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DaBraink
Samba Member
Joined: August 12, 2005
Posts: 172
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 Posted: Sat Oct 29, 2005 10:57 pm Post subject: Stale Air/Fresh Air? |
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What is the difference between stale / fresh air engines and do all years use thermostats?
1963 with a 1966 1300
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If it ain't broke.................find something else to fix.
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24764
Location: Olympia Wash Rinse & Repeat
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| Posted: Sun Oct 30, 2005 8:19 am Post subject: Re: Stale Air/Fresh Air? |
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Hi DaBraink,
Almost ALL of the engine tin is differant, and of course the HEs. All VWs from about 1950 used a thermostat. Before that it was a hand flipped lever on the tin for Winter/Summer.
Check out the engine stuff in the type 2 parts manual you can view at:
http://failsure.net/oacdp/
Eric&Barb |
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swanlakers
Samba Member
Joined: July 17, 2005
Posts: 370
Location: Lost in space
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| Posted: Sun Oct 30, 2005 1:30 pm Post subject: |
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| The 1963 and 1964 fresh air 40hp engines had unique fan tin. The tin looks just like later tin except that there are no holes for temperature control flaps. The 63-64 40hp still used the fan ring behind the fan housing, identical to the 36hp and 61-62 stale air 40hp engines. Interestingly the heater boxes on 63-64 40hp engines were different also. They had a slightly smaller diameter outlet where the boxes hooked to the pipe leading into the cabin, but otherwise looked and worked like common 1600 fresh air boxes |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24764
Location: Olympia Wash Rinse & Repeat
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| Posted: Sun Oct 30, 2005 6:14 pm Post subject: |
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| swanlakers wrote: |
| They had a slightly smaller diameter outlet where the boxes hooked to the pipe leading into the cabin, but otherwise looked and worked like common 1600 fresh air boxes |
Hi swanlakers,
Close! The problem is that MOST of those early fresh air HEs have a small round tube inside for the exhaust to pass through. The 1964 and later HEs have a bigger finned interior pipe so as to extract more heat from the exhaust. Using these early HEs on an engine larger than a 1200cc creates too much back pressure due to the exhaust not being cooled, and in turn higher engine temps!!
To avoid this, with larger engine we either convert/weld the smaller 50mm outlet or have split the outer sheet metal skins and installed 1964 and later exhaust tubes in them.
Eric&Barb |
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swanlakers
Samba Member
Joined: July 17, 2005
Posts: 370
Location: Lost in space
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| Posted: Mon Oct 31, 2005 12:32 pm Post subject: |
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Well, I know I just said that there was a difference between 1963-64 heat exchangers and the later ones, but now I'm not so sure. I took a look at my stash and can't find any important differences. Specifically, I could not find a "late" style heater box with a 40mm outlet to the cab - all were 50mm. What I remember (now that I am left with 14 braincells total) was that when I dissassembled my 1964 engine that looked unmolested was: "Hey, never seen that small thing before, better stash that so I can put it back together right." Now of course the parts have scattered and so has my memory.
So help me out - Was there anything special about 40hp fresh air heater boxes, or with the pipes etc. which connect them to the cabin? |
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glutamodo 
The Android
Joined: July 13, 2004
Posts: 26325
Location: Douglas, WY
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| Posted: Mon Oct 31, 2005 3:45 pm Post subject: |
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There never was a 40mm heater outlet, just 50 and 60.
Here's some 40HP heater box info from the Bentley 1200 manual: (click on the pic to enlarge)
- Andy
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swanlakers
Samba Member
Joined: July 17, 2005
Posts: 370
Location: Lost in space
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| Posted: Mon Oct 31, 2005 5:55 pm Post subject: |
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since I didn't have a ruler with me I used that "mark one eyeball" to measure - I guess it needs adjustment.
Thanks glutamodo!
I was sure that I saw some smalled diameter outlets, now I know that I am not totally loosing it. |
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DaBraink
Samba Member
Joined: August 12, 2005
Posts: 172
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| Posted: Tue Nov 01, 2005 3:32 pm Post subject: |
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Thanks for the replies, now I know why the outlet end the the heater box is larger than the inlet on the body side I was told that there is a composite ring gasket that fits between the plastic tube and the metals that it attaches to.
But what is the functional difference between stale and fresh?
_________________
If it ain't broke.................find something else to fix.
There's never enough time to do things right, but always enough time to do them over. |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26325
Location: Douglas, WY
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| Posted: Tue Nov 01, 2005 7:40 pm Post subject: |
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Stale air heating uses the air the cools the engine to heat the car - plus bit of manifold heating from the number 3 and number 1 exhaust pipes. Engine oil leaks often result in oil smell and even smoke in the car.
Fresh air uses air from separate ducts off the engine that blow through contained heat exchangers - this manifold heating is all you get. The air that cools the engine is separate.
andy |
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