BajaRunner

What are the limits on a cast crank. I am building a 454 for my nova, and ran the numbers on the crank i have and it is cast. I would like to get a ~450hp engine, and not looking to wrap it up super high ~4800rpms, am I ok with a cast crank or should i find a forged?

Nordicflame

iTrader: (4)

I personally wouldn't have any problem running the cast crank.
It will take much more abuse than what your planning for it
Just make sure it checks out OK as far as runnout and such.
Dave

mopower

450 hp and 4800 rpm aren't bad for a cast crank. Have it magnafluxed and you should be good to go

Is that a Wellcraft Nova or Chevrolet Nova?

BajaRunner

Chevy Nova

Big Block Billy

You wont have any problems in the Car with this crank. Make sure you have a good balancer and , plastigauge the bearing fit. I like to run around 2.5 thousandths clearance. This will hold up. Also deburr all the oil holes, But most importantly, make sure the oil passages in the block are absolutely clean,
because any dirt will kill a cast crank faster than a forged one. Make sure the rods are perfect. If I was you I'd go for the Arp 3/8" bolts. I have a cast crank and 3/8 rods in my 72 Monte with the 454. I have a 4000 stall converter, and am making apx 450 hp. This motor has easily seen over 5000 rpm's no problem. Also am running M-77hv oil pump, windage tray, and bigger oil pan. I beat the hell out of it !
I would not advise this for a boat though because it is under much greater load, and high rpm load will kill the stock bottom end quick fast and in a hurry ! BBB

WETTE VETTE

We have run a cast crank in our 66 Vette for the past 4 years with no problems. The motor is a 10.9:1 468 and puts out about 500 HP. We occasionally buzz it to 6500 RPM and hit the strip once a year. Most of the time it is just used for cruising. At the strip is turns 11.90 at 118 MPH! Cast crank and 3/8 ARP bolt, polished shotpeened rods and 2 bolt mains. You can get away with quite a bit with street / strip car applications!

Craig

formula31

One of my engines still has a cast crank, full size journals, straight, perfectly set up and balanced. roughly 450 hp and 5400 rpm, one of the few parts I havent broken. LOL, oh , now I jinxed myself.

Big Block Billy

It's amazing how almost every forged crank I have magged, comes back bad. Smack a forged crank with a hammer first and listen for a good ring, that rings along time, then get it magged. If the forged crank has any dull sounding counterweights, pretty much conclude it's cracked. The sound waves stop at a crack ! I guess the real answer is a billet cnc machined $3000 and up crank. Took apart 2 4.5" strokers, and both cranks were junk. Motors ran fine. One of the good things about the Iron crank is it absorbs harmonic vibrations better than a steel one. A boat crank is subject to extreme torsional loads as compared to an automotive unit. The steel crank especially can only withstand so many of these twisting cycles, before it gets fatigued. A cast crank is soft and bearings tend to grab at hi rpm, or lower oil supply / pressure. A cast crank also cant take as much of an overheating as a steel one because it expands more and grabs bearings. It's like most everything in this life, a tradeoff !!! Be careful buying a "magnafluxed" crank on e-bay the dumping ground of "liars crap ! " BBB

2112

For what it is worth, I ran a cast crank that was stroked .300" in a 540 inch Ford. Around 670 horse. Ran it at 6,000 rpm often until a blew a rod out the block at 63 hours use. The boat was a 24' warlock.

Welded the block back up, replaced two rods and detuned it to about 400 horses and it is still running in fishing boat 10 years later (easier life).

Big Block Billy

Yes, I hate to say it, but Big Block Ford, and Chrysler both have beefier bottom ends. With bigger mains, and in most cases were a y-block. It's my understanding that GM made improvements in newer style motors in the past few years.
The real reason for the sucess of the BB Chevy is it's cylinder head design. It's semi hemi valve angles and big heads allow for very good airflow and velocity.
The bottom end of a BBC was always a weak point, especially when it comes to severe horsepower. Hence aftermarket splayed main caps, stud girdles for severe blower applications. If building a really powerful motor , it's a better idea to start off with a Dart block. BBB