Adding Blower Motor in Engine Bay (Please expose all flaws)

[Herbst '71]

The temperature of the heated air in my 1971/1600 DP is acceptable. I still need to clean out the ducting. I am trying to increase air movement at idle with a blower motor from a 77. The goal is to tie the blower motor hoses into the current fresh air hose before they leave the engine bay or as close as possible to where the enter the heater boxes.

I am also looking at routing the ducting for the blower motor up the fresh air intake on the left side of the bus and pulling fresh air from the left side of the cargo bay.

Questions:

Will tying the second set of hoses into the current fresh air tubes completely destroy the air flow?

Does the booster fan push enough air to force warm air back into the fan shroud?

Will routing the ducting up the fresh air intake obstruct the air coming into the engine bay? (VW did not put it there and I would hate to discover the tolerances are so small that I cook my engine.)

Should the project be abandoned all together? (I could always inform the passengers that if they are uncomfortable with the temperature in the cabin, they can put on a jacket or walk)

Here is a diagram of what I am thinking about doing.

https://www.thesamba.com/vw/gallery/pix/319225.gif

Thanks for reading and tearing it apart
_________________
Rik
'71 Deluxe/1600 DP

"Fortunately my mistakes are serving as a warning for others."

[Wildthings]

I would think your best bet on a Type 1 engine would be to install a 3" bilge blower in each of the flexible duct between the cooling shroud and the heat exchangers. This would boost pressure which will in turn increase flow at all engine RPM's.

[Herbst '71]

I had not thought of that.

Rik
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Rik
'71 Deluxe/1600 DP

"Fortunately my mistakes are serving as a warning for others."

[busdaddy]

A later blower might help with airflow at idle but it will never equal what your engine fan puts out at speed.

If you were to tee it into the cold air pipes you would probably need anti return flaps upstream from it like the later ones have.

I tried the bilge blower and it helped a little (more noise than air), mount it as far forward as you can to avoid melting it and make sure all the leaks in your heat system are sealed.

A steel squirrel cage blower from a 60's car (I used one from a Datsun roadster) makes ALOT of air and really makes the heater effective (quiet too). I mounted it near the front of the center heat tube with some 3" pvc sewer elbows, duct tape and plumbers strap.
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[jered]

I put a 4" bilge motor in my heater channel under my bus... blows 250cmf...

believe it or not, it blows as much as the engine fan does at abour 3500 RPM...

Now to find a good set of german heater boxes... I'd be smoking myself out...

I have posted pictures of it before... and I can tell you that the squirel fan on my 77 does nothing compaired to the 4" bilge fan...! which IMO is a much better option...
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No VW right now....

[Duncwarw]

Bilge blowers don't push well.

Put them inline, as they're designed for, and they can really up the pressure. The problem is the low melt point and the noise.

I wouldn't even bother with the factory squirrel cage fan if I were in your shoes.

If you opt for something other than the factory hoses to push air, just block off the outlets on the shroud so your cooling air stays where it should be.
_________________
“To find yourself, think for yourself”
Socrates, 470 BC - 399 BC

[Herbst '71]

Dunc,

I had thought about blocking off the fresh air tubes at the fan and going with a bilge like you have on your website. It looks like it is in the housing of the factory blower. Did this set up push a more noticeable amount of air?

Rik
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Rik
'71 Deluxe/1600 DP

"Fortunately my mistakes are serving as a warning for others."

[Duncwarw]

No.

Bilge blowers are designed to boost pressure inline.
I took it out of the engine room and put it inline again.

The factory squirrel cage fan is now feeding the left exhanger alone.
I updated the write-up within the last couple of days.
Refresh on your next visit, that might make a difference.

I'm getting a lot of heat now. Not SO hot up front but a huge amount of warm air. The real heat comes from the back vent, about 235F last time I checked. I'm waiting for a freezing day to test and post the results but it was 36 yesterday and I was driving around in a tee shirt.
If you click on "Audio" on my site, you can hear the blower in action.

