Eric Hysteric
Hildesheim
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New posts in the topic! Nice! Very appetizing photos StingrayL82.
I bought an used IMPCO propane conversion kit. The kit comes from a GM and now i need an adapter between the IMPCO 300A Mixer and my Thermoquad 4BBL carburetor. Does anyone have a tip for me?
![[image]](https://img2.picload.org/image/dagpoapw/27497545_907600799402471_75560.jpg)
![[image]](https://img2.picload.org/image/dagpoogi/26613439_893267554169129_47476.jpg)
![[image]](https://img2.picload.org/image/dagpooaa/26694166_893713067457911_14937.jpg)
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Griff in Fairbanks
AK
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Eric Hysteric wrote:I bought an used IMPCO propane conversion kit. The kit comes from a GM and now i need an adapter between the IMPCO 300A Mixer and my Thermoquad 4BBL carburetor. Does anyone have a tip for me?
I went to the IMPCO website and poked around.
In the Technical Support dropdown menu is an Installation Instructions webpage. On that webpage is Thermo-Quad Adapter Installation Instructions for part # AA3-64.
The general installation instructions references National Fire Protection Association (NFPA) pamphlet #58. I strongly recommend getting this pamphlet and reading it thoroughly. (Weblink for the NFPA 58 .pdf file.) Have a bottle of aspirin on hand because it's in the typical standards/regulations format and uses technical jargon extensively.
Note: At the bottom of the general instructions is a prohibition against using Teflon tape on fuel fittings. (Bits of tape can come loose and plug propane orifices and mechanisms.) Presumably, use paste-type Teflon pipe thread sealant -- sparingly -- instead and only on external threads. (Use on external thread will push excess sealant outside the fitting instead of into the propane system.)
Verify what I said in the preceding paragraph with other sources ... while I have significant experience with household propane systems, I am NOT certified. (One company tried to hire me and offered to send me through certification training, based on their impression of the propane system in my cabin.). Likewise, I've never had any experience with motor vehicle propane systems, other than research into what you're doing.
Impco's Carter Thermo-Quad Conversion installation instructions, for p/n AA3-64, 'recommends' against using the conversion kit on carburetors with black plastic float bowls. (They imply propane could compromise the plastic.)
The Impco webpage Product dropdown menu has a link to a Catalog & Parts webpage. That webpage has links to Carburetors & Mixers and Adapters .pdf files, which probably has most of the info you need. (You may also want to download and peruse the complete Master Parts Catalog .pdf file.)
I strongly recommend doing more research, beyond the little bit I've done, and educating yourself.
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
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Griff in Fairbanks
AK
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Addendum: I assume the pictures you posted are of the GM installation. See if you can get the air cleaner housing ... the little bit of research I've done implies the housing is an integral part of the IMPCO 300A system.
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StingrayL82
Nampa, Idaho
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Griff in Fairbanks wrote:...Presumably, use paste-type Teflon pipe thread sealant -- sparingly -- instead and only on external threads. (Use on external thread will push excess sealant outside the fitting instead of into the propane system.)...
NO NO NO! Never use Teflon on propane systems. Propane will eat the Teflon away; at best, you'll have a leak; at worst, you'll blow up. There is a special tape made specifically for propane, gasoline, kerosene, benzene, etc... that will not deteriorate.
Attached is a picture of the tape container. You can purchase it at any of the home box stores.
![[image]](https://i.imgur.com/ywAUA8sl.jpg)
* This post was
edited 02/12/18 04:40pm by StingrayL82 *
Fred
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Griff in Fairbanks
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StingrayL82 wrote:Griff in Fairbanks wrote:...Presumably, use paste-type Teflon pipe thread sealant -- sparingly -- instead and only on external threads. (Use on external thread will push excess sealant outside the fitting instead of into the propane system.)...
