Hi Guys, Looking to "tap" the vast knowledge base of the forum to save me some expensive garage bills. I have been struggling to resolve a mechanical tapping noise which presents in such a way that I can't identify a logical cause. I have now run out of ideas and am reluctant to conceed that this is something like a damaged cam when there is no evidence or circumstances to back this up. The symptoms are that the car sounds fine for the first 20 seconds after starting from cold and then a quite pronounced tapping noise starts to become evident. This tapping continues up to normal operating temp and then gradually fades away to almost nothing. The car drives perfectly and there is no loss of performance at any time. I have re-done the valve clearances twice now and they are perfect (Ex - 0.35, In -0.25). The shims are is good condition / new and all spin freely in the valve cap, as does the valve cap itself. The camshaft looks just fine. The tapping noise seems to just eminate from the #1 Cylinder end of the camshaft, probably more so in the area of the actually pulley itself (bank nearest the back of the car) Things that I do not think are causing this problem : Valve clearances Checked as above Pre-ignition : Car runs perfectly Valve timing : Car runs perfectly Electrical arcing in the HT circuit : Car runs perfectly Damaged tensioners / water pump : Replaced in major service 6 mths ago Damaged Camshaft / profile : Tapping seemed to have started suddenly one day and also no tapping in 1st 20 seconds I have read on the forum about the a/c belt sticking and therefore creating a mechanical tapping sound. I duly cut the belt off and it made no difference. I am left wondering if this could be a similar problem with the waterpump and / or belt whereby the sound of the tapping is transmitted to give the impression that it is coming from the pulley area. I would appreciate any lines of investigation. Cheers, Steve
Valve guides could cause a sound. Oil quality or age of oil could cause sounds. You might want to pull the 1-4 cam cover off and take the cams and the shim buckets off to inspect the springs too, as that could very well be a broken spring too. Best of luck to you.
Hi, interesting thoughts.... The oil was changed 500mls ago and was filled with 10W60 fully synthetic...my understanding is that the 60 indicates a high viscocity at normal operating temp, which could be just too thick perhaps ?? The oil pressure is amazingly good at operating temp where the dial reads in the middle of the quarter and half graduations at 1000rpm (45k miles on odo). Also last time the covers were off I tried my best to move the springs when not compressed and all of them felt the same and no feeling that there was any damage to the springs themselves. I am thinking that a broken spring would manifest itself in the performance somehow.....yet the car idles, and performs really well. Cheers, Steve
Also an exhaust leak can sound like this and after heating up it goes away as metals expand etc. Look for small leaks near exhaust manifold on sampling tubes, air injectors etc.
Hi, yep..... Checked out the exhaust joint at the head with a bore scope so I can get in really close and there was no sooty evidence of a leak. Also tried the rubber hose to the ear trick to listen in that area and..... All quiet However, need to do the same with the injector to be sure....thanks
Manifold is a distinct possibility. It can be very deceptive. I had this on my Integrale and I was convinced the metallic tapping sound was coming from the cams & feared the worst. The mechanic's stethoscope (big screwdriver) didn't help source the location at all.
Sounds dumb but my car does this and it is caused by the alternator/ac "fan" belt. If you leave the car sitting for a few weeks it sounds terrible until the belts warm up then it goes away. Nothing major but you should perhaps change your "v" belts? Regards Chris
Oops didn't read your post fully. I see you checked the AC belt but to be honest I'm not sure which belt is causing the problem so could be the water pump but problem sounds identical. Regards Chris
Hi Guys, Getting some good stuff here....thanks to you all. This week I am going to scrutinise the exhaust / inlet manifolds and I would imagine that the rubber hose to the ear approach would be conclusive. I am also going to adjust the tension on the water pump belt and/or try get some belt dressing. Up to this point, no one has mentioned camshaft or follower or shim damage which is encouraging Another possible misleading piece of circumstantial info is that I was advised to buy a full service kit from Ricambi by the Ferreari specialist performing a major service approx 750 miles ago. as it turned out the fuel filter and spark plugs supplied were incorrect for a eurospec. Curious to know if the water pump belt is different between the US and eurospec such that it may be causing my problems ? All getting a bit tenuous i know but .... Cheers, Steve
Hey Chris, You say the belts warm up....do you mean when it reaches Operating temp or just when the belt gets a bit warm ?
Hi, Is a cracked header pipe obvious (exhaust manifold to us Brits ?)...would I expect to see any visual evidence or would it be conclusively the source of the tapping noise once I can get to it ? Cheers, Steve
It takes a couple of minutes but not that long. Usually all quiet but the time car is a mile or so down the road.
Yep, used this and the tapping was loudest with the probe on the end of the cam cover, closest to the exhaust cam pulley wheel. This is not to say that the sound is being transmitted from somewhere close by...could still be the header or even the belt slapping maybe ?? Cheers, Steve
