ma.jomaa

Hi All,

Sunday I took my c5 coupe with 112k miles on the clock to the track, and on my 5th session the motor made some noise for 3-5 seconds and went kapootz, smoke and oil everywhere, and found a piece of mangled connecting rod under the car when stopped. My question is what would cause such a catastrophic failure on these motors, I'm sourcing a good used LS1 now and want to make sure I address anything that would cause it before dropping the new/used motor in.

Thank you your input is greatly appreciated.

Josephu

Cause??? You ran the s*** out of it on the track and probably starved the rod bearings of oil. A lot of people forget that they have a stock motor and not a motor that was built for racing. You can only cheat for so long. Now is the time to take that new (used) motor to a good engine builder and make the upgrades that will ensure longevity on the track. Anything less, and you are just wasting your money.

ma.jomaa

Joseph thank you for your input, I've only tracked the car for a few track days based on information on people running their C5s on the track for 2+ years with no issues aside from adding a quart of oil before the track day and replacing the oil more frequently. I run a BMW shop and a couple M3s have rod bearing issues that we usually address with upgraded bearings, I was not aware that LS1s were prone to rod bearing failure.

gimp

LS1s are not prone to rod bearing failure specifically, but LS1s are prone to oil starvation in high-G, extended left-hand turns.

The higher your RPM, the more likely this is to happen.

There are a number of workarounds. In addition to not redlining the engine during a turn, the other solutions include: batwing oil pan if not already (depends on model year), oil pan baffle inserts, running extra oil (preferably with a catch can), adding drainback through various modifications, adding an oil accumulator, adding a dry sump system.

Josephu

Well......A few times was one two many. If you run a BMW shop, I dont have to tell you about racing and engines. Good luck in your venture.

aaronc7

Yeah, C5s dont normally have oiling issues until you get <100 treadwear tire and/or aero and you start getting fast. Normal street tire not really a big issue. What were water/oil temps? What oil were you running?

Like another guy said, rod bearing / rod failure is not that common... much more common is cracking the weak pistons, ask me how I know. If you tear down the motor you can probably figure out more.

i had a modded LS6 and cylinder 7 piston cracked and the liner cracked too. I think it just got too hot (no knock), and the piston ring butted up, caused tonso of heat and took out the engine. If this is going to be a track car or something, it may be wise to open up the motor and increase the ring gap a little. Stock LS motor with the ring gaps opened up a bit have proven to handle lots of power and you might not be making nearly that much power, but the enemy on the track is just the same--heat.

Josephu

When.....not if you open up the motor, a good set of Forged pistons with the correct ring package for what you are doing. A custom baffled oil pan being a must. Belt driven, external oil pump, with a 1 inch braided steel hose to the bottom of the pan. Right hand side preferably. .030 thousanths restrictors for the lifters and upper valve train to keep as much oil in the pan as possible. -6 drain back hoses from the back of the heads down to welded bungs in the pan. Facilitates drain back from the heads. Keeps oil off the rotating crank. Set the pump at no more than 60 lbs. of pressure at full song. Almost forgot a good set of rods. Discuss the build with a "Good",....Racing Engine Shop in your state, and go from there. Then,..go out and have some fun.

SaberD

Get LS2 lifter trays and drill holes in them like this:

https://ls1tech.com/forums/generatio...ification.html

redzg

Forget where I read it, but it's been noted that you will definitely know it if your ring gaps are too big, but if they are too small everyone will know it...

JHrinsin

Sorry to hear about you engine failure. The above is all good advise. Here is what the PO did when he replaced the failed factory stock short block and what I am in the middle of trying to protect his investment in a new engine.

https://www.corvetteforum.com/forums...post1598787779

ma.jomaa

Thank you all, still contemplating whether to go ahead with the replacement and sort it out or just cut my losses and sell the C5.

93Polo

What mods, suspension and engine do you have? Which track?

LS1/LS6s are actually reliable track cars. I would do Improved Racing's oil pan baffles and crank scraper If you are getting serious an Accusump would be nice to have. Heat can be a problem, Improved, LPE and Doug Rippie have oil cooler hits, and aluminum radiators.