[invinceable99]

Need some advice from my fellow V owners... Sad day but I think my LS6 has finally bit the dust and it only has 130k miles. I’m thinking of engine swapping, depending on cost of an LS6 vs LS2 (or other options, if anyone knows). I believe LS2s are cheaper due to supply, but if there are even better options out there, I’m all ears.
Not 100% sure just yet what’s up but here’s the footnotes (symptoms first, then story)

Long term (maybe the past year) symptoms:
-engine has been seeing a lot of blow-by lately (oil in coming out of cylinder 7 when checking spark plugs), so added a catch can, and it has caught a pretty significant amount of oil between changes (1/8qt or so)
-lose about 1qt of oil in 1k miles, especially if there’s more spirited driving.
-very slight/feint bearing/piston noise that occurs during cold start up, goes away when warmed up.
-no smoking at idle, but someone told me about a year ago that blue/black smoke can be seen under heavy throttle (I could never see any so it mustn’t be that much).

Now the story and current issue:
-changed my oil and subbed 1qt of oil with 1qt of Lucas oil stabilizer this past Tuesday (03/09) to try and further help with blow by.
-Friday after work (03/12), warmed up my car a bit and it started up as usual. Idled for a bit while I finished work, went to the gas station and everything still fine. Get on the freeway and about 4 miles into the drive, I notice some jerking in the engine. Few moments later, check engine light starts flashing but goes away. Feels like I lost most of my power, but the car is still going.
Finally get to my exit and car dies after letting out clutch. Able to start it, but it wants to die and now I can hear knocking since my window is down.
Drove home the remaining mile but it didn’t sound good, lacked power and continued to shut off if I didn’t keep it in gear.
In terms of codes I get: cylinder 1 misfire and mass air flow sensor signal.
Unplugged the battery to try and reset everything overnight tonight, but also going to drain the oil to see if I get shavings/metal pieces, but I’m guessing the engine is toast.
If that is the case, what are the best options? A search on eBay priced used LS6s around $4-$5k, LS2s seem to be about the same (but I thought would be cheaper), or is there an alternative option?
Any and all advice is greatly appreciated!

 

[AAIIIC]

Is a rebuild out of the question, or can you not afford to have your car down for the amount of time that would take?

 

[Billfrombyron]

If you're going with a new engine, I'd recommend contacting Thompson Motorsports as they have high standards and pricing for every tier.

I'd recommend avoiding an iron block as the upper mounts are different and they require a custom adapter. The ict billet adapters will push the engine an inch too high.

Drain and fill the oil and change the filter. Lucas is snake oil. Try a dexos 2 spec oil and see what happens before commiting to a rebuild or new engine.

-Byron

 

[invinceable99]

Is a rebuild out of the question, or can you not afford to have your car down for the amount of time that would take?

Not completely. I just hear rebuilding is typically a crapshoot. I’m in Las Vegas and don’t personally know of any solid LS engine specialists out here.
Plus the interwebs and popular opinion tends to recommend replacing the engine (with another used one) versus rebuilding.
I’ll have another car to use while the V is down though, so it’s definitely an option if it’s the best one (cost to value proposition)

If you're going with a new engine, I'd recommend contacting Thompson Motorsports as they have high standards and pricing for every tier.

I'd recommend avoiding an iron block as the upper mounts are different and they require a custom adapter. The ict billet adapters will push the engine an inch too high.

Drain and fill the oil and change the filter. Lucas is snake oil. Try a dexos 2 spec oil and see what happens before commiting to a rebuild or new engine.

-Byron

Haven’t had a chance to drain the oil yet, but that’s the goal as soon as I get a chance.
I’ll also check out Thompson Motorsports, thank you!

 

[TACoupe]

Try a couple of simple things to see if any of these will help. One, check your electrical voltage on your battery it should be approximately 12.4 to 12.6 while it's sitting there and close to 14 when the cars running. Two, Check all vacuum hoses to make sure you have no leaks. Lots of weird things start happening to late model cars when the voltage is low.

Roy

 

[invinceable99]

Try a couple of simple things to see if any of these will help. One, check your electrical voltage on your battery it should be approximately 12.4 to 12.6 while it's sitting there and close to 14 when the cars running. Two, Check all vacuum hoses to make sure you have no leaks. Lots of weird things start happening to late model cars when the voltage is low.

Roy

Voltage is good(battery is maybe 6 months old), the engine will not stay idling without a lot of throttle input.
What I thought was a knock yesterday is somewhere between a tick and knock, but it feels like it’s not getting enough fuel or spark and running extremely rough.
Fuel pump does prime and I actually smell a lot of fuel after trying to start it a few times, so I doubt it’s that.
It might be a vacuum leak but time/other tasks leave me little time to diagnose it, unfortunately.
Drained the oil and there was a very minimal amount of shavings (maybe 3-4 extremely small “dots” of metal about the size of a grain of salt, so I’m a bit optimistic that it’s not catastrophic failure.
I was able to get a hold of a highly trusted local mechanic that specializes in LS engines and he should be able to figure it out for me. Wish me luck and thanks for the suggestions so far!

 

[Albertan]

Bad idle etc sounds like it could be a fuel pressure issue or plugged fuel line. What have you found?

 

[invinceable99]

Bad idle etc sounds like it could be a fuel pressure issue or plugged fuel line. What have you found?

Forgot to update this, as I did get to the bottom of it, and happy to say I fixed it myself!

Turns out, the intake valve spring on Cylinder 1 snapped (literally split in half), which caused the valve to stay stuck closed. I got VERY lucky as the valve did not drop, so it never came in contact with the piston.

I got COVID at the end of 2021 and after I recovered, I got the inspiration to diagnose and repair it. The mechanic I found was actually trying to scam me, since after 5 months of hanging on to my car, he never properly diagnosed it, telling me it has low compression on several cylinders, and not giving me any proper paperwork or costs on a rebuild. So I towed the car back after letting him know "I'll think about it."

Immediately after opening the valve covers, i noticed cylinder one valve spring was loose.

Bought a new compressor, removed plugs, used air to hold the valves up, and replaced every valve spring (might as well since they're all old), all valve stem seals, and all retainers and keepers. All the parts came from Rockauto and parts were about $240, while the job itself took me around 6 hours, taking my time and going very slow since I've never done valve springs. The compressor set me back $400 but all in all, I saved a TON of money figuring this out and doing it myself!

The V is back on the road and running strong.. Since then, I've replaced the harmonic balancer, which took out the water pump, belts and pulleys, and radiator, and also installed Mark Woodruff's diff brace (what a difference!) and still very happy with this high performance super sedan after 7 years and 50k miles

Thanks to everyone who helped with suggestions!

 

[AAIIIC]

Congrats for figuring it out and getting it back on the road!