[zman921]

I have a 2008 Range Rover 4.2L Supercharged with 140,000 miles. Recently there was a loud knock coming from the lower engine. After removing the engine and inspecting I found that car had spun a bearing on one of the con rods. Inspected the entire engine and there is no other damage other than the crankshaft and one bearing. I was able to source a good used crankshaft but I am having difficulty finding the right con rod bearings. It seems that Land Rover has color coded these bearings and no one knows what they mean. One shop tells me the crankshaft determines the color while another says its the connecting rods.

Do anyone have any idea how I can make sure I match the bearings with the crankshaft I will be using? Are there any codes on the block that will help me decipher this?

 

[RRToadHall]

I was able to source a good used crankshaft but I am having difficulty finding the right con rod bearings.

You need to have the used crank measured for even wear and to figure out if it needs to be turned.

 

[kg74]

Do you know the color of the bearings the donor crank came from? That would help.

Are you reusing the same connecting rods?

What bearings are you looking to replace? Main bearings or rod bearings or only one rod bearing?

Do as RRToadHall suggests and take measurements of the crank. Does it need a polish or a full turn? If it needs to be turned this will define your selection. Pull up the manual and see what the specs are for the main and rod bearings.

If luck is on your side - the donor crank came from a similar color bearing RR and the donor crank is within spec and only needs to be polished. Then just get the same color and you theoretically should be fine. I would assume at 140k the crank will be on the wear range of the specs, but with modern engines it should still be in spec. Wear is designed to be in the bearings as they are replaceable parts. On a properly maintained engine the crank should only need a polish.

On a few Subaru motors I have just measured the crank, found them in spec, polished with a shoelace and some polish, and replaced the bearings with standard bearings. Never an issue. After build oil pressure always solid.

Every engine has three variables that impact bearing journal selection: 1)block, 2) crank, and 3) connecting rods. For a perfect build all of these items come into play.

As I understand it the machining of the crank and rods are extremely consistent with the variable defining bearing color being the crank.

Not sure if that helps.

 

[LuisC]

I just bought a 2008 supercharged. I hope this is a rare case of an engine grenading. I keep hearing the 07-09 were more reliable.



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[MARK_C]

Its kind of complicated and relies on a tag on the left side of the engine block. Hopefully you can get to the link, its the pages for determining the main bearing clearances from the service manual. Says its for a 4.4L but its the same for a 4.2L.

http://home.townisp.com/~markcanning/camaro/4.4L main bearing journal clearance.pdf