Bent rod - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Samspeed · 01-25-2023, 11:26 PM

Can a tuning issue cause a bent connecting rod while hitting the rev limiter?
Car is a 2010 ss with lsa blower. 2.5” upper Btr stage 3 cam headers cat delete e60 with zl1 pump and bap. Happened on a 2nd gear hit from 3,000 rpm , tires unloaded around 5,500 rpm and it hit the limiter. Let out immediately and there was a rattle.
Checked rocker arms/ springs / push rods all looked excellent.
Pulled plugs and checked gaps. They were good.
Turned engine over by hand and it stopped
Pulled cylinder heads and all the valves look great
Head gaskets are in excellent condition as well.
The intercooler brick is double plates and in excellent condition.
Pulled the engine and discovered the number 1 connecting rod was bent causing the piston pin bosses to make contact with the crank counter weights.
Any thoughts on the matter is very appreciated!

rednecks70 · 01-26-2023, 09:03 PM

Hopefully someone else who is more knowledgeable will respond but I'm curious to know how much power your making. Maybe the stock rods just aren't going to take the power your making.

xdamxincx · 01-26-2023, 09:09 PM

whats the plug look like ?

Vicster · 01-27-2023, 05:30 AM

Sorry to hear about your problem! Are you using stock LSA or after market rods?

Bent rods are commonly caused by hydro-lock. You will want to have your fuel injectors checked! The injector maybe leaking after shut down.

ZMEnow · 01-27-2023, 07:01 AM

Quote:

Originally Posted by Vicster

Sorry to hear about your problem! Are you using stock LSA or after market rods?

Bent rods are commonly caused by hydro-lock. You will want to have your fuel injectors checked! The injector maybe leaking after shut down.

Seems he has a stock LS with LSA blower and boosted. If that is the case, it was only a matter of time..

GT Kilr · 01-28-2023, 07:05 AM

It depends on how much cylinder pressure it was making. Rods bend at peak torque not hp and you definitely aren't making peak torque at the limiter so it probably bent before the tires unloaded.

Samspeed · 02-01-2023, 12:37 PM

It made 755whp/687 torque on E83 on a dynojet. this was with about E60 . Plugs look good .
I’m still going to have the injectors flowed to isolate any hydrolock condition. I had the tune file looked over and he didn’t find anything out of the normal that would cause this. He also thinks it just made too much torque for the stock rods.

FasNuf · 02-01-2023, 02:57 PM

That's starting to up there even for OE LSA powdered rods. Nice time to forge that bottom end if the block is good.

ZMEnow · 02-01-2023, 06:34 PM

Quote:

Originally Posted by FasNuf

That's starting to up there even for OE LSA powdered rods. Nice time to forge that bottom end if the block is good.

Reading his original post he only mentioned LSA blower in an SS, so still assuming its an LS not LSA. Fun for a little while then they all go boom...

Pkeen · 02-05-2023, 08:53 PM

Quote:

Originally Posted by xdamxincx

whats the plug look like ?

Badass looking camaro !

Samspeed · 02-23-2023, 11:14 PM

Thankyou to all of you guys that gave some knowledge on my unfortunate experience.
I’m going to chalk it up as a weak rod. My tuner is a top tier stand up guy with all the best intentions knowing my ls3 was a stock bottom end engine.
It made really good power even if the dyno is generous, how generous can it be?? it put down 755whp and 687wtq on E85 stock bottom end., I believe the BTR stage 3 torque cam and JLT big air CAI with a 2.5” upper makes some serious power on a stout LS3. Along with a set of Speed Engineering 1-7/8” LT with cat delete. Stock LSA blower with ZL1 pump and JLT BAP. Stock clutch and everything back.
Building a fully forged 407 stroker now. Hopefully get the same power dependably!

01-25-2023, 11:26 PM	#1
Samspeed Drives: 2010 2ss Join Date: Jan 2022 Location: Arizona Posts: 11	Bent rod Can a tuning issue cause a bent connecting rod while hitting the rev limiter? Car is a 2010 ss with lsa blower. 2.5” upper Btr stage 3 cam headers cat delete e60 with zl1 pump and bap. Happened on a 2nd gear hit from 3,000 rpm , tires unloaded around 5,500 rpm and it hit the limiter. Let out immediately and there was a rattle. Checked rocker arms/ springs / push rods all looked excellent. Pulled plugs and checked gaps. They were good. Turned engine over by hand and it stopped Pulled cylinder heads and all the valves look great Head gaskets are in excellent condition as well. The intercooler brick is double plates and in excellent condition. Pulled the engine and discovered the number 1 connecting rod was bent causing the piston pin bosses to make contact with the crank counter weights. Any thoughts on the matter is very appreciated!

01-26-2023, 09:03 PM	#2
rednecks70 Drives: 2013 AGM ZL1, '70 Chevelle 454 Join Date: Apr 2019 Location: Willow Grove, PA Posts: 105	Hopefully someone else who is more knowledgeable will respond but I'm curious to know how much power your making. Maybe the stock rods just aren't going to take the power your making. __________________ 2013 ZL1, M6, AGM, CAI, 1 7/8 Kooks Headers, 10% OD Pulley, ID1050 Injectors, 575 RWHP

01-27-2023, 05:30 AM	#4
Vicster Drives: 13' ZL1 Join Date: Jan 2013 Location: . Posts: 396 View My Garage	2 Cents Sorry to hear about your problem! Are you using stock LSA or after market rods? Bent rods are commonly caused by hydro-lock. You will want to have your fuel injectors checked! The injector maybe leaking after shut down.

02-01-2023, 12:37 PM	#7
Samspeed Drives: 2010 2ss Join Date: Jan 2022 Location: Arizona Posts: 11	It made 755whp/687 torque on E83 on a dynojet. this was with about E60 . Plugs look good . I’m still going to have the injectors flowed to isolate any hydrolock condition. I had the tune file looked over and he didn’t find anything out of the normal that would cause this. He also thinks it just made too much torque for the stock rods. Last edited by Samspeed; 02-01-2023 at 12:47 PM.

01-26-2023, 09:09 PM	#3
xdamxincx Banned Drives: zl1 blk Join Date: Nov 2017 Location: sth fl Posts: 152	whats the plug look like ?

01-28-2023, 07:05 AM	#6
GT Kilr Drives: 2011 RJT 2SS Join Date: Jul 2017 Location: Georgetown, KY Posts: 26	It depends on how much cylinder pressure it was making. Rods bend at peak torque not hp and you definitely aren't making peak torque at the limiter so it probably bent before the tires unloaded.

02-01-2023, 02:57 PM	#8
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,640 View My Garage	That's starting to up there even for OE LSA powdered rods. Nice time to forge that bottom end if the block is good.

02-23-2023, 11:14 PM	#11
Samspeed Drives: 2010 2ss Join Date: Jan 2022 Location: Arizona Posts: 11	Thankyou to all of you guys that gave some knowledge on my unfortunate experience. I’m going to chalk it up as a weak rod. My tuner is a top tier stand up guy with all the best intentions knowing my ls3 was a stock bottom end engine. It made really good power even if the dyno is generous, how generous can it be?? it put down 755whp and 687wtq on E85 stock bottom end., I believe the BTR stage 3 torque cam and JLT big air CAI with a 2.5” upper makes some serious power on a stout LS3. Along with a set of Speed Engineering 1-7/8” LT with cat delete. Stock LSA blower with ZL1 pump and JLT BAP. Stock clutch and everything back. Building a fully forged 407 stroker now. Hopefully get the same power dependably!