Loud timing chain noise.

andrewro · 09-08-2005, 03:26 PM

Some of you have seen my post on finding rust in my '72 T over the weekend as I prepared to do a valve adjustment. Now, I have an additional problem with this car.

When I was ready to adjust my valves, I found that my fanbelt was a little too loose to allow me to turn the crank with a wrench at the alternator nut. I squeezed the belt a little for more tension but the crank wouldn't really move. It would move maybe a quarter or a half-inch, and then when I released the wrench, it would move back. This frightened me a little bit as it means the crank was moving slightly counter-clockwise as it "rebounded" from my attempt to turn it.

Because I needed to tighten the belt, I decided to downgrade my service to an oil change. I just bought the reusable silicone valve cover gaskets, and there are only a couple thousand or so miles on this valve adjustment, so I figured I would button up the car and tighten the belt sometime before taking another shot at the valves.

Upon starting the car, there is now a loud chain-across-metal sound coming from the right timing chain housing. I am suspecting my attempts to turn the crank, and its springing back as I released the wrench and the fanbelt (which I was pressing against with my thumb) have caused this. FYI, this car has the Carerra tensioner upgrade.

I have had this car for over ten years, and I have done a valve adjustment twice before. Once with the motor in, and once with it out. I have gradually overcome my initial fear that it could fail expensively at any minute, and I have learned to fix many smaller issues as needed, from rebuilding brakes to rebuilding the shift linkage to replacing the clutch. Of course, right now I do not feel so good!

If anyone recognizes this sound, please share a moment of silence, or any comments you may have.

Regards,

Andrew

LFogelson · LFogelson's Garage

Here is what my car sounded like with a bad non-carrera tensioner.

http://home.comcast.net/~lfogelson/

andrewro · 09-08-2005, 03:40 PM

That sounds like what I am hearing. It is like someone dragging a chain across a metal post. Thanks for sharing the file!

Bobboloo · Bobboloo's Garage

Yes, even the Carrera tensioners fail but usually only when new, as in defective. Not that it can't happen though.

You need to remove the chain housing covers and take a look. It might just be a chain ramp.

The kick back you've experienced is normal. It comes from the compression of the valve springs and from the compression of air in the cylinders.

You can remove the plugs to help ease the turning or just go slow enough so that the air can escape.

Try turning from the crank pulley instead of the fan pulley.

Gunter · Gunter's Garage

A lot of people, including myself, squeeze the belt and use the fan nut to turn the engine. That should not do damage.
Make sure that the little oil line is providing oil to the tensioner.
I suspect that the tensioner was on the way out anyway and collapsed without oil pressure. As long as the cam timing did not change, it's not that bad. You may be lucky here.
Take the right chain cover off (Partial drop if you don't have enough room) If you find the tensioner is bad, get a set and do the other side too making sure that the alignment is good.
It is important that you don't change the came timing when exchanging tensioners.
I believe that the tensioners are spring-loaded as well as work with oil pressure. Can someone confirm? There is also some issue with a spacer needed on the earlier tensioners for proper alinment?
The tensioners I just took out of an '82 SC needed a good squeeze with large channel lock pliers before I could get the nail in to hold them compressed.
It could have been worse. Let us know what you find.

PhatRedHead · 09-08-2005, 04:35 PM

crow foot ratchet bits from sears work wonders for cranking on the crank pulley instead of the fan pulley

andrewro · 09-08-2005, 04:41 PM

This weekend I will double-check the oil line to the tensioner, and possibly get the cover off.

The oil fitting over by the end of the right-hand intake valve cover that spurs off to feed the tensioner might be loose. The line interferes with the removal of the valve cover and I usually have to gently press the line to rotate it out of the way of the cover. I will look there first.

Thanks!
Andrew

Bobboloo · Bobboloo's Garage

Quote:

The oil fitting over by the end of the right-hand intake valve cover that spurs off to feed the tensioner might be loose. The line interferes with the removal of the valve cover and I usually have to gently press the line to rotate it out of the way of the cover. I will look there first

Bingo!

RoninLB · 09-09-2005, 12:07 AM

being how you were working with the alternator I'd confirm that the alt bearings are not making the noise. Engine sound can sometimes be difficult to pinpoint. A cheap auto parts store stethoscope or a long piece of 3/4" hose placed near the tensioner and the other end to your ear. The fan shroud side air adapter can be easily removed to somewhat check the bearings. I'd probably start with removing the fan belt and see if you have any fan play.

Rikao4 · 09-09-2005, 07:37 AM

I agree with Ronin, had this just a few weeks ago.Stethoscope helped narrow it down further =Distributor shaft..easy fix's..I almost fixed the wrong item..take the dist. out, some play ok..mine was loose.
Rika

andrewro · 09-09-2005, 03:05 PM

Okay, I had a chance to listen to the chain again today. The noise is definitely coming from the right-side chain cover. I checked the oil feed line, and it is tight. Started the car and there isn't a leak in the line.

After idling for maybe five minutes, the sound became a lot quieter. Before it was loud inside the car, but it gradually sank to a minimal level. I now think perhaps there was some crud blocking the oil feeder line. My chains are old and stretched, and a little noisy. Now the car sounds pretty normal to me, but I will try it again after a while since I may be listening irrationally right now!

This weekend I will also be digging into my rust spots again. I'll post what I find and let you guys know whether I think I can afford to keep the car and do the work.

Thanks for all the help!

Andrew

RoninLB · 09-09-2005, 06:26 PM

Quote:

Originally posted by andrewro

I now think perhaps there was some crud blocking the oil feeder line.

Other pelicanheads have reported the same thing happening as far as the noise. No hard info on why that I can remember, although I think JW/john walkers workshop reported on this event.

randywebb · 09-09-2005, 07:21 PM

"After idling for maybe five minutes, the sound became a lot quieter."

- sorta sounds like the tensioner is taking a while to pump itself up...

andrewro · 09-10-2005, 08:41 AM

I lowered the car to the ground today and moved it to the front of my driveway, taking it around the block in the process. All seems well. I'll drive it some this week and I will post again if the sky falls. Sorry for the worry, thanks for the help!

Regards,
Andrew