Magneto cowling: singles vs. twins

Magnetoman

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VOC Member
I fear I already know the answer to this, but can someone tell me the spacing between the holes at the bottom of the cowling on a twin (i.e. FT163)?

Twenty years ago I bought some parts for my Vincent at the Netley Marsh autojumble. For twenty years I've lived with the tranquility of knowing these parts would replace the ones that were missing on my still-being-restored Vincent. That tranquility was shattered recently when I discovered the sidestand assembly I bought is from a Comet. Well, on the bright side, this means I've finally started seriously working on the Vincent.

I fear the beautiful cast Al housing I have also is from a Comet (FT113), but before I spend the money to buy one for my twin I'd like to be absolutely sure. The spacing between the mounting holes on it is 5-7/8". Thanks in advance for your help with this.
 

davidd

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VOC Member
I hope someone else can give you the exact dimension. I remember the side plates as being roughly 6 inches apart on the twin and 4-7/8" apart on the Comet.

Happy New Year!

David
 

Magnetoman

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VOC Member
I hope someone else can give you the exact dimension. I remember the side plates as being roughly 6 inches apart on the twin and 4-7/8" apart on the Comet.
Which, if your memory is correct, sounds like it would save me ~$200. I eagerly await confirmation. Happy New Year to everyone.
 

chankly bore

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Non-VOC Member
Confirmed David's figures by measuring abutment faces on FT40/2 and FT40/3. Happy New Year! Comet on Steroids is up and running and has done its first 28 miles. Comet magneto cowl is F113, Twin is FT163 or 163/1
 
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nkt267

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VOC Member
the Comet cowl has a bulge at the top to get around the mag.i think the twin version is almost flat on that side..john
 

Magnetoman

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VOC Member
Thanks, guys. It looks like my first expense of 2014 isn't going to be for an FT163 after all. I must have purchased that cowling from a different vendor than what turned out to be a Comet front stand assembly. Well, at least I didn't haul that Comet assembly back from England for nothing, since it will supply the R propstand leg that went missing whenever the FT118 bracket broke when owned by someone prior to me. (note: I've already determined I'll have to bend it to be appropriate for a twin).

By the way, the reason the lug broke on the FT118 (through which the FT122 bolt goes, on which the R propstand leg pivots) was due to a defect in the casting. It was quite porous and I had to grind away a fair bit of material to get to a solid base to begin welding. I've already built it up and am waiting for a piece of 4130 chome moly steel to arrive to finish the repair. In the end the repair will cost me only a few dollars instead of £114 for a new one so I'm way ahead (not counting the 8 hours with my TIG, lathe, and mill...).

While the identity of my autojumble magneto cowling was still uncertain I checked the VOC Spares site to find a new, reproduction would cost ~£187. Two original cowlings sold on eBay in recent months, one for a reasonable $179 and the other for an unreasonable £321. There were two bidders on the latter, with one dropping out only after £311, so at least two people were ready to pay over £130 more than a new one costs. Is it because there were two uninformed buyers, or are the reproductions that much worse than original ones?
 

clevtrev

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VOC Member
Thanks, guys. It looks like my first expense of 2014 isn't going to be for an FT163 after all. I must have purchased that cowling from a different vendor than what turned out to be a Comet front stand assembly. Well, at least I didn't haul that Comet assembly back from England for nothing, since it will supply the R propstand leg that went missing whenever the FT118 bracket broke when owned by someone prior to me. (note: I've already determined I'll have to bend it to be appropriate for a twin).

By the way, the reason the lug broke on the FT118 (through which the FT122 bolt goes, on which the R propstand leg pivots) was due to a defect in the casting. It was quite porous and I had to grind away a fair bit of material to get to a solid base to begin welding. I've already built it up and am waiting for a piece of 4130 chome moly steel to arrive to finish the repair. In the end the repair will cost me only a few dollars instead of £114 for a new one so I'm way ahead (not counting the 8 hours with my TIG, lathe, and mill...).

While the identity of my autojumble magneto cowling was still uncertain I checked the VOC Spares site to find a new, reproduction would cost ~£187. Two original cowlings sold on eBay in recent months, one for a reasonable $179 and the other for an unreasonable £321. There were two bidders on the latter, with one dropping out only after £311, so at least two people were ready to pay over £130 more than a new one costs. Is it because there were two uninformed buyers, or are the reproductions that much worse than original ones?
Just hope you don`t have to do any machining after you`ve welded it.
 

b'knighted

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VOC Member
I've already built it up and am waiting for a piece of 4130 chome moly steel to arrive to finish the repair.

Check out previous discussions on propstand angles as someone, possibly Paul Ennis, has worked out an improved pivot angle which improves the angle of the stand once deployed. If you are already welding on a block for one side, doing both may be worthwhile.
 

Magnetoman

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VOC Member
Just hope you don`t have to do any machining after you`ve welded it.
Luckily for me I enjoy machining, because will have to do some to get the 4130 ready, and then more to finish the job after welding.
Check out previous discussions on propstand angles as someone, possibly Paul Ennis, has worked out an improved pivot angle which improves the angle of the stand once deployed. If you are already welding on a block for one side, doing both may be worthwhile.
Offline I was give the helpful suggestion to check an old MPH for this modification.

A related question is, are the bends in the propstand legs different for the singles and twins? They are for the Comet assembly I have and the sole remaining twin leg. But perhaps it's because that one is misshaped(?).
 

clevtrev

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VOC Member
Check out previous discussions on propstand angles as someone, possibly Paul Ennis, has worked out an improved pivot angle which improves the angle of the stand once deployed. If you are already welding on a block for one side, doing both may be worthwhile.
Originally thought out by Burt Weisz, now deceased, from Windsor, Canada, some 30 years ago. 5 Degrees is about the max, you can go, before fouling.

Mr Magnetoman, I`m sure that I have had a little more machining time than you.

Same part number for the propstand leg, they`re all the same, twins and singles, apart from the B`s with it`s foot.
 
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