577 SOHC Post Mortem

[WConley]

Re:  Using remaining rods.

Knowing Jay, he's probably going to set those aside.  I think after a good non destructive inspection, and maybe a dose of shot peening, they'd be great for a less demanding future project.

JMO, of course!

[jayb]

Bill, that is exactly what I plan to do.  Those rods ought to be fine for a run-of-the-mill 800 HP engine 

[My427stang]

Re:  Using remaining rods.

Knowing Jay, he's probably going to set those aside.  I think after a good non destructive inspection, and maybe a dose of shot peening, they'd be great for a less demanding future project.

JMO, of course!

Me too, matter of fact I'd change brands and go overkill but I am pretty conservative.  It helps at high altitude in unfriendly places

But for me they wouldn't go in anything until I had some sort of definitive-ish  test, same lot, same metal, who knows if one of the others isn't a day behind it or  30 days behind it at 600 hp?

So still the begs the question, is there anything that anyone can do?  I know they do a lot of fancy NDI to our airplane to check compressor blades, even fuselage structural stuff.  Is there just x-ray and mag for these or is there something else?  Also would x-ray show a little defect as a "occlusion" or spec with a different density?

Don't take this wrong, but less concerned about that rod than the science behind potential NDI.   Work is keeping me from building a turbo build for at least a year, but potentially planning something with less rotating and reciprocating weight than this build but more power.  So this is a pretty good "thinking time" while the AF has me separated from the fun

I'll go tactical geek on you and  throw out a response I give to my guys for crisis management.

- Initial conservative response or heroism (heroism doesn't apply here....but it could in a real crisis, can't always be conservative)
- Gather information
- Turn to the offense

Step 1 - Bring the car home
Step 2 - Figure out options, testing and backup plans
Step 3 - Jay comes back out with even bigger guns

So Jay is in step 2, and I am trying to avoid the entire checklist by bootlegging

[sumfoo1]

What's the bore/stroke on it..  i'm pretty sure those are the rods in my engine  but she's only a 511...

maybe i shouldn't plan on making it into a blower/turbo motor.....
 

Are those the maxi light or the regular billet?

[jayb]

Bore/Stroke is 4.47/4.6, and those are the regular billet rods, not the maxi-light rods.

[cammerfe]

"...even bigger gun..."

600+ CID High Deck!

KS

[Lenz]

Bill, that is exactly what I plan to do.  Those rods ought to be fine for a run-of-the-mill 800 HP engine 

Nothin' quite like a "run-of-the-mill" 800 HP engine - I'd sign up for one of those if they came at run-of-the-mill cost 

[jgkurz]

Just my .02C but I'm looking forward to seeing what Crower says about the rods. The FE folks in my circles swear by Crower and have had no issues at some big power levels. I am a complete rookie and haven't earned my stripes yet, but I'd still run Crower without hesitation. However, it now seems like a good idea to hedge your bet with any rods and x-ray/maganuflux.

[sumfoo1]

Bore/Stroke is 4.47/4.6, and those are the regular billet rods, not the maxi-light rods.

crap... think i'll be ok/better keeping the rod angle a little more vertical and slinging a smaller piston?

I'm kinda pissed i went with crower over oliver cause they were making everything else... this motor was built with the ultimate goal of being a 6500-7500rpm motor under 20psi on e85 from day 1. 

[cjshaker]

I think the rod failure was just a fluke, albeit a very bad one. There are lots of guys consistently running those rods for years on end making 1000+hp. BUT, having said that, I would also be hesitant to use them again in Jays case. Once you get bit it's hard to overcome that feeling. It would be interesting to do a careful center-to-center measurement on the remaining rods to see where they are.

And the problem with second guessing another set of rods and going the full X-ray treatment is where do you stop? Crank, pistons and pins, rockers, valves, cams, retainers, even blocks themselves....they can all cause a catastrophic failure due to a not-visible-to-the-naked-eye minute flaw. If you don't overcome that fear the next engine will end up costing you thousands more and you'll still be afraid to run it hard.

