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Gilardoni Barrels
Many thanks for the reply. And yes I am on the Isle of Skye. By coincidence on ebay.co.uk I have just found somebody who is selling some bolts for this. I hope this is OK I am pasting in the info off their lot (minus the selling infor:
"Nicasil, also marked Gillardoni, alloy barrels for Triumph T140, first came to prominance when Harris produced his Newton Abbot T140 Bonneville. As a French speaker I helped him sell many in France. The head studs he used at that time were standard T140 items threaded at both ends with 3/8" UNF on outer eight bolts and 5/16" UNF on the two inner head bolts
A lot of problems arose with the studs all being ripped out of the barrels through even minor over-torquing of the head studs.In France the barrels got a very poor reputation with everyone tearing them off and replacing them with iron products.A second run of some 500 barrels were ordered for Harris production with the the threads in the barrel changed to UNC, coarse thread @ 3/8" and 5/16". The specification of the stainless steel studs was also changed to a material capable of coping with the expansion rate of aluminium,albeit more expensive.
This production run never reached Harris, and ended up being distributed through Europe and the UK. I myself distributed over 250 barrel sets. I found out the special material specification and had the studs made in batches of 1000 units of each, and also the tappet blocks in 50 ton dural. I also ordered at the same time the base studs out of the same material.Out of all 250 units sold not one barrel was ever returned under warranty because of threads being pulled out through over-tightening.
The studs being offered are part of the remains of my stock,and no,I don't have any barrel kits left, but.................well,keep watching. So these barrel stud sets are not suitable for UNF/UNF iron T140 barrels,nor are they suitable for original Harris Nicasil barrels with good threads at UNF/UNF. But they are suitable to repair Harris items if the barrels are heli-coiled ,wire inserted to 3/8"UNC and 5/16"UNC and they are also suitable for the rest of the second production Barrel run with UNC threads as standard, some of my production went to the recipients of the other 250 barrels. In recent months I have sold quite a few sets over the world as studless barrel owners find out I have these items in stock. So e-bay is the natural way to tell everyone that I have these items available. The base studs are similar to standard T140 items but longer to go through the much thicker flange on the alloy barrel assembly and no, they will not fit the iron barrels correctly. Unless they are shortened they will foul the base fins of the standard barrel prior to tightening down the flange. See dimensions below.
In my opinion the Nicasil barrel is a superb product, the engine runs as cool as cucumber,the pistons don't clatter due to the very tight tolerance piston/cylinder and, correctly maintained, they never wear out, only slight wear of the piston rings after about 80,000miles (128,000Kilometres),so if you've got some lying around, or you know someone with a set,grab them fast,with or without damaged threads.To fix the threads you know where to come.
The Nicasil alloy barrel design is currently used on most Italian big twin motorcycles, most BMW motorcycles and big alloy blocked BMW cars,to name but a few.
Answer to Ebay Question from Jim: You should not use ordinary Hepolite pistons and rings in these barrels. The special Asso (make is marked inside on the piston crown) original pistons supplied with these items should be used.There are two "fits" marked H and L (High & Low?) The barrels are stamped on the head gasket face with the size originally fitted,and this size should be used when replacements are required. Remember these barrels and pistons run with a fitted piston/bore tolerance of approx .002" (two thou) as opposed to standard iron barrel & recommended Hepolite tolerance of up to .007" (seven thou). Now you know why standard T140s' rattle and pink like gluck, and these don't !!!!
**The rings are also special. If you use ordinary hepolite rings in these bores they will normally be worn out within 100 miles (160 kilometres). They also have a tighter fitted gap which I will post on a future listing.
Stud Dimension 3/8" stud threaded UNF @ top, UNC @ bottom Overall length 110mm or 4 and 3/8"
Stud Dimension 5/16" stud threaded UNF @ top, UNC @ bottom. Overall length 95mm or 3and 3/4"
Base Stud Dimension 3/8" UNC lower thread to upper step 1" or 25.4mm. 5/16" UNF top threaded to base step 1 1/4" or 28.5mm
Overall base stud length. 2 & 1/4" or 54mm. (Standard T140 stepped stud is 44mm long.)"
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