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Hello, I am looking for the valve clearance gap measurement for an 89 alfa spider 2.0L...Appreciate your help......
 

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I appreciate the four significant digits in the inch dimensions for L Jetronic. I always felt negligent not setting my clearances to the correct ten thousandth.

And yes, I am joking.
 

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Well . . . since you brought the subject up . . .
I was going to say something, but thought the gentlemanly thing to do was not to.
 

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I just set the valves on my 92 Yamaha with its large Fiat-style shims. They come in thicknesses of x.xxx millimeters. I can't even measure that finely.
Andrew
 

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I just set the valves on my 92 Yamaha with its large Fiat-style shims. They come in thicknesses of x.xxx millimeters. I can't even measure that finely.
Andrew:

Are they labeled in units of .00X mm, or are shims available in every .001 mm increment? I am going to guess the former; otherwise, you would need 1,000 shims in your kit just to accommodate a range of 1 mm.

For example, Alfa shims are available in .025 mm increments, so it takes 40 shims to span 1 mm of range. While the dimensions of the shims are labeled to the nearest .001 mm, that doesn't mean you are expected to adjust your valves to the nearest .001 mm. That's why I found the page from the shop manual that ghnl published, giving settings in .0001" units (= .0025 mm) to be kind of funny - that's an order of magnitude greater precision than off-the-shelf shims provide.

Admittedly, this is only amusing in an "engineers' humor" sort of way.
 

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One thing about the Fiats, you don't have to remove the cam to change shims!
 

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One thing about the Fiats, you don't have to remove the cam to change shims!
True but Fiat shims weight a lot more. Not an issue on street engines but some Fiat racers with unlimited budgets changed to the Alfa bucket over shim method to reduce valve train weight.
By the way did you know VW paid royalty to Fiat for years to use that system in their Golf engines?
 
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