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Discussion Starter #1
I have 4.7 engine that has 160,000 miles that has a rod bearing knock but as normal oil pressure and has no loss of power and runs normal just has a knock. If I would put a crank kit in would I be good for another 100,000 miles. But I don't know the history of engine.
 

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rebuild the whole thing. then you wont have to worry about nothing down the road,
 

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Discussion Starter #3
I thought about that but I can get a motor with 50,000 miles for 1100 and that is about the same price to rebuild a motor. If could put a crank kit in and be good for another 100,000 I might do that.
 

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What exactly is included in the crank kit? If it is a new crank, rods, and pistons, rings, you will most likely need to go to a machine shop anyway. A rebuild isn't that much more work. Not sure what is in a crank kit that would eliminate a knock for sure?
 

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Not sure as though that will fix your problem. I believe the old crank could be machined for less cost.
 

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find out whats causing the knock (not trying to be smart). sure you can buy a used engine but you dont know whats wrong with that one. when you rebuild you know everything is checked and redone. I would go the rebuild as it may cost more but you will have peace of mind.
 

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Discussion Starter #10 (Edited)
I guess the only way to find out what is causing the knock is to tear the engine down. What is a good rebuild kit that I can buy to rebuild my motor.

If was to rebuild my motor would I have to hone the block, or do anything to the heads. When you have spun a bearing doesn't that sometimes lead to your block getting groves put in them. One thing I am worried about if I rebuild my motor I going to tear down the motor to find out the block and heads are trashed. I guess if that was the case I could then just go out a buy a replacement motor.
 

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If you trashed the block and heads you wouldn't be able to use the new crank anyways. Unless you overheated it, a valve job should be sufficient for your heads. And to be honest, I don't think the new crank can just be thrown in. The tone ring has a stamp which identifies each main bearing size as it was determined from the factory. A machinist will need the block and crank to size bearings anyway, so a "crank kit", as I see it, is inherently risky.

Here is what I would do if you are considering this rebuild option. Remove your engine and take the block apart if you have the skills, which assuming you are talking about a crank kit, I am guessing you do. A stripped block will save you money when you take it in since they don't have to do it for you.

Call around to a few machine shops in your area, talk to them about what you have and what you want to do. Get some prices.

YOu are going to want to explain the block you have and ask them if they can first check the cylinders to see if they are tapered or still in spec. This will determine if you need to hone or bore the block. My best quote I have received from a guy who was knowledgable as a machinist was $30 a hole. On average I was quoted $300 to $350, so you get an idea. This was bore and hone.

Anyways, they will tell you what you need to do with the block and what size rings and pistons you will need. From there you can take this info and start looking for what you need, whether you decide to do all new pistons and rings or just rings. Since you have a knock, if you don't find anything, you may want to consider all new pistons and rods, but wait to hear back from the machine shop.

The shop should be able to tell you what you will need to do with the crank. Meaning it is either good and they can do nothing to it or polish it or it needs to be spun. In addition, they can give you new bearings sized to the crank you have so you know you have the right ones in there.

Once you have the crank addressed and the cylinders addressed, you can start getting parts and assembling again. If you can snag a factory service manual you can read up on it, it is pretty good in terms of covering everything, just maybe not in the best order for a rebuild. It isn't like reading a book, more like a cookbook. If you aren't familiar with engine rebuilding go online and order a few books. YOu won't find one for the 4.7, but there are a few good cheap ones out there for the old Magnum series engines. It is all similar in concept, except the tolerances are tighter now and you don't have hydraulic tappets with pushrods. But you will learn a lot about the rebuilding process.

If you want a complete rebuild, it is a good time to also ask the shop to redo your heads. Prices I have gotten ranged from $155 a pair to $275. Parts were extra.
 
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