I have a 2000 v10 Excursion, I have replaced the crankshaft on another vehicle before, so it's not anything new to me but with that vehicle I had a place outside where I could pull the motor out and do all the work outside of the vehicle. What I'm wondering is is it possible to replace the crankshaft while it is still in the engine compartment. I know that i will have to disconnect the transmission from the engine and slide the tranny back in order to be able to remove the crankshaft along with removing other items from under the motor, oil pan etc. I'm just wondering I have the twin I-beam suspension for the front tires and it bolts to the cross-member so I know that I will have to unbolt the cross-member and raise and support the motor from above by chain and beam in order to remove everything from the bottom and pull out the spark plugs in order to release the pressure on the top of the pistons so that I can slide them up and down easier during removal and installation but I'm just wanting to get thoughts from everyone about whether it can be done without pulling the motor out becauseI don't have the area this time to pull out the motor.

 

Just curious, how do you know that you need a new crank if you haven't even seen your old crank yet?
Not trying to bust your stones, really just asking.

Welcome to the forum!

 

+1

Is all this just because your main seals are leaking? If so, you can just put in a new seal, or an oversized main seal if needed.

And if your crank is well and truly worn out, then there are other, fairly important engine components that will also be worn out as well. How many miles? Have you done a compression test? Checked the valves/cam lobes?

What are the symptoms that lead you to believe that your crank is "worn out"?

 

I wouldn't attempt this job without removing the engine. I'm sure it's possible, but I suspect it would be much more difficult.

I have never EVER heard of a crankshaft that has worn out though. I've heard of all kinds of other reasons for needing a rebuild, but I really don't think you have a worn out crank without having lots of other stuff being worn out as well.

 

Well I should clarify I believe that it's actually the main or rod bearings on one of the piston arms that bolts to the crankshaft. I had a Dodge Dakota that was run without the proper amount of oil in it and it also caused the same issue i am having now but worse. With the Excursion it only does the knocking sound at about 1500-2000 RPM's through the gears but when it is idling you can slightly hear it and when your in top gear cruising down the road every time that you put the gas on you can hear the piston rod where it mounts around the crankshaft tapping on the shaft. The shaft I could possibly get turned and put over-sized bearings on that one or two however many they are but I would rather just replace the crankshaft and put all new bearings in it since they do come with the new crank. A compression test I have not done yet but I feel from listening to the motor and using a motor stethoscope that I have pin-pointed the problem to the area of the crankshaft. So from what I have read so far at least one person recommends pulling the motor out in order to do the work. Any other suggestions would be greatly appreciated.

 

I would suggest not going through the trouble of replacing the crank and bearings. Unlike the engine in your Dakota, these use overhead cams that ride in the aluminum head. From what I understand there are no bearing races, and one of the first things that happens when ran low on oil is the steel cam grinds into the aluminum head causing irreparable damage. If it was run low on oil, there's a good chance you need new heads.

How much would it suck to rebuild your bottom end to discover that your heads are shot? Sounds to me like you need an engine. Much cheaper to replace with used than fix your current one IMHO.

 

This time the vehicle wasn't run low but it is a used motor, I believe that the bearings that go between the crank and where the pistons bolt to the crank have actually slid around the crank from where they would normally sit causing the piston arm to tap slightly when the vehicle is at higher rpm's because when you first start-up the truck it will knock for a second loudly and then quite down and if you have the truck in drive and it is just idling you can barely hear it, the only time that it knocks is when it gets to above about 1500 rpm's then once it changes to the next gear it quiets down again and continues this process throughout changing gears. Then once your in cruising gear you can go down the road without having the gas on and barely hear any sound at all unless you have the gas on above about 55 then you will hear the tapping. I have listened to the motor outside with no other noise around me and listened at all different areas of the motor to trace where the knocking is coming from and every time I do that it always leads down towards the bottom of the motor and toward the front of the crank.

 

The term you are looking for is "spun rod bearing". And it is possible that this is your problem. If that is the case, I would still strongly recommend a complete tear down and rebuild of the entire engine. You will have metallic debris in your engine oil, oil passages and bearing clearances of other bearing surfaces. It really all needs to come out, get torn down, cleaned up and reassembled. Unless you're just trying to do a quick fix to temporarily quiet the engine knock and unload the X before it returns.

Plan on replacing the affected rod(s) as well as the crank, as they will no longer be able to "hold" the new bearings in place.

Of course, if you keep driving it or running the engine as is, the problem will likely solve itself soon on it's own. And not in a good or cheap way.

 

This is the reason I got my parts truck for cheap. Described it to a tee. Then It let go in my driveway just as we were getting ready to move it in the open bay

 

So you're saying the metal flakes get hot, melt down and go back into where they wore out from fixing the problem without any other work? This is AMAZING! (I love only seeing what I want out of peoples post )

 

So far I haven't noticed any metal flakes on the oil dipstick but I have not drop the pan yet to see if there's any in the oil pan, the only reason I'm trying to replace the crankshaft from the bottom end by itself is because to get a whole gasket kit and crankshaft with main and rod bearings is going to be more than I can afford so unfortunately I'm having to replace just the lower gaskets, oil pan, timing so forth and the crankshaft and main and rod bearings, believe me I would much rather tear down the whole motor and replace all the gaskets and get everything cleaned up but unfortunately money wise I can't.

 

Sounds like you would be better off throwing a junk yard engine in than trying to patch yours and maybe not even fix it.

 

jump it across a creek like the dukes of hazzard!

 

OP,

I understand your predicament, but if you don't also replace the affected connecting rod(s), you will be wasting your time. There will be nothing to stop the next set of rod bearings from also spinning in the rod journal.

Don't know your situation, but perhaps you could just park the X for a while until you can afford a complete tear down and do it right?