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I'm going to guess it's a second ring land that's broken. Summit did just release the Pro LS pistons. The n/a 5.7 pistons have a small 3cc dome to bump compression to 11:1. Gen. 3 press fit rods, 6.125 aftermarket versions, and 4" stroker versions in boost and mid compression 5.3, 5.7, 6.0, 6.2L. If you want to use Gen. 4 rods (full floating, the 5.7L pistons come with circlip grooves and clips...you just hone the rods to .9458 and you're good to go.
Update 2
- catch can prob fine, but took the filter media out
- looks like front seal is leaking... thought was catch can at first.
Testing today
- added second clean side vent from both rear VCs tapping the air bridge (pic below)
- this seemed to work well in minimal or no front seal leak
- ran 15psi gauge to dipstick... seemed less pressure with 2nd vent but hard to tell at WOT looking at gauge. Maybe 0.5psi vs 0.2 between 1 and 2 clean side vents.
- blocked intake and just passively vented... this puked crap ton oil from front seal... nixed this idea.
Smoking
Only time I can see smoke is after WOT to upper rpms and let off, then give “slight” gas... this produces a CLOUD. Happens with blocked intake so definitely rings or seals from the high vacuum.
Rings or seals?? I can see reasons for either with vacuum pulling oil.
I’d love to try a finer pressure gauge, like inches of water, but they spensive! One concerning part with gauge is the fluttering needle when letting off at high rpm... of course closer to 0 you are the better.
Anyway, next action I’m not sure yet. Prob drive for a bit with the 3 vents to the intake watching the front seal.
Save the block and pull the engine. You have a broken ring land.
Yep, I'm leaning toward a new engine but may try to get a few more track days out of it.
For engines, I'm not too trusting of anyone doing work for me. But not so confident in my short block rebuild skills. Searching the web, there's LS1/6 advertised short blocks for $3,500-ish... this seems like a reasonable price. And I can run it til it breaks.
As for rebuilding, would the only outside work be to the block... everything else is assembly purchasing the right components? Can engine builders and machine shops clearance the block/heads for oil drainage?
engine builders generally suck. They all claim more than they can really do in reality. if you get a good engine from a rebuilder consider yourself almost a unicorn.
engine builders generally suck. They all claim more than they can really do in reality. if you get a good engine from a rebuilder consider yourself almost a unicorn.
engine builders generally suck. They all claim more than they can really do in reality. if you get a good engine from a rebuilder consider yourself almost a unicorn.
You mean the available new short blocks are a crap shoot? Or a shop rebuilding my engine.
You mean the available new short blocks are a crap shoot? Or a shop rebuilding my engine.
Are you saying find a used GM engine?
I think what he's saying, and what I 100% agree with, is the level of competent shops/individuals available these days dealer or not is pretty low. They promise the moon & stars & deliver crap. Why I do almost everything myself now. If I thought my engine was about to crap, I'd park it and part out (or if your conscience allows) sell it to carmax or some such company. Put the $$$ to a nicer/newer/lower miles one.
I know you probably have a lot of nice racy parts on it. A guy I know who has a full race Subi has gone thru a couple of engines from a "builder" he trusts. You should expect it with 99% race engines, but more stock ones should last mucho long. Exception the heads on early ls7. Known issue.
I gotcha Froggy… wish it was a straight fwd decision. My car is considered a piece of crap for the used market, but solid on the track except for the smoking. On track body damage, bad paint, lots of miles, smoking maybe 7k if I’m lucky. Lower mileage, solid car prob 12-ish + unknowns until you get it on track. 5k into my car theoretically will make it a track weapon… assuming quality engine work.
I’m leaning toward the “easy now” rout and run it til it pops… whether engine or clutch goes first I’ll refresh the whole drivetrain.
Anyone with good engine builder experiences, please chime in with recommendations.
I gotcha Froggy… wish it was a straight fwd decision. My car is considered a piece of crap for the used market, but solid on the track except for the smoking. On track body damage, bad paint, lots of miles, smoking maybe 7k if I’m lucky. Lower mileage, solid car prob 12-ish + unknowns until you get it on track. 5k into my car theoretically will make it a track weapon… assuming quality engine work.
I’m leaning toward the “easy now” rout and run it til it pops… whether engine or clutch goes first I’ll refresh the whole drivetrain.
Anyone with good engine builder experiences, please chime in with recommendations.
Yeah, well get as good a personal referral as you can & still cross your fingers, no I don't know any I'd recommend. If a national shop like Katech or such would work with you that'd be it.
Yeah, well get as good a personal referral as you can & still cross your fingers, no I don't know any I'd recommend. If a national shop like Katech or such would work with you that'd be it.
