Any idea how/what/why this weld would be on a brand new BBC Scat Forged Crank?

 

Just a guess......to add weight

 

They needed a bit of weight to balance it.

 

Problem I see is that its the thrust surface. Looks like it has some scuffing on it. make sure weld doesn't hit the bearing surface

 

Not a thrust surface, it's a counterweight. Not going to hurt a thing.

 

Any weld protruding from a machined surface has a [potential] risk of interference with some other moving part. You just need to assess whether the protruding metal on that weld presents any risk to the engine's operation.

In general, that is a s4i++y weld to put on a finished part. Very cheaply done. A proper job would be to over-weld what was needed, bump grind to clean up protruding metal, then balance and REMOVE excess weld material from a risk-free surface.

I don't know who made that crank (or who balanced it, if it wasn't done at the factory) but it is shoddy work.

 

Where did you get it? Sure it's not a "second" that someone fixed? SCAT stuff is usually pretty nice. Are you sure it's SCAT? Some folks have been know to substitute others...

JIM

 

looks used to me

 

I would say that you got what you paid for. Scat and eagles are the bottom feeders of forged cranks

 

The usual method of adding weight to balance a crank is to drill and press in a tungsten insert (heavy metal) as the weight of tungsten is just over twice that of steel. For very small adjustments it's acceptable to weld it like that. Depending on pistons, pins and rod combinations crank weight sometimes has to be changed to get the proper balance ratio. That one doesn't look very sanitary but it is done on the back side of the counter weight and is not in the way of anything. If it was balanced with your pistons, pins and rods that would be why it's there. Basically, it was quicker than drilling a hole and pressing in a frozen tungsten weight.

 

Awww...c'mon George...the entry level parts aren't the top of the heap.....but there's a lot of 2000+ HP turbo/N20 big blocks running around on Scat and Eagle cranks and rods. I usually find the machine work closer on the SCAT stuff out of the box.

I've actually been to the SCAT "factory" in CA and toured the whole place one-on-one with the owner. They do some VERY high end stuff there....pure billets etc plus tons on OEM stuff that is used in all the crate motors. The parts are forged in China (like the majority of these parts), but the machine work is done here.

JIM

 

Wow. both these manufactures have been highly recommended on this forum and I have been seriously considering purchasing one of their 496 forged stroker kits through Summit Racing.
If not Scat or Eagle, who offers a good stroker kit?

 

I have a callies crankshaft in my engine. Machine work has great reputation but comes in at a higher cost.

 

You're right upon closer review of the picture I see the thrust surface is lower, down closer to the journal.
My mistake

 

I've used SCAT stuff without issue. I ran their rods in my 540 making 850+ HP and 8000 RPM and the bearings always looked perfect. Cranks are Ok also.

I've got a Callies in mine now. I had an Eagle one time and it seemed to have an issue with flexing. But again...I was spinning it hard and it didn't have center counterweights like most do today. Always a good thing on stroker cranks.

Callies makes good cranks. Forgings are imported from Japan. The same forging is used for the Dragonslayer and the higher end ones...just more machine work and lightening. The Compstars are Chinese..but overall seem to be good with excellent machining. Howards also gets machine work done by Callies and are good. They make some killer rods too.

Eagle stuff has come a long way and is better than it used to be I believe.

I've got Oliver rods in mine now. Not cheap and many 2000+ HP guys use them...but lately I've heard they've changed hands and may not be what they used to be.

These are the main "sportsman" type parts and I'd use them anytime. I'd avoid the House brand stuff in most cases unless I could verify who made it for them.

JIM

 

After having a 427 SBC light weight forged crank shaft break in the main bearing. I just started buying high end light weight cranks and never had another problem. both of my cranks are over $2000 each though. At the shop where i worked for 10 years most of the racing American V-8's had very expensive Bryant cranks

It was a 350 main bearing size and it had been balanced by taking out to much weight out of the rear most throw instead of weight out of several throws. So the person that did the balancing on the internally balanced rotating kit at scat or eagle is the one to actually blame

 

I would agree a 427 with a 350 main needs a good crank for sure...especially if you drive like you and me!! And definitely needs to be balanced correctly.

My crank has been through several rod/pistons assy's over the years and needed rebalanced. First was SCAT rods and SRP pistons. Then I went to Oliver rods (heavier) and Mahle pistons (lighter) and it needed a little more taken out of it. THEN...when I went turbo I used the Oliver rods and some Diamond turbo pistons (heavier). I had to add some weld to one of the old balancing holes to put it back in the right place. "Just a little dab'll do you". (OK...you're telling your age if you caught that last part).

JIM

 

Eagle here, no issues.

 

I run a Scat crank on my stroker too ... 9 years, no issues .. looked extremely well made to me . very satisfied