[fbernard]

Well, of course, when I say it's a nice surprise, it takes some explaining....

I already knew the crank was broken before taking it all apart, I just wanted to know if the bleck was also toast of not.
Turns out it's alright, and even the rods and pistons are OK.

One more happy Eagle customer here...NOT!

[Adrian Worman]

How old is that piece?

[dave-r]

That is down to a flaw in the casting.

[Eddie]

I would like to know the history of that Crankshaft! What was the bearing clearance? How high did the engine rev to? Any detonation? Is it an Eagle 4340 Forged crank or a cast piece? Failure of a 4340 Forged Crank is pretty rare. What did the bearing shells look like? Stock oil passages in the crank saddles?

[fbernard]

That's the engine which was in the cuda when I bought it.
A friend of mine had it built in the USA then shipped here.
It had some detonation (which we later traced to a poor piston choice), which killed two pistons and led to a rebuild by another shop in France.
I don't know whether it's a cast or forged piece, I'll check.
I know it looks like a flaw, the way these indentations are in the metal.
Before taking it apart, I had other suspects. My damper problem from 2010 (the Professional Products damper which separated was on that engine). But that alone breaking a crank, I don't think so.
I found out the French shop had numbered the cylinders 1-2-3-4 on the driver side, and 5-6-7-8 on the passenger side, and I heard they had a hard time starting it the first time... No kidding!

I found out last week that another guy on Moparts had the exact same picture, crank broken right after the front main journal.

I drove to a drag race in 2011 (400 miles), thinking my clutch was not in the best shape (It had been racing for 3 years then). I started noticing a bad vibration by the time I got there (which I attributed to the clutch), and decided to drive back home without racing, to make sure I'd make it with my ailing clutch. Alas, the clutch was not the problem...
That crank drove me home for 400 miles, and the pressure was OK.

I really don't like the oil pressure sender position on the small-block, I'm thinking of someway to install a fitting in the driver side lifter galley, after all the mains get their oil. The current sender position (right above the pump), with a high volume oil pump, just means "pump is rotating".

Only the front main bearing is dead (worn to the copper, but much less than I thought, I believed the block would be worn too there). The #1 rod bearing and journal showed some wear, but nothing extraordinary.

I have yet to do a full blueprint of the parts I have (especially the bores and pistons) before I decide on what to replace. Crank only, rotating assembly, camshaft.
Some parts were a bit mismatched, and need a replacement.

This clearly won't make me a big fan of Eagle. Besides what happened to the clutch, I can't say I'm thrilled by the quality of the rods in this engine.

[Eddie]

Interesting! I wonder what the bearing clearances were,(on all the mains). A few guys are still in the old school thinking of bearing clearances in the .003 plus range. I think this is too much and causes crankshaft failure from flexing especially in higher RPM ranges, 6500 plus. Another thing, but not probably in your engines situation, is the oiling of the smallblock Chrysler engine. Many SB used a modified oiling system,,routing the oil from the cam galley back to the mains,,via a lifter valley tube. However, this also lessened the valvetrain oiling supply. It doesn't look like heat caused this. If you find anything during blueprinting,,let us know! The Vibration you experienced is clue and possibly sounds like a main was either out of round or excessive clearance was an ongoing problem that got worse with age! Was the damaged bearing that was worn to the copper underlay concentrically worn thru out the shell? Or only in one spot? The again it could be just a bad crankshaft I see that Tom Molnar is making some nice cranks for BB/SB as the K-1 Tech line, both Crankshafts and H and I beam Rods,,all in 4340 CM Steel. I hear some good things on other boards,,but have no experience with them. Good Luck!

[dave-r]

Fault or inpurity in the casting I am telling ya. It wouldn't matter what bearing clearances were it would still go eventually. The smallest fault in the casting will cause stress fractures that slowly grow until the part fails.
Obviously the more it flexes - the faster it will fail. But it was always going to happen.

[fbernard]

The #1 bearing was worn all around (and the crank snout/damper assembly could be move around 10mm in every direction before I took the engine apart! That's what had made me think the block was gone!

From the parts list I have ont he last rebuild, the block is bored 4.070, so +030 (I'll check this).
I have only light scuff on the thrust face on the #7 piston.

I already have some work on the heads (Edelbrock closed chambers, unported). Two chambers bear the scars of the first piston accident, so they're a little pitted, and I'd like to smooth that out a bit, then see if I can at least gasket match the intake and exhaust ports, etc. If I was in the USA, I wouldn't bother and send the heads to SDSS. I might still do this anyhow, depending on the shipping costs.
And I'll probably ask them or another reputable builder for a new, balanced crank.
Molnar Technologies is on my list, as is K1. Maybe also Mopar Performance, Scat?
I hear horror stories about Eagle and Ohio crankshafts, but I'm wondering how many different foundries in China actually make the forgings for all these different US-based companies...

I just want to make sure someone with experience and the proper tools checks the crank dimensions, does the machine work if needed, balances it, and ship it to me along with the appropriate bearings.

I like my clearances tight, my engines see a lot more street than race.

[Eddie]

I didn't see any parting lines,, smooth rounded surface,,looks like a forged piece.

Forged steel has a gain to it. When castings break they break like a "scab" as the steel has a chrystaline structure to it that the fault lines pread through. That is what that crank looks like.

Here is a couple of photos of the cast Eagle crank I fitted in my old Challenger.

[cv70chall]

Yikes!
I hate when that happens! At least everything else is ok.