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Potential problems? (403 stroker noise)

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Old Aug 11, 2018 | 08:02 PM
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Default Potential problems? (403 stroker noise)

Hey everyone,

​​​​​​This was my first top to bottom build on my GTO. LS2 aluminum block, Lunati crank/rods, weiscos all bought balanced from Texas speed with bearings. Melling high volume pump, shimmed windage tray, 242/250 hydraulic cam with Lunati linkbar lifters, 8.100in pushrods and Mast 245 heads done by Ed Curtis. Holds 55psi+ at cold start for oil pressure, a hair over 20psi hot oil pressure at 850RPM. I'm horrified that something may be wrong with the bottom end even though I did everything according to manufacturer spec and the book, so here's a video of the noise I'm concerned about.

I've heard people say that linkbar lifters can be loud, and the valvetrain is verified to be in good order. Fires up nicely and idles fine, but makes this noise for some reason. Thoughts?

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Old Aug 11, 2018 | 08:35 PM
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Yikes. Hopefully for you that is a terrible exhaust leak, but man it sounds bad. I’d cut the oil filter apart before I started it again.
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Old Aug 11, 2018 | 09:17 PM
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Got my ears in closer, it's the valvetrain nose echoing through the headers and my injectors are ridiculously loud...
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Old Aug 12, 2018 | 10:22 AM
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That's valve train, not bottom end. (whew...)

I'd be re-checking push rod length and rocker trunnions if it was mine.

That thing sounds mean.
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Old Aug 12, 2018 | 01:53 PM
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Good for you man! I’ve never heard valvetrain clanking like that under a car. Should be easily identifiable under the valvecovers, with it making that much noise.
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Old Aug 13, 2018 | 12:10 PM
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I think my Mast heads have a taller than stock rocker pedestal, so I think my Holley stock height valve covers are making contact and echoing, plus the lifters are just loud being link bars on a cam with basically square lobes.

Had my friend and tuner come over to ease my nerves about it, especially since this was my first "build" and It took me years to save being 21 and living on my own for 2 years plus juggling other projects..
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Old Aug 14, 2018 | 01:12 PM
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Always hard to say from a video but that sounds bad, like not just an exhaust leak bad. That sounds more like bottom end to me.

One trick for finding rod knock is to kill one cylinder at a time by either pulling the injector connector or coil connector and seeing if the noise stops on one cylinder. It doesn't always work, but it works more than it doesn't for finding a rod knock.
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