dforristall

Hello all,
Firstly I wanted to say thanks to everyone on this forum. I was on the LS1 forum for years when my F body with an LS3 was my primary toy until 2013 when after my first session, on my first HPDE day, oil starvation took out my oil pump and kaboom'd the motor. Yea, I didn't read up on the oil starvation issues in high G left handers until afterward. fml...

Consequently picked up a supercharged 01 Z06 shortly afterward. Got on this forum and havn't looked back. I got back in the game and have done about 10 track days with the Z and have been loving it!!!! I'm soo gunshy on the oiling issue, so always run a qt over, and watch my oil pressure and temps.

My last race was in Homestead, and after the morning sessions, I noticed I was a quart low on oil. I put in 2 quarts of 20/50 and got back out on the track. Suddenly on lap 1, I started building ALOT of oil pressure ( about 70psi at 6K rpms) . Enough to force oil out of the dipstick tube and spray it all over the underside of the hood. All I could see going into turn 6 was a plume of white smoke trialing behind me as it burned off the exhaust manifolds. I limped it back to the pits, and called it a day until I could figure out what was wrong.

The LS6 is basically stock except for the Magnussen supercharger which is only pushing about 7psi. Engine temps never get above 205, oil temps never get above 220. I'm on an 18 square setup on street tires, so am not pushing more than 1.1G's in corners. Even when not under boost at idle, my oil pressure had risen from about 25psi to 47psi!! There was no drop off in performance at all though, so I limped the car home figuring a ring had gone bad, or something was a-miss internally. I haven't had oil consumption issues except the normal quart a day at the track, but it is an 01 so I know they've had ring issues anyway.

Once home I went ahead and changed the oil. No metal flakes or pieces that I could see, but even with new oil in it the psi was the same. I figured I was getting too much blow by on the rings that was causing the increased oil pressure... On a whim I threw in a can of engine restore just to see what would happen. Within 5 minutes of running my oil psi dropped back to normal!!! WTF?? I went ahead and put a catch can system on the car, and in the process vented crank case pressure to atmosphere just to see how much blow by I am getting. It turns out LOTS... All kinds of smoke coming out of the oil fill neck when I tested. With the catch can and PCV system doing thier jobs though you'd never know it though.

So, everything runs great, but I'm sure the motor is on borrowed time with that much blow by, and I know the supercharger isn't helping the issue. I'm still going to run it on the track as I've already pre-paid for 4 races this year, and see what happens... time will tell.

I would consider rebuilding the LS6, but am not confident with any of the engine builders in my area. LS6 crate motors are nowhere to be found anymore unless someone knows something I don't. So I was considering the lsx376-b8, possibly with or without my current supercharger, but wanted to post first and get some of your opinions before I did anything. My plan is to call GMPP sometime this week and walk it by them as well. I know the cast iron block would add another 100lbs as a weight penalty, but it should be a bulletproof motor right?? I wouldn't change anything aside from putting the supercharger back on at 7psi, and I think their 8psi rating on the motor is pretty conservative.

miracle_whip4130

If I were in your position I would try to line up an LS3 replacement. You don't want the extra weight of the LSX for road racing and your issues haven't been caused by the engine block itself, if you think about it: Your LS1 just died due to oil starvation. Your current engine just has blow-by due to stock piston/ring durability issues. If you're definitely keeping the supercharger and don't feel comfortable with local engine builders, just buy an LS3 shortblock that's built for boost from a reputable vendor and upgrade the oiling system as well. I think at the low boost levels that you're running, a heavy LSX is overkill and not worth the extra weight. I don't think you're lifting heads or destroying the engine blocks themselves, so I don't think upgrading to an LSX would be worth it. That's my $0.02......

J.R.

Agree with above. Don't need LSX unless you are going over 800 plus HP. Too much weight on front end.

Another option: put in a 480HP crate LS3, add dry sump and lingenfelter 58x to 24x adaptor harness. - have fun and race for 3 plus years - refresh engine and do it for another 3 years. With headers and tune you will have approximately 450RWHP and not have so much HP you are breaking other parts (diff, trans etc).

cwikstro

I agree that running supercharger isn't really needed. I run a stock LS1 with valve springs, hardened push rods, headers and cold air intake. My race class is 10 to 1 so I don't need more HP, just have to add weight. Also, I don't have any luck running extra oil as it just blows it out. The Z06 winged pan seems to take care of this at full level fine. If I over fill it just smokes in hard corners! I say try full oil only and run it to see what you get. If you do blow it, you can get a forged bottom end LS Aluminim block and put your top end on it. Good luck!

miracle_whip4130

There's also the option of buying a used LS6 if you just want to swap engines and roll the dice on another one. At least the LS6 seems to have a better oiling system than the LS3. You could then also possibly sell your current motor as a "core" depending on what the insides look like when it comes out. Anyway, PM this guy if interested:

https://www.corvetteforum.com/forums...25k-miles.html

REVHARD

theres an ls6 long block in the classifieds right now

miracle_whip4130

Haha you're probably talking about the same one I linked to in the post above yours............

