SBF Balance question.. Neautral... 28.. 50..
 

Has any one done any type of testing to figure out the performance changes in a SBF that has been neutral balanced vs the stock 28 or 50 oz balance.. is it worth enough to spend the money on the Mallory or is it so minimal that it'd only be worth trying if you wanted to be #1 at Indy...

Brad

Re: SBF Balance question.. Neautral... 28.. 50..
 

0 balance all day...I've ran 0 and 50oz...

Re: SBF Balance question.. Neautral... 28.. 50..
 

I believe the newer cranks like eagle are manufactured for 0 balance, so they don't require mallory. Last two cranks I had done required lightening, no mallory

Re: SBF Balance question.. Neautral... 28.. 50..
 

Is this from a performance improvement stand point or just bearing life and overall dependability of the engine's life? Is it actually worth HP?

Re: SBF Balance question.. Neautral... 28.. 50..
 

[QUOTE=HawkBrosMav;628249]Is this from a performance improvement stand point or just bearing life and overall dependability of the engine's life? Is it actually worth HP?[/QUOTE


Dependability and reliability ....cracked blocks are not good

Re: SBF Balance question.. Neautral... 28.. 50..
 

you can get the eagle and scat in 0 or 28

Re: SBF Balance question.. Neautral... 28.. 50..
 

[QUOTE=Stephen & Horace Johnson;628251]Fortunately in the combo we are running it's never seeing over 6500 RPM we've had a stock crank 50oz motor together for going on 10 years now and have never had any issues outside of now having 1000+ passes on it we finally wore the bearing out.. Don't really need to spend to money/effort on neutral balance if there isn't any performance gain, but wanted to consider the option of if verse the cost buying the Eagle crank and going neutral. if we were having reliability issues I could justify the expense for it, but at this point the investment is simple for potential HP gains for a car that will never make the top half of the sheet on the current budget.

Additional info; were making 300-350 HP tops... not a speed demon by any means haha

Brad

Re: SBF Balance question.. Neautral... 28.. 50..
 

I had a few Boss 302 cranks I ran for years, and then I broke a crank, caught it in time. But the metallurgy has changed, So I ran this Boss 302 crank for a long time came to rebuild with rods and pistons, and I opted for a new crank. The cranks wear out. I felt better with a new crank that was made for neutral balance, that one that had seen service since it was made

Re: SBF Balance question.. Neautral... 28.. 50..
 

Go neutral balance and get the crankshaft from Molnar Technologies. Every time I use Eagle or Scat, it requires work to correct issues.

Re: SBF Balance question.. Neautral... 28.. 50..
 

I've got a 28oz cast crank 351c that goes to 7300. It's been together 7 years and didn't get twisted that high till I figured some things out. I had a local machine shop balance it and it feels smooth @ rpm. The external balance gives a tiche less iron flying around Inside the crankcase.

I've also got a recently acquired Molnar massaged crank for my good engine. That's going to be a while though, too many projects.

Re: SBF Balance question.. Neautral... 28.. 50..
 

Bret Velde could probably shed some light on the subject I believe he played with external balanced SBF a long time ago.

Re: SBF Balance question.. Neautral... 28.. 50..
 

Brad, we did pick quite a bit going from 50oz to 28oz, but we also changed some other things to, so not sure how much was just the change in the weight.





Bret Velde
2003 ??/SA

Re: SBF Balance question.. Neautral... 28.. 50..
 

[QUOTE=HawkBrosMav;628254]

also makes a difference if its stick or auto.I was turning my sbf 68-7.... I'd rather be safe then sorry

I have not had any issues with scat or eagle in my engines or the ones I have built for others ... maybe I was just lucky .....good luck

Re: SBF Balance question.. Neautral... 28.. 50..
 

Stephen,

It is touch and go with Eagle and Scat. I have heard that Eagle improved their machining, but some issues still linger. The last two Scat crankshafts I used, required rework.
Still, if a replacement crank is available from Molnar or Callies, that is the way I prefer to go. Everything I get from Tom Molnar is right on the money. Tom was the guy at Oliver Rods for many years and the quality of his products is outstanding and he stays behind his products.

Re: SBF Balance question.. Neautral... 28.. 50..
 

Not sure if it's actually enforced, but being a stocker only the Eagle and Callies cranks are legal... looking at Callies it doesn't even look like they produce the stock legal crank any more. I've run Scat stuff in all my bracket car motors with no issues. I agree all the eagle stuff I've ever bought needed to be turned to use it.. at this point I think we're just going to stick with a stock crank at 50 oz. on our budget with our performance goals it doesn't sound like this is really worth it.. we'll focus on other places to better invest our money that may be worth something as we know there are places elsewhere in the car that could use some attention. This was more of an opportunity presenting itself type situation ha

thanks for the input all

Re: SBF Balance question.. Neautral... 28.. 50..
 

Brad
In your Combo a nice well prepped OEM crank will work great at 6500 rpms. Cryogenic treatment helps but it’s not a must.

Eagle steel crank 3.00 stroke neutral balanced turning 8800 for 2 years now with no issues.

Good luck.’
RJ

Re: SBF Balance question.. Neautral... 28.. 50..
 

I ran a Boss 302 crank stroked to 3.25. Pin width was 1.820 @ 2.00 dia. BME Aluminum rods 5.35 length big end width.900. Assembly was 100 percent internally balanced with a Fisher damper. Ran this combo to 9500 rpm for 3 years with no crank or Block problems. Block was a Boss 302 ( D1ZE- B service block. Bore started @ 4.030 and ended up 4.080.