Connecting rod bearing or piston pin knocking..

Hi,

I have Jeep Cherokee 1989 190Kmiles 4.0 l engine

I checked that 5th piston makes knocking.

I want to take off the oil pan and check the connecting rod bearing.

When I disconnect connecting rod I would like to check if there is something wrong between connecting rod and piston.
You think guys that I will have enough space to make some small movements to check if everything is tight. I do not want to take off the head - not yet and I will have crankshaft installed.

Maybe it is because cylinder wall is worn out or scored - I hope not.

Does this engine (old 4.0l) - have problem with worn out piston pins?

Thanks for any help
Pawel

About the only thing you can check would be bearings and crankshaft journals. Use a product called "plastigauge" to check bearing fit; see: http://www.fast351.com/enginerebuild/index4.htm and http://www.plastigaugeusa.com/how.html for insight on how to use it. I personally wouldn't feel comfortable using plastigauge on the crank main bearings while the engine is still in the truck; however, It would be fine to check the rod bearings with. I would pull the main bearing caps and visually inspect the bearings and journals for signs of extreme wear. In fact, at those miles, if the crank looks good (mains journals not badly grooved/scuffed, or galled, and the rod journals check out visually as well and with a micrometer for roundness) I'd replace all the bearings. I'd still use the plastigauge on the mains, especially if you change them, but I'd probably have all journals but the one I'm checking torqued to specs to make sure the crank isn't sagging, giving an incorrect reading.