Another Eagle casualty -

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Rat Patrol

Rat Patrol

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Although my engine was built "on a budget" - using KB pistons, Eagle crank and cast iron heads - The assembly and machining was done with a view to the engine withstanding 500HP if I ever chose to make it work that hard.

The block was sonicced and magged - the crank was index ground, the assembly was internally balanced, and the block was square decked and trued.

The engine has never been taken past 6200 rpm and at the strip sees little more than 5800 as this is where it performed best.

Imagine my dismay last week when after a half throttle squirt - the engine develped an appalling vibration and rattle.

Today I found out why - the #7 / 8 rod journal has cracked - the overlapping journal then caught the windage tray and ripped part of it out, and the bearings were demolished.

None of the bearings removed show any signs of heat or detonation - and the converter (PTC) and balancer (Powerbond) are both SFI approved.

So folks - THIS IS A SIMPLE CASE OF COMPONENT FAILURE IN A SITUATION WHERE THE PART SHOULD HAVE COPED EASILY.

I would therefore encourage anyone looking at building ANY engine - to ignore the temptation to save a few $$ on the alleged "500 HP rating" of Eagle cast cranks - and simply by something better.

I will be.

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Man that sucks something terrible. Nothing else was hurt? That's good at least. I would contact one of our resident engine pros and see what knda deal they can get you on a new crank. I would go with a SCAT if it was me.
 
Thanks Dusted - I'll be looking at a SCAT or MP cast crank - the engine will never make more than 480 at the crank as I'd be happy with that.

I just hope this serves as a warning to all and yu stay the H@%ll away from this cr@p!!

Don't believe the "up to 500 HP" BS!

- there were NO mistakes made in the machining or assembly - it was all done on the basis of making 480-500HP - I just "cheaped out" on the cam/crank/heads because I decided I didn't need a 500HP engine .
 
I assume it's a stroker. My first build will be a stock stroke 360 with stock crank and rods. I will eventually build a stroker....maybe. I want 400-425 at the flywheel so it should be no problem.
 
That really blows no matter what. Hopefully you can get it sorted out without killing the bank to fix it.
 
I could be wrong but isn't it a kind of rule of thumb that if the engine will be used with NOS that it needs a forged crank?
 
mullinax95 said:
I could be wrong but isn't it a kind of rule of thumb that if the engine will be used with NOS that it needs a forged crank?
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No where does it say it he was running spray on it. So anybody who has ever run a stockish motor a "NOS" will break?
 
mullinax95 said:
I could be wrong but isn't it a kind of rule of thumb that if the engine will be used with NOS that it needs a forged crank?
Click to expand...

No, but it depends on the egnine and the intended performance level of the NO2.

Mal - What do the backsides of the intact rod bearings and the parting lines of the caps look like?
 
The title of the thread should be "Another nitrous casualty" LOL
Sucks!
 
Hi,

the right rod in your lower pic shows signs of high pressure at the contact area to the left rod, don´t know if this is normal. Could it be that the left rod was put in wrong direction? side clearance was ok? Maybe this helps to find the cause for this damage.

Michael
 
Eagles cast cranks are junk but their forged are great.
 
i have a friend that runs 9.70s in his 408 cuda with a eagle cast 4" crank makes probably 600+ at the motor.. its made hundreds of passes at the track..
 
Quality Parts break too. Man, I hope my Eagle holds up! I pulled a pin out of a MP forged 340 piston while revving up my motor at a car show, how embarrassing do you think that was! When Eagle says all are X-rayed prior to shipping (from China) wonder what that means?
 
I run a nodular iron crank from ohio crankshaft, i think it's really just a scat/mopar crank...but anyways...I had it balanced but later went from .030 pistons, to .040 pistons and then even milled the quench domes off and never rebalanced it....I even later found the crank had it's trust surface ground too far to one end and that the crank had clearenced the block .020 on a couple main webs........but even with all that, I rev'd it 6600 rpm and it NEVER failed..lol...that eagle crap is just that, CRAP!!

never buy eagle anything other than h beam rods and maybe the forged cranks..jmo
I would rather run stock rebuilt 360 rods than run brand new eagle i beams.jmo

Sucks that it happened, hopefully it didnt wreck the rest of the parts, though id be having them rods checked and or resized..
 
Sorry folks - language issue - "Squirt " means "blast" or "run" - No NOS on this engine.

Moper - I'll ask the builder to check the backsides of the bearings -
 
360duster said:
Hi,

the right rod in your lower pic shows signs of high pressure at the contact area to the left rod, don´t know if this is normal. Could it be that the left rod was put in wrong direction? side clearance was ok? Maybe this helps to find the cause for this damage.

Michael
Click to expand...

The seperation of the journal caused the two big ends to "clash" and crush the bearings - thats why there is excessive side clearance now.

Like I said - there are NO build issue with this engine (except me using a cheap crank) - its been running 12 sec passes for 18 mths .
 
If you didnt have a windage tray, what would have happened? I mean the crank failed for sure but if it didnt create the windage piece in the bearings, what would we be looking at, maybe just 2 scored rods and a cracked crank?
 
BrianT said:
Half throttle squirt. I took that to mean spray?
Click to expand...

That's the way I took it.

Rat Patrol said:
Sorry folks - language issue - "Squirt " means "blast" or "run" - No NOS on this engine.

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Click to expand...

I should be used to the language issue. I'm a member of a Triumph motorcycle forum and there is a lot of members from AU. I do pretty good but ever so often I here a new word that I don't understand or I miss interpret word.

Sorry for you misfortune with eagle.
 
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