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Engine Gurus - Need help...

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Old May 6, 2010 | 10:25 AM
  #1  
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Default Engine Gurus - Need help...

Please bear with me as I try to explain in as little detail as possible as not to lose your attention.

Background:
1999 FRC stock LS1 134K miles on the clock.

Problem:
Broken pushrod on #5 intake side. Lots of oil entering the cylinder causing massive smoke.


I obvioulsy twisted the the thing a little too hard and broke the pushrod, but that's not my concern/confusion. The issue is this. As soon as the pushrod broke, the car started smoking like a 5 alarm fire out of the left side exhaust -so much so that I honestly thought the car had caught on fire.
I pulled all of the left bank spark plugs to do a compression test before pulling the head and the #5 cylinder was blowing oil out of the hole and onto the frame rail of the car. That's obvioulsy where the smoke was coming from, but it didn't crack the piston and the head gasket was 100% intact so where could the oil be coming from?

1st pic shows #5 intake pushrod. 2nd pic is #5 and #7 piston.



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Old May 6, 2010 | 10:45 AM
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What did the valves look like on that cylinder?
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Old May 6, 2010 | 11:47 AM
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the piston looks pretty clean.
check the intake and exhaust ports for a crack.
check the exhaust manifold ports for signs of the oil to help locate source
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Old May 6, 2010 | 12:11 PM
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I'll be putting on a different set of heads, so if these are ruined it's no big deal. I just don't want to go through all the trouble to put it all back together and find that there's a problem in the cylinder. I just can't imagine how there could be.
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Old May 6, 2010 | 12:57 PM
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Originally Posted by sperkins
I'll be putting on a different set of heads, so if these are ruined it's no big deal. I just don't want to go through all the trouble to put it all back together and find that there's a problem in the cylinder. I just can't imagine how there could be.
I know you probably did already - did you check for a groove in the cylinder wall?
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Old May 6, 2010 | 01:08 PM
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Examine the Valve Guide seal, the area around the valve guide for cracks/damage. If that area or the seal is damaged,,you will get oil in the cylinder.

Heres a post of a guy that may need a LS1 head if your getting rid of yours:

http://www.c5forum.com/cgi-bin/ultim...ic/1/2020.html
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Old May 6, 2010 | 02:23 PM
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Thanks guys.
Jeff - I have not rotated the engine to examine the cyl walls. Will do that tonight.
Bill - I'll check those items tonight as well. Nothing seemed out of the ordinary, but I didn't look very hard since it was after midnight.
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Old May 6, 2010 | 02:46 PM
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Hope that it all goes well for you.
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Old May 6, 2010 | 03:58 PM
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You probably damaged a valve seal.

Tim
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Old May 6, 2010 | 04:03 PM
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Good thing you're changing the heads. Those have valve damage, at the least. Good news, the block should be OK, from what I can see.
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Old May 6, 2010 | 05:12 PM
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What heads?
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Old May 6, 2010 | 06:00 PM
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Originally Posted by varkwso
What heads?
843's from a friends 2000 FRC. He left them in my basement after a head/cam swap. Hopefully he'll go for my offer of $10 per head (after they're already on the car).
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Old May 7, 2010 | 05:22 AM
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Originally Posted by sperkins
843's from a friends 2000 FRC. He left them in my basement after a head/cam swap. Hopefully he'll go for my offer of $10 per head (after they're already on the car).
- It is tough to spend money on LS1 heads so they need to be almost free...

According to my engine builder the 2004 LS1 heads are the best.
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Old May 7, 2010 | 05:30 AM
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Have you checked out this post?????

http://forums.corvetteforum.com/c5-t...post1573996360

Looks like you have the same shifting issues to work on.
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Old May 7, 2010 | 11:16 AM
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Originally Posted by Bill Curlee

Looks like you have the same shifting issues to work on.
Unfortunately, my shifting issues (or lack of shifting) was caused by a mechanical clutch issue/failure the day before. But if you don't run, you're guaranteed to lose and I'm not a good loser.
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Old May 7, 2010 | 11:41 AM
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Originally Posted by sperkins
Unfortunately, my shifting issues (or lack of shifting) was caused by a mechanical clutch issue/failure the day before. But if you don't run, you're guaranteed to lose and I'm not a good loser.
And you should not be!
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