Socko

Smoke out the dipstick is likely a ringland failure, specifically with that heat pump on there. Makes sense that the det you had from the heat pump also has a rod bearing failing causing your oil pressure issues. I would sell the blower and buy a big cubic inch short block if you are serious about the track. If you don't have a good tuner, you will just see the issue again. Even if you do have a great tuner, you can probably get simmilar hp at 15 minutes into a session from a large cube bottom end and a decent cam then that blower and a safe tune.

dforristall

Thanks everyone for the advise so far. I don't know that I'll stay with the supercharger long term, and actually would like to get away from it for racing anyway. I like the idea of the additional LS6 and then look at swapping every so often depending on time/abuse. I contacted the owner of the one in the classifieds now and am looking at picking it up. I like the LS3 ( I have one in another car), but am afraid that unless I went dry sump on it I would blow another one up. I've had good luck with that lingenfelter converter needed to go from 58 to 24 tooth reluctor though as well.

With the "spare" LS6 motor setup, what if any mods are done to increase longevity in your opinion? If I pick up the used LS6, I'd probably want to at least do the Z06 winged pan, valve springs, and hardened push rods before putting the motor into the car. Anything else besides that? Keeping the rest stock seems to help with longevity. On the current stock motor coming out I would rebuild it in similar fashion and keep it as a backup.

I also agree on the trying the batwing pan and just try running at full on oil level. Mine was the same way prior to the last race, where any extra oil would burn off at the track, but was fine the rest of the time. I've always had other drivers say I had a little white smoke coming out the exhaust when exiting the hard corners.

J.R.

LS6 engine:
Batwing pan
Drill lifter trays (assists in oil return to pan)
Restricted pushrods (also lessens pooling of oil in heads - not necessarily recommended on street only engines).
Accusump ( this is a good cost effective backup for any potential oiling problems).
Oil breather to minimize oil in intake manifold. (Double lets it pull from intake valley and valve cover).
Keep cam lift at approx. .600 or below and engine rpm's at 6500 or less.
( 243 heads - unless highly modified - don't flow too much above .600 and no need to twist engine much above 6500 with most cams. Note: the goal here is to maximize efficiency and dependability. This is a balancing act.

cwikstro

Unless it has been changes, you should have the good oil paint that is stock on a Z06. Yes having the guys behind you telling you that you are smoking is no fun! Can even get meatballed.

One thing that my nephew experienced with a motor with blow by was the rear seal coming out due to crank case pressure. Again I would run it at full and see what happens before you go crazy with the checkbook. Just saying!

Doing an engine is a lot of work in a C5 so you wnat to do it once and be done. I would really look at a bottom end using forged rods and pistons, fresh to go. Mine cost about $3000 to do the stock LS6 and is still in the bag as a back up.

dforristall

Roger that, I'd forgotten about drilling the lifter trays. I just found the tread on that last week. I'll do that as well.
I'm looking at adding a secondary catch can breather now, but aren't they supposed to be a closed system by design? or are most guys venting them and blocking off the vacuum port(s)?
Cam would keep stock, but if not then below .600 for sure with a 112 or 114 LSA.
I'll look at forging the bottom end, as well.
On Accusumps, the 3qt is the way to go? Any other best practices on the accusump? I'd been avoiding the accusump since I read about some people having issues on them on dual purpose vehicles, but if it's working properly it would be a nice thing to have.

Thanks everyone!! :-)

J.R.

The only issues with LS6 bottom end has been the rod bolts. I do not think there is a need to go a forged crank unless you are going to be over 550 HP. I have used ARP bolts on stock rods with stock cast crank without issues. Obviously there is no disadvantage to forged crank and rods except cost. If staying with supercharger at 7 psi I am guessing you are going to be around 525-550 HP, depending on tune.

cwikstro

Agree on the crank! Rods and pistons are good investment though.

dforristall

Correct, I'm at 525 or so now putting 460 to the wheels. I de-tuned it a little and run meth injection to prevent heat soak and detonation. I'll price out rods and pistons, but will at least go with rod bolts as a minimum. The rods seem to be the weak point in the lower end on most LS motors correct?