[BLANK1]

I know I'll probably catch heck for this question and I've read all the posts on how the Eagle cast cranks are junk. I just want to know who out there are running the Cast Eagle cranks in their motors without any issues? I'm talking about the 4.250 stroke cranks for a 400 block and over 600 hp.

[BruceWilkie]

Interesting question. I've seen some who used to say they were just fine, change opinion as soon as forged became available. Usually with little valid basis for changing their opinion. Early Eagle castings had thrust area issues that got corrected a long time ago.

IMO properly prepped, reasonable application in terms of rpm and max power level, they will hold up just fine. Going racing regularly and liklihood of making big power at high rpm as your program develops then the forged does make more sense.

I dont recall many failures of 600-650 hp level cast Eagle crank 4.25" stroke 400 block strokers that you could HONESTLY attribute to crank strength. Most part failures tend to get blamed on the part vs the guy who prep'd or assembled the part regardless of real cause of failure.

[Cliff R]

The failure rate at 730 hp is 100 percent, at least from what I've seen from a friend of mine who "windowed" two 400 blocks trying to use them at that power level.

I'd be OK with one at 500hp or less. Some folks claim they are OK for 600hp or so, but I'd never get a "warm and fuzzy" using one in an engine making that much power.

The forgings are nice $400 upgrade. We've got several in service to about 750hp, zero issues with any of them at any power level, and both myself and my customers sleep better at night!.....FWIW.....Cliff

[Mr. P-Body]

Blank1,

Corey Thompson's '70 Firebird has made 540 documented mid-to-low 10 second passes with 93 octane gas with one. The pan has never been off the engine. Dan Steward put 20K street mikes and 220-plus passes on his in the low 11s. He sold the car last month and the new owner is out "pounding on it". No issues.

Under 700 HP, these cranks are absolutely fine. AllPontiac's test "mule" made over 800 before cracks began to show in the fillets. The crank did not "fail".

Most crank failures (regardless of type) can be traced to other issues. Lack of oil is the most common.

If your budget can "stand" it, the forging is of course, "better". If it meets your power requirements, don't be shy about the casting.

Jim

[Skip Fix]

How many of these 4.25 cranks are in motors that made big HP for years before we had forged cranks? I'd bet the Butlers sold a bunch. Heck before there were Eagle rods lots of guys used heat treated 58-62 forged "rubber" rods including the Butlers.

[Brian Baker]

I ran a 4.25" stroke, 3.25" main cast Eagle in my 455 block I had in the Discomobile with BME aluminum rods, splayed billet caps, filled coolant passages to halfway across the water pump holes, etc. Over 200 passes in the 550-HP range, never a lick of trouble. Then I sprayed it more then 20 times at the 200-HP level, and about a half dozen times with a 250-HP shot. Best run on the car was a 10.12 @ 135 MPH with a 1.58 60' (spinning) weighing 3850 lbs. Still no trouble.

The biggest problem with cast crank failures at higher HP levels has been people insisting on running heavy forged steel rods. They simply won't live. I personally witnessed an Eagle casting make more than 830-HP on a dyno after making more than 20 pulls that day, all in excess of 790-HP. Heavy steel rods were used, spinning the engine to 7200 rpm. On the last run, oil pressure went south and a teardown later revealed the crank was beginning to crack. It was still running however.

IMHO, they'll live if you make the reciprocating assembly as light as possible...this means using expensive aluminum rods, which most people only willing to spend money on a cast crank won't spend the extra cash for better rods that are not only lighter, but help absorb the shock to the crank. When I built mine, the only crank forging option available was to find an old '990 421-SD crank...so it was either go cast, or spend $2500 on a billet.

Options are better now...I wouldn't even consider a cast crank for anything over 550-HP...I'd go with a new forging.

[Probird]

A forged crank will let you sleep better at night when getting to the 700hp level.

I ran one for about 3 seasons in my 3200 lb. car running in the low 10's one season and 9.70 and '80s for the next 2 seasons shifting at 6600 with Eagle rods and Ross pistons. I put right aboutt 200 passes a year on the car. It was a cast 4.21 stroke with 3 1/4" mains. Never had one bit of problem with that setup. It was probably near the 700hp level.

When the forgings came out I figured I could sleep a little better at night with a tighter pin in my grenade. I wouldn't be too worried about the cast crank till you start getting over 650hp. Even then with my experience it sjhould live a long life.

[65nss4spdGTO]

Originally Posted by Probird

A forged crank will let you sleep better at night when getting to the 700hp level.

I ran one for about 3 seasons in my 3200 lb. car running in the low 10's one season and 9.70 and '80s for the next 2 seasons shifting at 6600 with Eagle rods and Ross pistons. I put right aboutt 200 passes a year on the car. It was a cast 4.21 stroke with 3 1/4" mains. Never had one bit of problem with that setup. It was probably near the 700hp level.

