Just an idea. But I bought a 99 Cherokee at the sale that had no body damage so I was thinking either motor or trans problems. Got it to the shop and started it up and had a knock that sounded like yours. Removed the drive belt and knock went away. Found out it was the water pump. If the dizzy doesn't do it for you, you might remove the belt and make sure that it is not coming from any belt driven acc.
Finally got the distributor installed today..... No luck... Knock still there....
Don't want to pull the engine apart to try to chase this down.
At this point will drive it till it ceases and then swap out unless can find something easy.
Thanks to everyone who helped out, your input is appreciated.
I must say that from the video it seems that the knock is on every crankshaft revolution. Whether it is on every crankshaft rev or every other is important.
If half speed, that means valvetrain, so perhaps a collapsed lifter.
If on every rotation, that implies crankshaft.
Now, take another video and get the revs down as low as you cen get the motor and with the fan and pulleys in the shot. We don't need to see the air cleaner nor hear you rev the motor. The slower, the better and we want to judge the sound to the movement, hence seeing the pulleys/fan.
If it is something like a rod bearing, using Seafoam or MMO is the worst thing you can do. These are thin oils. The motor wants thick as you cannot replace missing metal and thinning the oil even more makes matters worse.
It is possible that you wiped a rod bearing as a result of the oil not flowing on that cold start you mention. On any frigid start, let the motor run at no load and at idle speed until you get some warmth into the lower end. The motor can run all day at no load/idle speed with insufficient lubrication but as soon as you intoruce load (by driving) or increase the revs it can be bye-bye time.
BTW if that knock is on every crankshaft turn, the swapping distributors was irrelevant.
I did not read the entire thread but assume that the basic troubleshooting steps have been outlined.
You do not need a stethoscope. Just get a long screwdriver, dowel, welding rod or whatever. Press one end on what you want to listen to and the other end against the bone behind your ear. It is all you need to hear any engine noise and you will amazed at how well it works.
Assuming you have a bearing knock, I would run 20W-50 with plenty of Lucas oil additive. You want the thick oil to create a cushion so that the knock does not get worse.
Mechanic said the knock is on the half turn of cam and also stated lifter.
Pulled valve cover and all lifters working well, specially since change of all lifters. Oil Pressure at 40 lbs.
He did state it sounded upper end but could not determine exactly where, did tell me to go thicker oil also.
Note: Day of the freeze I stated the engine and let it warm up for about 10 mins while I finished working.
Besides changing to heavier oil I pretty much done chasing this, if anyone else can figure it out with out taking head off please let me know.
Thanks again to all for assistance.
Many people have a hard time differentiating half and full speed knocks.
The easiest test for lower vs valve train knock is sharply increase the load (throttle) at moderately low speed. Valves are NOT sensitive to load whereas rods, wrist pins etc are.
I have used the big screwdriver technique for years, but once I tried a stethoscope
I found it far more precise._
'89 Wrangler YJ
97 Grand Cherokee (ZJ)
87 MB 560SL roadster
It sounds like your timing chain is starting to scrape up against you TC cover.
While it is idling put your hand on the TC cover...BE CAREFUL!! to feel it.
Timing chain noises usually occur on changing engine speeds. As the engine rpm changes, faster or slower, the slack in the chain whips and it hits the side of the timing cover. The noise then subsides as the rpms become constant.
A bad lifter OTOH will make noise all the time, sometimes getting less at higher rpm.
If all 12 valves are opening and closing that is good news. A noisy (loose) valve will never burn. Chances are you can just drive it and it may resolve by itself.
In a situation like this, use the mfr recommended grade of oil - not heavier - and one with a high detergent rating, like a synthetic. The idea is for whatever is plugging that lifter to come loose.