OKsweetrides

I was just heading into a 2nd lap of a shakedown run (being very conservative and not really stressing the car) and something went boom followed by a white/gray smoke that had a super-fine dust particle kind of cloud. Oil all came out and found some shrapnel which is aluminum that is obviously cast and with a large grain structure.

Here's the kicker, it was the first time to actually drive the car in 9 months.... more downtime again! wooooo! party!

I'll post details after I get a gander at it up on a lift. The post-mortem should be fun. Maybe I can be back on the track by Xmas time

update: shop called, block is cracked.

Dirk Miller

Sorry to hear.
How many miles did you have on the engine. Can you estimate how many track days?

OKsweetrides

It's a cracked block.

From the ARE oil pan all the way to cylinder head. The shop just relayed that information to me. I'll try and snag some pictures tomorrow morning and get some up.

Itd say a rough estimate is 4000 miles of HPDE style things.

0Randy@DRM

Been there, done that, but had to sell the t-shirt to pay for the repairs. Sorry to hear, and hopefully she is back running soon!!!

Randy

0Adam at RSI

We were only on our second lap...

I can't wait to see what Mike comes up with. This is going to be one sick puppy when completed.

I actually snapped some pics before we went out:

OKsweetrides

UPDATE:

It looks like the small end of a rod (3rd cylinder back on drivers side) went through the top of the block and the crack just continued all the way through the block.

When the engine gets replaced with an LS7 here in the next week or so, the ol' LS6 will get a tear down and see what exactly failed.

jmorgan07z06

Sorry to hear about your red headed b... the LS7 will be nice!

Gray Ghost GS

I feel your pain. I get my C5 back in one week from Virginia Speed and plan to take it to VIR at the end of October for a conservative 'shake down'. Good luck with the new LS7 project!

OKsweetrides

Thanks for the well wishes for it. But I think the engine is more a testament to durability than initially telling. I *BEAT* on that engine. To have it survive as many mis-shifts and still perform till the second it let go; venerable engine design.

funny side note, it was a good thing I did the shake down at the track, made things a whole lot safer.

but Jmorgan07z06, your car flies, so power remotely close to that would be nice!

GeorgeZNJ

Besides the sump, any other mods and what tires do you run?. Sorry for all of the questions, but I'm really trying to decide what I want to do "this time around"

OKsweetrides

It's ok, ask as many questions as you want!
I have Moton coilovers front and rear with 800/600. These are paired with T1 sway bars and T1 lower A-arms (a hold over from when I had the T1 suspension bits).

Tires, well, I have steering "knock" (can't think of the term off the top of my head) with 315's in front but stuffed 345's in rear in Hoosier R6's on 18x11 and 18x13's. They stick out a healthy bit. I'll actually run a narrower tire to help reduce the knocking around that I feel in the steering wheel. It settles down significantly turns however.

Things to note: I run a few mm spacer in the rear. The front steering wheel rotation has to be limited or you'll cut the A-Arms (may be that T1 bars are different geometry).

I have some power mods and various other things, just shoot me a PM if you wanna know. I've accumulated a list of things/changed over the years.

GeorgeZNJ

Thanks, just trying to decide if I need a dry sump, or if an accusump is fine. I'll be running a new crate LS6 with bolts ons and a cam. My car is mostly a street car with 6-10 track days (HPDE's) a year. I was impressed that you got 4k out of yours. track tires are 295/30/18-F 315/30/18-R. I'm really starting to think theses sticky tires have a lot to do with the oiling problems.

OKsweetrides

GeorgeZNJ,

To further bolster your confidence, I had TF215's and a pretty healthy cam with .600 lift. I went with those because I damaged the stock valvesprings when I had a really bad misshift and let out the clutch. The engine despite all the times of accidental downshift, quite a durable thing!! I've yet to see my bimmer friends survive as many miles with such... brute abuse.

Stickies will always lead to oiling problems, no bones about that. Just make sure that your oil pressure gauge works really well and keep an eye on it. My stock sensor crapped out at the ~7000mi. mark. It got replaced by an autometer one.

sothpaw2

Were you running Hoosiers too George? I think a lot of it is the tire, I will not go beyond the Nitto RII. Also, courses with a lot of banking like Pocono scare me. I ran NJMP Lightening once and I won't again--banking too severe.

GeorgeZNJ

Yes, a6's and r6's. Right before this one let loose, I ran Watkins Glen for two days hard, with the NNJR PCA guys, red/black run group. To the OP, sorry for the thread hijack.

GeorgeZNJ

I have a cam very close to yours and ran it in a forged ls2/402 wiith TFS-225's-503rwhp/492rwtq. The first two engines were ls6's/cam with bolt-ons. We never figured oil starvation because the timing chains snapped ( one ls2 and double roller) rods through the block and too much carnage to determine what happened first. So the thinking was timing chain broke first. But thanks to guys like you that post when something goes wrong we can all get an education and start to make more intelligent decisions

trauma

Is Lightning that bad? I have heard a few comments about it's banking but I didn't realize it was that drastic. I haven't heard of any engines letting go there yet.

argonaut

Regarding banking - I've asked this question before and nobody seemed able to answer it: why do banked corners cause greater oil starvation than flat corners? I see this time and again - people comment on how concerned they are to take the car on banked corners...why? I'd really like to see data (lateral G in banked vs lateral G in flat). Does anyone have data of the "lightbulb" at Lightning and can show us lateral Gs (assuming lateral Gs are the cause of oil starvation). I'd really like to know if this is an internet/urban legend or if there is truth to it.

George - are you going to have a new engine in time for that TrackDaze event at Lightning in October?

GeorgeZNJ

Brad, trackdaze cancelled the event. someone(I forgot who) is running thunderbolt the same day. bob and roger are thinking about running with them, I'll get more info on that for you. I don't know if i'll be ready in time. I'm sending you a pm.

sothpaw2

Here's why:

Back in 2005 with my C4 I took a first taste of HPDE at Pocono in May. The car had around 70k mi and was really well maintained with a cam. I had new supercars on the front and new NittoRII on the rear. I had a great time at the 2 day event. I went to another 1 day at Summit in July. I had been to Summit before though once or twice over the years (single day, 80 min, on street tires strictly, running very slow in beginner groups).

So right a day or so after the July event a grinding noise developed. On inspection of the engine, the GMPP timing set gears were destroyed (that's a GMPP issue), but also, the Main & rod bearings were found to be badly worn. It's conjecture on my part, but I feel it's logical to conclude that most of the wear to the bearings and the timing gear occurred at Pocono. From an engineering viewpoint, if I were designing a sports car, I would design it for street use which would not include a lot of banking for sustained periods of time. I've asked a few turners in the PA area and yes--when the run at Pocono--they use a sump.

You can say it's a legend...but I still have the bearings.