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Old 03-10-2010, 11:34 PM   #1
gchemist
BAD BOW-Silverado XST
 
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ZZ4 maintenance - problem found!

Well, I found the rocker arm causing all the noise. Boy was it loose!! Checkout this short video.
http://www.youtube.com/user/Silverad.../3/HY6it2e-U7c

I've loaded three other short videos. While adusting the passengerside, the engine ran on four cylinders! Only the driverside cylinders were firing.
Video after the first adjustment.
http://www.youtube.com/user/Silverad.../1/sDOiHokViZk

Video after third adjustment: http://www.youtube.com/user/Silverad.../0/O1bCGZ5VpAs

Notice the idle change from the second adjustment to the third. The ZZ4 cam lope is noticable with only four cylinders firing.

I'll finishing it tomorrow. I can't wait to take it out for a spin. No more rocker arm noise! You can hear the exhaust now while standing near the engine bay. I should have made these adjustments a long time ago!!
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Last edited by gchemist; 03-11-2010 at 09:47 AM.
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Old 03-10-2010, 11:52 PM   #2
68Timber
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Re: ZZ4 maintenance - problem found!

Glad it was that simple, G!
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Old 03-11-2010, 04:26 AM   #3
MylilBowTie
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Re: ZZ4 maintenance - problem found!

No new rocker arm nuts??
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Old 03-11-2010, 08:46 AM   #4
Eighty-6
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Re: ZZ4 maintenance - problem found!

Wow, that was loose. Glad you got it going sounds awesome.
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Old 03-11-2010, 04:38 PM   #5
gchemist
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Re: ZZ4 maintenance - problem found!

I'm not installing new nuts now. I'll run it a few days. If it comes back. I know either the stud or nut is bad. Aluminum heads have screw in studs. I can install new studs with some locktite. Crate engines are not started up when they are built. Adjustments are needed as soon as they are fired up. The previous owner probably did not adjust them. I know he ran his car hard. He totalled is late 70's Vette with the ZZ4.
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Old 03-11-2010, 04:56 PM   #6
68Timber
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Re: ZZ4 maintenance - problem found!

A friend spun a bearing at the track some weeks back. I helped him tear it down. Hadn't seen them before, but he had some rocker nuts with inner allen head nuts you locked them down with after adjustment. If it happens again, that may be the trick.
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Old 03-11-2010, 06:24 PM   #7
Driveway Dreams
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Re: ZZ4 maintenance - problem found!

Holy cow! Good thing you caught it when you did. That sucker was looser than...(self censored to maintain a family friendly atmosphere). Sounds really good now.
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Old 03-11-2010, 06:38 PM   #8
old Rusty C10
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Re: ZZ4 maintenance - problem found!

glad to hear it was a simple fix for now
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