Dependent on where the sound is or how loud it is, will be the factor on whether this could be a simple fix or a "Don't wanna go there thing"!
Lets try 2 people---STAY CLEAR OF MOVING PARTS!!!!!---1 is possible if you can move the throttle by hand....Throttle up while someone listens under the hood...Common sounds similar to this will be Just under the Valve Cover (Thingee on top of the engine)This may be rocker arms/ lifters push rods...Another may be at the front, sorta under the water pump (Mr. Timing Chain). If it seems to be in a different location or hard to find---Try shovin' a piece of 1/2-3/4 heater hose about 2-3 feet long in your ear, use it like a stethoscope. Did this just start or has it been getting worse over time? We can help you with this, and I go way overboard to help CJ people--I am one also, I learned the hard way over many years! I have a 258 in my CJ 5, I have many REAL pics of mine and other friends stuff. Do you own a repair manual (you outta have one!)? Are you mechanical? I'm not a Paid Mechanic Either, A Jeep is much like a Plastic model kit, The parts are bigger and heavier, But you sorta need to know how things work and fit together...Still, we can help you through all of that, Jeep Guy To Jeep Guy.........You need to learn how to do it with a manual also (use it here and now, to reference by) Use it later with confidence when we are not around! I can help a lot with almost any CJ issue, keep on asking here, no need to submit another question. We can no longer "Link" here, but you can copy and paste the info I leave on to a new tab...Here's a feller, I've been-a-helpin' , You will see the extent we will go....
https://www.2carpros.com/questions/1980-jeep-cj7-timingtuning-problem-with-a Pic of My '77 (Have a '46 also) with a Holley 4 barrel now (below)The Medic
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Wednesday, March 9th, 2011 AT 8:02 PM