2008 Acura TSX Timing Chain/Tensioner/Guides Replacement - My Take
I wanted to provide my perspective on replacing the timing chain, chain guides, and tensioner (plus additional parts). I used the Helm's Factory Service Manual (FSM) to perform the repairs and of course the many posts from this forum.
First of all, I don't know how some individuals have done this job in 8 hours and reading that techs do this in 3-4 hours? Sure, maybe with a lift it is easier. I am pretty mechanically inclined, but this would be my first timing chain job. It took me 2 Saturdays (8/4 & 8/11, ~20 hours total) and half a Sunday (8/12, ~6 hours) to finish this job. I performed the repair with the engine inside the engine bay, as directed in the FSM. Working with 2-3 inches of room is not fun at all. The FSM and online Honda/Acura parts websites don't do a good job of including all of the bolts on the timing chain cover/case cover. For instance, there was one huge bolt and goes through the chain cover that i did not see on the FSM. I felt like a lot more bolts came off than the FSM or online diagrams showed. I had to jack up the engine high enough to remove the bolts using a piece of wood and a floor jack on the oil pan as instructed. I felt like I was on the verge of snapping something but it held. The VSA/brake lines were in the way and so was the wire loom. I actually got stuck installing the VTC Oil Valve Assembly (installed new part), so i had to remove the bolts attaching the VSA module and wiggle it out of the way some. Back to removing the bolts off the chain cover - there was one bolt above the VTC oil valve assembly that I missed initially so I was attempting to pry the cover off. I thought this was normal because the Hondabond is some tough stuff and does an excellent job of sealing and preventing leaks. Also reasoned that prying would not be an issue since the Hondabond would conform to the imperfections on the mating surface since it does not use a typical paper gasket. Rechecked and found that middle bolt above the VTC oil valve assembly (15830-RBB-003). Taking off the 3 bolts from the oil pan was very difficult. Not enough room for your hands plus socket and ratchet. The Hondabond didn't help as it was tough to remove.
Second, installing the new timing chain was a pain. It was tighter than the one that came off by half a link (stretched, but surprised not more). I had to have my brother assist holding down the camshaft sprocket with a box wrench and then the VTC actuator with a box wrench so that the timing marks on both intake and exhaust sprockets aligned with the colored links set at the dot marking on top to ensure it was TDC. Once he took off the wrenches, the timing chain skipped because it was so tight. The FSM stated to install the chain first then do the guides. I decided to install the guides first then try to line up the colored marks. Of course once the tensioner was put on (with pin still in), you couldn't move the chain. I uninstalled the tensioner and we aligned the colored links and my brother held this position by using box wrenches on the camshaft sprockets (intake + exhaust). Then I installed the chain guides and tensioner as quickly as i could. It worked!
This is where things get interesting. I had everything lined up. The dot indentations were in between the 2 colored links on both the intake (VTC actuator) and exhaust sprockets, as well as at the crankshaft. Tensioner pin removed and chain was nice and tight with guides installed (including the top guide at this point). To install the crankshaft pulley, you had to torque down the bolt to 49 ft lbs, then mark the bolt and the crankshaft pulley so that the bolt turns another 90 degrees. Had to use a breaker bar plus a hollow metal pipe to do this (which is how I remove the bolt). I heard a loud snap/thunk when tightening it (same as when removing). Checked the mark on the bolt and pulley, maybe halfway there. Tried again, but would not budge. At this point i was using a lot of force and was afraid, but the FSM said to turn another 90 degrees. I added more force and heard another super loud snap/thunk. Checked the bolt and the pulley marks and they lined up perfectly. I then proceeded to check the timing marks on the sprockets and to my utter shock, the colored links moved and were not aligned at the top dots/indents. Of course the timing chain cover bolts were all on, with Hondabond sealed and cured. I almost cried because I did not want to do this job again. I was telling myself i knew i should have paid the dealer $2,000 to do this job. I tried to collect myself and I decided to check the timing marks on both sprockets and at the crank. Everything lined up perfectly, just not the colored links. I went on a google search and couldn't really find anything here. All I have been seeing is that the colored marks need to line up or your timing will be messed up. I did another google search and located one about Mustangs where it stated that because the chain has so many teeth and the sprockets have less teeth that the chain links would move position and eventually line up after X revolutions. I'm not sure where the logic is with the colored links having to match in between those dots/indents. They are just links. Maybe to see after the initial set up if they jump? Anyways, I marked one link and marked its position in relation to the sprocket. The link was not in the same position after 1 revolution. I should have taken out the spark plugs, as rotating the crank was burdensome. I think the links reach the initial position after an even amount of revolutions (2, 4, 6?). However, after maybe 4 revolutions, the best i got was the colored links off by 1, as in the dot was to the left of both colored links. I was so pissed and already prepared to scrap the car/engine as the issue arose at startup at the end of July and would not start. Sounded like chain slap. I was prepared for valve damage, but wanted to take a $500 gamble instead of paying $2,000 at the dealer and then having them tell me my valves are bent and need to take off the head and pay another $2,000. I finished putting everything together and started the car on 8/12. The engine started up with no issue! It runs so much better now and the idle is perfect whereas prior to this it would kind of bounce slightly around 750 rpm. Also, the acceleration and power delivery is much smoother (before it felt like i was using cheap gas, or had bad coils, misfires). Engine is quieter as well (although i did not adjust valves). I did not replace the VTC actuator because I felt uneasy using an open ended wrench to hold the camshaft lobe then unbolting the VTC actuator bolt. At first startup, there was a slight rattle (which i thought could be the VTC actuator). Second startup after sitting overnight there was a louder rattle. I started this morning and there was not rattle. I've already replaced/fixed most exhaust rattles but it could be something resurfacing. Doesn't make sense for it to be coming from the engine since it didn't rattle this morning. I'll have to look into the oil pump/balance shaft chain/guides/tensioner repair as well. Will monitor the rattles at startup closely.
End rant/story. Probably the most stressful repair I have done so far.