Odd noise after timing belt change

[Tango]

Right after i changed my timing belt I started my 81 for the first time since October. It started great, only needed a boost, but I became aware of a faint, gentle clanking sound, intermittent, almost like a bell-like sound. klank....klank klanka klank...klank....klank. Like that. It made me think for some reason "water pump". I know I had the sprockets aligned correctly. The aux drive sprocket had been almost 180 degrees out of sync, but I fixed that and I was very particular about how the belt went on. Cranked the engine at least two full times by hand before closing it up. Then I wondered if air bubbles working their way through the cooling system made any noise. While I ruminated, it faded and stopped.

I've put less than 20km on it since then, but went out for a spin tonight. Just as I sat in the garage listening before turning it off, I heard it again, faintly.

From what I've read below I should get a mechanic's stethoscope -- they're cheap at the local place -- and see if I can isolate it.

Any thoughts with that slim info what could cause an intermittent sound like that? I am quite confident there are no tools or missing parts sitting on the engine anywhere. I think.

T

[Mathew26]

Man searching our a klank-klank-klank problem is always fun. At first I thought water pump or aux. as well, but if you checked both then hmmmm.... What grade oil are you useing in it. I always put 10W40 in for winter months and 20W50 in for Fall,Spring, and Summer. These old cars sometimes are just a little worn-out and thicker oil is all they need. Good luck on finding the cause of the noise I know it can drive us all nuts.

[Mathew26]

[narfire]

I was going to say aux shaft but you mentioned the belt was put on with the shaft sorted. I had a noise in my VW the other day and the tech came out with a long handled screwdriver and put the metal to the head and the handle to the ear. I tried it and could here the ticking and when put on the water pump, the water flowing and a noise that might be a bearing on its way out. That was a cheap method and it worked.

[So Cal Mark]

I'd suggest you re-trace your steps; check all of the pulley bolts for tightness as well as verifying timing marks. Klanking noises indicate metal-to-metal contact and that will cause a failure in short order. Were the spark plugs removed? Could an object have fallen into a cylinder? Stethoscopes are about $3 at Harbor Freight and are much easier to use than a screwdriver for finding noises

[Tango]

Yes, a stethoscope is on my shopping list.

I did have the plugs out, but every single thing I removed was placed in a little baggie and labeled according to source. I definitely will check out the pulley bolts that I replaced. I remember torquing everything with a torque wrench, but you know how memory can be. NOthing is left over. I did have to chase down a little hose clamp for the overflow hose, but found it and put it on.

I dont really know what oil is in there -- I got it in September and put it away in October. I guess as a preventive I will change it out. kilrwail send me something last fall about a good choice for Ontario I think.

Tim

[kilrwail]

Hey Tim - Klank doesn't sound good. You're sure you had the aux shaft at 1 o'clock? Make sure your pulleys are clear all the way around too. You can usually find Quaker State 20W50 "SL" grade oil at CTC, which is suitable.

[Tango]

I have yard and house repair duty today madated by the higher authority, but will check it out tonight.

SOMETHING's making the noise, but:

1. It is not continuous, as I would expect things hitting due to sprocket misplacement to be. It fades away entirely. But dont worry, I will quadruple check. I felt I was being very careful and specifically checked and rechecked each sprocket before closing it up. Aux drive indexing hole was at 1 or 1:30. I've always been puzzled by why the PO had it at 6:30. I am guessing that his mechanic a year or two ago did that when he redid the head gaskets. No idea why. The shop manual was in the trunk.
2. I cranked the engine by hand at least 3-4 times around to be sure I didnt hear anything amiss and that the belt slack was where it should be.
3. It is not at a frequency that matches the engine speed. It is much slower, I think, certainly not 10 per second,or even 5. I need to confirm that.
But I will take some time today to be more methodical about it, look at the pulleys and make sure they are clear all around, etc. Thanks for the suggestions.

[launieg]

Aux drive indexing hole was at 1 or 1:30. I've always been puzzled by why the PO had it at 6:30.

