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IDK-1980
Samba Member
Joined: June 29, 2018
Posts: 12
Location: California
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 Posted: Sat Oct 06, 2018 6:31 pm Post subject: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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I've scourred the internet and scanned through my Chilton's manual, but have been unable to find an answer as to what the function or name of this mystery hole in the back-right of my engine bay is (this is on a 1973 bay window, which is totally new to me). Questions:
1) What is it?
2) Should there be something connected to or covering it?
3) (Most importantly) should there definitely not be a plastic bag shoved in it?
Thank you.
_________________
1972 Super Beetle w/ Sunroof, Saturn Yellow
1973 Bay Window Bus, Wild Westerner 2-Tone Green
Last edited by IDK-1980 on Sat Oct 06, 2018 11:37 pm; edited 1 time in total |
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hazetguy
Samba Member
Joined: April 06, 2001
Posts: 10797
Location: iT StiNgeD iTseLf tO dEAd
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| Posted: Sat Oct 06, 2018 7:19 pm Post subject: Re: Type 4 Engine mystery hole |
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Original preheat tin for stock dual carbs.
If the other ducting is still in place (even if it isn't), and since you're running aftermarket dual carbs, you'll want to have it plugged. Otherwise you'll be pumping hot air into the engine compartment.
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Sat Oct 06, 2018 8:42 pm Post subject: Re: Type 4 Engine mystery hole |
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| Air preheat stove, helpful if you want your engine to run its best in cold weather and if you want the best gas mileage possible. Easy to hook up if you have stock carbs and a stock aircleaner, but an awful lot of work to hook up if you are running non stock dual carbs. |
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IDK-1980
Samba Member
Joined: June 29, 2018
Posts: 12
Location: California
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| Posted: Sat Oct 06, 2018 11:41 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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Thanks, much appreciated! I'm sure I'll have more questions in the future.
So the plastic bag was serving a purpose... 
_________________
1972 Super Beetle w/ Sunroof, Saturn Yellow
1973 Bay Window Bus, Wild Westerner 2-Tone Green |
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Wasted youth
Samba Member
Joined: July 06, 2012
Posts: 5173
Location: California's Hot and Smoggy Central Valley
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| Posted: Sun Oct 07, 2018 9:17 am Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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I use it to pre-heat my Weber carburetor:
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Sun Oct 07, 2018 9:31 am Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| IDK-1980 wrote: |
Thanks, much appreciated! I'm sure I'll have more questions in the future.
So the plastic bag was serving a purpose... |
By wary of using a plastic bag or any large sheet of plastic or paper for anything in the engine compartment. Were it to move around and block the fan off overheating would happen almost instantly and you might not notice anything amiss until the engine locked up.
The piece in question is lovingly referred to as a commode, just like the ones that get hugged on Saturday morning in frat houses all around the country. The commode itself is easy to remove and can be replaced with a piece of sheet metal cut from the lid of a large tin can or a piece of plastic cut from an oil jug. Since some oil comes in a black gallon jug if you use thus for you next oil change you will have a matching patch to go over the opening. |
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60vwnewengland
Twin #2
Joined: June 25, 2003
Posts: 1808
Location: Cape Cod & District of Columbia
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| Posted: Sun Oct 07, 2018 5:13 pm Post subject: Re: Type 4 Engine mystery hole |
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| hazetguy wrote: |
Original preheat tin for stock dual carbs.
If the other ducting is still in place (even if it isn't), and since you're running aftermarket dual carbs, you'll want to have it plugged. Otherwise you'll be pumping hot air into the engine compartment.
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Isn't the "technical term" of this referred to as the "toilet bowl" pre-heat tin??
_________________
77 Westy - Cape Cod Sage
70 Beetle
71 Super Beetle
RIP TheWalrus (Big Jack) 1988-2024 |
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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3804
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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| Posted: Sun Oct 07, 2018 7:52 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wasted youth wrote: |
I use it to pre-heat my Weber carburetor:
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And how about a T-stat on the pre-heat when it's not needed any longer?
_________________
1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Sun Oct 07, 2018 9:08 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| udidwht wrote: |
And how about a T-stat on the pre-heat when it's not needed any longer? |
Without manifold heat I doubt that is ever a problem. |
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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3804
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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| Posted: Sun Oct 07, 2018 9:09 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wildthings wrote: |
| udidwht wrote: |
And how about a T-stat on the pre-heat when it's not needed any longer? |
Without manifold heat I doubt that is ever a problem. |
Unless it's 200F outside....LOL!
