Eagle 4.250 Cast Crank Broken

Eljaro · #1 (**permalink**) 10-19-2011, 02:09 PM

It was a beautiful Wednesday morning and I was out with friends during a classic car meeting. It was a holiday and we were out for a sunny ride.

While accelerating and and at about 5000 rpm something exploded in the engine compartment.
Pieces and bits flew out the back and white smoke came out of the engine bay.
Stopped the car and opened the hood. Oil all over, and what I saw was that the crankshaft snout with the pulley was pointing sideways at an angle.
No doubt, the crankshaft has broken somewhere at the front journal , and the counterweight has knocked out one big piece off the engine block.
Can not explain myself how such a crankshaft can just break. Sounds like a material defect. This should not happen.
I got the engine about 2 years ago and have driven with it maybe 1000 miles, no more (Mallorca is only about 60 miles across).
I will take the engine out this weekend and see what damage it has taken, but I have no hope that the block can be reused.
As soon as I have opened the engine I will post more pictures. For now you can see the same s..t I do not even want to look
at.

Michael4yah · #2 (**permalink**) 10-19-2011, 02:34 PM

I can feel your pain bud. I hope this thread is as educating as it looks like it'l be. With all these foreign made cranks and parts hitting the market we need this info. Thanks and I hope you recover soon. A quick run down on the motor build might help us all understand whats involved.
Thanks Michael

DAVID GAGNARD · #3 (**permalink**) 10-19-2011, 02:48 PM

That falls under $hit happens,could be any one of a hundred things that caused the failure........been there,done that, got a lot of pieces and pictures to prove it!!!!!!!!!

No, it shouldn't have happened, but anything and eveyrthing made by man, can be easily broken by man......

David

Barry_R · #4 (**permalink**) 10-19-2011, 05:52 PM

In five years of selling FE parts in volume and building very many FE engines for a living (before that I just did it for my own projects) I have held only a couple or three physically broken FE crankshafts. The only thing they have had in common was that they were all Eagle brand. Not sure that this means anything - but I do not install or sell them unless the customer provides them and insists on their use.

AL427SBF · #5 (**permalink**) 10-19-2011, 06:42 PM

cryin' shame, need to get to root cause but already I'm thinking in those fractured parts there's an argument for forged.

Michael4yah · #6 (**permalink**) 10-19-2011, 07:33 PM

There is someone selling forged FE stroker cranks on ebay and I think they are connected with Precision Oil Pumps in Clovis Ca.
Does anyone know about these cranks?

blykins · #7 (**permalink**) 10-19-2011, 07:47 PM

Quote:

Originally Posted by Michael4yah

There is someone selling forged FE stroker cranks on ebay and I think they are connected with Precision Oil Pumps in Clovis Ca.
Does anyone know about these cranks?

You don't need a forged crank, but just a good cast one for most applications. I've used the Scat 9000 series crankshafts in many applications, and they perform just fine in 700hp BBF/FE engines.

The forged crankshafts that Michael is talking about are RPM brand crankshafts. They need a little machine work out of the box to be dead on.

fordracing65 · #8 (**permalink**) 10-19-2011, 07:58 PM

Would this ever happen with a billet crank, for the amount one costs is it bulletproff.

blykins · #9 (**permalink**) 10-20-2011, 02:44 AM

It can happen to anything. The Mountain Motors can crack a brand new Sonny Bryant billet crank, so they are not above the law.

Forged is more than adequate for most applications.

Gaz64 · #10 (**permalink**) 10-20-2011, 03:05 AM

The timing chain appears to be broken.

Sorry to say, I see a lot of damage.

Block, crank, rods and cam (from hitting each other), and some valves from kissing pistons.

I'd say while stripping the engine, you'll be making a list of what you can salvage, going by your first pic will only be the top end.

Can you post any more pics?

RICK LAKE · #11 (**permalink**) 10-20-2011, 04:19 AM

Eljaro Sorry for the motor failure but would really like to see pictures first. Cast Cranks are just that. They are in millioms of motors and run to 6,000 rpms without failures. I raced a 428 cast crank for 7 years and no failures. I ran eagle rods when they first came out in my motor, again no problems. 6,000 rpm limit, IMO is key. I perfect balance of parts also. Waiting to see other pictures. Rick L. Ps looks nice the snout snapped in the front. This is a FE problem with only about an inch diameter and 3 inches long having a balancer weight out to the end. Who's make of balancer is that and was the WHOLE rotating mass done as one piece??

