idler boss paranoia......................

1660bob

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VOC Member
I am reaching the latter stages of timing chest assembly, but i keep hearing tales of doom about the standard `C` two piece idler boss-tales of it disintegrating with catastrophic results don`t aid restful sleep!.Mine is the original item, but looks fine, no cracks, or appreciable wear.I believe the ideal is a one piece item, but the new ones supplied are a two piece affair anyway, although one would presume stronger than original. How much of a liability are the originals? Is the accepted wisdom to dump it and go for new as a precaution. Also, while I`m on-torque figure for the half time pinion nut anybody? cheers, Bob.
 

jim burgess

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VOC Member
My shadow was running fine, I stripped it to repaint. Found the safht loose in the ally housing and the cast iron bush in the large idler split through i.e. forming two seperate rings, can't imagine how this happened and the parts have been in my possesion since 1980 when they were secondhand, i.e. stripped out of that motor (basket case). Maughans replaced the bush they then machine the centre to make it concentric to the teeth. I have fitted a new large idler to another motor that is slightly eccentric in running. That constant low level pounding is probably responsible for any problems people encounter.
Y'pays y'money...
Cheers
Jim Burgess
 

davidd

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VOC Member
It is difficult to find the Series D one piece idlers new. I have one in one race engine. I used a Maughan two piece in the last engine built believing that they would get the assembly correct and so far it has worked as it should. I have used all new Maughan timing gears in the chest to minimize problems.

I do not know the torque spec that I use because I remove the nut and install it with an air impact wrench.

David
 

A_HRD

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VOC Member
Now I am paranoid. I am not aware that I have changed the idler shaft assembly in my C Rapide that I have owned for 40-odd years (second owner). It's probably the original and done about 1/4 million miles. Should I be changing it?!

Peter B
Bristol, UK.
WANTED: Series 'A' Frame. Please!
 

1660bob

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VOC Member
I spoke to Graham at Maughans today and he said that they had seen several fail over the years, so it seems that the poor reputation of this component is no myth. Working on the logic that the price of a nice new, stronger item is much much cheaper than the catastrophic failiure of an old one, I ordered pronto............ cheers,Bob.
 

greg brillus

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VOC Member
Hi there Bob, Re the torque to tighten the crank pinion nut, I have found it is handy to have a spare half time pinion of any size and to wedge it between the large idler teeth and the teeth of the half time pinion on the left side of the gears looking at them. This will lock the crank assembly and let you tighten the said nut with out any damage to anything. I believe there is a locktab available now to avoid punchlocking the nut ( a very "OLD SCHOOL" and crude method of nut retension), but i generally use some blue medium strength loctite, and using a GOOD fitting socket....I would say about 35 to 40 Ft lB'S at the most, given it is a thin section nut.......Greg.
 

ogrilp400

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Non-VOC Member
Another way of locking the crank is to pass a bar through the hole in the back of the timing chest through balance holes in the flywheels.

Hi there Bob, Re the torque to tighten the crank pinion nut, I have found it is handy to have a spare half time pinion of any size and to wedge it between the large idler teeth and the teeth of the half time pinion on the left side of the gears looking at them. This will lock the crank assembly and let you tighten the said nut with out any damage to anything. I believe there is a locktab available now to avoid punchlocking the nut ( a very "OLD SCHOOL" and crude method of nut retension), but i generally use some blue medium strength loctite, and using a GOOD fitting socket....I would say about 35 to 40 Ft lB'S at the most, given it is a thin section nut.......Greg.
 
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