348 ticking noise

Does the noise go away after the car is hot?

 

"Ticking noise".....hmmm, that could be a lot of things:

- Could be a valve that needs adjusting.

- Could be an exhaust leak.

- Could be that the timing belt cover is loose or broken.

- Could be a problem with the alternator, or its bracket or belt. I'd kinda lean in this direction. There have been cases where the bracket cracks and the alternator isn't securely attached. The bracket is a casting, so it's about impossible to fix, you have to replace it (brackets are unique to the Delco or the Nippondenso alternator, you can't interchange them). The other thing that happens is that the alternator belt tensioner doesn't get properly tightened, and the belt goes slack. This is fairly easy to correct, but it's hard to check and fix if the car is on the ground. But try to get under there and find out if the alternator and its belt appear to be as they should be, and report back.

 

Ticking sounds that remain static regardless of engine temperature or RPM is odd.

 

I think what you should do is get the car shipped to a tech, get the car on a hoist, disconnect the alternator and A/C belts then start the car and listen for the sound. If it's gone you have isolated the problem.

 

Don't hesitate to ask questions.

This is what it looks like, looking at the front of the engine. The alternator belt tensioner is the round object at D and C. Notice how it pushes upward on the belt. What happens is the nut C doesn't get tightened all the way, and the tensioner drops down enough for the belt to get loose and the tensioner to rattle. If you can easily spin the pulley/fan on the alternator by hand, the belt is too loose.

To retighten, you have to loosen the nut C, then turn the bolt D to raise the tensioner. See the slot behind the nut C? That gives the tensioner a range of adjustment. Once the belt is tight enough (not "gorilla" tight, but tight enough to drive the alternator without slippage), then you retighten nut C, and things should be OK.

Of course this won't help if the problem is a loose valve, etc., but it's something worth checking.
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A valve adjustment is something that is a bit too complicated for you to handle at your current skill level, so let's rule out some of the simpler possibilities first.

 

JT- If it is a valve that needs the shim thickness adjusted, the ticking noise frequency will be directly proportional to the RPMs you are using, also likely with an accessory drive belt problem. For a loose valve adjustment, you can use an old mechanics' trick and take a long piece of rubber hose, put one end near your ear, and move it along the cam covers to see if you can isolate the ticking location. Not recommended for anything near the accessory belts for obvious reasons.

Valve operating clearances are adjusted by replacing the shims under the camshaft lobes with different thickness shims. Not difficult, but does require removing the cam covers and various parts.

Taz
Terry Phillips

 

Like he said - don't worry about other things until you rule out the simpler ones. First task is to rule alternator and AC. Report your outcome and we will go from there. Good luck.

 

Have you checked your oil level? Turn the car on and let it warm up, then with the car in neutral and idling check the oil level. The manual says to turn the car off immediately, and then check the oil, but I have done it both ways and it reads the same. It could be as simple as you being low on oil

If the oil level checks out fine then you need to isolate exactly where the ticking is coming from while the engine is running.

 

Had to find a ticking noise in a old van once & I could hear it tick as I drove it into the shop. The funny thing though is that it did not change with engine revs. It did not take me long to find it once I shut off the engine As it was still there. The bugger had an alarm clock in the parcel shelf under some junk & you could hear it tick over the
engine noise.

 

My testarossa "ticked" from the front of the engine, we found it to be the AC compressor pulley.

 

Any luck?

I'd like to hear a fuller description of the noise.

Another thought occured to me, I wonder if maybe one of the one-way valves on the air injection system has failed (we've seen that several times lately here on Fchat) and the sound might be coming from exhaust pulses going up the tube.

 

Mine sounded like a box of rocks during warmup, so I just removed the whole system. Less clutter, and no rattles! However, if you have emissions inspections, it's always possible they could fail you for having plugged exhaust ports.

 

If as you say the "speed" of the ticking does not change with engine speed you can safely rule out any of the rotating internal parts of the engine.

If pushing the clutch, turing on A/c, turning on all the lights etc, does not change the speed or volume of the noise you can rule out clutch, A/c, alternator.

If ticking "volume" changes with engine speed/temp this makes me think it is something to do with engine vaccum system. When the engine is making the noise have a look at all these lines and valves http://www.eurospares.co.uk/userImages/078/Large/078_008A.gif

Make sure none of the lines are cracked or split, put your finger on the valves and see if you can "feel" the tick, if you can, check electrical fittings etc and track it from there

PS the 348 is injected ie no choke but it does have a butterfly between the 1-4 & 5-8 plenums if something wierd is going on with the vacuum this could be slaming open and shut?

 

Have you used a stethescope yet???

 

John,

Where are you based in the UK??

We are having a free tech session on Saturday at a Ferrari specialists in the West Midlands area, if you are near to us you will be able to get it checked out for free!!

Regards,
Phil.