FUNFER2 · #12 (**permalink**) 10-20-2011, 06:34 AM

It could be a problem with machining the journals or the crank improperly or not balancing the rotating assembly correctly ?
Mistakes happen.

ted · #13 (**permalink**) 10-20-2011, 07:39 AM

Beside material failure, the resolution or degree of balancing and journal filet sizing can be root causes for crankshaft failure. Additional pictures once the engine is torn down will possibly be helpful in narrowing down the cause.

JBCOBRA · #14 (**permalink**) 10-20-2011, 09:15 AM

Hi Eljaro!
That sucks! Especially when we understand how particular and meticulous you are with everything.

Rick Parker · #15 (**permalink**) 10-20-2011, 01:45 PM

The problem is China.

fordracing65 · #16 (**permalink**) 10-20-2011, 01:53 PM

The problem is with Eagle using china for there manufactoring, almost all go fast parts nowdays are Chinese, too bad we just cant keep it all in the USA.

RICK LAKE · #17 (**permalink**) 10-20-2011, 05:15 PM

Guys I don't like Japan, China and some other countrys that make and sell parts that are not up to spec, hardness, or cheap labor. I also don't think that waiting 4-12months for a forged crank is ludicrist. If you don't believe me call LAE, Milidon, or Velesco and check waiting time. We have no steel industry in the US anymore. China can make and ship crank blanks cheaper than making them here. I don't believe that they are the 4340 steel they claim to be. It's still a get what you pay for game. What does a Scat forged crank go for?? An LAE crank with a 4.25" stroke is $2,500.00 dollars this is finished basic crank. Aero edges, lightening, and balance are on top of this price. Scat crank with all the tricks, about $2,000.00. This country is going down a rabbit hole. If we could buy USA made I would but company after company are going under. Just look at Crane cams. I have been buying Crane valve train parts since 72. Never had a problem with them until hydro lifters where being made from some company that was not Johnson or the other main hydro roller lifters. It's about supply, demand, and who's paid for in DC. Taxes on imports is half of what we paid to export. Who thouight this idea up??? Rick L.

D-CEL · #18 (**permalink**) 10-20-2011, 05:23 PM

Eljaro,

I feel for you brother! That is awful. It is interesting (to me) that it broke under acceleration at only 5k rpm. We always used to break cranks on (the transition) deceleration going into turns.
I would be happy to evaluate the failure (at no cost) to try to determine the cause. Ship me the broken end and Ill have a FA done on it and post the results and some photos.

Jason

Michael4yah · #19 (**permalink**) 10-20-2011, 06:07 PM

Rick, its all about globalism. The people we elect are more interested in the global agenda than helping Americans. Not one single time has any elected leader in the USA explained how the working American can compete with someone making 20 cents an hour and living in a cardboard shack. Im voting for Ron Paul.

Barry_R · #20 (**permalink**) 10-20-2011, 06:37 PM

Cranks - in no particular order

We did this to ourselves. Nobody else to blame.
I tried - hard - to get U.S. suppliers interested in making cast 383 Chevy cranks back in the 90's when I was running the parts side of F-M's performance program. They always claimed that there was not enough volume to do it and turned me down without ever even trying to do a quote. I was stunned - and if they would not do the SBC what are the odds of them doing an FE?

I have run the cast Scat cranks that retail for under 700 bucks in FE engines at documented dyno power levels approaching 800 horsepower, and in five years they have proven to be startlingly durable. Realistically they should probably not be considered for a road race, continuous load application beyond 600 or so - but they are living in that environment better than anybody would imagine.

In FE forged cranks you have a couple options - RPM and Scat. The RPM forged cranks have been around for a few years now. Intuitively they should be stronger than the castings - they are definitely forged. They theoretically retail for around the same price as the Sat castings, but the machining quality is marginal at best, and you need to budget a couple hundred extra to square them up - assume around $900 for one that is truly usable. Probably a modest upgrade. No way to verify actual material - caveat emptor.

The Scat forgings are fairly new to the market, and are decidedly different than the RPM in terms of forging quality, shape, and machining. Costs a couple hundred more, but worth it without question. Probably the best choice for 700+ horsepower and/or mid-level road race use.

At the top of the pile are billet cranks. Most billet cranks are the only FE ones that are domestically made. Scat is the only supplier that does both offshore sourced castings & forgings, and domestic billets. The other billet suppliers include folks like Moldex, Bryant, Crower etc. Billet cranks are what you really want for seriously high power (800+) or professional level road racing applications. You also want to keep at least $2500 or more set aside for one of these.



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