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Mark Samba Member
Joined: January 20, 2003 Posts: 1523 Location: Victoria, BC Canada
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Posted: Wed Jun 03, 2009 6:29 pm Post subject: Fanshroud & Oil Cooler Sealing Frame (Hoover Bit) Combos |
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Not all fanshrouds are created equal. By now, most people on the forums here have heard of the doghouse sealing tin (or more commonly referred to as the "Hoover Bit"). They may not know that not all fanshrouds will work with this piece, and in one case the seal isn't needed at all.
So, let's give a visual explanation as to the different setups to find out what fits what:
Original German Fanshroud - sealing frame fits, no surprise
PUMA low-profile Fanshroud - sealing frame also fits
New VW Mexico Fanshroud - no frame required, no room for one (despite the lower screw fastener cutout)
Scat Fanshroud - frame required, but needs to be modified to work
(Other 36 hp aftermarket fanshrouds compare similar)
Scat Fanshroud (again) - modified frame
This subject was touched upon in the Split Window Bus forum recently, but I wanted to post this here for a broader audience that this subject relates to. _________________ www.zwerks.ca |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76761 Location: Sneaking up behind you
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Posted: Wed Jun 03, 2009 6:32 pm Post subject: |
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Mark... many thanks for the pics. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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Towel Rail Horizontally Opposed
Joined: April 15, 2005 Posts: 4622 Location: SE CR IA US NA PE
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Posted: Wed Jun 03, 2009 8:15 pm Post subject: |
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Good stuff!
- Scott _________________ 1974 Thing -- under the knife
1967 Beetle -- spring/summer/fall driver
1996 Subaru OBW (EJ22, 5-speed, AWD) -- winter car, 3-seasons "don't feel like biking today" car
049 > 070 > 053 > 009 |
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don.ville Samba YardMan
Joined: February 07, 2008 Posts: 2813 Location: West Palm Beach, FL
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Posted: Sat Jun 06, 2009 3:47 am Post subject: |
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Required reading for everyone. Now I have a link to point folks to. The Scat photo is especially good since you left it in the CAD color you can really see the big gap.
They should really fix that! _________________
67 Standard 11 window How I Keep My Bus Alive
04 Jetta TDI Page (SOLD)
01 Mexican Beetle Hello Kitty Rescue (SOLD)
29 Ford Model A Rat Rod (SOLD)
2015 Audi A8L TDI Quattro
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don.ville Samba YardMan
Joined: February 07, 2008 Posts: 2813 Location: West Palm Beach, FL
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Posted: Mon Jun 08, 2009 8:42 pm Post subject: |
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From my bus blog
don.ville wrote: |
Based on forum feedback, I added a rivet to the foam hoover bit seal to prevent it from getting sucked away by the fan.
I had to angle the new piece downwards too since
the SCAT shroud was made that way...
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_________________
67 Standard 11 window How I Keep My Bus Alive
04 Jetta TDI Page (SOLD)
01 Mexican Beetle Hello Kitty Rescue (SOLD)
29 Ford Model A Rat Rod (SOLD)
2015 Audi A8L TDI Quattro
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1961bluebug Samba Member
Joined: November 11, 2002 Posts: 1137 Location: Czech Republic, Europe
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Marv [UK] Samba Member
Joined: January 07, 2009 Posts: 2225 Location: UK
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Posted: Wed Aug 05, 2009 12:51 am Post subject: |
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As I've just taken a Scat 36 HP shroud with air outlets off my motor, I thought I'd post a comparison photo or two with the stock shroud I'm about to put on
Scat 36 HP next to Stock
The biggest differences I found are coming up, but some of the smaller differences are harder to spot.
The sealing part to the hoover bit has been included on this scat shroud, but it stands a bit further back off the cooler and at the wrong angle
The curved aerofoil adjacent to the cooler, the one visible in the pics, is a different shape to the stock aerofoil. It extends further to the right and is not as curved... the only effect I can see from this is that it's directing air into the wrong place, but thats just a supposition, not tested.
The other thing I noticed was that the rear of the shroud (the bit against the firewall) was not parallel to the front and the fan was not as close fitting as it is in the stock shroud
Also, the opening to the cylinder tin on the left (over #1 and #2) is not as big as the stock shroud
The following two photos show the vent openings supplying air to numbers 3 and 4 cylinders. With the air outlet on the 36HP shroud as it is, and the wrong shaped aerofoil, the amount af cross sectional area is drastically reduced. The stock shrouds airway is very clear and directed.
This is likely the reason why I've been having heat issues at higher speeds. |
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volkaholic1 Samba Member
Joined: October 31, 2004 Posts: 781 Location: ohio
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Posted: Fri Aug 07, 2009 10:03 am Post subject: |
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Since discovering this issue, I have started modifying all the SCAT fan shrouds I deal with to eliminate this problem. I use the Zerks hoover bit & remove the little piece of tin in the SCAT shroud and weld on a new piece that properly fills the gap, eliminating the problem. Now that I know about the problem, no fan shroud leave the shop without this modification.
