Cobra4B

2001 LS6 - Stock
123,xxx miles - Last 3000+ all track use
Made 364 rwhp this February during dyno verification
Had a lifter go last race weekend, no other issues with it

Finally tore into it and confirmed the lifter damage today. I can't get the #7 cylinder lifters out the top. They'll move up and down freely, but the rollers are destroyed and I'm sure the area around them has expanded some. I have to pull the cam anyway to replace it so I was wondering if it was possible to let the lifters come out the bottom then get them up through the rear hole in the valley. I really don't want to pull the engine and take the pan off as I'm trying to get the car ready for the next VIR event the 2nd weekend in October.

Hey roller pin... you're not supposed to be there...


RIP #7 cylinder lifters... good work for 123,xxx miles. Lifter didn't turn, roller tip failed.



It appears the rear lifter tray and tray mounting boss got boogered up. I have new LS2 trays for it anyway, but is this of any concern?

Messed up tray mount boss


Normal


Messed up tray


Normal


Noticed some slight grooving at the bottom of the cylinders. You can feel it with your finger but not your nails... can't catch a nail on anything. I've never had the heads off of any of the Corvettes I've had (a testament to the LS motors I guess). I've only done cam swaps in the past. Thus, I have nothing to compare to.

A quick google image search shows lots of this. I'm not planning on doing a rebuild until it starts to make reduced power, but curious if this is "normal" on higher mileage motors that get used? I always seem to see people bragging about being able to see the cross-hatching no matter what the miles.

#1


#3


Thanks,

Brian

Cobra4B

#7 Exhaust lifter was completely destroyed and the pin ejected. It fell into the pan when getting it out. Cam lobe for this lifter was beat up.

#7 Intake - Roller worn... probably not far from ending up like the exhaust lifter. Cam lobe wasn't beat up yet.


Camshaft


Time to pull the front cradle and get the pan off.

BERETTA

Hopefully all the metal from the lifter and camshaft didn't damage the bearings and crank. The old small block chevy days would sometimes wipe out the bearings and crankshaft when a cam lobe went down...

Cobra4B

Yeah the crank didn't like lifter pieces falling on it at RPM... those are nicks, not shavings.



The car made normal oil pressure last time I started it and I haven't found any metal grit in the other lifter galleys etc. I'm going to pull the cradle so I can pull the pan and clean it all out.

I'll probably pour a bunch of oil through it and then put it all back together and see what happens. Not trying to do a full rebuild right now... no way I'd make the October VIR event if I had to go through all that.

dvandentop

damn that blows atleast you were able to get the cam out with the lobes being messed up

JDIllon

That engine has to come completely down! There are going to be metal filings through out the engine. In my opinion, you would be throwing money away if you try to rebuild just the top end. I had the same thing happen to a LS7, it looks like the lifter turned side ways or the pin came out and destroyed the cam. I can almost guarantee you that the bearings have been scored. Mine was caused by an over rev on a down shift. Also you may want to consider linkbar lifters as replacements. Check the lifter bores!! they are probably scored also, due to the pin coming out. If so? they can be sleeved and or over bored and larger lifters used. Sorry to say this is not a small problem. And will require a lot more than cam and lifter to repair. Just my .02 Good luck with the rebuild. JD

Cobra4B

Yeah that's slowly sinking in... going to pull the pan and open the filter before I'm ready to throw in the towel and rebuild. The last thing I want to do is put it all back together with fresh parts and have it fail. FWIW the lifter wasn't turned sideways at all. When I pulled the heads they were both in the proper orientation in their trays.

rbl

I don't have experience with that exact engine Brian but I doubt you will have any trouble if you just clean it up, run a couple of oil/filter changes through it then hit the track. Fill with clean oil and run it 15 minutes to get a little temperature on it then change it and the filter ... twice. I would also cut the filter and see what you are getting if anything. I have also added about 1/2 qt. of kerosene to the oil as a flushing agent on the first go.

I have had about a dozen lifter failures in the SRF that also tore up the cam lobes when the rollers cratered (bad center cam journal was the cause) and all that crap passed through to the pan and was caught there or by the filter. The oil pickup was/is high enough that the small fines did not get picked up. If you have normal oil pressure I would bet that none has got past the filter (none may have gotten that far either) and into any of the oil passages. I had no issues and the engine was still running strong.

Cobra4B

Good idea... thank you for the feedback.

