LS6 Kaput
08-16-2013, 10:55 AM
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LS6 Kaput Earlier this week I went out to start my '04 CTS-V and was greeted by a plume of white smoke from the exhaust. I assumed head gasket but when I got the drivers side head off I found a piece of the #1 piston missing! Where to now?
First some context: The car has 130k miles on it's LS6 and about 115K of those miles are with a Magnuson supercharger. Despite the piece missing from the piston I can't see any cylinder or head damage (the only evidence that anything happened is the lower electrode of the spark plug was bent.) The missing piece of the piston is no where to be seen.
Additionally, I've been running without intercooler on the blower since it has a leak in the heat exchanger (the one in the blower not the one by the radiator) and when I put coolant into the intercooler system it also produced white smoke from the exhaust.
Soooo,
Looks like maggie needs to make the journey back to Magnuson for intercooler repair and any other 100k mile checkup items that may come up (bearings, belts, oil...)
Heads: Minimum - do a valve job, Likely - springs, retainers, trays, lifters, Hopefully - CNC porting, cam and timing set. Looking for options and input here? Note, I have a friend at Comp Cams and will likely be biased to using their hardware.
Block: Minimum - replace the bad piston, Likely - new pistons and rods, Hopefully - complete forged rotating assembly and up the displacement. Here again, looking for options and input. Don't want to go crazy, this is a daily driver with occasional road course trips that I wouldn't mind driving for another 130k and I plan on still using the maggie.
Other options to considering: Just pull out the LS6 and do a crate motor. Another LS6 or LS3 or LS1/6 short block or ???
As for the rest of the car, it has a Katech LS9 clutch and Level V RPM Transmission T56 upgrade so the weak link is certainly the stock rear diff. In other words, getting crazy with HP to the wheels will grenade the rear so no sense in going too over the top.
First some context: The car has 130k miles on it's LS6 and about 115K of those miles are with a Magnuson supercharger. Despite the piece missing from the piston I can't see any cylinder or head damage (the only evidence that anything happened is the lower electrode of the spark plug was bent.) The missing piece of the piston is no where to be seen.
Additionally, I've been running without intercooler on the blower since it has a leak in the heat exchanger (the one in the blower not the one by the radiator) and when I put coolant into the intercooler system it also produced white smoke from the exhaust.
Soooo,
Looks like maggie needs to make the journey back to Magnuson for intercooler repair and any other 100k mile checkup items that may come up (bearings, belts, oil...)
Heads: Minimum - do a valve job, Likely - springs, retainers, trays, lifters, Hopefully - CNC porting, cam and timing set. Looking for options and input here? Note, I have a friend at Comp Cams and will likely be biased to using their hardware.
Block: Minimum - replace the bad piston, Likely - new pistons and rods, Hopefully - complete forged rotating assembly and up the displacement. Here again, looking for options and input. Don't want to go crazy, this is a daily driver with occasional road course trips that I wouldn't mind driving for another 130k and I plan on still using the maggie.
Other options to considering: Just pull out the LS6 and do a crate motor. Another LS6 or LS3 or LS1/6 short block or ???
As for the rest of the car, it has a Katech LS9 clutch and Level V RPM Transmission T56 upgrade so the weak link is certainly the stock rear diff. In other words, getting crazy with HP to the wheels will grenade the rear so no sense in going too over the top.
Last edited by ronr; 08-16-2013 at 11:58 AM. Reason: typos
08-17-2013, 10:15 AM
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I had the exact thing happen to me, my piston looked exactly the same as your pic. Little piece broke off and went out the exhaust valve but didnt do any damage other than bending the electrode on the spark plug. I sold the LS6 and went with an LSA engine which is probably the best block you can buy for the money, they are factory rated at 800 hp, the only thing higher is the ZR1 block which is rated at 900 but is alot more expensive.
