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1989 Range Rover Classic
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147 Posts
Discussion Starter #21
Piston sap is totally possible but usually goes away after the engine warms up unless the cylinder bore is way out of spec. Brake torqueing would allow you to get a good sound clip and possibly isolate the noise better with the vehicle stationary. If the noise is present it could indicate a possible issue that should be looked into. A freshly rebuilt engine should not exhibit that sort of knocking noise. The next level of investigation would be to pull the oil pan and removing bearing caps and inspecting bearings.

Were your pistons reused when the engine was rebuilt? Did the engine builder hone each cylinder to match a specific piston?

Have you drained the oil to see if there is debris present?

Your other option is to just drive the truck and hope it fails within the warranty.
The pistons were re-used from the old motor, but each cylinder was honed to match it's specific piston. I replaced the oil at 500 miles, but didn't check it since the noise hadn't appeared yet. I'll give it a shot and seem what comes up.
 

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1989 Range Rover Classic
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147 Posts
Discussion Starter #22
Video results from brake-torque test, one with the camera sitting on the front tire, second with the camera sitting on top of the radiator. Idle to about 1500 rpm.


 

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There is definitely a noise. As I said before, if it's in warranty, just take it back. If you do too much messing it may well void it...
 

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1995-2002 Range Rover P38A
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45 Posts
It is a very mild knock and i could bet money it isn't piston/bottom end related.

Top end is more than likely...
 

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Great videos! Noise come through very well. I don't know what that is but there's definitely a knock coming from somewhere. Given the low tone and the frequency I'd strongly suspect it's a rod bearing that's slightly out of spec or a noisy piston. Really hard to confirm either without taking the engine apart and analyzing components.

What's the mileage/time term of your warranty? It may be worth putting a lot of miles on the truck in varying situations to try and exacerbate the issue to a point where the builder recognizes there's an issue and does something about it. That would also allow the engine to fully break in and see if the noise changes or goes away completely.

This is a great thread and helps to get me in the right mindset. I'm in the middle of rebuilding my 4.2 in my 94 LWB. Stuff like this is what I'd like to prepare for.
 

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1989 Range Rover Classic
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147 Posts
Discussion Starter #26
I sent him the videos I shared with you all and he agrees there is a noise that shouldn't be there, so I'm taking it up to him next week. Hopefully it's not a "whole teardown" kinda problem, but for whoever's interested I'll post an update once he figures it out! Thanks for all your insight!
 

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I sent him the videos I shared with you all and he agrees there is a noise that shouldn't be there, so I'm taking it up to him next week. Hopefully it's not a "whole teardown" kinda problem, but for whoever's interested I'll post an update once he figures it out! Thanks for all your insight!
I'll be very interested to see if anything is found.
 
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