_________________
1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Sun Oct 07, 2018 9:19 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| udidwht wrote: |
| Wildthings wrote: |
| udidwht wrote: |
And how about a T-stat on the pre-heat when it's not needed any longer? |
Without manifold heat I doubt that is ever a problem. |
Unless it's 200F outside....LOL! |
Give us a few more years we are getting there.  |
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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3804
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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| Posted: Sun Oct 07, 2018 9:42 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wildthings wrote: |
| udidwht wrote: |
| Wildthings wrote: |
| udidwht wrote: |
And how about a T-stat on the pre-heat when it's not needed any longer? |
Without manifold heat I doubt that is ever a problem. |
Unless it's 200F outside....LOL! |
Give us a few more years we are getting there. |
We go into one and come out of one. Science barelys understands how the planet fully works at this point. Barely.
_________________
1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires |
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P24p1
Samba Member
Joined: August 20, 2020
Posts: 365
Location: Canada, Quebec
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| Posted: Wed Nov 11, 2020 7:43 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wasted youth wrote: |
I use it to pre-heat my Weber carburetor:
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I'm thinking of doing something like that. Do you have any more pictures? Also, what kind of gas mileage do you get with that setup? |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Wed Nov 11, 2020 7:59 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| P24p1 wrote: |
| Wasted youth wrote: |
I use it to pre-heat my Weber carburetor:
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I'm thinking of doing something like that. Do you have any more pictures? Also, what kind of gas mileage do you get with that setup? |
Read up on the cookie tin setup. You can also peruse the earlier pictures in my gallery to see my setup, it uses a Datsun air cleaner housing with a thermostatic valve for the preheat. I also run a heated manifold. Back in the good old days before ethanol ended up in out fuel I used to get 24-26 mpg, but with ethanol I get about average gas mileage anymore. |
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Whaanga
Samba Member
Joined: May 07, 2016
Posts: 642
Location: Rochester, NY
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| Posted: Wed Nov 11, 2020 9:00 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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Does anyone know where one can source the rubber gasket that goes on the pre-heat duct?
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Late 1973 Bay w/a transplanted 914 Engine |
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P24p1
Samba Member
Joined: August 20, 2020
Posts: 365
Location: Canada, Quebec
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| Posted: Wed Nov 11, 2020 9:50 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wildthings wrote: |
| I also run a heated manifold. |
How did you set that up? On your pictures it looks like a type 1 manifold to type 4 heads, how did you do that? And then you have two of those heater things they sell for type 1 engines? |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Wed Nov 11, 2020 11:03 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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The "dual port" ends are just reworked fuel injection manifolds. Just a bit of cutting, twisting, and welding. They actually come out looking very close to what VW used on their T-127 industrial engines.
Yes I kind of have a two level system for the manifold heat. The one pipe heats the bottom of the center section of the manifold and the upper one supplies heat to near the base of the carb so is very good at preventing icing, the manifold is double walled at that point so intake air goes down through a center pipe and the exhaust gases flow through a chamber built around the center pipe. |
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P24p1
Samba Member
Joined: August 20, 2020
Posts: 365
Location: Canada, Quebec
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| Posted: Thu Nov 12, 2020 8:24 am Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| Wildthings wrote: |
The "dual port" ends are just reworked fuel injection manifolds. Just a bit of cutting, twisting, and welding. They actually come out looking very close to what VW used on their T-127 industrial engines.
Yes I kind of have a two level system for the manifold heat. The one pipe heats the bottom of the center section of the manifold and the upper one supplies heat to near the base of the carb so is very good at preventing icing, the manifold is double walled at that point so intake air goes down through a center pipe and the exhaust gases flow through a chamber built around the center pipe. |
What kind of MPG do you get with your system? |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52290
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| Posted: Fri Nov 13, 2020 5:06 am Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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| P24p1 wrote: |
| Wildthings wrote: |
The "dual port" ends are just reworked fuel injection manifolds. Just a bit of cutting, twisting, and welding. They actually come out looking very close to what VW used on their T-127 industrial engines.
Yes I kind of have a two level system for the manifold heat. The one pipe heats the bottom of the center section of the manifold and the upper one supplies heat to near the base of the carb so is very good at preventing icing, the manifold is double walled at that point so intake air goes down through a center pipe and the exhaust gases flow through a chamber built around the center pipe. |
What kind of MPG do you get with your system? |
I presently get the pretty standard 17-19 MPG but am considering going back and tuning the carb to run on ethanol free gas and see if I can get the gas mileage back up into the mid 20's where it used to run before ethanol lace fuel entered the scene. |
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Whaanga
Samba Member
Joined: May 07, 2016
Posts: 642
Location: Rochester, NY
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| Posted: Fri Nov 13, 2020 6:13 pm Post subject: Re: Type 4 Engine mystery hole (SOLVED: It's the preheat duct) |
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Thanks for the info on this thread. And thanks Wasted Youth for the method of heating your single carb. I hope you don’t mind but I borrowed your idea.
Am anxious to go for a drive tomorrow in the cool Western New York temps and hope to see improved conditions at stop lights.
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Late 1973 Bay w/a transplanted 914 Engine |
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