For future reference: Is it possible and has anybody done a main/connecting rod bearing change with the engine still in the car? The reason I ask:

I still have good compression on all cylinders (150psi to 143psi) on the cylinders, but I can hear a very slight knock(s) at idle and a little above. Also, oil pressure drops down to 45psi after driving for 20 miles or so at freeway speeds (60-70mph).

If I remove the center steering link, it looks like there is plenty of room to work under there, especially after lifting the engine up a couple of inches. Would be a good time to change the rear seal also. Any constructive ideas? Thanks.

I've never seen a main bearing change done that way, but I helped my grandfather replace a con. rod bearing in my uncle's 318 that way...
(jack up motor, pull pan, rotate crank, pull cap, push rod up pull bearings, inspect crank surface, install new bearing, put on some goop, put it back together).
Of course that's a barnyard repair, just to get my uncle by for a little while longer...I'd be more worried now, about clearances...

I'm sure pulling the crank under the car would be fun, sorta like doing a tranny swap...

-D.Idiot

Been there, done that... Search archives. You probably don't need to, though... Your oil pressure seems fine to me, the slight knock could be anything, including the fuel pump or a piston pin, neither of which would warrant a bearing change. There are many non-life-threatening things that can cause a subtle knock on a motor with some miles.

D/W

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If it ain't broke, fix it!

In addition to the above, you could actually make the knock worse. Changing the bearings will slightly change the position of the pistons in the bore leading to the possibility that the top ring of one or more pistons will strike the wear ridge at the top of the cylinder bore. This, of course, will cause an annoying knock and can lead to broken rings as well. 45 psi oil pressure is more than adequate and does not indicate bearing problems. You should determine exactly what the noise is before trying to repair it.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

But you can, if you want to