Hello everyone,

So the timing belt on my 2000 Accord (2.3) was due to be replaced. After doing some research online, I decided to be brave and try and tackle this job myself. Everything SEEMINGLY went well, but after putting the whole thing back together, the engine now has a concerning tapping noise from the top end.

I’ve checked valve clearances and timing marks and both appear to be a-ok, but there were a couple of things I did “wrong” during the job that probably contributed to this issue:


1.) Before breaking the crank bolt loose, I hand-turned the engine to find TDC, but I accidentally (and instinctively I guess) turned the engine over CLOCKWISE a handful of times instead of counter-clockwise. Doh! I quickly realized my error and henceforth rotated the engine the correct direction.

2.) I also replaced the cam and crank seals. However, I VASTLY underestimated how tight the cam sprocket bolt was going to be. I used the old timing belt to try and hold the cam sprocket while breaking the bolt loose and… it didn’t work too well! The belt slipped off the sprocket and the cam gear rotated waaaay off of TDC. So far that that the cam sprocket moved about 1/3-1/2 of a revolution and made a harsh “click” sound and “jerking” motion in the process. I rotated it back into alignment and - with another reassuring “jerk/click” in the opposite direction and the “UP” mark back at high noon - I hoped for the best, but I’m assuming that this is what’s caused my issue.


I know these are interference engines, so I’m fearing the worst, but are there any other ways to check the timing for the top end besides the “UP” on the sprocket and the marks on the back of the cam gear?

Why did the engine make that awful jerking motion when the belt slipped and the cam gear turned? Is there any way to check for damage or reset it back to where it should be?

I’m merely a DIY mechanic who doesn’t do much more than oil changes, but I picked up this car for cheap to hopefully learn on and I fear I may have just gotten quite an education on what NOT to do. I just hope I haven’t done any irreparable damage. The engine is still fairly young (149k) and ran absolutely perfectly prior to me “fixing” it.

I appreciate you making it this far into my post. Any pointers or suggestions would be welcome.

Many thanks!

 

Your probably didn't cause any damage rotating the engine clockwise.

When you turned the cam sprocket out of time, was the timing belt off the crank pulley?

 

Yes, the timing belt was off of the crank pulley.

 

Hey guys,


This morning I got a chance to make a video of the tapping noise. I recommend wearing headphones to hear it best. Hopefully it's helpful.




To expand a bit about what's going on, here are a couple of other symptoms that I've noticed:


- The car runs (obviously), but not that well. The engine runs somewhat rough with a noticeable shake, and on occasion the idle will drop very low and act like it's going to stall, but it never does.

- While driving, a high-pitched whining noise can be heard. It's almost like an alternator whine, but the car didn't sound like this prior to the timing belt replacement. It's noticeable in the third part of the video.

- The transmission seems to shift much harsher than before. There was already a slight lurch when shifting out of Park, but now it seems to have worsened and the transmission is hesitant to upshift. When it does, it's not very smooth.


Perhaps the timing is in fact just a little bit off? Please let me know what you all think. If I have to, I'll take it in and have a shop look it over, but I'm hopeful we'll be able to solve this riddle before it comes to that.


Thanks again!

 

When you slipped and moved the camshaft, that might have caused the problem. I'm presuming that the engine was at #1-TDC of the compression stroke, and the crankshaft was still at that position. Half of a cam revolution corresponds to a full crank revolution; but the crank isn't turning and the #1 & #4 pistons are at the top of their strokes. During the first 1/4-turn of the camshaft, the #4 intake valves would open, hitting the piston. During the second 1/4-turn the #1 exhaust valves would open, if you turned it far enough. However, listening to the video, it doesn't sound as horrible as I expected so maybe they're only "slightly" bent??

I don't have a real good idea of how much force it would take at the cam pulley to bend the valves. But you're cranking on that bolt when it slipped, so I bet it all happened very quickly.

I suggest you go through the motions of adjusting the valve clearances (especially for #4 intake and #1 exhaust). If those valves appear to have very large clearance, that's a sign of bent valves. A compression test would also show worse results for #1 and #4.

For the benefit of others, if you want to mess with the camshaft when the timing belt is off; it's safest to move the crankshaft 90 degrees away from TDC which puts all 4 pistons at mid-stroke. (That's true for an in-line 4-cyl; other types are more complicated)

 

Appreciate your input, Jim. Cylinder #1 was indeed set to TDC when this occurred.

All signs seem to be pointing towards bent valves. I'm going to rent a compression tester from the parts store and post the results a little later. Not sure if they rent leak down testers, but if they do I'll get one of those as well.

Kind of a bummer because as I said before this car ran really, REALLY well prior to me fussing with it, but I didn't give much $$ for the car, and if I have to dump a few hundred bucks into a valve job, I guess it won't hurt too bad. The threads in the head for one of the valve cover bolts are pretty much trashed right now (NOT done by me, surprisingly), so if the head is in the machine shop for valve work, I might try and get them to fix that, too.

I'll keep you posted!


P.S. I like your avatar! The 9-2x was probably my favorite Saab, even though it was largely a Subaru underneath. The 9-2x was just such a handsome car. Much easier on the eyes than the WRX of the time IMO.

 

I liked it too, even with the Saab purists whining about it not being a "real" Saab (it was ALL Subaru underneath). That photo was during a track-day at Nelson Ledges during SOC-2010. It turned out to be the end of that car for me because I spun a bearing or something. Wish I had time then to pull the engine and figure it out. Between the oak tree & the carousel there's a rather long time with the oil sloshed to one side of the pan then the other, and the oil pump sucking air. That was an expensive lesson learned that day. The suspension & tires far outclassed the ability of the oil pan to keep the engine lubricated.

 

you might want to double chk if you installed the balancer belt correctly

 

heard engine running, it runs even ,no bent valves, tapping noise could be coming from valve clearance,( too loose ), wining noise sounds like you got either t-belt or balancer belt too tight or balancer belt misaligned