08-18-2013, 12:27 AM
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I hate to be the only guy to say this but Why not pick up a cheap 6.0 truck short block rework your heads and get the Blower repaired by a overdriven pulley to increase boost and be back on the road making as much if not more power for less than 10 grand with the blower repairs and all. Take your heads apart yourself only requires a 13 mm socket and a hammer put the socket on the spring and hit is with a hammer it will compress the spring and allow the spring retainers to pop out. you may have to hit the a couple of times but remember your hitting a valve spring not trying to knock a ball joint loose. then pick up some burrs, sand paper rolls and polishing wheels and have at it do a light hand port and polish job for your time plus 120 bucks clean the heads real good with brake clean or some other parts cleaner then take them to the machine shop for decking and a valve job. With you being forced induction even a light hand port and polish will yeild noticable gains plus you can polish the chamber while you are at it. Sry Kinda a DIY'er so I think cheap instead of cubic dollars lol.
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08-18-2013, 02:35 PM
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I hate to be the only guy to say this but Why not pick up a cheap 6.0 truck short block rework your heads and get the Blower repaired by a overdriven pulley to increase boost and be back on the road making as much if not more power for less than 10 grand with the blower repairs and all. Take your heads apart yourself only requires a 13 mm socket and a hammer put the socket on the spring and hit is with a hammer it will compress the spring and allow the spring retainers to pop out. you may have to hit the a couple of times but remember your hitting a valve spring not trying to knock a ball joint loose. then pick up some burrs, sand paper rolls and polishing wheels and have at it do a light hand port and polish job for your time plus 120 bucks clean the heads real good with brake clean or some other parts cleaner then take them to the machine shop for decking and a valve job. With you being forced induction even a light hand port and polish will yeild noticable gains plus you can polish the chamber while you are at it. Sry Kinda a DIY'er so I think cheap instead of cubic dollars lol.
I'm a "kinda cheap DIY'er" myself but unfortunately my job keeps me on the road quite a bit and I don't have the time to do all that I would love to do myself. That being said, I've actually got some downtime from travel right now so the plan is to do as much as I can myself and then, based on my work schedule, hire out the rest.
I did get the other head off and everything in there looks great. I'm actually amazed that after 130k miles I can still see the crosshatching on all the cylinders.
08-20-2013, 08:19 AM
#11
LSA engine which is probably the best block you can buy for the money
For alot less money that you can get a fully forged stroker that will hold power alot better than a engine with powederd metal rods and hyper pistons.
08-20-2013, 02:24 PM
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I said "Block" which I paid $2,500. And I put my own forged internals in it. K1 4" crank, Manely rods & pistons, total seal rings, ARP main and head studs, King tri-metal bearings, Dart Pro 1 CNC 250cc heads with dual valve springs, Lunati hi reve lifters and roller rockers. All less for ten grand, so what I said still holds true. The LS9 block is rated at 900 HP but costs $3,900..therefore the LSA is the best block for the money in my opinion, and it still has piston oil nozzles for piston cooling just like the LS9.
08-26-2013, 08:09 AM
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Update: Everything is out of the car and apart now. Blower is at Magnuson. Motor is apart and piston is out.
Next steps: Still exploring short block/crate options but leaning toward a simpler rebuild of my existing motor. Specifically:
1. Replace pistons/rings - thinking about Mahle LS1314908F04 but not sure if compression would be too high with this given my blower, although I'm not running very high boost.
2. Port my existing heads - David (xRaTeD), AI or similar
3. Valve job
4. Valve train upgrades - double springs, Ti retainers, lifters, trays, cam, timing set
5. Look over transmission - I'm headed down to the US Nationals in Indy this week and will drop my T56 by RPM Transmission to have them look it over and make sure everything is as it should be (it's an RPM Level V T56 already)
6. I'm still going back and forth on whether I'll put headers on while I'm changing things.
Next steps: Still exploring short block/crate options but leaning toward a simpler rebuild of my existing motor. Specifically:
1. Replace pistons/rings - thinking about Mahle LS1314908F04 but not sure if compression would be too high with this given my blower, although I'm not running very high boost.
2. Port my existing heads - David (xRaTeD), AI or similar
3. Valve job
4. Valve train upgrades - double springs, Ti retainers, lifters, trays, cam, timing set
5. Look over transmission - I'm headed down to the US Nationals in Indy this week and will drop my T56 by RPM Transmission to have them look it over and make sure everything is as it should be (it's an RPM Level V T56 already)
6. I'm still going back and forth on whether I'll put headers on while I'm changing things.