...

 

Wow!

 

ouchy i guess you were not at idle speed?

 

.

 

Oooooffff that's a tough one.

 

Valve float I assume.

 

.

 

"How does that even happen?"

Harmonics

 

.

 

Sucks, but now is your chance to build an even better one! We can build it, better, faster ...stronger. I see to have heard this before! lol

 

Thats possible, but I did see a awful lot of holes drilled in your crank, that always makes me nervous.

 

.

 

Correct as the rods and pistons get lighter weight has to come out of the counter weight side of the crank. But the correct way to remove weight is to cut the counter weights down, this leaves you with less holes which can hold oil.

 

I can appreciate that, plus you're concentrating the weight closer to the centerline. In a perfect world with unlimited funds.....

 

Sorry to hear about this happening.... really stinks.


So, what is your plan? Is it in the cards to do a new build with all new parts, starting over?

 

.

 

ouch that just makes me cringe. Give opportunity to start fresh????

 

.

 

That is not your bob weight. How much does the rod weigh? I would bet your bob weight will be around 1800-1900 grams, But that is fairly light for a Olds, but then then again how reliable is a aluminum rod in a street strip car?

 

.

 

Ok, so lets look at the math.

820 grams approx Piston, piston rings, wrist pin, locks
175 grams approx small end of rod
995. Total

432 grams big end of rod
55 grams rod bearing

432+55=487X2=974+5=979
979 total

995+979=1974 Bob weight. For example the last 455 with steel rods I built had a 2120 gram bob weight.

This should be close to your bob weight. Theres no problem until one of those rods breaks, hopefully that doesn't happen, I know on our race cars we replace them after 150 passes. I've been told people have been running them on the street, I guess oil temp is important. What weight flywheel do you run?

 

The problem with aluminum is it doesn’t have a fatigue limit like steel does. Meaning no matter how low the stresses are, it will eventually fail from fatigue. Steel, in theory, can be designed to never fail from fatigue (in practice there are always microscopic flaws that will eventually cause failure, but nowhere near as soon as aluminum).

So by running the engine on the street, you’re putting fatigue cycles on rods that have a limited number of cycles before breaking.

One reason they tend to be limited to race cars is that it’s much easier to keep track of use. Street driving has variable loading that makes it more difficult to know when they’ll fail than the predictable environment of racing. Aluminum rods are essentially a maintenance item.

 

Did I miss all the rod failure threads? Seems to be a bunch of theory and speculation. I'll let you know when I break one. Later, fvcknuts!

 

Apparently - there are plenty out there.

Yes...theory taught to every engineer on the planet who designs every piece of machinery you've ever directly used or indirectly benefited from.

Best of luck. Hopefully they're built for an absurdly higher power mark than you're putting out.

 

This is strange, what happened to this thread??

 

That sucks!
Good luck with the new engine build.I don't know of anyone that beats on there engine without eventually hurting it.
Thanks for sharing and the heads up on the importance of valve spring choice and maintenance.