Engine making a bad tapping sound... - Alfa Romeo Forum
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Engine making a bad tapping sound...

hey guys,

my 1996 155 V6 is making a VERY bad tapping sound. I believe itís the hydraulic lifters and if the shims are adjustable, and knowing the clearance this can help. Iíve been to a garage and the guy said there is nothing to worry about. But I want it done, it sounds terrible and he cant do it

And help will be much appreciated
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You could try this together with an oil and filter change. Would be a free fix if it works so worth a try.

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no hydraulic tappets unless you've had a 24v engine fitted at some point.

Other than that I have nothing to offer you in the form of help, I never worked on the 12v engines. Some sound from the tappets is normal though.
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The cam has shims going to inlets and are adjustable tappets going to exhaust valves
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This one brought up some memories, this is exactly what happened with my 164 3.0 V6
and is not a easy fix. usually the culprit is the exhaust side of the camshaft, but I can tell you is not a certanty.
My advice is for you to take the car to a proper specialist, and get some warranty for the work that requires to be carried out.
The good thing is that apart from the noise, the car will still drive normally.
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The 12v has adjustable lifters (small lock nut) but I can't remember if it's on all valves or just the inlet or exhausts. I remember that they are ALL adjustable.. and quite why your mechanic can't do it, is beyond me.

It's 1970 tech. You need a small spanner, a screwdriver and a feeler gauge...

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As noted, most likely the exhaust valve clearances, which are adjustable easily. Inlets don't tend to go far enough out to make much noise assuming the car is looked after properly.

BUT....a problem I used to see a lot on the 12V engine was serious wear on the cams on the exhauut lobes, and the exhaust followers. My old 155 V6 was so bad that the followers had worn their bores in the head into oval shapes, both cams were knackered and all the followers were too. Inlets just fine though.

You won't know until you have a look inside though - take off the front cam cover and carefully inspect the cam and followers - if there's a problem, it'll be apparent and you'll have to decide how to proceed. If not, adjust away! If the frnot cam is OK, chances aer the rear one wil be to so it'll be owtrh the effort to remove the plenum etc so you can get at the rear bank.
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....so, any news then??
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