Thorp Air Command - T18.net

Supporting Owners, Builders and Pilots of the Thorp T-18 and its variants.
It is currently Tue Sep 18, 2018 7:16 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 14 posts ] 
Author Message
leewwalton
 Post subject: Fuel Cap Needed
PostPosted: Tue Apr 17, 2018 8:34 pm 
Administrator
Administrator
User avatar

Joined: Tue Oct 20, 2009 4:09 pm
Posts: 1468
Images: 107
Location: Houston, TX
Hey Gents,
Does anyone have one of these laying on the shelf? This was the standard fuel cap the came with KB's fuel tanks .. most of us have moved on from these. I'm hoping one of you has a spare on the shelf, I have a friend in need. Pic attached to post.
Thanks!
Lee
Image

Image

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD


Top
 Profile Personal album  
 
Rich Brazell
 Post subject: Re: Fuel Cap Needed
PostPosted: Wed Apr 18, 2018 1:08 pm 
Hero Member
Hero Member

Joined: Wed Oct 21, 2009 12:33 pm
Posts: 2875
Images: 64
Location: Jamul, CA (San Diego area)
That appears to be the "OLD Style ACS cap ? They no longer make the rubber gasket if it is the cap in question . I got ALL the remaining rubber gaskets (free) from the ACS factory and mailed them out to folks that wanted one (this was several years ago) . ::) I MIGHT have the metal portion of the old cap ( I would have to search and destroy ) to find it , I do not have the rubber portion . ??? Why doesn't he want to go with the new style Vitron O-ring cap ? :P

RB O0


Top
 Profile Personal album  
 
leewwalton
 Post subject: Re: Fuel Cap Needed
PostPosted: Wed Apr 18, 2018 1:46 pm 
Administrator
Administrator
User avatar

Joined: Tue Oct 20, 2009 4:09 pm
Posts: 1468
Images: 107
Location: Houston, TX
Thanks Rich,
This is a unique case he just needs a complete cap. Going with another type is not an option at this point. (Not a Thorp)
Lee

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD


Top
 Profile Personal album  
 
Rich Brazell
 Post subject: Re: Fuel Cap Needed
PostPosted: Wed Apr 18, 2018 3:18 pm 
Hero Member
Hero Member

Joined: Wed Oct 21, 2009 12:33 pm
Posts: 2875
Images: 64
Location: Jamul, CA (San Diego area)
If it is an ACS cap it wouldn't hurt to contact the ACS factory in AZ to see if they have the WHOLE cap (with gasket) . ;)

RB O0


Top
 Profile Personal album  
 
James Grahn
 Post subject: Re: Fuel Cap Needed
PostPosted: Wed Apr 18, 2018 8:00 pm 
Hero Member
Hero Member

Joined: Sat Oct 24, 2009 7:16 pm
Posts: 1006
Images: 0
Location: USA
I have one of the Spruce caps that I milled down 100 thou to fit my tank. I don't use it right now because I could smell fuel. If you want me to send it to try it out, I will.
Cubes


Top
 Profile Personal album  
 
Binder
 Post subject: Re: Fuel Cap Needed
PostPosted: Mon May 07, 2018 6:07 am 
Sr. Member
Sr. Member

Joined: Thu Sep 01, 2016 10:50 pm
Posts: 220
That's the cap that you sent me for my thorp Lee. It fits on mine and has been working well although I have a really hard time removing it. If anyone has a better fitting cap for the thorp I would gladly trade and send this back to Lee for his friend.


Top
 Profile  
 
DanaL
 Post subject: Re: Fuel Cap Needed
PostPosted: Mon May 07, 2018 5:45 pm 
Jr. Member
Jr. Member

Joined: Mon Nov 09, 2009 9:39 pm
Posts: 60
Location: USA
Your friend may want to consider converting to a more available cap. Check with Newton Equipment and let Mike Byrne know Dana LaBounty sent you. I've been friends with Mike since 1983 and if anyone can get you a cap that will work it would be Mike. I don't use anything but his products on any of my projects.


Top
 Profile  
 
Binder
 Post subject: Re: Fuel Cap Needed
PostPosted: Wed Aug 29, 2018 10:31 am 
Sr. Member
Sr. Member

Joined: Thu Sep 01, 2016 10:50 pm
Posts: 220
Bringing this back from the dead.

So that cap in the picture is the one I have from Lee. Recently the rubber portion swelled quite a bit and now is almost impossible to remove or replace. I'm not sure what happened with it that caused it to swell. It was difficult to remove before but the swelling was quite a bit. I had to actually trim the outer edge about 1/8th inch (portion that is outside of the tank) because it wouldn't fit down into the recess.

Since they no longer make them I need to find another solution. My old cap that I used prior to this has dry rot and will no longer work. Since my panel is back in and everything working as I want it I will not remove the tank to perform a retro fit. I currently don't have the time with my work load to perform a lengthy task.

I've heard I can mill down the new ACS cap and it will work. Truth? I think this is the part number on spruce: 05-01391 or 10455


Top
 Profile  
 
Jeff J
 Post subject: Re: Fuel Cap Needed
PostPosted: Thu Aug 30, 2018 7:18 am 
Sr. Member
Sr. Member

Joined: Wed Aug 31, 2016 8:18 am
Posts: 375
Images: 0
Location: eastern OK
The swelling came from being in contact with something it wasn't compatible with. Hard telling exactly what but alcohol was the first thing that came into my mind.

