577 SOHC Post Mortem

[rcodecj]

I am amazed that the block is considered repairable.

[Barry_R]

I side with the defective part group.

A mid-beam failure is definitely not an assembly issue.

I believe that you could put about hundreds of pulls and passes on a drag race rod without approaching the cycle life of a serious oval track or road race effort in a single race.  I also do not think piston weight or piston speed were outside of the expected life parameters for a good billet rod - only a couple hundred pulls or passes ain't that much in the context of such things.  I suspect a flaw in the material.  Does Crower use a 300M or similar?  Seems to be the current darling of the oval track crowd these days.

I wonder if your elusive rod knock noise could have been piston to head contact as the rod stretched prior to failure - would have quieted down with variances in temperature?

[fe66comet]

I see the suggestion has already been voiced but I thought. I would throw it out there anyhow. In my SB chubbies I used to run Carrillo rods and Venolia pistons. I could run that set up with a 400 crank up to 8 Gs all day long. For some reason the aluminum rod and of course the lighter piston helped immensely with stabilizing harmonics. I actually still have the engine as it held together for over 10 years of severe abuse and street ( Ahem) use LOL. I did however have issues with melted pistons due to alloys were not what they are today. One issue I ran across a lot is the invariable rod twist that occurs naturally does do the paper clip effect eventually on steel, the harder the steel the more brittle it becomes. This natural twist from loading and unloading of course has a greater effect on steel than something like 7005 aluminum.  1540 steel and 7005 aluminum are both heat treated metals but aluminum is more forgiving. Just some food for though :-)
 

[Ford428CJ]

Man.... Super sorry to see and hear that Jay! With those light weight pistons and all... Wonder if the rod material had a defect in them and you found the one that did. Anyways, I hope things go better for you Jay!!!

[CaptCobrajet]

All good points by Mr. Conley, and Barry mentioned the 300M.  You can get them, but they are spensive.  I think a little more meat in the beam couldn't hurt.  A feller could also X-ray the new rods, and be sure there are no issues beforehand.  An X-ray is cheaper than a redo.  It ran alot considering the power level, and the stroke.  Most engines that run sustained have no where near that power level, or that stroke, or that piston weight.  I worry about the fuel, the rev limiter, and maybe the need for a larger diameter on the damper.

[Barry_R]

Welding is a comparatively easy deal in Detroit.
You just need to bring your checkbook.
Marcella would weld that one up in a minute...in his sleep.
Razor could do it underwater...blindfolded.

[Joe-JDC]

I agree with material failure as the most likely culprit with the mid beam break.  I also wonder if there is an issue with the offset cylinders causing stress on the rods and sideloading them unevenly.  I would not consider re-using any of those rods until they were thoroughly sonic tested or x-rayed for metal fatigue.  I also agree that piston speed is not a problem for short bursts of time at your rpm/stroke.  Sorry for the carnage, it would/will be interesting to know how quick you can go with a healthy engine.  Joe-JDC

[blueoval67]

2X on the material flaw with that rod. At these power levels X-raying them is the way to go no matter who's rod they are. We broke an Oliver rod at the beam on a 331 SBF making 1500 hp. The crank and all the other major parts were saved but the piston was turned sideways in the bore so the block was junked. It did end up being a flaw with the rod after closer examination. I'm really bummed about the breakdown Jay, very sorry. Like they said about the 6 Million Dollar Man (1 Billion in todays $$$) Steve Austin...."we can build him better, stronger, faster"....

[jayb]

Got the engine the rest of the way apart yesterday.  The #5 piston wasn't stuck in the bore too badly, and came out with a couple of taps of the hammer handle from underneath.  After I got it out I knocked out the pin and gave the remains of the rod a good once over.  Sure enough, there were the striations that Bill Conley had predicted:





In the oil pan I found various shards of connecting rod, but most of it was missing, obviously exiting through the hole in the pan or the block.  Here's the broken #5 rod next to the intact #1 rod:



That is a LOT of material that went flying out of this engine LOL!

