So here is the situation: I just performed a sudo-rebuild on this engine. Ill split this post into multiple sections for clarity.

Original diagnosis:
I found the coolant overflow reservoir had black oil sludge caked on and around the plastic lid and neck. This led me to believe the head gasket failed, allowing oil and exhaust gasses to blow by into the coolant passages. Another thing to note, the engine would run low on coolant without it draining onto the floor. This led me to believe that the engine was consuming some coolant too. Given this, i decided to order a top end rebuild kit, a timing kit, as well as an oil pan gasket as it was leaking all the way around. Do note, this engine has not had any history of knocking or low oil pressure, no overheat. The car ran relatively fine when pulling it in to the "repair bay". Also note that the engine oil, at no time, ever seemed to be white and frothy, like it had been contaminated by coolant.

The repair, disassembly:
First, i drained the coolant and engine oil. The engine oil was dark, but di not seem contaminated with coolant. I pulled everything off the engine to do this work: the entire wire harness, the intake and exhaust/cat manifolds, almost the entirety of the coolant and vacuum lines were disconnected from the engine and moved out of the way. Relatively overkill, i know. Though this isnt my first rodeo, this was my first time on a d17 and i wanted to make sure i didnt have any weird things hiding somewhere that would get forgotten about, break, rip, snag, or otherwise cause a headache while i lifted the head off. I also wanted to get a good understanding of how everything was routed and where all the components were. Anyways, I pulled the rocker carriage, the camshaft, then the head, removed all the timing covers and components, had a fun time with the harmonic balancer pulley bolt, dropped all relating trans stiffeners and the shifter linkage to gain access to the oil pan, and then dropped it. At this point, the block only had its rotating assembly attached within it, and thats it. I didnt crack open the bottom end, the con-rod and crank bearings, as well as piston rings, remain untouched. I also reseated the exhaust valves, as they were pretty pitted and not sealing properly. the intake valve seats were in great condition, however, so i didnt redo those seats. I also r+r'd the valve stem seals as well.

The repair, assembly:
Going back together, I cleaned all sealing/gasket surfaces. Once complete, i cleaned the oil pan and rinsed it with pb-blaster to make sure there werent any silicone debris floating around. I rinsed (pb-blaster) and wiped everything down on the bottom side of the rotating assembly to remove any possible grit that might have found its way onto the oiled surfaces, and then immediately reinstalled the oil pan with gasket, and reinstalled the shifter linkage and trans stiffener. then, ensuring the dowel pins were in the block, i installed the new head gasket and then the head. i torqued the head down to spec, and then assembled the timing components. I made sure to align the crank to tdc, then i installed the cam at tdc, and then the rocker carriage, torqued everything to factory spec. then, i installed the new water pump and timing components. I made sure to put the tensioner on as follows: dont remove tensioner alignment pin, place tensioner, hand tighten bolt, string the spring to its stud, still leaving the tensioner pin in, then ran the new belt on. now, everything is at tdc and should be timed. i rotated the crank 2 times and rechecked tdc, and then 2 more times for peace of mind. Everything at this point is timed properly, so i torqued the tensioner bolt to factory spec, removed the tensioner pin, and then reinstalled all the timing covers. Finally, i reinstalled the intake manifold, exhaust/cat manifold, wire harness, tubes/hoses, etc.

First run:
Obviously, i installed a new oil filter, filled with oil and coolant, p/s fluid, the works. i had an issue where the engine coolant temp sensor broke, and I wrongly figured the engine would be able to start, idle, and warm up to allow me to check for leaks and engine operation. However, the engine did NOT like running without the ECT sensor input, so after about 60 seconds of engine operation, i stopped for the night and i ordered a new ECT sensor before testing the engine again. With the new ECT sensor installed, i ran the engine and let it warm up for a minute or two before attempting to go for a test drive. Immediately upon putting the engine under any kind of load, i can hear some type of knocking. This is the issue I am currently facing.

Post-repair, engine knock diagnosis:
I pulled the car back in to the "repair bay", and i pulled the valve and timing covers off to inspect the timing. The timing marks are dead on, no way the timing is off. Im considering that maybe while replacing the oil filter, while it was off for 2 minutes or less, a piece of debris from the tree above or SOMETHING could have fallen into the oil inlet for the block, clogging an oil passage. Something else ive considered, though it doesnt sound like it, is that the issue could maybe be valve lash? i havent checked, but i seriously dont think its valve lash; the sound is not ticking or tapping, its like a knock.. Ive also considered maybe the harmonic balancer is failing or wasnt installed correctly on the crank, but the thing looked straight and the pulley bolt was tight af so i dont think the harmonic balancer could have been loose.

Conclusion:
At this point, im at a loss. I spent a week tearing this thing down, ordering parts and fixing small issues here and there as they arose, and now the car is worse than when i started, somehow. This car has to get fixed ASAP and out of my "repair bay". Short of dropping the pan again and doing the bottom end bearings, as well as blowing out all the oil passages with the oil filter off in the hopes that something blows out, im completely stumped right now. The likelihood that some debris fell into the block oil inlet is so miniscule, i hesitate to even entertain the idea. Also note, the oil pressure light goes out immediately upon starting the car. This tells me that at least the oil pump pickup isnt clogged by some silicone or something, but also could be indicative of a oil system blockage, if its building pressure too fast.

Im not a honda tech, i specialize more in older merecedes benz vehicles. Im not sure if this is a honda quirk, or if im an idiot. Any help would be greatly appreciated. I really dont want to have to disturb the bottom end if i dont have to.

Thanks in advance!



Below are images of the following, respectively: block bottom end with the pan off, mid-repair; block top side with the head off mid-repair; cam alignment post-repair; crank alignment post-repair.


mid-repair bottom end

mid-repair top-end

Post-repair cam alignment

Post-repair crank alignment

 

I’m dealing with a very similar issue after doing a head gasket, intake/exhaust manifold gaskets, and a bunch of other stuff, including all belts. I could wear my timing belt and timing were lined up perfect. I only had some valve lash which I adjusted, but that’s when the knock started. It only starts when I start to reach running temperature around 170 to 180 and gets louder towards 190. I reset the ECU and it goes away, but it comes back when I try to start it again and it warms up.

I’ve checked more things than I care to mention, but even though the timing is on. I think there’s a caveat to doing the tension. Rotating it to full rotations by hand, then three teeth. However, the indexing pin that you pull. The first time I noticed a lot of slack because that little index arm had slid all the way up. I went back and did it by the book and pulled the pin after and I still have the knocking noise. It feels like I have a little bit more tension on on the water pump side, and I think it’s due to when I did the valve adjustment to ensure I was at top dead center. I rotated the crank shaft maybe a 16th of an inch clockwise. This kills the tension from the cam to the crank. So essentially it’s messing up timing. I’ve seen videos where they were having similar issues and they said after you get everything set, you have to slide that indexing arm all the way down to lock it in place. Again, not to be the blind leading the blind, but I’ve literally checked everything else.