Sorry in advance for the longwinded post.
I rebuilt the 4.0 engine in my 2000 D2 last summer and all was well for about 2000 miles. The engine started ticking at this point.
Here is a video of what the "tick" sounds like:
https://www.youtube.com/watch?v=K6clqLLypFg
I took the video after changing the exhaust manifold to head gaskets and exhaust manifold to y-pipe gaskets.
I have not hooked up an oil pressure gauge to the engine yet, but the light has never come on. I know the light has a very low threshold to ultimately let you know the engine is already in big trouble, so a gauge may enter the diagnostics soon.
There is also no check engine light currently.
The rebuild included Darton flanged liners, reconditioned rods to factory spec, new piston rings, new camshaft, new lifters, new oil pump, new water pump, all new bearings, new timing chain and gears, a new 180 degree thermostat, new plugs and wires, and ARP head studs.
I did not replace the pushrods or rocker arm assemblies.
I use Rotella 15w-40 dino oil with a bottle of Competition Cams break-in oil additive mixed in. During the break-in of the engine, I used Joe Gibbs Racing BR30 break-in motor oil. It was recommended by the machine shop owner when I picked up my parts to build the 4.0. I had a cam wipe the lobes flat once when I was younger and aim to throw as much zinc dialkyl dithiophospate at flat-tappet cams as needed to prevent a repeat of that fiasco.
After changing the exhaust gaskets and making the above video, I dug deeper by removing the driver's side valve cover. The oil underneath the valve cover was a pretty golden color and looks new. I guess it should with only having about 1500 miles on it in an almost new engine. I checked the pushrods for any play, though I didn't turn the engine over to check each rocker for lifter preload on each cam lobe's base circle. I was in too much of a hurry to check the cups in the rocker tips. I pulled the rocker assembly and the pushrod tips are flattened in appearance, though I don't remember if that was the case during the rebuild. Also, I would expect for one of the pushrods to stand out from the rest to account for the frequency of the sound. They all look more or less the same.
Here is a photo:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0251_zpsbccpqecx.jpg.html
Also, the rocker cups all appear to be firmly staked in place. I tried to check if they move with a small screwdriver gently turning in the oil hole. I didn't find one loose.
The only thing that appears out of place is one of the rocker pads that contacts the valve stem has an odd wear pattern.
Here is a photo:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0255_zpsglorhgp5.jpg.html?sort=3&o=6
All the others look like this:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0253_zpsyk6vssqm.jpg.html?sort=3&o=7
Also, the oil under the pedestals was thicker and black. It was hard to tell with the garage lighting or with my work light, but I thought I could see some metal in it. I took some of the oil and smeared it on a piece of white paper to let it dry and get a better look at it, but the dried product just looks like gray ink. No metal pieces that stand out. It almost looks like the lubricant that ARP supplies with their studs. I am thinking this may just be normal for break-in, as this is the second oil fill in the rebuilt engine's life. I will change the oil in the next couple of days and cut open the oil filter to further investigate.
At this point, I am thinking I should torque the rocker assembly back down and pull the passenger valve cover too and check how the cam lobes open the valves to see if I have a dead lifter or wiped cam lobe. I really didn't want to think about that, but it looks like the most parsimonious explanation at the moment. I followed a strict break-in procedure with the new cam (start engine immediately and keep between 2000-3000 rpm for 30 minutes right from the start, changing RPMs frequently to splash different parts of the cam, while watching live data of the coolant temperature ). The engine has never ever overheated during my ownership and certainly not after the rebuild.
Does anyone have any other suggestions to what may be causing this noise?
I rebuilt the 4.0 engine in my 2000 D2 last summer and all was well for about 2000 miles. The engine started ticking at this point.
Here is a video of what the "tick" sounds like:
https://www.youtube.com/watch?v=K6clqLLypFg
I took the video after changing the exhaust manifold to head gaskets and exhaust manifold to y-pipe gaskets.
I have not hooked up an oil pressure gauge to the engine yet, but the light has never come on. I know the light has a very low threshold to ultimately let you know the engine is already in big trouble, so a gauge may enter the diagnostics soon.
There is also no check engine light currently.
The rebuild included Darton flanged liners, reconditioned rods to factory spec, new piston rings, new camshaft, new lifters, new oil pump, new water pump, all new bearings, new timing chain and gears, a new 180 degree thermostat, new plugs and wires, and ARP head studs.
I did not replace the pushrods or rocker arm assemblies.
I use Rotella 15w-40 dino oil with a bottle of Competition Cams break-in oil additive mixed in. During the break-in of the engine, I used Joe Gibbs Racing BR30 break-in motor oil. It was recommended by the machine shop owner when I picked up my parts to build the 4.0. I had a cam wipe the lobes flat once when I was younger and aim to throw as much zinc dialkyl dithiophospate at flat-tappet cams as needed to prevent a repeat of that fiasco.
After changing the exhaust gaskets and making the above video, I dug deeper by removing the driver's side valve cover. The oil underneath the valve cover was a pretty golden color and looks new. I guess it should with only having about 1500 miles on it in an almost new engine. I checked the pushrods for any play, though I didn't turn the engine over to check each rocker for lifter preload on each cam lobe's base circle. I was in too much of a hurry to check the cups in the rocker tips. I pulled the rocker assembly and the pushrod tips are flattened in appearance, though I don't remember if that was the case during the rebuild. Also, I would expect for one of the pushrods to stand out from the rest to account for the frequency of the sound. They all look more or less the same.
Here is a photo:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0251_zpsbccpqecx.jpg.html
Also, the rocker cups all appear to be firmly staked in place. I tried to check if they move with a small screwdriver gently turning in the oil hole. I didn't find one loose.
The only thing that appears out of place is one of the rocker pads that contacts the valve stem has an odd wear pattern.
Here is a photo:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0255_zpsglorhgp5.jpg.html?sort=3&o=6
All the others look like this:
http://s1308.photobucket.com/user/Rover_On_The_Rocks/media/IMG_0253_zpsyk6vssqm.jpg.html?sort=3&o=7
Also, the oil under the pedestals was thicker and black. It was hard to tell with the garage lighting or with my work light, but I thought I could see some metal in it. I took some of the oil and smeared it on a piece of white paper to let it dry and get a better look at it, but the dried product just looks like gray ink. No metal pieces that stand out. It almost looks like the lubricant that ARP supplies with their studs. I am thinking this may just be normal for break-in, as this is the second oil fill in the rebuilt engine's life. I will change the oil in the next couple of days and cut open the oil filter to further investigate.
At this point, I am thinking I should torque the rocker assembly back down and pull the passenger valve cover too and check how the cam lobes open the valves to see if I have a dead lifter or wiped cam lobe. I really didn't want to think about that, but it looks like the most parsimonious explanation at the moment. I followed a strict break-in procedure with the new cam (start engine immediately and keep between 2000-3000 rpm for 30 minutes right from the start, changing RPMs frequently to splash different parts of the cam, while watching live data of the coolant temperature ). The engine has never ever overheated during my ownership and certainly not after the rebuild.
Does anyone have any other suggestions to what may be causing this noise?