The only other area of real concern was the left head, and I figured I got off light there because the valvetrain still looked good.  After pulling the head I cleaned up the chamber and saw some witness marks where the piston had smashed into the chamber.  Here's a picture of the #5 chamber:



This really isn't too bad, and I'm sure I can still run the head as is after cleaning up the chamber a little. 

This week I'll get the crank into the shop to get checked and work on finding someone to weld up the block.  If I can't find someone around here to do it I'll ship it to Barry and he can have Marcella or Razor do it.  I'll have to make some decisions on the rods, get some new pistons and sleeves ordered, etc.  Depending on part lead times I should be able to get this engine back together early in 2015.  When I get it back together and on the dyno I'll post the results in the technical forum.  In the meantime, now that Drag Week is over, I can get back to my endless list of other projects 

[mike_burch]

If I can't find someone around here to do it I'll ship it to Barry and he can have Marcella or Razor do it.  I'll have to make some decisions on the rods, get some new pistons and sleeves ordered, etc.  Depending on part lead times I should be able to get this engine back together early in 2015.  When I get it back together and on the dyno I'll post the results in the technical forum.  In the meantime, now that Drag Week is over, I can get back to my endless list of other projects 

Barry was referencing those guys to weld up that ROD.  The block will be too easy for those guys!   

Good Luck, and I'm glad it's not nearly as bad as it could have been!  I guess you'll be getting the rods checked for cracks whenever the engine is down from now on? 

It's so odd that you got a flawed rod like that from Crower.  I guess when you're pushing parts like that, flaws that would go unnoticed by lesser engines, make themselves known when you're pushing almost 1000hp at close to 8k rpm.

I admire your positive attitude!  That, and your energy can be contagious! 

[jayb]

  I guess you'll be getting the rods checked for cracks whenever the engine is down from now on? 

Boy, you've got that right!  I always considered the Crower rods "forgettable" because they have such a stellar reputation.  Now, not so much...

By the way, nice to see you here, Mike!

[turbohunter]

I'm no metallurgy specialist but it sure looks like there are some voids in the center of that casting.
It looks like a casting to me anyway.

[machoneman]

Wow, Mr. Conely was right on the money! Impressive.

But, Bill do you think an x-ray would have shown this? I wonder.......

[WConley]

Sometimes it's not fun to be right 

If you follow the striations to their center, it looks like a flaw at or near the surface.  Magnaflux would probably have caught that, but X-rays aren't as effective at spotting stuff near the surface.  Like Barry says, there really weren't very many cycles on that piece.  It must have been a pretty sizable flaw...

It would be interesting to see a magnaflux inspection of a few more rods.  That would really tell you if it was a fluke. 

The photos that Jay posted above could go right into a Strength of Materials textbook.  This failure could possibly have been prevented by shot-peening, but it depends on the alloy and heat treating.  Crower could give more insight on this.

I'm glad to hear you're on track to get the engine back together!

- Bill

[cjshaker]

If you follow the striations to their center, it looks like a flaw at or near the surface.  Magnaflux would probably have caught that, but X-rays aren't as effective at spotting stuff near the surface.  Like Barry says, there really weren't very many cycles on that piece.  It must have been a pretty sizable flaw...

- Bill

Bill, just trying to learn here. Are you saying the flaw was in the material or the machining process? If it was below the surface it would seem likely that it would have been a material flaw, something that should concern Crower themselves. If on the surface, then perhaps a result of the machining process itself?

It's also interesting that you say a magnuflux would have likely caught that but an X-ray probably wouldn't have. I thought the whole purpose of an X-ray was to see flaws within the material itself and that magnufluxing only detected surface flaws? It reminds me of the airliner that crashed at Sioux City, Iowa that was traced to a small internal flaw in a turbine blade that was smaller than the size of a piece of tiny sand. At these power levels it does drive home the point that even the smallest surface "nick" can lead to catastrophe, and that the high stress components like rods and cranks should be treated with kid gloves.

And Jay, thanks for sharing all of this so that we can all learn. Bills signature saying is something we should all strive to remember...."A careful study of failure will yield the ingredients for success."