Piston Slap. Usually cylinder 5.

Has this 35 year old motor ever been rebuilt? 35 years is outstanding for cast rings. Especially without modern crankcase ventilation/oil separation.

Can't expect rings to maintain tension and cylinders to hold oil too well for that long. A failed lifter is actually extremely rare and very easy to diagnose by just pulling the valve cover to verify that they are holding oil.

No big deal, some rings, a ball hone and new gaskets. A fun weekend.

 

Im not sure if it’s been rebuilt. I’ll pull the valve cover off and verify it’s not a lifter. Guess if it’s not that I got a really fun project ☹️
Thanks for the help!

 

rod knock. sounds like my old Volkswagen with worn out engine bearings. Does the engine do this cold? and if so does it smooth out or go away when warm? And then do the same knocking.

 

I start hearing it about a minute after start up and any time after that at idle. It goes away after about 1200 rpm’s.

 

Sometimes a small exhaust leak can make that ticking sound as well. Sometimes hard to find as it echoes. What is your oil pressure at?

 

These engines do not have lubrication issues. Bearing failures only occur when the engine is run without oil or it's run with severely contaminated oil. Rod knock is also audible throughout the entire RPM range and temperature range.

Piston slap becomes inaudible around 1500 RPM due to decreased piston dwell time and splash lubrication. For any straight 6 with piston slap, pulling the spark plugs and spraying WD40 into each cylinder will almost always remedy the issue temporarily. The rings can become seized with burnt oil if the ventilation system is not fitted with an appropriate catch can/separation system.

 

oil pressure is good, hovers in the middle of the gauge.

 

Great info,I really need a catch can setup. I’ll try the wd40 trick. Thanks!

 

As I am new to Jeeps I appreciate sharing the wisdom with newbies like me!!