What about my oil cooler and lines? Should I disconnect the cooler or have it flushed? I'll know more when I pull this pan. So far I haven't found any metal shavings in other places.

rbl

My oil cooler lines were easy to get to and I disconnected them at the manifold by the oil filter. I don't know how yours are. I blew air (not high pressure ... 10-15 psi) and blew out most of the oil, Then I put a little kerosene in one line and blew it out again ... did that twice. I never got any metal but I sure did get a lot of sledge out! I think it had never been flushed before. You could also pre-charge the cooler for the 2nd go bu adding a qt of oil to it if it is possible ... I didn't do that though.

If you can run the car on the first go I'd leave the cooler disconnected - I did. Then put it all back together, fill it up with just teh opil and run (idle) for 10-15 then change it. I would also use some cheap oil for the job and a straight weight 30. Probably will need another change after the first track weekend.

The residual oil will mix with the tiny bit of left over kero (will be very little and it will not dilute or cut it ... don't use gas or any other solvent as that will strip the oil.

BTW ... that cylinder wall looks just fine to me. I built my last 3 engines and I would not be excited about seeing that at all. Normal wear I would think. If you aren't getting blow-by or having oil consumption issues I'd run it until you want to do a total rebuild.

Another thing ... do you have the metal drain plug thingy? I sold my corvette and can't remember if the plug is on the side of the pan. Can you stick a flexible pickup magnet in there? I have one that is round and ! 3/8" diameter on a 12" flex wire. Also, If you can jack the car in such a way I would think you could collect all of the metal (if any) without removing the pan with the help of some light weigh oil. Best to remove it however to be safe.

sleeper02Z06

Brian,

Do a basic rebuild. Period. Re-ring (new), re-bearing (new), and rebuild etc. using all salvagable parts and finding other good new or used oem parts such as the cam. It will take time but it is fairly affordable especially tackling it yourself. You are pretty lucky it did not have a huge failure aka all hell breaking loose if that lobe wiped or something else happened, do you really want to roll the dice again? I waited to replace my last engine and it went from a 5k remove and replace to a 14k hole in the block and fire damaged car repair. Do yourself a favor, do it right and do it now.

That 123k likely didn't cause what happened. The 3k on track likely did. I was in the same situation with a street engine that had a lot of miles. Put it on track and got about 3500 more out of it. Put a brand new engine in and went right on track, it lasted 4000 miles. It's the track that abuses them not the street. If you have any small issues like all the crap that you may or may not get out of the motor, and you put it right back on track like I said, dice roll. If it was going back on that street, less of a dice roll. IMHO with all the work you put into it, do it right.

Cobra4B

Well... I do have this sitting about 5' from my car... but it's for my father's Panoz that I'm rebuilding



Seriously though... it might make more sense to swap heads/cam/intake/pan and put it in my car and then rebuild my LS6 and put it in his car with the LS1 heads/cam off of this motor.

JDIllon

Certainly you can do as you see fit? But where do you think the other half of that lifter roller and the metal from the cam went??? It has gone through and is stuck to everything that the oil touches. Any engine builder will tell you that the coolers, hoses and block, heads, Ect. all have to be flushed and cleaned before reassembling the engine. There is no way the filter has caught all of that stuff. Also as mentioned before, at 123k you are ready for a rebuild. It really is time to go through everything and freshen it up. But if you don't clean and flush everything there is a good chance you could score a new bearing or even worse the crank. My builder even had me take out the radiator with the oil cooler and have it completely flushed along with the lines. Just some things to consider. JD

Cobra4B

Where do you have something like that flushed? I need to have the radiator and oil cooler from the Panoz flushed as well.

moespeeds

Can't comment on the rest, but the cylinder wall grooving I've seen on motorcycles running open intakes/no filter. We run a ball hone through them on a hand drill just to clean them up, new rings, and put it back together.

JDIllon

My engine guy had all of the equipment and did mine for me. They boiled out the block, heads and flushed the coolers and lines. Try a large radiator shop or shops that do engine rebuilds also industrial engine shops probably can do that sort of thing. JD

NASAblue

$.02
I'd rebuild that motor and upgrade the valvetrane on the crate (at least the springs).

Good luck with it!

Cobra4B

Crate motor already got LS6 springs and Smith Brothers pushrods.

As for my LS6... Anyone want to make some posters with glitter? I'll bring the silver


Is the bottom of the lower pan supposed to be 100% smooth? Mine isn't... bits of metal are fused to it making it feel like 60 grit sand paper in places.

sperkins

Good grief. I'm never pulling the pan off my engine.

JDIllon

I think you found the other half of the lifter roller and the cam lobe! Sorry! That's what mine looked like also. JD