Balancing a Scat Stroker: How much Mallory is typical?

[jimeast]

I got a call from the shop that's balancing a Scat 2.25 stroker crank and rods I picked up yrs ago.  It's for a 482 stroker.

Rods: Scat H-Beam 6.7"  (not sure of the weight)
Crank: Scat 2.25 stroker
Pistons.  Lightweight from Blair P.

The shop is concerned they will need to use around 3 slugs of mallory and it seems excessive to them.  Is it typical to need this much mallory in a scat stroker? 

*** I thought this info as I learn it might be helpful in future searches.
***EDITED After Barry's Comments: 
***Scat 6.7 H-Beam Connecting Rod: Wt 815gm; Big End: 567gm; Small End: 248gm
***Scat 6.7 I-Beam Connecting Rod:  Wt 771gm; Big End: 545gm; Small End: 226gm (Ross's data from below post)

[My427stang]

With the heavy H-beams I think that's about right, I would think you are likely at a bobweight around 2200 which takes some metal.

When you get down to the 445s and 461s with lighter rods and a dished piston, you can end up around 1900s, then it takes less metal, but SCAT H beams are plenty hefty and when you add the big bore, the piston is usually 500g as well.

[blykins]

Usually takes one piece of metal with the right rods and pistons. 

Everyone always wants H-beam rods with the stroker kits, but the I-beam rods will support 700+ horsepower and are lighter (and cheaper). 

[jimeast]

The H-Beams came w/the crank.  I see the I-Beams are 810 grams, but it looks like Scat does not list the weights for their H-Beams.  So, I don't know what the difference is.  Does anyone know the weight of the H-Beam to compare.

[gregaba]

Just weighed one of my Scat H beams for a stock stroke 428.
618 grams
Greg

[My427stang]

I am looking at a very old bob weight calculation and I am showing

814g for a 6.70 SCAT H-beam in 2006

518g for an old 1/16 / 3/16 ring dish Diamond piston at 4.277 bore 1.325 CH
157g for pin
4g for spriolocks
246 for rod small end
53g for Mahle rings

53g for rod bearing
568g for big end

All rounded to nearest whole number.  With oil, recip was 985, rotating 621

We balanced with 2230g bob on a 2227g calculated.  Heavy pieces.  I tend to avoid them now if I can as Brent mentioned, a SCAT I beam drops that bob weight by about 100g, and a set of Molnars drop it another 50g

150g = .33 pounds when balancing, but more importantly, is hanging there a 6500 rpm too

[Barry_R]

Anywhere from one to three is common.  Depends on how large a slug they are using (a 1.00" dia x 1.200" is as big as will easily fit without clearance work on the rear flange if they're just drilling the hole) and the required location.  Usually best to chase one end and recheck - seem like you'll sometimes get one where it wants weight added/removed outside of the counterweight area and you can rotate things a bit with the first placement to reduce the need for extra work.

[jimeast]

Does anyone have information on Scat's 6.7 I-Beam rod (overall wt, big end, little end)  Scat lists overall wt as 810, but not the big & small end

The H-Beams I have are 815gm total, 567 big end, 248 small end.  No surprise, the weights are very close to My427Stang's data shared above.

[My427stang]

545 big, 226 small, 771  total, set built 4/16/20 on the shelf. That’s from the label I didn’t weigh them yet

[jimeast]

For Ross:  Can you share the part number for the I-Beams.  Scat lists weight at 810gm for 26700716 or 2-ICR-6700-7/16

[My427stang]

I'll do one better

Here is a pic of the box



Additionally, the last two sets prior to this one, I measured at 544/226 and 541/231 rounded to nearest gram, they must vary after machining and they just group similar weights.  I'd have to guess that number you are seeing is maximum, but I haven't seen one that heavy yet

[blykins]

Yep, and Molnars are even lighter at 740-ish. 

I can't remember the last time I used a Scat H-beam rod on an FE.

A Molnar or K1 rod with a Mahle piston makes for a stupid light bobweight. 

[pbf777]

The shop is concerned they will need to use around 3 slugs of mallory and it seems excessive to them.  Is it typical to need this much mallory in a scat stroker? 

     Is the "shop" asking you, if it is doing the job properly?  Or is their concern whether your prepared to pay the bill?         

     The consistency in the this Chinese import product is not good, and it is impossible to predict from afar how much effort will be required to balance your crankshaft assy., but as stated previously the three slugs (per end?) would not be unheard of.       

     Scott.

[jimeast]

Scott was right!!!  The shop quoted me their typical fee ranging from $250-$350 to balance a rotating assembly and was concerned I was not ready for a $700 once they realized the stroker crank would need lots of mallory.  The way it was communicated to me seemed to come in the form of question on whether the rods were too heavy or that maybe they never balanced a stroker.  Upon further communication, it was the larger fee

It came home today.  I left $700 at the shop ($50 less than anticipated).  If I do another stroker FE, I'll try the lighter rods and see if there is a significant difference in the balance fee.

[blykins]

How many total pieces did you need?  3?  $700 is a lot of money for 3 pieces of metal...……..

BTW, the "consistency" is pretty stinkin good from my end.  I can pretty much count on what they need every time with the same combination.  It really burns my biscuits when someone looks down at Scat because it's a "Chinese import" when Molnar and K1 are too.....as well as Callies/Compstar and about every other I-beam/H-beam rod that you see advertised.  I'll take Scat every time.