Forums » Grassroots Motorsports » LS3s seem to have a problem on a race track 1 2

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  Nov. 18, 2011 3:47 p.m. carguy123 SuperDork

  I don'ts got one of these, but this has come up in another forum I'm on and thought it might be helpful to those of you who do.

  http://forums.corvetteforum.com/autocrossing-and-roadracing/2824807-let-me-ask-ano...

  The root of the problem seems to be lack of oil drain back. On sustained high G corners, the oil gets trapped in the valve covers and heads instead of draining back into the pan.

  Apparently you can't run and LS2 or LS3 (for long) without dry sumping. The LS6 is supposed to be OK.

  The cornering forces of full slicks and high rpms both seem to aggravate the situation.

  As I said, I have no first hand experience with this, but since so many seem to want to stuff an LSx into everything except the commode I thought this might be a good data point..

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  Nov. 18, 2011 3:59 p.m. DirtyBird222 SuperDork

  accusump?

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  Nov. 18, 2011 4:02 p.m. imirk Reader

  LSx in the cammode....Brilliant!

  Targa Miata seems to have held up alright, but it isn't a strait LS3, (it is a L33 with LS6 heads i think) and it might have some oiling mods.

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  Nov. 18, 2011 4:02 p.m. pres589 Dork

  Wondering if drainback hoses could run from the back outside corners of the valvecovers down to the top of the oilpan to let the oil drain back that way.

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  Nov. 18, 2011 4:03 p.m. carguy123 SuperDork

  Accusump helps delivery, but not the drain back.

  Yes, I'm surprised we haven't seen a commode pit bike powered by an LS

  "mobilito ergo sum" I drive therefore I am!

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  Nov. 18, 2011 4:03 p.m. DILYSI Dave SuperDork

  I wonder if external returns would fix it. Braided line that runs from the valve cover to the oil pan.

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  Nov. 18, 2011 4:05 p.m. imirk Reader

  carguy123 wrote: Accusump helps delivery, but not the drain back. Yes, I'm surprised we haven't seen a commode pit bike powered by an LS

  Challeng budget required the use of an LT1 :P

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  Nov. 18, 2011 6:35 p.m. Keith SuperDork

  The L33 in the Targa Miata is more closely related to the LS1/LS6 than the LS3. 4th vs 5th generation, although I can't comment on the oiling issues. The Targa car doesn't see a lot of sustained high-g operation either. But we've had no complaints from any of the LS3-powered cars we've built, including Elvis. I'll look into it. I don't know if any of our customers are running slicks and seeing sustained 1.2g (!) as reported in that thread.

  Square left in 50 caution ocean!

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  Nov. 18, 2011 7:02 p.m. Taiden Dork

  Oh L33 how you tempt total destruction of my wallet

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  Nov. 18, 2011 7:44 p.m. oldeskewltoy HalfDork

  pres589 wrote: Wondering if drainback hoses could run from the back outside corners of the valvecovers down to the top of the oilpan to let the oil drain back that way.

  Toyota 4AGE.... had similar problems with sustained long left hand sweepers. The last generation 16V 4AGE had a secondary drain in the right rear of the head, then went to a drainport in the side of the block

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  Nov. 18, 2011 7:59 p.m. MG_Bryan Reader

  Taiden wrote: Oh L33 how you tempt total destruction of my wallet

  E30 with an L33 > wallet. Just sayin'

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  Nov. 18, 2011 8:25 p.m. Shaun HalfDork

  That thead might have been the most expensive trail of 1st person gentleman racer cash loss carniage I have read. Mayby I missed the post, but I think the OPs question, and I parphrase, "if you went fast with this motor did your engine NOT blow up?" failed to yield a positive answer. I wish I was the 1% and could post about that sort of loss. Pisses me off. I want to blow up expensive E36 M3.

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  Nov. 18, 2011 8:31 p.m. carguy123 SuperDork

  If oil return is THE issue then it would seem the external return line would solve the problem. Now does anyone have an LS2-3 they'd like to donate so we can run it to death?

  "mobilito ergo sum" I drive therefore I am!

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  Nov. 18, 2011 8:47 p.m. Brett_Murphy HalfDork

  In reply to carguy123:

  As pressed for time as I am, I'll bite the bullet and chip in my time for this experiment as well.

  If brute force isn't solving your problem, you're not using enough.

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  Nov. 18, 2011 9:14 p.m. kb58 HalfDork

  Yeah my brother has a new LS3 he's putting in his Super Stalker. Research did show a serious oiling issue during cornering, and the only right solution is to dry-sump it. Expensive, but but the only absolutely right way to fix it, and is pretty much the perfect oiling solution... did I mention that it was expensive?

  Kimini, and now a mid-engine Seven, www.midlana.com

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  Nov. 18, 2011 9:16 p.m. Taiden Dork

  Does this oiling phenomenon apply to all Gen III chevy v8s?

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  Nov. 18, 2011 10:21 p.m. carguy123 SuperDork

  kb58 wrote: Yeah my brother has a new LS3 he's putting in his Super Stalker. Research did show a serious oiling issue during cornering, and the only right solution is to dry-sump it. Expensive, but but the only absolutely right way to fix it, and is pretty much the perfect oiling solution... did I mention that it was expensive?

  THEY say the dry sump helps, but does not stop the issue. Oh, they also say the dry sump IS expensive.

  "mobilito ergo sum" I drive therefore I am!

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  Nov. 18, 2011 10:21 p.m. carguy123 SuperDork

  Taiden wrote: Does this oiling phenomenon apply to all Gen III chevy v8s?

  As I read it, it's only the LS2 & 3.

  "mobilito ergo sum" I drive therefore I am!

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  Nov. 19, 2011 7:49 a.m. Maroon92 SuperDork

  If an external return line isn't the fix, then perhaps an auxiliary electric pump would.

  two lines from each valve cover converge at a pump, and a line exiting the pump leads to the top of the oil pan.

  thats sorta like dry sumping.

  XBL GamerTag: bcbrownell Racing is the process of turning money into noise.

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  Nov. 19, 2011 10:05 a.m. DILYSI Dave SuperDork

  Dry sump doesn't seem like it would help the top end accumulation issue, since the scavenge pump is still in the bottom of the engine. Maybe the reason it helps is the 12 quarts of oil in the tank you have to run through before it starves, means that it's got enough reserve for any corner.

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  Nov. 19, 2011 10:08 a.m. Taiden Dork

  I was trying to think if there was a way to increase oil capacity in corners only. A dry sump with the external tank would sort of be like that I suppose.

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  Nov. 19, 2011 12:05 p.m. pres589 Dork

  So if the issue is described as a drainback problem why are there so many comments in here about adding system capacity? It could help and may be easier but why not attack the root cause? Polish the lifter valley, add drainback routes like hypothetical tubes, and maybe some light machine work to add volume to drainback routes already in the motor. Right?

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  Nov. 19, 2011 12:16 p.m. fasted58 SuperDork

  yea, what pres said

  I'm not familiar w/ them but could there be a breather/ vent problem slowing drain back?

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  Nov. 19, 2011 12:31 p.m. Ranger50 Dork

  Maybe you aren't supposed to drive Vettes fast????

  "Never trust an intelligent man with no money to play fair."

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  Nov. 19, 2011 12:44 p.m. docwyte Reader

  Campaigned my LS1 equipped 951 all season with no issues. 4 30 minute sessions a day, 6+ weekends...

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