Knocking motor after swimming

i just bought this really clean 91 2dr for $340. the catch is that is swam and now has a big knock. the kid drove it home 4hrs. i dont jack about motor noises. my friends think that it spun a bearing and this could be fixed. it starts easily, drove well considering, and the oil is clean on the dip stick. we have not opened anything yet. share any thoughts. thanks

How many miles on the motor?

the motor has 170k miles. i hear these motors run like diesels if you take care of them.

$325 is a nice cheap price to start with. If your xj is as clean as you say it is and it has a BIG KNOCK, replace it. You can probably do the whole swap yourself if you are mechanically inclined at all for under $1000. I took mine swimming a few months ago and ultimately ended up replacing mine. It now has 500 miles on it with all the bugs worked out. It is a greater piece of mind then worrying when I am going to throw the rod. Point is, is that for less than a total of $1500 you will have a nice rig with a new motor. That is cheaper than what most of us bought ours for and most of them need some kind of work. Just do it.

If it hydrolocked and now has a knock, you probably have a bent rod or worse. I hate to say it but the engine is probably on its last legs. A long block will most likely be required. At the price you got the rig, fixing it is definately worth while, otherwise, I'm sure there are lots of people on this board who would take it off your hands for what you paid for it.

When water gets inside the cylinders, it doesn't compress so it's almost certain that you have at least one bent rod. You could either rebuild the engine or buy a low mileage long block from a junkyard and swap it in. The latter might be the most sensible choice.