That seems suspicious. I wonder if everything is aligned correctly; perhaps that aux shaft really is touching the rod bolt now? If it wasn't noisy before you changed it from 6:30 to 1:30 and now it is noisy...Could something else have been changed when he did that head work, I wonder? Someone who knows more than I do might have a suggestion about that.

[minimike]

Sometimes coincidence happens. the spelling of the sound makes me think of a loose exhaust heat shield, loose exhaust system, or if you have the metal timing cover, maybe it's not snug all the way. I assume that you took the rad and fan assembly out. Maybe re check them for loose nuts and vibration caused sound.

[Tango]

Well, last night it did not cooperate, although I only had a few minutes. I took the advice offered and looked for a loose cover or something and I did find something. I found that the rearmost sheet metal piece behind the plastic timing belt cover (the metal that is behind the cam sprockets) gets bolted to the engine along with the internal metal timing belt cover via the same bolt. This would be on the passenger side, around behind the whole timing belt assembly.

When I put everything back together I said that there were no leftover parts and that is true, but I did find on the garage floor at some point a little piece of pointed sheet metal with a hole through it. This is what it was: the corner of that sheet metal piece. When I unbolted the metal cover, it must have already finished tearing off the parent piece and landed somehwhere below. I have no idea how I will McGiver a patch piece to pop rivet that back in place. It would mean a lot of work to get at it properly and I dont think it is harmful the way it is. It flexes quite easily, but doesn't seem to strike anything.

I dont know if that is the source of the phantom noise. I doubt it, but interesting what you find when you start really looking.

[Tango]

I had some time tonight to try out my stethoscope. I can hear the clinking noise again faintly, off and on without the stethoscope, but not through it. I listened to cam covers, lower engine block, both sides, alternator housing, water pump casting, at least as close as I can get from behind, all over basically. Then engine sounds quiet, it just whirs.

One interesting thing is that the No.2 fuel injector is continuously much quieter than the other three. The engine is idling smoothly, by my standards, so I think they are all firing.

The only thing that comes close is that after I shut it down, I checked all of the pulley bolts / nuts that I had off during the timing belt change. They all seem tight by hand, but the water pump pulley / shaft will move side to side very, very slightly and the pulley makes a similar bell-like sound. Hard to explain. But when running I hear nothing from the water pump and there are no leaks.

My feeling is that it is either something to do with the water pump or something outside the engine irregularly clanking softly against it. Or maybe I am just whistling past the graveyard.

[Tango]

It's back. If anything louder after I restarted it after doing the distributor cap/roto/pickup/wires/plugs thing. Not when the car first started, but then it came on perhaps louder than ever. I didnt have it running long enough to see if it faded away again. IT seems to me that when I increase the rpms it disappears, but could just be drowned out by other noises. Nothing I can reach with the stethoscope is noisy.

I guess I am going to have to drain the coolant and take off the timing belt cover and see what is what under there. It started after I did the timing belt -- at least that is when I first noticed it. Logic says there should be a connection. I double and triple checked everything.

BTW, I turned the engine completely over at least 3 times by hand before closing it up, and got no hint of anything resisting, all seemed smooth and quiet.

Kilrwail: I do need to change the oil. previous owner's garage put 10W30 in there last year. But do you think that could lead to noise on a cool night so quickly after starting? The oil would have been still quite viscous.

I know there is not much anyone can do remotely. Just thinking by writing I guess.

[BurbankJalopy]

Hi
My guess is that it's something just simply rattling at low or certain RPMS. The sheet metal around the timing gear tends to rattle on mine at low rpms or under certain loads. Even the front grill rattling on mine has tricked me into thinking the engine was ready to blow. I had to put rubber washers around the timing belt covers to get mine to stop. To find it on mine, I had it running at the rpm to produce the rattle and used a screwdriver to carefully press on items. I found it to be the timing covers behind the cam sprockets.

[So Cal Mark]

from the description it sounds like something fell into a cylinder when you had the plugs out. It's common for debris to find it's way into the spark plug wells. You should always blow out the wells with compressed air before removing spark plugs