NO NO NO! Never use Teflon on propane systems. Propane will eat the Teflon away; at best, you'll have a leak; at worst, you'll blow up. There is a special tape made specifically for propane, gasoline, kerosene, benzene, etc... that will not deteriorate.
Thank you, thank you, THANK YOU!
Decades ago, I used Teflon thread compound on propane systems. Knowledge and technology evolves, so I'm always wary of "doing things the way we've always done it." This is new information for me and looking into it is at the top of my to-do list.
If you could provide links to relevant information and sources, it would be greatly appreciated.
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StingrayL82
Nampa, Idaho
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Griff in Fairbanks wrote:Thank you, thank you, THANK YOU!
Decades ago, I used Teflon thread compound on propane systems. Knowledge and technology evolves, so I'm always wary of "doing things the way we've always done it." This is new information for me and looking into it is at the top of my to-do list.
If you could provide links to relevant information and sources, it would be greatly appreciated.
Let me correct myself....the yellow propane thread tape DOES have Teflon in it, but the white tape that everyone knows as Teflon Tape (i.e.: the stuff that comes in a white or blue case) is what I was referring to, when I said don't use it.
The yellow tape is specially formulated for use on propane systems.
Also, there are different ratings of the yellow tape. Some yellow tape is rated for up to 10,000psi, which is overkill for our RV systems.
I stand by my statement of the propane eating the regular white tape, as it was a mistake I made with a previous RV I had. I wrapped it correctly and it was about three years later that I developed a leak, while I was in Sierra Vista, AZ. If it hadn't been for my dog waking me up by barking, I would have been dead.
Here's a link to a pdf of all of the different colors of tape: http://www.allsealsinc.com/pdf2/Teflon%20Tape.pdf
* This post was
edited 02/12/18 04:50pm by StingrayL82 *
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Griff in Fairbanks
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I use a flexible arctic grade hose, suitable for propane, between the tank and regulator. (I have these custom-made by a reputable local company.) POL fitting on the tank end and NPT (National Pipe Thread Taper) on the regulator end. (Up-to-date two-stage regulator ... regulators do have expiration dates and you should not use an expired regulator.)
I use NPT threaded black iron pipe exclusively for my distribution networks. The tapered NPT threads create a liquid-tight connection when tightened sufficiently. Careful extra tightening can lead to a nearly gas-tight connection. (Gas as in gaseous, not liquid gasoline.). Over tightening can crack the pipe and fitting, rendering the connection useless.
Until now, I used Teflon thread compound or tape to ensure the NPT connections remain gas-tight. As soon as I find a source for the compound/tape that StingrayL82 mentioned, I will switch to that. (Purchased on or before the next time I work on a propane system.)
The NPT threads and thread compound/tape is a 'belt-and-suspenders' approach to insuring gas-tight connections. Flare nut fittings are inherently gas-tight, as long as you ensure the flares are well-formed, kept clean, and adequately tightened. (NO thread compound/tape in or on the flare.)
I use brass flare nut fittings at the distribution network terminals. Final connection to propane devices is via flared copper tubing or manufactured metal flex hoses suitable for propane (LPG) or natural gas.
All connections are tested, under pressure, with a dish soap/water solution prior to being put into service. (Special focus on connections within the building.)
My cabin was originally set up for off-grid use. In addition to a non-electric propane cookstove, we had a propane refrigerator, several propane light fixtures, and a propane heater. The propane light fixtures are still there and used during power outages. The propane refrigerator was replaced with an electric one when the electric grid reached the edge of our property. The propane cookstove was more than my wife and I needed and took up precious space in our 16' x 16' cabin. So, it was removed and replaced with a countertop convection oven, a microwave, and electric hotplates.
The system terminations for the propane refrigerator and cookstove were capped so we can revert to off-grid configuration if we want. We have discussed installing a propane cooktop but what we have works for us.
The cabin's propane system was inspected and subjected to an extended leak-down test, with no discernible drop in system pressure. (The inspector/tester was impressed with my installation, which is why the company tried to hire me.)
