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2004 C5 Z06 Broken Valve or Valve Spring - spun bearing - bad lifter?


Drewster67

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Lost the original thread comments due to recent upgrade -

Car is currently at Cordes Performance Racing having a new short block - exhaust - CAI installed.

The piston on the #7 cylinder went south - causing some damage to the valves as well.

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Certainly not good news ..... Difficult to diagnosis based on the info given, but most likely will reveal itself as it comes apart .... piston/rings not likely .... but top end issues would be most probable ... don't ya hate the wait and see scenario??? unfortunately that's what you're faced with at the moment .... sorry to hear ,.. keep us informed !!!

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EXACTLY - that wait and see crap is stressing me out.

I will definitely post an update and hopefully pictures Thursday afternoon (3/20/14)

Thanks for the reply.

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I've had coolant in oil with a blown head gasket but if you have valve-piston contact, you've got issues beyond head gasket. I floated a valve in my '65 GTO with a missed shift into third. Rod, piston, block, head all gone and that was iron block. How many rpm's were you at when valve broke. That's probably the factor that will determine what's broke.

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Dont recall the exact RPM but it was up there ..... Today is the day I find out how much damage was done.

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Spun Bearing #7 Cylinder - Engine needs to come out and be replaced or rebuilt.

So now comes the fun part - what do I do???

In the meanwhile - I'm going to start drinking to ease my worries ....

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Since the Porsche appears to be your track car, maybe do an LQ9 or other Iron block swap. Yes, it will throw the weight of the nose off a bit, but you can get more power for less $.

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Just wondering. Just a spun bearing and no other damage and you have water in the oil? Mmmm...

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Crash Test Dummy

LQ9 with LS3 heads and a nice cam will get you over 400 to the wheels for a budget if you can deal with the 80 pounds. I did this in my 06 GTO and loved it 426Hp/375TQ to the wheels

Might be able to find a nice LS3 that has been pulled out of a wrecked Vette for a fair price.

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Just wondering. Just a spun bearing and no other damage and you have water in the oil? Mmmm...

I'm with you on this. Spun bearing has nothing to do with oil in water or piston/valve interference. But it would definitely increase damage to the point that it's not rebuildable or at least not economically feasible to rebuild the motor. Now you have to add the crank into it. Time to call Scoggin-Dickey.

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I have been down your same road.

you have several choices.

yes you can go iron block, forged pistons, heavy cam yadda yadda. but you haven't said what you want to do with the car?

take a breath for a moment and imagine that the car was 100% healthy and good to go.

then ask your self "what mods did you pan on doing in the next 3 months?"

if the answer is nothing, then you have

2 choices.

LS6 short block crate engine. Rebuilt unit costs $3500, new Long bock is $6,200.

some of your parts can carry over to help reduce the cost.

The other option is getting a LS3 long block @ $6,600

the LS3 will need a reluctor timing thing adapter.

if it were me, I would get a complete LS3 assembly and call it done.

no cam, no heads, no fluf. more CI and TQ than the LS6.

your biggest long term issue is 'something' else breaking on the car and de-valuing it past the point of no return.

No one will care about the LS3 if the window module does nto work and dash lights keep filkering out.

you still have a 10 year old car that is now 2 generations old.

food for thought.

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Just wondering. Just a spun bearing and no other damage and you have water in the oil? Mmmm...

I'm with you on this. Spun bearing has nothing to do with oil in water or piston/valve interference. But it would definitely increase damage to the point that it's not rebuildable or at least not economically feasible to rebuild the motor.

I have to agree .... the spun bearing is likely the result of coolant in the pan ... got to be more of the story .... tho just the bearing issue would require a rebuild ... but not knowing the cause could lead to possible some parts not reusable .. now the price to play just went up .... short of a new GM crate ... a pulled used piece could probably be found .... any of the LS model vehicles would work .... #justathought
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I'm way over my head with the amount of choices I have but I think I have a plan. My Z is my daily driver and I do occasionally track the car (moving forward maybe not so much anymore) so I'm not looking to build a beast of a motor - I just need it back to running order. So I think I'm going to do a long block assemblyhttp://www.turnkeyenginesupply.com/ls6-5-7l-450-hp-long-block-assembly/ from turnkey engines (Oceanside California) delivered 5300.00 then R&R then tune. Then once have the old motor out - Ill rebuild it if its not too far gone.

I definitely appreciate the advice and direction everyone has offered - you guys Rock!

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brother I KNOW the feeling of being over your head.

my 99 c5 has a similar and more painfull ( $$$) journey.

I will offer your this counterpoint.

look at this

http://paceperformance.com/i-7141040-19301326-ls3-6-2l-430hp-gen-iv-engine.html

Posted Image

this is complete LS3 engine. NOT a long block. an entire engine.

pulley, water pump, intake, fuel rails, senors, injectors, throttle body, coils. all of it.

for $6,298.00 plus free shipping and no tax.

so for an extra $997 ,heck lets round up and call it $1,600 more, you get the following

- new engine

-new accessories

-an increase in cubic inches from 346ci to 376ci.