I think there is a post about milling down the cap you are referring to. The filler neck on mine was big (original to the drawings?) and about the only thing I could come up with that didn't require welding, excessive amounts of sealant or money was an old Willys Jeep filler neck and cap I had in the scrap pile. I had to expand the filler neck from the Willys to fit over the filler neck on the Thorp. A little sealant to fill what little gap there was and a rivet or 2 to make sure it stayed and I was done. There isn't a lot of room to get a hold of the cap but it works well. There are vendors on the internet that sell bits and pieces for building fuel tanks that may have something you can adapt.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


Top
 Profile Personal album  
 
Binder
 Post subject: Re: Fuel Cap Needed
PostPosted: Sat Sep 01, 2018 6:50 am 
Sr. Member
Sr. Member

Joined: Thu Sep 01, 2016 10:50 pm
Posts: 220
I just realize what happened to the cap. My grease had worn off and the only thing I had access to was dielectric grease which is silicone based. I used a tiny amount in order to get my fuel cap in. That had to be the culprit. Having worked with alcohol fuels in the drag car I have found that the myth of ethanol damaging fuel safe Orings and rubber is false so even if I had contaminated fuel it wouldn’t have caused a problem, especially a 10% mix. I’ve used 90% on rubber oring systems for years.

Stupid silicone. I didn’t even think much of it because I had to get my fuel cap back on and it wasn’t going. What a shame.


Top
 Profile  
 
jrevens
 Post subject: Re: Fuel Cap Needed
PostPosted: Sat Sep 01, 2018 11:04 am 
Sr. Member
Sr. Member
User avatar

Joined: Thu Oct 22, 2009 10:13 pm
Posts: 708
Location: USA
Binder wrote:
I just realize what happened to the cap. My grease had worn off and the only thing I had access to was dielectric grease which is silicone based. I used a tiny amount in order to get my fuel cap in. That had to be the culprit. Having worked with alcohol fuels in the drag car I have found that the myth of ethanol damaging fuel safe Orings and rubber is false so even if I had contaminated fuel it wouldn’t have caused a problem, especially a 10% mix. I’ve used 90% on rubber oring systems for years.

Stupid silicone. I didn’t even think much of it because I had to get my fuel cap back on and it wasn’t going. What a shame.


Jeff,

FWIW, I used a small amount of silicone grease on my fuel cap gasket - same type - for years, with no adverse effects. Silicone grease will not harm (or cause swelling) of any rubber compound that I know of. Silicone rubber, on the other hand, will swell from contact with many hydrocarbon-based lubricants, fuels, etc. there is generally no permanent harm to the silicone rubber, and the swelling goes down after the hydrocarbon evaporates. I believe it has to do with the size & structure of the silicone molecules. You said the grease you used was “silicone based”... perhaps it contained something else that caused the swelling? Anyway, alcohol in fuel can very definitely cause swelling of certain compounds used in some o-rings. There are rubber o-ring compounds that are not affected by alcohol, but there are others that are, for sure. That may apply to the rubber that your gasket is made of.

_________________
John Evens
Arvada, Colorado

T-18 N71JE (sold)
Kitfox 7 SS N27JE


Top
 Profile  
 
Rich Brazell
 Post subject: Re: Fuel Cap Needed
PostPosted: Sat Sep 01, 2018 12:07 pm 
Hero Member
Hero Member

Joined: Wed Oct 21, 2009 12:33 pm
Posts: 2875
Images: 64
Location: Jamul, CA (San Diego area)
I am NOT a chemist , but I think the Viton O'ring used with my ACS fuel cap is compatible with "Moon Shine" based auto fuels . ??? I also use a silicone spray on my o-ring from time to time to keep it happy . :P Bottoms up ! ::)

RB O0


Top
 Profile Personal album  
 
Binder
 Post subject: Re: Fuel Cap Needed
PostPosted: Sun Sep 02, 2018 4:42 pm 
Sr. Member
Sr. Member

Joined: Thu Sep 01, 2016 10:50 pm
Posts: 220
Quote:
Jeff,

FWIW, I used a small amount of silicone grease on my fuel cap gasket - same type - for years, with no adverse effects. Silicone grease will not harm (or cause swelling) of any rubber compound that I know of. Silicone rubber, on the other hand, will swell from contact with many hydrocarbon-based lubricants, fuels, etc. there is generally no permanent harm to the silicone rubber, and the swelling goes down after the hydrocarbon evaporates. I believe it has to do with the size & structure of the silicone molecules. You said the grease you used was “silicone based”... perhaps it contained something else that caused the swelling? Anyway, alcohol in fuel can very definitely cause swelling of certain compounds used in some o-rings. There are rubber o-ring compounds that are not affected by alcohol, but there are others that are, for sure. That may apply to the rubber that your gasket is made of.


Well, I guess that makes sense. I've used pump gas before without issues and I checked ethanol content with a hydro tester and didn't find any. Today when i pulled the fuel cap to fill it came out easy and most of the swelling is down. I have to use a flat head screwdriver to get the end tucked into the tank when I put it back in but other than that it comes out easy.

Not sure what could have caused the issue. It will continue to work for me now. I'll have to search for long term solutions. Although it will work I'm nervous that the oring ACS cap won't hold as strong in an accident like the large one I have that allows the rubber to expand under the rim instead of just against it.


Top
 Profile  
 
Jeff J
 Post subject: Re: Fuel Cap Needed
PostPosted: Mon Sep 03, 2018 8:42 am 
Sr. Member
Sr. Member

Joined: Wed Aug 31, 2016 8:18 am
Posts: 375
Images: 0
Location: eastern OK
Mine had a PA23 fuel cap on it. The problem I had was the opposite. It became hard enough that I couldn’t tighten the screw enough to generate enough friction to hold it securely in place. That is when I searched out an option that used tabs or threads to hold the cap on instead of squeezed rubber. I don’t think I would have ever known the cap wasn’t secure if I didn’t try to pick up the tank by the cap when it was out of the airplane.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


Top
 Profile Personal album  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

[ Time : 0.062s | 12 Queries | GZIP : On ]