95_Civic_4dr

D16Z6, 1995 EX
***Issue resolved...kind of...***

Do you guys ever hear a pop/clicking coming from the timing belt area?
I'm trying to figure out if this is normal or not. As I'm rotating the crankshaft (CCW), every time the cam gear rotates 90 degrees and a piston reaches TDC I hear a popping or click. The side of the timing belt towards the front of the engine (only this portion) also tightens gradually as I come to TDC on each piston, then it clicks, and the belt isn't as tight anymore. Other areas on the belt pretty much stay the same as far as tight/loose is concerned.

Is this a sign of a stretched belt? Bad tensioner maybe? or normal?

I thought at first it was piston/valve contact but looking down the spark plug holes the pistons look fine and my compression ratio is #1 162, #2 155, #3 154, #4 175.

I need the car asap, but I'm afraid to drive it like that.

ls_turbo50

sounds normal when ur turning it over by hand ur gonna hav some noise as well as it tightening up on u due to compression if u remove all the spark plugs it should turn over easy bc u release the compression... is it noisy when it runs or does it run?

95_Civic_4dr

When it last ran it was pretty noisy and I also felt a power loss. It did idle fine, never died, but struggled accelerating.
Later when I got home I found that the distributor rotor screw back out and tore up the inside of my distributor and the rotor was completely loose, I shrugged that off as being the cause of the new noise and replaced the distributor.

I discovered this timing belt click when setting the timing, she also clicks/pops when I turn the engine over with the starter.

Edit: It does turn over easy with the spark plugs out

habib

Could be the tensioner or the belt, your compression numbers do not look good between #3 and #4, your headgasket could be blown

95_Civic_4dr

Yeah, I actually have a cracked leaking injector on #4 causing a lot of carbon build up (barely passed smog cause of it). Headgaskets only got 10k miles on it, I just haven't fixed the injector yet since I'm waiting on my new intake manifold anyway.

95_Civic_4dr

So, has no one else run into this problem before?
I'm gonna order a new tensioner from Honda tomorrow, unless anyone has other suggestions...
I've searched and searched for all the symptoms of a bad tensioner or belt and none of them mention anything about a click/pop whenever a piston reaches TDC.

95_Civic_4dr

One other thing before I get some sleep, does the Z6 have an auto or manual tensioner?

Jimster480

It shouldn't be the tensioner. But you can also pull it out and spin it around and see if the bearing on it is gone. It shouldn't really make a click. But if its TDC on every cylinder then it could be your head, since you are opening and closing valves. It depends on how loud it is though. if you could make a video it would really help out.

95_Civic_4dr

Here's a vid, the first noise about 10 seconds in was me, I hit the LCA.
Aside from the ratcheting, you'll know the noise when you hear it.
Video quality isn't the greatest so I marked the TDC spot with a sharpie.
http://www.youtube.com/watch?v=G9tXTWwFNM8

KevinBrown

iTrader: (2)

If you're still having trouble while accelerating, it's very possible you could have a couple burnt valves...

Jimster480

That **** has a real problem. it sounds like a seal is completely blown somewhere. It should never make that noise.

Edit: I'm really mulling this over as to what could possibly make that noise.

95_Civic_4dr

I'm not sure yet, I haven't ran her since I discovered this problem.

You think I should pull the head then?

Jimster480

I would, because something is def not right inside of there. The popping almost sounds like the compression just completely blowing out at one point. But I'm trying to point where, you should probably pull it to be safe before you blow it up.

95_Civic_4dr

Well I know it's not compression blowing out, she does hold compression and also when I shot that video, all of the spark plugs are removed.
I'll go ahead and pull the head this weekend, hopefully the crank pulley tool I'm waiting on arrives before then.


The head bolts can be reused at least once right? I just replaced them with Honda OEM bolts about 10k miles ago when I did a HG job.
And could this have any relation to the camshaft I installed a day earlier?

ozh_hawaiian

that does not sound right at all, and now that you say that you just changed out the camshaft, that definitely raises some red flags. I think the problem is definitely in your head. did you torque the cam bolts down in the right sequence? does it look like the cam caps are sitting flush?

95_Civic_4dr

I'm starting to think if there is a problem, it's my head too. I found my old stethoscope and went over the motor trying to pinpoint the source of the noise, I found it's actually coming from all of my exhaust valves not the timing belt or tensioner like I thought. None of the intake valves do it (but they are noisy), so I don't think I'm having valve-to-piston contact....I mean, pistons not gonna choose which ones to hit...maybe the noise is just a result of the higher profile cam? I heard it makes them sounds like diesels, and I was expecting some noise but holy crap.