When the forgings came out I figured I could sleep a little better at night with a tighter pin in my grenade. I wouldn't be too worried about the cast crank till you start getting over 650hp. Even then with my experience it sjhould live a long life.

I watched your video last night for the first time, you interested in going heads up racing???

Calvin Hill
Hill Performance
708-250-7420

[lust4speed]

So which has a better chance of surviving at 650-700 HP, Eagle or a well prepped Pontiac crank?

[65nss4spdGTO]

I'll take the factory Pontiac cranks.

Calvin Hill
Hill Performance
708-250-7420

[Probird]

Originally Posted by 65nss4spdGTO

I watched your video last night for the first time, you interested in going heads up racing???

Calvin Hill
Hill Performance
708-250-7420

I'd love to, but my wallets not big enough!

[Cliff R]

"So which has a better chance of surviving at 650-700 HP, Eagle or a well prepped Pontiac crank?"

The Pontiac nodular cranks are tough, and failures with them are pretty rare at any power level. The problem with "N" cranks is the lack of availability for them, and they aren't a "drop in" for the 400 blocks. One must also consider they will have millions of duty cycles on them already.

The rest of the story on our customer who broke two of them at 730hp is that he also installed one in a 500hp engine and decided to pull it down for inspection after blowing up two engines in his race car.

It was intact, but was cracked in several places.

We have observed several other complete failures at pretty high power levels with the Eagle cast cranks, it's just going to happen when you use a $200 part in a $10,000 engine. Folks should realize that it is 2010, and we have forgings available for $600. $400 is a pretty inexpensive upgrade to protect your expensive investment. It makes no sense at all to use a cast crank at any power level, IMHO.......Cliff

[old66tiger]

I totally agree with Cliff. While my car is not a 'race' car, it made total sense to pony up the extra cash for a forged unit for this new motor. Total piece of mind at any power level.

[PLAY400]

Some info on what is now available from Eagle

http://www.bangshift.com/blog/Bangsh...-Products.html

[Gach]

Originally Posted by Cliff R

"So which has a better chance of surviving at 650-700 HP, Eagle or a well prepped Pontiac crank?"

The Pontiac nodular cranks are tough, and failures with them are pretty rare at any power level. The problem with "N" cranks is the lack of availability for them, and they aren't a "drop in" for the 400 blocks. One must also consider they will have millions of duty cycles on them already.

The rest of the story on our customer who broke two of them at 730hp is that he also installed one in a 500hp engine and decided to pull it down for inspection after blowing up two engines in his race car.

It was intact, but was cracked in several places.

We have observed several other complete failures at pretty high power levels with the Eagle cast cranks, it's just going to happen when you use a $200 part in a $10,000 engine. Folks should realize that it is 2010, and we have forgings available for $600. $400 is a pretty inexpensive upgrade to protect your expensive investment. It makes no sense at all to use a cast crank at any power level, IMHO.......Cliff

agree 100%

[roadrage david]

pff blablablabla The never ending story!!!... For every crank failer, there are proberly 200 ore more cranks that do there job just fine, and to blaim these failers on the crank is very EZ. Dont some of you ecsperd feel rediculess bij using these poor eczamples everytime. while ALL the time sins the beginning of crank basing, new engines ARE being build on a DAILY bases with these cranks, and the failing rate stays the same. And we alsway hear the same old stories.............

[PONTIAC DUDE]

Over 625 hp I would consider the Forged unit.

A lot of vartiables not mentioned in this post.
Bob weight
RPM
Compression
Block support. flex in the block will contribute to crank breakage.
Race or street has to do with how much a cast crank can take.

I have seen more issues with factory cranks and stress cracking on the journals. That and snapped cranks back in the day when all that was cheaply available was the Factory cranks.

[PLAY400]

So this would be cheap insurance????

http://www.bangshift.com/blog/Bangsh...-Products.html

[Gach]

The main problem with Eagle cast crank stuff is the quality of material...flip a coin coz you never know what your gettting..yes some have had good luck while others not so good luck.

Cliff R: I think has done a beautiful job on explaining his experiences with them.

Here's how I see it...( my opinion ) many of the Engine builders can't find good used stock Pontaic cranks, even when they do, they need work, 99% of the time they need turning...mag...balance. rod ends trun down to BBC, because 99% of the after market rods are sold with BBC rod ends. Once they become a dealer for these Eagle cranks they can put a kool $200.00 bucks in their pockets and not even have to tuche them...Nice !when one fails they have a miillion excuse why...so it's either your fault or the guy building you engine. Are they all bad...no!...but which one did you get.

[PONTIAC DUDE]

Gach. Quit making assumptions about engine builders. Now your slamming all Pontiac engine builders and no " Personal" experience with Eagle cranks except 2nd or 3rd hand info.

For someone that has built less then 5 engines in 50 years you sure ASSume alot.