[Qikbbstang]

You think a rod is pretty sturdy and not subject to flexing.  I was in a local performance machine shop that had a factory stock road racing Viper motor in for rebuild as it was tired - the builder was surprised to find the cast oil main that resides in the center of the alum block under the lifter galley had a series of "machined" notches where the rods had been flexing their stuff and contacted the casting.
        I enjoy reading about shot peening and have a feeling anyone strolling into a facility to have their rods x-ray'd may find themselves in the same sort of pricing mess that they'd find themselves walking into a shot peening shop. There's literally thousands of shot peening "mix" combinations that range from speed of shot, type of shot, mass of shot, duration of shot etc.. When Joe Average walks into a shop and asks to have a mystery set of rods shot peened, the reality is the guys all laughing like the "you want it when?" comic sign comes into play. There is enormous skill involved just to determine what the right combination of the above "mix" is to properly shot peen the rods. (this in itself is a service that takes the time of a knowledgeable individual = $$$)  The fact that these are used rods further puts the peener at a disadvantage because he does not know what peening was previously done to the rods, heat treating and for that matter even the alloy. I'm not even going into they use strips placed beside the product being peened to determine the degree of shot peening received and nor did I mention you get surface hardness and depths of hardness. The problem is IF the shot peening is not correct the surface can be to hard and more subject to a failure point starting.
          I'd think strolling into an X-ray lab and asking for rods to be x-ray'd may involve all sorts of variations and complications ...If you had 20 sets of rods and planned to bring in more each month that's one thing BUT I have a feeling you could end up with a bill that is right there with the cost of a set of new rods just walking in with eight rods to x-ray. 
         I find it fascinating that the "defective" rod in Jay's motor likely saw 10,20,30 or even a whole lot more max rpm/max power cycles while it was literally hanging on by a thread (a forged steel thread but just the same). That thread was progressively getting smaller and weaker as that inclusion opened up/was sand beaching itself.

[cbolze]

http://en.wikipedia.org/wiki/Stress_corrosion_cracking
http://corrosion-doctors.org/Forms-SCC/scc.htm

Jay, first my condolences to you on the early end to drag week. As it has been pointed out by others on this forum and thread topic concerning the failure of the number 5 connecting rod, I would like to add a few comments for thought. Looking at the fractured end of the small end of the rod, it shows the classic crack propagating fatigue failure, no need for magnification here! The crack started on the inside edge of the beam, worked its way across the beam and into the web where cyclic loading caused failure. No doubt the crack started with a stress concentrator or riser, could have been a small nick, scratch, dent or gouge. It does not take much where a part is loaded with high stress and heat. Stress risers are easy to inspect for on a part like a connecting rod, just look for scratches, nicks etc. Also all the beam edges of the rod should be rounded, no sharp edges at all as sharp edges are a stress concentrator looking for a place to start. It would be interesting to get an elemental analysis of the alloy of the rod. It would be easy to do as only a small piece of the rod is needed (plenty of that in the windage tray  ) and sent to a testing lab. Our lab here at work could do that but I'd need a job order. Maybe Crower has the alloy in their records. Why the alloy? If the chromium levels are high enough, then there is the possibility of chloride stress corrosion that lead to the rod failure, which stainless steels are very susceptible to. See the attached links. Where does it come from? Chlorinated brake cleaners are the best source for this. Check and see what's in the cans of brake cleaner if you are using them. I even doubt if the can says its nonchlorinated if it really is. The Navv deals with detrimental material control for everything used in the nuclear program, due to the use of stainless steel for the plant. Halogens (Bromide, Chloride and Fluoride), sulfur and mercury are the worst ones, we get certified leaching tests to hold the limits to 250 ppm on the halogens and 10 ppm on the hg (read low!) Just something else to think about. So don't use brake cleaner on those high dollar stainless steel rod bolts!
Courtney.

[Qikbbstang]

BBC Carrillo Rods $2,700/8 includes CARR bolts that are normally a $50per rod option.  This is competitive pricing on a set of common size BBC Carrillo Rods, obviously quite difficult for most to swallow but then again so is a broken rod.

http://teaguecustommarine.com/em0011/carrillo-pro-h-rods-417.html

[jayb]

I agree with the previous comments that Crower makes an excellent rod.  My 1200 HP supercharged FE ran the same Crower rods as the SOHC engine and has never had a problem, and that engine saw even more use than the SOHC has.  So I think I just got a bad rod, and I'm inclined to go back to Crower for the next set.  Maybe do a custom version with a thicker beam or something...

[KMcCullah]

You could spend more and not get a better rod than the Crowers I think. Just got a bad one that slipped through QC. The beam design seems to be a popular one, so it must be a strong one. Heck even the mass produced oriental stuff looks very similar.

http://www.racingpartsmaximum.com/sae4340ibeam-3.html

 I'm rethinking my choice of Scat 6.7 I beams now. I thought I would be safe using them and going with the ARP 2000 bolt upgrade since I've seen so many BBC rods with the big end stretched or broke. With this length of rod I don't think the big end is the weak point now. I think it's the beam if the metallurgy isn't spot on.