On the contrary, for accurate measurements, you need very dry/clean measuring tools and shims. As a matter of fact, when you set your valve clearances, you’re working with a 1/100th of millimeter precision. Another good reason to want to use a micrometer rather than digital calipers. Measuring Openers: As opening shims are flat on both sides and lay flat on the valve stem, they are very simple to measure. Zero-in your tool. And measure a dry/clean shim. This one was out out the 2.65mm box, so only 0.014 off. Not bad at all. Measuring closers: Closers are hollow. And lay on half rings located somewhere on the valve stem. Measuring them to get the clearance you need/want is a little trickier. First, you need a piece of flat metal to solve the « hollowness » problem when using a micrometer. Zero-in the micrometer on it. 1st problem solved. Then you need a « measuring tool » which offset is known (and certified) to the 1/1000th of millimeter (we’re talking micrometers now…) to measure only from the half ring groove inside the closer. That tool replicates your valve stem with the half-rings in. This is how you use it. This shim is measured at 12.910-10.003 = 2.907mm. I call it a 2.91. And it’s coming out of the 2.95mm closer box. That’s 0.04mm off, which is a lot. In the end that’s the difference between a 0.10 and 0.06 closing valve clearance, for example. Notes: 1/ In order to get shims’ thickness exactly where you want them, you can sand a couple 100th off them. Use a thin grade metal sanding paper and a very flat surface. About 30 seconds of sanding will give you 0.01mm off. And clean the shim before measuring again. 2/ Always measure a shim two or three times without forcing on your tool, to get the most accurate measurements. 3/ Only measure perfectly clean and dry shims (same goes with your feelers when measuring valve clearances. Make sure they are clean and wipe that drop of oil you get when you first put the feeler in…) 4/ All of this is perfectly explained in LT Snyder’s books in D2/D3 and D4 maintenance books.
Nice write up @Guillaume69 . FYI @Mike 999 I too bought the JMP shim measuring tools but just couldn’t get on with them, like you there were significant differences measured v written. I subsequently bought the certified ones from Desmotimes (LT Snyder) in the US, much much better now the measured value is in line with the written value. I’d advise ordering some from him. You may as well get the shims off him too if you’re going to the bother of ordering from the US, his service is top notch. A word to the wise, not all shims have the size stamped on them, I’ve encountered numerous ones that are devoid of any sizing so have to be removed to be measured before ordering the correct size required.
I live in London. Anyone who knows a good UK website to order it? One last question. When you remount the camshafts on the top of the shims, then you torque them down to the correct setting, will that not change a little the clearance every time you do it, even if you try to be as precise as possible with you torque wrench?
@Mike 999 As Paul @West Cork Paul said, you should take a look into LT Snyder’s website. Plenty of tools, advice, books, desmo discussions, etc. That’s where I get all my valve related stuff, from France. https://desmotimes.com/
I'm not sure what stem size valve you are measuring but here is one in the UK for the 8 mm: https://laceyducati.com/ducati-part...0_390_394/8mm-shim-measuring-tool-p-1163.html
I think your only option in the UK is a Ducati dealer. Desmotimes in the US will have them which will be slightly cheaper but your best bet is your local dealer. Part numbers for the various shim sizes are all available via bike-parts-ducati, you can buy through them too, it’s Ducati South London or Croydon or whatever they’re called these days but support your local dealer.
Just to keep this tread alive for future references. I re measured all the shims cleaning them pretty well first. Then re measured the tool which was 9.03 from the top to the start of the shoulder and now the measurements are extremely close to the shim sizes or in some cases even smaller as it should be. If anyone has done this before, what I would like to know is, once I install the new Shims, do I need to tighten everything back up again before measuring the new clearance or can I just sit the cams on the top and bolt them in enough to keep them in place?
Put the cams back on and torque them down it doesn’t take long, then check the clearance. If you’ve measured correctly they should be at or very near what you’ve calculated it will be with the replacement shim. It’s not uncommon for them to be slightly out from your newly calculated clearance depending whether the 1/2 rings you put back were the same ones for that valve stem and the same way up. As long as it’s within the spec range (for service, not factory that is) then it’s fine. Don’t overthink it.
This is a question for someone who has done this before. Ducati says to lube the camshafts before installing them with Molycote 55 plus. But I can't find this anywhere unless is something like 5kg. Can i use engine oil instead or something else? like this one https://www.amazon.co.uk/Lucas-Oil-...ube&nsdOptOutParam=true&qid=1733432236&sr=8-1
Yes, you can use engine oil, or the product you link to. I use Permatex Ultra Slick 81950, a little goes a long long way. As you’re not doing it that frequently engine oil will be fine, just take the plugs out and spin the engine over a few times to get oil up in the cam heads before firing up.
