Mike,

In watching a lot of your posts, it sounds like you use a lot of Scat stuff.

The question that I have is about crankshafts. I'm considering starting to peice together a stroker big block (496). I want to purchase a piece here and a piece there, as the budget permits.
I have been considering a Scat 4.25" crank and was wondering the difference between the 4130 and the 4340. I know the 4340 is a stronger piece but how much?

My plans are mainly a street engine with a little strip time. The RPM's will be kept UNDER 6500 rpm (probably 6200-6300 rpm) and on a rare occasion give it a little NOS (150hp MAX). I would be shooting for around 575-600 HP normally aspirated. Would the 4130 work for me or should I bite the bullet and get the 4340?

What about the Scat H-beam rods. Would they be up to the task?

Thanks in advance. smile.gif

Darren,
The 4130 will be fine. Actually you could probably use the cast crank if you were so inclined ;)
I prefer the 4340 for a couple reasons.
First, it is stronger as you said.
Second, my understanding is 4130 does not take hardening as well as 4340.
Another thing is while Scat imports all their cranks, the 4340's are finished in house.
The finish grinding, profiling etc.
The cast & the 4130 are finished offshore but they are all inspected & polished before you get them.
What this means is if you get the crank from Scat directly or a Scat dealer (like me :D )you will be getting a pretty fair piece.
The reject rate because of sizing & overall quality on the 9000 series (cast) was or is upwards of 20%.
You know all those "great deals" you find on ebay? A lot are these rejects.
I have been trying to get Scat to grind their name off of the ones they sell as blems for quite some time as it reflects on them but so far they are still showing up.

Anyway, back to your question,,, I would prefer the 4340 & the rods will handle about anything within reason you want to throw at them.
They also have an I beam 4340 capscrew rod now that is pretty nice in both 6.135 & .385

Let me know if I can help,,just send me an email ;)

Mike,

Have the cast and 4130 cranks had problems (QC)? I have heard stories about some of the "off shore" cranks being way out of balance and costing a couple hundred dollars to bring them within spec. If that is the case, I might as well pay the extra and get a 4340 that does not need to be balanced. Are you saying that Scat does not have this problem?

In "your opinion", is it worth the price difference for my application?

This may be a difficult question to answer but how much stronger would you say the 4340 is over the 4130, 20%,30%, more? Does Scat have a horsepower rating on there cranks or is it the RPM's that kills cranks?

Sorry for all the questions but I'm real anal about getting as much info as possible before making a decision.

Thanks again for your input.

Glad I sold my Scat 9000 and bought a Scat 4340. Did not knoiw they had these probelms before I sold the 9000. I just wanted an all forge bottom end so that it will handle whatever I through at it in the future. get your self a 4340 and put your mind at ease.. I sleep so much better at night knowing I have a 4340 Crank graemlins/waving.gif

Originally posted by 71454Chevelle:
Mike,

Have the cast and 4130 cranks had problems (QC)? I have heard stories about some of the "off shore" cranks being way out of balance and costing a couple hundred dollars to bring them within spec. If that is the case, I might as well pay the extra and get a 4340 that does not need to be balanced. Are you saying that Scat does not have this problem?

In "your opinion", is it worth the price difference for my application?

This may be a difficult question to answer but how much stronger would you say the 4340 is over the 4130, 20%,30%, more? Does Scat have a horsepower rating on there cranks or is it the RPM's that kills cranks?

Sorry for all the questions but I'm real anal about getting as much info as possible before making a decision.

Thanks again for your input. =
Not the ones that have been checked by Scat & are sold through their regular dealers or direct.
Difference between direct & me is I sell them a little cheaper ;)
As for balancing, all aftermarket cranks need to be balanced regardless of what they are made out of.
In my opinion, any time you are building a performance engine it should be balanced & if it is any kind of stroker or even piston, rod type change it is almost mandatory.
If you are ordering a crank from someone like Oliver, Bryant or Winburg you can specify the counterweight & it will come right,, but we still check them ;)

Scat doesn't rate their cranks by HP, too many variables.

As to the price diffeence, we are only talking about $80 difference between the 4130 & 4340. I would get the 4340.

And you can't get too "anal" as far as I am concerned, sometimes people think that is my middle name when it comes to machine work :D

===

Deeboo,
If you got it from a Scat dealer there should not be any problems.

What I meant in my post was their are quite a few "seconds" or "blems" out there & to be aware of where you are buying from.

Every one has some slip through on occasion but in over 12 years I have not had to send one back or had any problems to speak of that were the fault of Scat.

Here's a link to some pretty fair info about the material differences.
I don't think I will be buying cranks from them but the tech info is really very good.

Crank info (http://www.ecranks.com/)

Thanks Mike. I knew that all cranks need balancing, what I meant was I have heard of some cranks being "way out" of balance and needing a lot of work to bring them into spec.

I didn't realize that there was only $80 difference between the two. I thought it was closer to $300.

I may send you a e-mail to get some prices.

Thanks again. smile.gif

Thanks Mike. I knew that all cranks need balancing, what I meant was I have heard of some cranks being "way out" of balance and needing a lot of work to bring them into spec.

I think you might be confusing "Scat"(good) with Cat ("junk").....been there
Ken
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