Broke connecting rod?

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lance flake
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Broke connecting rod?

Post by lance flake »

I am in need of some help guys. I have had a rod failure an not sure why. Will post pics shortly

All parts new with about 40 passes. Engine has enderle hat/victor ram set up. 0 1/2 Ron’s pump on alcohol. Engine ran clean but not 100 % sure if tune up was perfect.

This guy has had a bad run and I am trying to find a problem. At the end of last year he had an aftermarket block sbc that had the main webbing broke in it (engine had lots of passes around 650-675 hp range). He put a spare engine in while we were building his new engine and it broke a rod after about 4 passs. I had nothing to do with these engines but new one with broke rod is all my build from scratch.

I will put the brand names out there if y’all want them. I am in no way putting a particular part(manufacturer) at fault. I just want to prevent another failure

Rod bearing good and wrist pin not seized up
lance flake
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Re: Broke connecting rod?

Post by lance flake »

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lance flake
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Re: Broke connecting rod?

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lance flake
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Re: Broke connecting rod?

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lance flake
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Re: Broke connecting rod?

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swampbuggy
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Re: Broke connecting rod?

Post by swampbuggy »

Lance Flake...with NO signs of blueing or seizing ....wow, it appears as if the rod just flat failed. American (or) off shore forgings ? Mark H. :(
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Re: Broke connecting rod?

Post by prairiehotrodder »

How high is it revving ?
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Re: Broke connecting rod?

Post by GARY C »

Can you post a complete layout like this?

It may give guys a better idea if hydroliced and compressed the rod causing the failure.

Also a shot of the top of the piston.

SAMPLE PICTURE.
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Re: Broke connecting rod?

Post by ProPower engines »

lance flake wrote: Mon Sep 17, 2018 11:34 pm 62CA9DF5-D649-452C-89D2-0822E5AC4CB9.jpeg
A pic of the upper bearing would tell more of the story. #-o
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lance flake
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Re: Broke connecting rod?

Post by lance flake »

2nd pic is upper shell
lance flake
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Re: Broke connecting rod?

Post by lance flake »

I will piece the rod together as best I can tomorrow evening

Something foreign did hit the piston but I don’t think it was enough to break the rod. Will get pic.

3.75 stroke 7200 rpm

Was not a cheap rod! Lol
lance flake
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Re: Broke connecting rod?

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Re: Broke connecting rod?

Post by lance flake »

What puzzles me is the 3 catastrophic failures in such a short time with 3 different build 3 different builders. Same fuel system and ignition system. 6 al2 Msd box

First engine ran for a long time. Lots of passes probably 1000 or so. The guy had fellow racer freshen it and it broke the block within that season
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Re: Broke connecting rod?

Post by MadBill »

Face-on pix of both surfaces of the break would be very useful. Pix/description of the chamber appearance too. Open headers I presume, so no chanced of finding a stray part that might have caused to piston damage?
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lance flake
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Re: Broke connecting rod?

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