Repair threads of the fixings of the big idler wheel boss

Achimes

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VOC Member
On my series C- Twin on reassembly, I discovered, that one of the three threads that hold the boss of the large idler wheel was gone. I intend to repair it with heli coil. Is any body out there , who has done that before and has got any experience with that sort of repair? Is there anything special to look for when I am doing it?
 

timetraveller

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Alternatively, make a special stud with a larger diameter where it screws into the casting and then drill and tap the hole to take the new stud. Good luck.
 

davidd

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It is rare that I find cases with the studs still in place so I am in the habit of using Allen heads. I would just drill and tap the hole for the next size Allen screw that you can find. I have one big Allen in the racer. You may have to enlarge the idler hole slightly.

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David
 

roy the mechanic

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A lot of times I would bow to the time traveller, but making a stepped stud (two different diameters) is maybe beyond most amaters. Provided the helicoil tap goes in "nice+ square" you should be O.K! Be lucky, roy.
 

bmetcalf

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I was about to ask about you wiring the large idler nut, but then I remembered I have a one piece D spindle that "shouldn't" need it.
 

timetraveller

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Well. there you are Achimes; three replies and three different ways of doing the job. You will have to decide which method suits your equipment and capabilities best.
 

davidd

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I think Timetraveller's is the most elegant, but beyond my skill level.

Bruce,

All of the nuts are wired except for the two delivering oil. I use Allen heads in place of some of the steady plate studs also. I prefer the one piece "D" idler boss, but they are no longer supplied. I have one left, but the Maughan two piece bosses have never come apart. I would wire the nut on either. Several times I have removed covers only to find nuts and washers sitting in the bottom of the timing chest. The nice part about wiring is its systematic nature: if it is not wired it is not tight! This is a valuable check.

David
 

ogrilp400

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Non-VOC Member
Helicoil it. A simple and easy solution that provides a hard wearing thread and you replace the standard stud in it. Whats more if you buy the kit you then have the means of helicoiling other same size threads that may go on you at inopportune moments

Phelps.
 

nkt267

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Whats more if you buy the kit you then have the means of helicoiling other same size threads that may go on you at inopportune moments
1/4" whit very handy for all those timing cover and chaincase cover threads..John
 
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