1970 Jeep cj5 restoration

[GARRY SMITH]

I have been working on my wife's 1970 cj5. I had the engine rebuilt and it seems to run good except there is a knock that I can,t fiqure out where its comming from. Any help would be appreciated.

[LarrBeard]

Okay - let's get a bit more information:

Does it knock at idle?

Does it knock under acceleration?

Does it knock at speed just moving along?

Does it knock under deceleration?

[56willys]

What motor is it? Another thing to add to Larry's questions. Does it knock when cold, hot, or all the time. If its a rod bearing then the knock should fade after warmup. If not its likely something else.

[bmorgil]

Does it have oil pressure?

A wide open question you posed there Garry!

[gmwillys]

Welcome Garry Smith,

The more information the better on when you are experiencing the knock. Another question to add is what is the speed of the knock? Is the knock at crank speed or faster than crank speed for a valve train?

[bmorgil]

Serious engine knocks (the kind that ruin crankshafts, rods and blocks) typically also have low oil pressure. A knock combined with low oil pressure is serious. A "tick" or knock occurring at twice engine speed as gm is asking, are probably coming from the valve train and doesn't usually affect the oil pressure. Knocking sounds that are not rhythmic with the engine might be coming from the exhaust or other sources.

[gmwillys]

Exhaust dampers can come lose and cause a knock, but as Bmorgil said, it is usually non rhythmic.