She has compression. I did a leak down test earlier and all seems fine, it's making more power in the top end than it did before the cam switch - this is an obvious night and day difference to me. I checked the valve timing for the 5th time again, looks good. I did another valve lash adjustment. With all the tests and such I decided to play a game of Russian roulette with her...this is what she sounds like at operating temp...

(Taken from cell, sry about the bad audio - if I can find something better to record it with I'll switch the vids later)
http://www.youtube.com/watch?v=LtXGIiC5yeU

95_Civic_4dr

Throwing CEL #4 (CKP)
Took for a drive, not even a 1/4 mile out and CEL came on.

Jimster480

yea it is way too loud. I said that is what it sounds like when compressed air pushes something. Not that you were losing compression since you already did a compression test. It def shouldnt sound like that. It gets louder but not loud like that. Something in the head is off. Are you sure that the cam is degreed properly?

95_Civic_4dr

Oh, I just misunderstood it then.

Yeah I was pretty sure everything was degreed properly.
So, after putting it all back together and going for a test drive when the CEL came on and power went out the window. I came back home and pulled it all apart again, I set it to TDC and then noticed something...now it doesn't make the pop/click noise at all anymore when I hand crank it. I left alone for a few hours and let it cool down, hand cranked again and the noise came back. So now I know it does it when it's cold but not when it's hot....

Gonna pull the head tonight.

95_Civic_4dr

Ok, I pulled the head off and here's what I have. None of the pistons have touched the valves (no visual damage) and all of the valves appear to have never made contact with the pistons. Secondly, I turned the crank over by itself, everything is dead quiet in the block. And third out of curiosity, before I pulled the head off I installed the OEM camshaft to see if the pop/click would disappear, no change, stayed the same.

So now I'm back to square one thinking it's the tensioner or something in the timing belt area, but now I also have to figure out why it threw a CKP sensor CEL....i had driven for a good 30 minutes on a test drive, went back home, parked the car. Then went for another drive 20 minutes later and it threw the CEL within a mile...

These head bolts can be reused at least once correct? I installed them about 10k miles ago, I am just gonna replace the gasket though.

Here's some pictures:




#4 Cylinder


#3 Cylinder


#2 Cylinder


#1 Cylinder

Jimster480

well you said that when you put a stethoscope on it, you found that the exhaust valves were what was making the noise. if you turn the head over by itself when its outside of the car does it make the noise? that would be what really tells you if its the head or not. Since the block is all quiet. The tensioner shouldn't be able to even make that noise. I mean snice you have the head off you could always pull the tensioner off and spin it around and see if it makes that noise. its just that it makes it only when each cylinder is at TDC, and if the bearing in the tensioner went, it should make the noise all the time.

itsnotfast

As for your question about the head bolts, you can reuse them. Its not always advisable because the bolts stretch when torqued. Since you just changed them 10K ago, I don't see a problem reusing them as long as your not boosting.

95_Civic_4dr

I'll try turning the head over by itself later then. I'm also gonna pull the crank pulley off and inspect the tensioner and what not. Yeah, the whole only at TDC thing is throwing me through a loop, so idk....

Hmm...idk why but you made me think about it, I may just replace them then cause of the stretching. Already gonna be buying a new gasket anyway...

95_Civic_4dr

Ok, I'm officially stumped and out of ideas.
I assembled the valve train back onto the head and cranked it over by itself. I've sourced the problem to be only in the cylinder head.

As I was cranking it and watching the valves, I noticed they all come out smoothly just like they should, but just when the valves (appears to be Exhaust only) reach their peak - I hear the pop and they shoot back in but not completely only partially in (maybe 1/4 the way back in) then continue on normally. The intake valves don't appear to do this.
I'm having my cousin come over tomorrow to crank the valves over while I get a better look and both them and the rocker arm assebly. I will also pull some valves out tomorrow and check them for any bends. Today I also checked the cylinder head for warpage and it all looks good.

It's doing this with both the stage 2 camshaft and the OEM.

Thanks to everyone who has replied so far
I'm still open to more thoughts and opinions.

Update: It's both the exhaust valves and intake valves slamming shut. If I rotate the cam CCW like normal the exhaust slam shut, if I rotate the cam CW then the Intakes will slam shut. I have no idea why they are slamming shut and I can't figure it out. They seal and hold compression and are not bent. The head is not warped and the last time I drove the car it threw at #4 (CKP) CEL at me..

0JDMEngineImports

I don't know what you're options are, but they're pretty cheap motors. Maybe try the same cam in a different head? Something is slipping in that head to make those valves slam closed. May have to have the head rebuilt. Bad lifters?