PS - the EMPI brand shroud has the same issues.
_________________ Volkaholic |
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1961bluebug Samba Member
Joined: November 11, 2002 Posts: 1137 Location: Czech Republic, Europe
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Posted: Mon Aug 31, 2009 10:25 am Post subject: |
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another possible approach:
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Fri Sep 04, 2009 9:24 am Post subject: |
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thats pretty nice,has it been tested to see the defrance? also the bubble top cases are defrent. is any one making the shroud for them?I modifyed my old one but it is now probly useless for my spair moter ,witch is fixen to go in pretty soon. a nice set of stamped properly profiled pieces to weld/rivet with epoxie would be nice,just trim old shroud to a template then add the new peaces!!! |
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1961bluebug Samba Member
Joined: November 11, 2002 Posts: 1137 Location: Czech Republic, Europe
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Posted: Thu Sep 24, 2009 1:12 am Post subject: |
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Mark I believe it doesn´t need to be tested. With this mod we are only returning the condition of engine tins to the state factory produced them. You definitely want all the cooling air to be spend on the oil cooler and cylinders and heads and not going through large gaps to your engine bay. |
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vugbug68 Samba Member
Joined: June 25, 2006 Posts: 2696 Location: sacramento
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Posted: Fri Oct 02, 2009 9:31 pm Post subject: |
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I discovered something very interesting recently regarding fan shrouds.
Here is a shroud from a fuel injected beetle.
basically the same except for the added venturi ring, also there is no scoop surrounding the opening to the oil cooler. as like the earlier shroud pictured below
I have used both shrouds on my 1955cc, with the FI shroud the head temp stays around 300 most of the time, if i'm stopping and going its like 250-275, pulling hills on the freeway 350 is the hottest its gotten. (this is measured with a VDO guage and sender at spark plug 3)
with the standard doghouse my head temp was 325ish most of the time.
but i had a problem with my oil pressure!! somehow my oil was not getting cooled properly with the standard shroud. after cruising for a while, when i came to a stop my oil light would come on and my psi would be at like 5 and my cruising psi would gradually get lower too. my oil was breaking down and thinning out.
the only thing i changed was the shroud, I went back to the FI shroud and after driving all day my psi at idle never got below 12ish (idle is about 900 rpm) I did not change oil either, its rotella 15-40.
I just thought this experiment was interesting. _________________ 71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin |
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AlteWagen Troll
Joined: February 23, 2007 Posts: 8497 Location: PNW
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Posted: Wed Oct 14, 2009 1:04 am Post subject: |
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vugbug68 wrote: |
I discovered something very interesting recently regarding fan shrouds.
Here is a shroud from a fuel injected beetle. |
does your FI shroud have the long oil slot with no scoop or the small "peanut" slot? |
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vugbug68 Samba Member
Joined: June 25, 2006 Posts: 2696 Location: sacramento
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Posted: Wed Oct 14, 2009 7:47 am Post subject: |
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derluftwagen wrote: |
vugbug68 wrote: |
I discovered something very interesting recently regarding fan shrouds.
Here is a shroud from a fuel injected beetle. |
does your FI shroud have the long oil slot with no scoop or the small "peanut" slot? |
it looks just like the one in the picture except without that scoop around the opening. the opening is the same length, i dont think i've seen one with the "peanut slot" _________________ 71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin |
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AlteWagen Troll
Joined: February 23, 2007 Posts: 8497 Location: PNW
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Posted: Wed Oct 14, 2009 12:15 pm Post subject: |
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Here is a pic of an industrial shroud from the gallery. My FI shroud has the fresh air ducts and the small slot.
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vugbug68 Samba Member
Joined: June 25, 2006 Posts: 2696 Location: sacramento
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Posted: Wed Oct 14, 2009 2:41 pm Post subject: |
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interesting, no mine is how i mentioned earlier with the large slot. I wonder if anyone has done any tests with FI shrouds? _________________ 71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin |
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volkaholic1 Samba Member
Joined: October 31, 2004 Posts: 781 Location: ohio
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Posted: Tue Nov 24, 2009 6:35 pm Post subject: |
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I put together this little video on how to install the hoover bit. I know it seems obvious to most of us, but some folks need to see it done to absorb it.
Link
_________________ Volkaholic |
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vintagevinni Samba Member
Joined: August 10, 2003 Posts: 13
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76761 Location: Sneaking up behind you
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Posted: Thu Nov 26, 2009 8:43 pm Post subject: Re: Some photos of my SCAT doghouse fan housing kit. |
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OEM _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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volkaholic1 Samba Member
Joined: October 31, 2004 Posts: 781 Location: ohio
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Posted: Fri Nov 27, 2009 8:23 am Post subject: |
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yes, the aftermarket stuff needs work. That is why I modify all of the doghouse oil cooler exhausts to line up properly, modifiy the hoover bit area to flow proper, etc. _________________ Volkaholic |
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