around 440 rwhp

onehunglow

i can see them being over torqued and causing destortion, i'll be building my short block, you have any ideal what to run theses down to, or will i use the factory spec on torquing? I've heard 100ftlbs.

Taxman20

iTrader: (11)

All the shop does is tighten them to spec and check for roundness. If they are out then they hone them. My shop knows about this issue and said that most of them he has seen are fine with no hone needed. But he does check all of them. All shops should at least check instead of assuming they are good.

madmike9396

iTrader: (29)

Not sure on specific torque as I had a friend assemble my stuff

speedtigger

iTrader: (16)

The rod bolt argument again eh? This has almost reached the status of the oil and spark plug wire brand arguments.

In all seriousness, if you read the dozens of threads on this, anecdotal evidence is provided by people who "got away with it" and people who spun rod bearings and try to warn others against it.

In reality, when you change fasteners, you WILL affect the rod bore concentricity and size. How much will vary. You may find that out of 8 rods, some may be within tolerances and some may not. You may find all 8 will be out of tolerance. Or, less likely, you might find that all 8 remain within recommended tolerance.

Whatever the case may be, it should be considered mandatory to at least have the rods properly measured by a machine shop for tolerance after the bolts are installed. Considering the cost of having them measured vs. the cost of trashing a new build, it is not a reasonable gamble in my opinion.

onehunglow

Thats how I figured it, the shop I'm using been around for a long time and puts out quality engines and machine work.

onehunglow

yeah nothings a perfect world. I'll get done right if needed. ill have them check it if they don't already know, and if they're out then they will get whats needed to move forwards on this build.
Thanks everyone for the input.