aux shaft issue ?

[ga.spyder]

That is very helpful. Thanks for that. I went thru your photobucket album on that previous thread and thought that was the one. As soon as my unheated garage warms up I will get back at it

[FiatMac]

This is the picture I referred to. Crank at TDC and other pulleys properly aligned; aux pulley pulled:

The position of the aux shaft in this picture would put the timing hole in the pulley at the 7 o'clock position, not the 1 o'clock position -- 180 degrees off. However, since the crankshaft rotates 2 revolutions for each aux shaft rotation the crank would be in the same position relative to the aux shaft lobe so there should not be an issue. Just not per the manual.

[ga.spyder]

Thanks Stan.I got your email,also.I appreciate the help.I am going to go ahead and time it per this picture.I will carefully run it thru by hand to make sure I am in the clear.If I have any issue,I will borrow the pulley you aren't using,and do it that way.It amazing how big a issue can be created by a little thing like swapping a pulley!!

[phaetn]

Within the past two weeks I had my timing belt replaced by a very competent mechanic who specializes in older sports cars (especially English stuff like MGBs, Triumphs, etc.). He came well recommended.

I had the timing belt replaced, new water pump and tensioner bearing installed, plus all new seals behind the crank pulley, the aux shaft, and the cam shaft pulleys. He noted when I got it back that the exhaust cam had been off one tooth.

I was happy on the way home with power (seemed to pull better at higher RPM) but I heard a misfire at idle when in long stop-and-go traffic. I eventually in a parking lot and verified that the cam shafts were aligned with the marks on the cambox housing while the crank was at TDC. It was all fine, so then I went on a quick (less than 5 minute) burst on the highway, up to about 80mph. The next morning I started to hear a ticking that later became more of a rattle. It was quite pronounced. I immediately pulled the timing belt cover and verified that the aux shaft was pointing at 1 o'clock because of the issue with the interference of the fuel pump lobe. It was properly aligned. This is how it sounded at its worst:
https://www.flickr.com/photos/1974_fiat ... ed-public/

I brought it back to the mech. He mech pulled the rad, checked orientation, and even called me in to verify it running with the water pump disconnected (if memory serves the rad may have still been out, too -- definitely the rad hose at the T-stat was not attached so no coolant was flowing). There was no noise. The marks all lined up. I had noticed earlier when troubleshooting that the nuts on the exhaust manifold were a bit loose and I thought that might account for something, so I sent some more money his way to put on a new gasket.

Picked up the car later that afternoon. The rattle came back by that evening. I brought it to another very trusted mech who has worked on these cars for years. We pulled the alternator belt and the sound seemed to just go away. That seemed to suggest that it wasn't the aux shaft and was good news. I have listened numerous times with a stethoscope and he did this time, too, but we couldn't pin-point the source. Brought it back to the original mech to schedule yet another appointment.

A couple of days later (this past Friday) he pulled the rad again (third time if you include the original work!); he indicated that he thought that the crank nut might have been loose (but wasn't sure). He had spun the water pump and alt by hand and hadn't heard anything there. To be safe, he loc-tited the crank bolt and buttoned everything up again. Marks all still good. He mentioned that the used the screwdriver with a hose trick and seems to think the sound may be from the lower right of the block (looking from the front). This is worrisome.

I'm about to drive to FFO and I am very nervous about this. The slight noise has returned. It's not nearly anything as bad as in the video above, but it's still something. As my battery light charging light had come on I pulled the alternator belt this morning and this time the sound WAS STILL there, even without the alt or water pump spinning. Uh oh!!

I am wondering if originally, before any work was done, that the aux shaft may not have had a proper alignment. Would I be safe to try and move the aux shaft from about a 1'oclock position to a 1:30 or so?

The interference area of the aux cam is not tight. When I had my aux shaft out, i rotated the crank and found the non-interference timing for the aux shaft is between 12:30 and 2:30. I know the aux shaft pulley is the same as either the intake or exhaust, i dont remember which one. Here are pictures of the intake and exhaust and the timing hole is very close to being aligned with the bolt pin. Using this, I would set the aux timing at 1:30, then rotate the motor by hand a few times to make sure it doesnt hit.

Edit: added pics to confirm the settings.

Crank at TDC (white and orange marks)


Intake and Exhaust Cam Pulleys at 1 o'clock and 11, respectively


Timing belt cover removed.
Auxilliary shaft at one o'clock, in line with tensioner bolt


I'm wondering if I should try and slip the aux shaft further over to 1:30 or so.

Thanks and cheers,
phaetn

[azruss]

If the alt shaft is a 1 pm, it should be ok. Moving it to 1:30 without moving anything else should not be a problem. I doubt that this is the problem as the knock in the video sounded like a double knock some of the time and this wouldn't occur if you were at the edge of interference with the aux shaft and crank. I also see you have a pulley on the PS side of the block. My car had an AC pump there. If the bolts are even the slightest bit long on those mounting holes, they will go through the block and make contact with the crank. I suggest pulling the plugs and rotate the crank by hand and see if you can feel an interference spot.

[phaetn]

Thank you for the very quick reply.

As part of one again reconfirming the aux shaft pulley orientation to take the above pic I took off the timing belt cover and have left it off this time.

The ticking seems to be gone. I will want to drive it around today just to confirm. It was definitely on tight and had wiggled it back and forth before to see if it had affected the noise, but now it seems gone. shrug It has a very long bolt for the bottom mounting -- maybe that somehow was making noise. I dunno. Here is how it sounds now.

A side effect of having the cover off seems to be a slightly lower temp reading -- I wonder if because of the increased airflow, especially over the top of the engine which allows the fan to draw more air through. The fan kicks on a little earlier than it did (so coolant temp is the same at the bottom of the rad) but it's definitely indicating a bit cooler.

Thanks again for the response, Azruss.

Cheers,
phaetn