| Author |
Message |
    
Robert B. Price
Senior Member
Username: rbprice
Post Number: 230
Registered: 11-2001
| | Posted on Tuesday, March 17, 2009 - 09:29 am: | 
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Hello - can someone plse tell me the specifications for the threads on the outlet of the exhaust dome that sits on top of the expansion chamber on a P-55. It's the one that is about 2.125 in. diameter and 10 threads per inch, straight sided. But is it a Whiworth or SAE or what? That part and the brass dome that sits on top do not appear anywhere in any of the S-T literature that I have.
Also, is there a standard part that threads on to make the transition to the exhaust pipe? Can't find a picture of that either.
Thanks
Bob Price |
Jon Lewis
Member
Username: spinning_props
Post Number: 16
Registered: 05-2007
| | Posted on Tuesday, March 17, 2009 - 01:55 pm: |
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Hello Bob
I beleive it's 1" 3/4 BSPP. This is a non-standard pipe size (you won't be able to get hold of valves etc to fit it). I had to get an adaptor made to take 1"1/2 BSP up to 1"3/4. I have a drawing of the adaptor which includes all the info you'll need on the 1"3/4 thread. I did the drawing using MS Word so should be easy to read. If you send me an e-mail to [email protected] I'll send it to you.
Jon |
George Martin
Visitor
| | Posted on Tuesday, March 17, 2009 - 03:37 pm: |
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Thats as said 1"3/4 bsp. it is the standard size, but just not used I believe. Its 11 tpi 55deg whitworth form.
I assume you want the gland nut rather than changing it to something different, or is there some advantage in that which I have missed?.
I made a brass gland nut for the P5 last week (thats 1"1/4) it took me all day. I used a 45deg internal chamfer and made it similar to a conventional nut and olive form. I made a drawing which you could alter the dimensions in if you want it. Just e-mail.
arhing(at)tesco.net |
Matthew Balkwell
Senior Member
Username: matt
Post Number: 94
Registered: 04-2006
| | Posted on Tuesday, March 17, 2009 - 07:56 pm: |
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There is one on ebay for 44 pounds, surely someone can tool up to make a few dozen, i know i would buy one.
Robert, a lip on the exhaust pipe is held against the exhaust outlet by this collar nut.
Matt and Ron. |
Robert B. Price
Senior Member
Username: rbprice
Post Number: 231
Registered: 11-2001
| | Posted on Tuesday, March 17, 2009 - 08:27 pm: |
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Thanks for the response guys - some research confirms what you stated: 1 3/4 in. BSP 11 thrds./inch with a Whitworth tooth form.
George I will send you an email and see if one of the shops I deal with can make some that won't cost quite so much.
Again, thanks very much for the help.
Bob |
Robert B. Price
Senior Member
Username: rbprice
Post Number: 232
Registered: 11-2001
| | Posted on Tuesday, March 17, 2009 - 08:34 pm: |
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Matt - what is the eBay number for the exhaust fitting?
Thanks
RBP |
Matthew Balkwell
Senior Member
Username: matt
Post Number: 95
Registered: 04-2006
| | Posted on Tuesday, March 17, 2009 - 10:40 pm: |
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Here it is
Item number: 170306204155 |
Peter Ogborne
Senior Member
Username: peterogborne
Post Number: 292
Registered: 09-2002
| | Posted on Wednesday, March 18, 2009 - 12:35 am: |
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Robert...pretty sure this question has come up before ,I did post an answer and I am sure an image of a fitting that I made.If you need it I can email you the image and if you can make it yourself ,a machine shop would oblige if you dont have the facility. |
George Martin
Visitor
| | Posted on Wednesday, March 18, 2009 - 06:03 am: |
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Thats interesting, they are using a similar system on their own engine (Dolphin). Does not state the size though but must be 1.25 or 1.75 BSPP.
The price for 1" of brass round about 600mm is about £17 so that needs to be taken into a/c. |
