Twinchargedlsx

So I've had two engine now that had rod failure on cylinder 5 and 6. But all the rest of the rods are fine. One engine was an lq4 and now and LSX engine. I was wondering if anyone knows why those rods are breaking?

Jontall

They are installed backwards? https://ls1tech.com/forums/generatio...y-install.html

KCS

iTrader: (20)

Can you provide more info? Like what rods? What application (guessing power adders)? Fuel? Has your machinist/engine builder had a chance to look at it and give their diagnosis?

Twinchargedlsx

Forged powder metal rods, 91 octane, turbocharged and they were crate engines. All the other rods are perfectly fine. Not bent or heated.

KCS

iTrader: (20)

Pictures? What happened to the pistons?

Twinchargedlsx

Twinchargedlsx

Pistons and heads are fine. No stamped valves or anything. Rods just snapped.

redtan

iTrader: (5)

How much boost, power and RPM were you running.

Sounds like you need some better rods, dunno why you went with the stock ones yet again after snapping the first set. They are good rods, but they still have limitations especially with boost.

Twinchargedlsx

It was a crate engine with warranty or I would have changed rods. And we had t red lined 400 rpm below max recommended. Just dunno why those two went but the others show no sign of stress

Gray86hatch

iTrader: (83)

Oiling issues

Tim

Twinchargedlsx

Bearings have no scores or heat marks tho? And no signs of wear?

FourG63 97GST

iTrader: (1)

sounds like you don't want to accept that you're just overpowering them.
since you're keeping the details to a minimum, unless you're trying to warranty this one too

Twinchargedlsx

Boost was set at 12ls made 621 rwhp. But Chevrolet performance is warranting it. Thanks though guys.

redtan

iTrader: (5)

So you're going to pull the engine apart and send in the rods for warranty every month now?

Great that they're taking care of you, but clearly you need some better rods unless you like tearing into your engine and sitting around while GMPP sends you a new set then doing it all over again next month.

Twinchargedlsx

Yeah I believe I'm gonna change the rods this time around and upgrade to Callie's. It'll void the warranty but at least my engine will last