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Discussion Starter #1
I have recently hotted up a mid 70s 2 litre and I'm a bit concerned about the level of valve train noise that it produces :(

The head has been ported and fully rebuilt using the stock valves with heavy duty springs. I've fitted new cam followers and timing chain and checked all tolerances and they were ok.
The cams I've installed have been built up and reground to the following specs. 11.1mm lift and 260 deg @ 50 thou.
The supplier specified that the valve clearances be set to 9 thou for the inlet and 010 thou for the exhaust.
I've rechecked mine after a couple of thousand k and they were 9-11 thou inlet and 10-12 outlet. Reasonably close I would have thought.

When the engine is cold it is reasonably quite but it gets much noisier when it warms up. I've checked the clearances warm and they were about 2 thou greater than when it was cold. I've also noticed that is far noisier at idle and quietens down over 2000 rpm. Or maybe it just seems that way :rolleyes:

At the moment I'm using Valvoline synthetic oil and I'm beginning to wonder if this is too light. Should I switch to a heavier oil like a 25W60 ?

What if I were to reshim to give clearances of 7 and 9 thou? Given that it's quite when cold and the clearances increase by 2 thou when hot maybe this would work. Will I be too close to the limit though? :confused:

Some say that all Alfas are fairly noisy and when you install hot cams they're worse. Should I just learn to live with it if that’s the case? Maybe I should invest in a louder radio or some earplugs :)

Thanx
 

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Did the supplier specify the specs as hot or cold? If not, tightening the clearances by one or two thou will probably quiet them and have no other ill effects. Then again, the noise may just be a result of these cams' particular lobe profile and is normal. What does the supplier say about the noise?
I'd think that going to a heavier oil would have no effect on the noise. Besides, it takes more horsepower to pump thicker oil.
 

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Discussion Starter #3
Thanx papajam,
The specs for the valve clearances were cold and when I contacted the supplier about the noise the reply I got was that they may be a bit noisier than normal, what ever that means. What's normal for an Alfa? Some I've heard sound like chaff cutters and yet others are real quiet. Maybe I'm just being a bit too pedantic.
I reckon though that if I tightened these clearances by a couple of thou then things will improve.
I'll let you know how I get on.
 

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Discussion Starter #4
I rang the supplier of my cams the other day and he told me that his cams were noisier than stock because they don't have the take up ramps like the stock ones. I checked a pair of standard 105 cams and sure enough at the 3 and 9 o'clock positions there were these tiny bumps. My cams don't have them.
I rechecked the lash and they were on average a couple of thou less than what I had measured 6 months ago. I asked the supplier about reducing them even further but he recommended I don't because of the effects on duration and also I may end up burning a valve sometime down the track.

We discussed the synthetic oil I was using and he recommended that I go back to using non-synthetic multigrade because it better suits the tolerances of these engines.

So I guess I'll either just have to put up with the noise or go back to stock cams.
Though I'm led to believe that washing and polishing your car always seems to make it run much much nicer, so I'll give that a go.
 
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