Rod failure

Not really a question I just wanted to share some information. A while ago I built an engine for myself using left over parts from my old mans bracket car. I had a 4.150 stroke RB crank that I had welded and repaired. I had four used eagle h beam rods. I posted an ad in the wanted section and a nice fellow sold me three used rods to match mine. I ordered one new rod from Eagle to complete the set. I also still had a nice set of pre tested (used)JE dome pistons. I toped it off with a set of stage 6 heads that I built right after I bought my flow bench. Long story short the engine in my fathers car cracked so in the interest of time I let him use the engine I had ready. And as it goes this engine worked very well. The 2800 pound Duster ran 5.72's. Almost matching the best time of the B1 engine that it replaced. Lived through one ring and pinion, my fathers great idea to try 5:13 gears, and a transmission failure. Over 200 passes. Well the other night at Red River (now Thunder Road) during a time trial water on the track caused the engine to over rev its last time. The pics are of one of the used rods.

pics

That blows. Hi high did it go?

Looks like it was very well pre cracked, What else did it hurt?

Oh just about everything

I do think it was cracked and I just didnt catch it.

Fell your pain as we had a similar issue in November. Had a similar rod issue as well. Trashed everything including a nice megablock

Maybe time to start praying to the Rod God that my Eagles don't try to come out in so many pieces like those did.

Oh that's just one side. The other side is no prettier

Not sure but he has a 7500 pill in the rev limiter.

Thats not good. I only lost a factory block.

The other side..Took out about a 7" long section once we got it all apart.

Just curious, how did the piston pin look on the failed cylinder? Slide out of the piston OK?

I got one too. From last weekend (5-2), OEM crank failed, tried to pitch the 5/6 rod journal out the side of the block. Stud girddle and steering link tunnel in the oil pan kept it from being any worse than it was (I ran over a large piece of the block w/ the right rear slick at 100+ mph)
Ohio Crankshaft H beam rods bent, but didn't break.

Brian

the pin looked fine! why?

A few years ago I decided that stronger pins are better for the long run (1000 passes). Rather then the 0.155" wall pins in higher power applications the piston manufacturer's now offer 0.185" wall pins.

Well I started on our replacement B1 low deck. I ordered some new Scat HBeam rods to complete the rotating assembly and one of the rods is defective out of the box. .003 over sized on the big end. As in 2.503. Im shocked, and awaiting word from Scat on what to do.

If they are numbered close id send the whole box back and ask for a new full set, who knows if the same person/shift/batch are ok.

Its your money, you should expect decent parts. Another example of why its best to check things asap after receipt.

From the rust on some of the edges of the broken rod in the first pic, i would say it had been cracked for quite some time - possibly before you installed it - there would be no reason for rust to form inside a motor with oil flung everywhere regularly

Im sure they will be cool about it and replace them. But now I have to answer to the old man

I'm glad you mentioned the rust. I was intending on sharing something that I found out the hard way about blocks that have been crack repaired. DON'T USE THEM As I stated in my first post this engine was built using parts that really had no value. Perfect place for me to test a repaired block.

I do believe there is something to pin strength depending on the piston weight and power production. I have a friend that used TRW pistons in his 440. To help reduce weight he removed material from the inside of the pins. During a tear down and inspection he found a hand full of pistons that cracked in the pin boss area. I still can't convince him that the pins flexing is what caused the cracks.