* This post was
edited 02/12/18 07:40pm by Griff in Fairbanks *
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StingrayL82
Nampa, Idaho
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Griff in Fairbanks wrote:...(Up-to-date two-stage regulator ... regulators do have expiration dates and you should not use an expired regulator.)...
Well said. Another rookie mistake I made years ago with an old Streamline travel trailer we owned.
Here's another good link to the thread sealant: http://allthumbsdiy.com/plumbing/when-to-use-ptfe-teflon-yellow-or-white-tapes-or-pipe-dope
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Griff in Fairbanks
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StingrayL82 wrote:Let me correct myself....the yellow propane thread tape DOES have Teflon in it, but the white tape that everyone knows as Teflon Tape (i.e.: the stuff that comes in a white or blue case) is what I was referring to, when I said don't use it.
The yellow tape is specially formulated for use on propane systems.
Thank you for the link. I looked at it and dug a bit deeper.
The issue with thread tape appears to be related to other plastics in the tape, rather than the Teflon (PTFE). So, it appears the yellow tape uses other plastics versus what's used in the white tape.
It also appears the primary purpose of PTFE in thread tape/compound/paste/sticks is thread lubrication.
Compatibility between PTFE and liquified propane (LPG) is rated A-Excellent. (PTFE compatibility with gasoline is rated B-Good.) I verified the compatibility across multiple sources.
I've never run into issues with white thread tape in propane connections. This may be due to the tape being a secondary part of my 'belt-and-suspenders' approach to propane connections. I am, however, switching to yellow thread tape in the few cases where I do use thread tape. (Will also be replacing existing white tape.)
The paste- and stick-type thread sealants, with PTFE/Teflon, that I commonly use are listed as compatible with gasoline. (Still trying to find a reliable source that specifically states compatible with propane/LPG.)
We've all run into this type of issue in our older motorhomes. (If you haven't yet, you probably will at some point in the future.) Some types of alcohol in common gas line antifreeze and 'gasohol' eat the older type of seals in carburetors and elsewhere. (I've mentioned before having to repeatedly rebuild the Carter BBD in my '77 Dodge B200 van due to excessive use of 'cheap' gas line antifreeze.)
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StingrayL82
Nampa, Idaho
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Griff in Fairbanks wrote:Thank you for the link. I looked at it and dug a bit deeper.
The issue with thread tape appears to be related to other plastics in the tape, rather than the Teflon (PTFE). So, it appears the yellow tape uses other plastics versus what's used in the white tape.
It also appears the primary purpose of PTFE in thread tape/compound/paste/sticks is thread lubrication.
Compatibility between PTFE and liquified propane (LPG) is rated A-Excellent. (PTFE compatibility with gasoline is rated B-Good.) I verified the compatibility across multiple sources.
I've never run into issues with white thread tape in propane connections. This may be due to the tape being a secondary part of my 'belt-and-suspenders' approach to propane connections. I am, however, switching to yellow thread tape in the few cases where I do use thread tape. (Will also be replacing existing white tape.)
The paste- and stick-type thread sealants, with PTFE/Teflon, that I commonly use are listed as compatible with gasoline. (Still trying to find a reliable source that specifically states compatible with propane/LPG.)
We've all run into this type of issue in our older motorhomes. (If you haven't yet, you probably will at some point in the future.) Some types of alcohol in common gas line antifreeze and 'gasohol' eat the older type of seals in carburetors and elsewhere. (I've mentioned before having to repeatedly rebuild the Carter BBD in my '77 Dodge B200 van due to excessive use of 'cheap' gas line antifreeze.)
Redundancy is the key to safe operation of our RVs. One of things I will be incorporating into our Monaco is a CO/Propane detector, a must for anyone who owns an RV. I was lucky enough to have my dog in 2010. I wonder how many people succumb to propane accidents in RVs.
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