Hi! I have a '94 Ranger with the 4.0 OHV, I have a knock over 2k RPM when its cold and when it gets hot it has it under all acceleration. My buddies say it could be rod knock or piston slap, god knows how many miles are on my truck so let's assume 235k (35k on 5 digit odometer) I have lifter tick too.

My thought is if I replace my crankshaft, camshaft and lifters along with bearings and gaskets I won't have to pay a ton of money for a remanned engine or take the risk on a cheap used engine. I wouldn't be replacing pistons, connecting rods or anything else, just those 2. I priced it out and it'll be about $500 and a weekends worth of work to do it, will this work or would I have to reman the engine no matter what?

EDIT: Also when the engine is warm at idle under 1000 rpm my oil pressure gauge starts having a seizure and flicking from no pressure to yes pressure (no numbers to read, sorry) could this be a bad sending unit or is my pump going out and thats why I have the knocking to begin with?

 

Don't think you would have to replace the crank or cam
May be one connecting rod if its out of round
And all the Bearings and Rings, 4 crank bearings and 6 rod bearings, and 4 cam bearings
6 sets of rings
Also front and rear main seals, head gasket set
Oil pumps are not expensive

Problem is you need to test the size of bearings you need to use with Plastigauge after engine is out

A Rod knock happens ANY time that Rods cylinder fires, may be quieter with thicker oil, cold, but still there even at idle
Whats happening is that the worn out bearing on that rod allows a gap to form between rod and crank journal
On compression stroke the crank is pushing the piston UP, then just after Top Dead Center, the crank is pulling the rod DOWN and THIS is when the gap appears in a worn bearing, and then the cylinder FIRES, closing that gap with a KNOCK sound
If you disable spark in that cylinder the Knock will for the most part disappear, so you can do that after engine is heated up and you can hear the knock at idle, shut off engine, pull one spark plug wire and restart
Repeat until you find the effected cylinder, this will help when you pull the engine so you know where to look