- lots more power than a stock LS6 could offer

for me that increase in money brings A LOT more to the table than a 'plain' LS6 long block.

if you go down this route of an LS3

you have 2 choices. the GM Performance Parts and the Gm Mr Goodwrench.

the only difference (to my knowledge) is the warranty provided and how its made.

Gm performance has a GMPP 24 month warranty and is brand shiny new

Gm good wrench is a rebuilt unit by Gm them selves to their spcs.

here is a GM GoodWrench LS3 crate for $5849.00 (a $549 increase now)

(there is a $1200 core, but your LS6 may suffice)

http://www.crateenginedepot.com/62-Ltr-379-CID-LS3-GM-ENGINE-2008-2011-New-19256529-P17671C719.aspx

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So many options it blows my mind - thanks for the leads and links. The LS3 does seem like a viable option but its more in depth than my finances would allow. I assume that the ECU would need to be flashed among other things. I need to turn this around within three weeks - that's my goal. Believe me Id rather be driving my Z06 instead of the family car a 2011 Ford Taurus. The right pedal doesn't do diddly when you hit it. ... Thanks again Chad for the information and direction - sincerely appreciated.

Peace

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joe@cpr.com

Heard this video the other day as you talked to my new tech about it. Another great option to shorten downtime is a Thompson motorsports shortblock. They are extremely well priced and offer a 1yr unlimited mileage warranty. We are a dealer for them and have used them a couple times already and are very happy with the results. We use this option when the car can't be down waiting on their engine to be rebuilt.

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Heard this video the other day as you talked to my new tech about it. Another great option to shorten downtime is a Thompson motorsports shortblock. They are extremely well priced and offer a 1yr unlimited mileage warranty. We are a dealer for them and have used them a couple times already and are very happy with the results. We use this option when the car can't be down waiting on their engine to be rebuilt.

Hello Joe -

One of the guys I run with at proautosports recommended you with high praise - Dan Klaudt.

Ill send you a pm with my contact information so we can discuss possible options and yes id like to know more about the shortblock - components ..hardware etc .... I'm looking to get her in the shop sometime next week to begin work.

Also - which Tech is yours? Ive talked to so many people about this my head still hurts ... lol

Peace

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So since you have a lot of options, then 2 more won't make your head explode.

According to the video and not a teardown, it's possible that you only have damage on the left head. That water is only on one bank and the engine still runs. Therefore pull the head before you go any farther.

After verifying significant damage that requires complete replacement, consider a used engine for your used car. Unless you plan on keeping the car another 100,000 or more miles and replacing all the other parts that will eventually go bad, the investment in a new engine is not worth the time and trouble. It's not like a new engine is going to make a 10 year old car feel any different. Any LS engine that doesn't require an ECM or reluctor change/compensation should be considered. There's a bunch of them in junkyards that were running fine at the time of the crash that put them there and the price is right.

Just for reference, 3 years ago, I picked up a used 2010 LS3 for my '08 with 4,000 miles on it for $3500. I now have 116K on the car and 45K on the motor.

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Heard this video the other day as you talked to my new tech about it. Another great option to shorten downtime is a Thompson motorsports shortblock. They are extremely well priced and offer a 1yr unlimited mileage warranty. We are a dealer for them and have used them a couple times already and are very happy with the results. We use this option when the car can't be down waiting on their engine to be rebuilt.

Hello Joe -

One of the guys I run with at proautosports recommended you with high praise - Dan Klaudt.

Ill send you a pm with my contact information so we can discuss possible options and yes id like to know more about the shortblock - components ..hardware etc .... I'm looking to get her in the shop sometime next week to begin work.

Also - which Tech is yours? Ive talked to so many people about this my head still hurts ... lol

Peace

I'd look into this hard because you probably only need a short block which is a huge savings from an entire long block. If the car can't be down then get the short block, swap it and be done. If you can afford a little down time, rebuild the LS6 with off the shelf parts and call it a day.

Either way I think a long block or entire engine isn't needed. Joe blew the ever living hell out of my LQ9, huge hole in the block missing piston, and I didn't need to order a long block or entire motor.

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Yep - just going with a LS1/LS6 short block and a few other goodies. Wanted to go a bit wild but simply too expensive. Either way - I look forward to CPR doing the work and getting her back on the road soon.

Thanks

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  • 1 month later...
Drewster67

Number 7 Cylinder Piston went Kaboom (minor)

The valves on # 7 were also bent.

Joe and his team are doing great work.

Pics are courtesy of Cordes Performance Racing.

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post-2332-0-11172900-1399474872_thumb.jp

post-2332-0-72674800-1399474887_thumb.jp

post-2332-0-32652300-1399474902_thumb.jp

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