Fiat Dino Forum (FDF)

This may seem like an odd question but has anyone got experience with rebuilding the valve gear on a Dino with alternative parts? I have heard that the original sodium valves should be replaced as they become brittle - I wonder if this true? My engine is an early one with shims under the buckets and it has been suggested that I swap it for the easier to maintain shim-on-top. But that leads to the idea that hydraulic lifters would be even less maintenance.....
I seem to remember Mike Morris mentioning that some VW valve parts were easily adapted to fit. I'd be interested to hear what other people have done in the past.

Unsure about Hydro lifters but sodium valves that do not get regular use tend to fail more frequently

Hydraulic lifters is not going to be easy because you will need an oil feed circuit to the lifters in first place.
I would not swap my shims for the newer style myself if it was originally equiped with the small shims. It's much lighter and all period high reving (motorcycle) race engines had these shims. It might be some 3 more hours in labour to set your valve clearance but how much time will it cost to convert? And you need to take out your cams anyway to convert so i would just set your clearances right and you can drive it for years and years before it will need attention again.

True. Adjusting valve clearances is no more trouble than a Jaguar XJ6 or Alfa Romeo 105. A lot of hoo ha is written about how difficult they are to adjust but it's not hard. The top shims (as in a Lampredi 124) are a bit easier if you can compress the valve springs enough, meaning the cams don't have to come out, but why make things more complex than they need to be? Replace the sodium valves though, typically they should only be the exhausts as the sodium was though to help conduct away heat better than a solid valve

My question is a little bit off topic, but might be also interesting here. What are the specifications for the shims? Do I need special shims for the Dino or is it only important to have correct diameter, thickness and material?

I assume that valve shims in general will meet all the necessary specifications like hardness, roughness and so on. Unregardless of weather they are on top or underneath the bucket. I think if you can find the correct size you will be fine.
The top shims seems to be easely available because they are interchangeble with other fiat shims. The small bottom shims are actually as easy to find because they can be replaced by shims from a lot more common car

It's been a long, long time but I seem to recall using Ducati shims in Alfas. The shims can also be licked by a surface grinder for fine adjustment.