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09-22-2019, 09:06 PM
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#1 |
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Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
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Rod knock?
Afternoon/Evening all, Got what I am fairly certain is rod knock on a rebuilt 5.3. Started after taking the truck to the drag strip. Ran fine for the year prior.
Problem starts after about 5-10 minutes of driving. Goes away when I let off the gas. I notice the motor is fully warmed up long before the noise starts and the oil pressure remains between 30-40. Researched the great web in hopes of finding something other than actual rod knock being the problem. Pulled the pan and checked the pickup tube oring (should of looked at the rods while I was at it). Didn't see any glitter in the oil pan. Checked the flexplate cause I heard that they could crack. Solid. Checked the rockers for anything loose. All good. Considered detonation. My AFR's look good overall but I'm only monitoring the left side of the motor. Reduced my timing (engine is carbed) across the board by a few degrees and the noise is all but eliminated. Is there anything that could of made detonation suddenly a problem? or are the lower cylinder pressures reducing the knocking force? |
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09-22-2019, 10:13 PM
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#2 |
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Senior Member
 Join Date: Aug 2019
Location: Cheraw
Posts: 1,305
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Re: Rod knock?
Check the internet on your roller lifters.
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09-23-2019, 10:38 PM
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#3 |
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Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
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Re: Rod knock?
First thing I considered but I don't know why reducing my timing would make a lifter stop ticking.
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09-27-2019, 06:25 PM
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#4 | |
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Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
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Re: Rod knock?
Quote:
I did notice when I pulled the manifold off many of the gaskets were disintegrating and several of them had big chunks missing. Replaced all the gaskets and put it all back together and so far no knock. Thinking it was detonation. |
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09-28-2019, 11:54 PM
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#5 |
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BMW & ASE Master Certified
Join Date: Feb 2004
Location: Houston, Texas
Posts: 1,255
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Re: Rod knock?
Do you have a cam? Do you have stock rockers? If so I'd check the rockers again to see if the caps are walking out of the rockers. If they walk out completely its gonna be a bad day.
__________________
1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress |
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09-29-2019, 08:20 AM
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#6 |
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Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
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Re: Rod knock?
I heard about that, so I rebuilt the rockers too with a kit that adds c-clips to the trunnions to keep the caps in place.
Just a mild cam in it. LS1 cam. |
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