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Now the fun really starts.
When I first checked the valve gaps I found all but 2 needed adjustment, and those were on the high side. Always good to check your work though .. on the second time around it became all but 1.
So the cams are off and the buckets and shims removed.
View attachment 37936 Now is not a good time to get them mixed up. So easy to do.
Adjusting the gaps on a Tornado is a bit more involved than usual. The valve springs are so strong (1000 N) that in a short time from new, the shims have an indent hammered into them by the valve stem. So far I haven't found a shim type that can withstand it, although Chris at Precision Shims in Melbourne is working on it. What I have discovered over time, is that the hammering work hardens the shim, so if a new shim is setup on the tight side, the gap will settle out at the high side and progress no further - mostly.
If there's one thing you don't want to do, its go changing shims more often than necessary. The manual specs the cam cap torque as 13 Nm, which for an M6x1 thread is extreme in aluminium, and worse in the alloy Benelli used for this head, which is too soft. If you use 13 Nm, the threads will strip after several valve gap adjustments. I've had to replace all of Nell's cam cap bolts with M6 studs after installing helicoils. You don't want to do this if you can help it. Some you can't get to with the engine in the frame.
View attachment 37937 Nell's cam cap studs.
When Gideon's caps get re-installed, the torque will be no higher than 10 Nm - which is still high for a lubricated M6 bolt in aluminium.

But I digress...
View attachment 37938 The indent in this shim is clearly seen here, by the flash reflection at the edge of the indent.
View attachment 37939 I determine the actual shim size by measuring over a ball bearing. In this case, the original shim thickness is 2.275 mm. Over a 4.760 mm ball in the indent, it is 7.025 mm, resulting in an actual shim thickness of 2.265 mm. So the indent is 10 um. I've seen this as high as 50 um.
In this case, the valve gap was measured at 405 um. The specified range is 300 - 350 um, so clearly, if it was set up correctly, there's been 45 - 95 um of wear happening else where. Maybe the valve stem has mushroomed slightly or the seat has a layer of carbon built up. Who knows, but it's worth keeping an eye on it over time.

Now that we know the actual shim height, the new shim height is calculated :-
ht = old shim + actual gap - specified gap
min ht = 2.265 + 0.405 - 0.350 = 2.320
max ht = 2.265 + 0.405 - 0.300 = 2.370 (which is the preferred value to compensate for indentation)

Now repeat for the rest ...
Hey Errol, I know you have a supply for shims, but just letting you know, I have a full set of Benelli shims if required. I got them, with more parts form a guy that was going to become a dealer but didn't last for some reason. Nigel.
 
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