I'm in 100% agreement with froggy47.......good luck finding a shop that can rebuild a motor correctly. 95% of the "shops" out there are waiting for your deposit to help finish the last guys build. Then you have to wait until the next sucker walks in the door to drop his deposit so your engine can get done....and hopefully they don't take a bunch of short cuts to help their profit margins. Lots of issues with motor builders out there (some are vendors here). Incredible considering how common the LS platform is.
I'm lucky to have been in the automotive trade all of my life and have only 2 machine shops I trust with doing machining work. I do all my own builds so I control all the clearances so my engines stay together.
I'm lucky to have been in the automotive trade all of my life and have only 2 machine shops I trust with doing machining work. I do all my own builds so I control all the clearances so my engines stay together.
I'm with you! The day the last crate LS6 was bought was the day I should have sold my C5Z06 racecar. Instead I have suffered through 3 bad rebuilds from geniuses. I'm building my own or buying crate or selling any car. Craftsmen with pride in their products are dead in the USA sorry to say.
"I hear ya! Had more trouble with machining BS trying to use aftermarket parts than I care to admit. Wish I would have stuck to factory short blocks as well. Tired of pulling apart "built" motors when guys are making twice the power on factory original stuff and racing the whole season." https://ls1tech.com/forums/forced-in...l#post19525070
Thanks for all the feedback guys. Let me ask few clarifications:
- having a shop rebuild is BAD idea
- I take it marketed short blocks from engine builders like Golen or Schwanke also not the best option for road racing.
- and GM engines now are all Gen IV, which may not be best opt in oil drainage and added electronic complications.
I just have a garage with limited tools and experience... but can read and follow directions. Option for me to rebuild? Basically just assembly right, with some machine shop work which I’d think I can check their work with measurements.
Im not scared of the work, just unsure I can obtain the knowhow necessary to rebuild a good engine.
I'm with you! The day the last crate LS6 was bought was the day I should have sold my C5Z06 racecar. Instead I have suffered through 3 bad rebuilds from geniuses. I'm building my own or buying crate or selling any car. Craftsmen with pride in their products are dead in the USA sorry to say.
And if you could find the one or two that are any good they would be back logged for a decade.
Thanks for all the feedback guys. Let me ask few clarifications:
- having a shop rebuild is BAD idea
- I take it marketed short blocks from engine builders like Golen or Schwanke also not the best option for road racing.
- and GM engines now are all Gen IV, which may not be best opt in oil drainage and added electronic complications.
I just have a garage with limited tools and experience... but can read and follow directions. Option for me to rebuild? Basically just assembly right, with some machine shop work which I’d think I can check their work with measurements.
Im not scared of the work, just unsure I can obtain the knowhow necessary to rebuild a good engine.
Don't take this as a negative, but every "little" job I end up doing (newest is 4 corner alignment on c6z) in my garage takes 2-4 times what I allow for the job. I am all in for guys doing their own whatever but the TIME is what gets ya. Ask anyone who has built a Factory 5 how many years it took. Sure there are exceptions so don't bother listing. Vid's up on the alignment, came out SWEEET.
There are other factors that can be contributing to repeated engine failures besides the wrong clearances and cast pistons. Excessive oil temps, coolant temps ,oil quality, not getting the engine up to temperature before hammering on it are just a few.
The vids I’ve seen it doesn’t look that bad... puffing changing gear and corner exit. Its a very smelly car though with a very oily backside. On the street I can throw down a smoke screen under very specific conditions, it’s kinda fun. Reading on LS1Tech, few peeps state this is “ring flutter”.
Cars running so strong, I’m gonna keep it going for a bit longer. Leaning toward an eBay/CL used engine when time comes... seems to be some pretty decent deals.
The vids I’ve seen it doesn’t look that bad... puffing changing gear and corner exit. Its a very smelly car though with a very oily backside. On the street I can throw down a smoke screen under very specific conditions, it’s kinda fun. Reading on LS1Tech, few peeps state this is “ring flutter”.
Cars running so strong, I’m gonna keep it going for a bit longer. Leaning toward an eBay/CL used engine when time comes... seems to be some pretty decent deals.
Run it to the ground. The LS1 is one of the better late model Corvette engines as far as reliability and longevity.
The first one I had was in a '99 Camaro Z28 SS that had the knock issue, a piston slopping around. Lots of noise on the internet about it. The sound of it was concerning. I ignored it beat the fuckign **** out of it daily. Like a red headed step child. Also drag raced it on weekends at the track. After a couple years I started lapping it on road courses. I eventually traded up to a '99 C5 Hardtop with the LS1 and T-56. When I bought the car new, I was hesitant about believing GM. They said the piston noise was fine. It really was a non-issue. The '99 Hardtop was a strong runner too. Never a problem with any of the LS1's.
When you replace it, look at the LS6. A great engine. 405 reliable HP.
06-04-2019, 04:47 PM