Silly, right?
_________________
“To find yourself, think for yourself”
Socrates, 470 BC - 399 BC

[NASkeet]

[rcnotes]

Does anyone use or have info on a bigger heating blower, one with more capacity to replace the stock squirrel cage??

I imagine someone has tried a larger blower in the stock position. The problem with that is that you're only moving more air, not heating it any more than would happen with the stock blower. In fact a larger fan with more velocity (and cfm) might not heat any better.

The big problem with blower heat is that the blower uses 100% untempered outdoor air (from the engine compartment). That system really needs a return air duct from the cabin to the blower inlet for the heat to work at temps below 20 degrees. Even a smaller duct that mixes with some OA would help. The problem with installing a return duct is getting it through the tin, either under or through the rear firewall on either side of the gas tank or perhaps through the spare tire pocket.

I sit and think about this situation. One of those blank stare kind of thinks.

[Duncwarw]

With the stock system as it was designed, all you need is more air flow as it gets plenty hot. When mine was as set-up by the factory, I always had 170-190F at the defrost vents.

The problem with the factory blower is that it simply can't produce enough pressure to give you that blast of heated air up front you experience in other (water cooled) vehicles.

Many people apparently add an inline bilge blower. The problem there is the high temperatures in the heating system exceed the capacity of the blower and it melts (not to mention the noise).

Bluebird in the UK sell a blower that is said to deal better with the temperatures. I was unable to find a similar product here so I took another approach. See my site for more.
_________________
“To find yourself, think for yourself”
Socrates, 470 BC - 399 BC

[MrBreeze]

I've had the same 3" bilge fan in my bus for 5 years now and no hint of melting. I have it inline in the hose up front that feeds the front vents. A tad noisy, but it does a great job pushing the air.

Another thing I do when it's really cold is use a curtain rod behind the front seats and hang a blanket. Then I'm only heating the front cab. I lose the rear window, but no big deal. I may make a cab divider this year so I can put a plastic window in.
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-=Rob

WTB: Bay Shore or Queensboro VW Frames

HBB 1984-2009
RW 1943-2011
ER 1964-2023

[Duncwarw]

Maybe it's a model year thing, but my heat WAS way too hot for a blower. Amskeptic has a '73 also and I recall hin reporting similar temps to mine.

Splitting my system allowqed me to use the blower.

It would e interesting to read temp reports for the various model years.
I keep reading the 73/4 exchangers were the best for heat...
_________________
“To find yourself, think for yourself”
Socrates, 470 BC - 399 BC

[Brian 11]

Does anyone use or have info on a bigger heating blower, one with more capacity to replace the stock squirrel cage??

Here is a place for an in line : http://www.800luvbugg.com/shop?frame=5.54.6320
_________________
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No computers, No abs. Yea! GOTTA LOVE THE OLD STUFF!!!
If everything I tell you is a lie and I then tell you I'm lying, am I?

[Duncwarw]

We've gone full circle.

A hundred bucks for a twenty dollar bilge blower and a switch.
If you fix your heat, you can watch your $99 melt.
_________________
“To find yourself, think for yourself”
Socrates, 470 BC - 399 BC

[Amskeptic]

Best to add boosted air before the exchangers, downstream runs the risk of sucking in exhaust.

One way flaps in the fresh air outlets of your Type 1 engine would help prevent the blower from losing boost to the cooling fan housing. The blower should already have flaps.

I do not recommend taking inside return air. Each cycle of air can increase monoxide danger.

If you do not have flow-through vents in your doors (pre-71) the blower will not work as well until you crack a window.

The heat exchangers on a Type 1 bus engine will not give you very good heat with boosted airflow at idle, unless you have the 5*ATDC timing specification with a dual advance distributor. That retard at idle does an excellent job of heating up the exhaust pipes.
Colin
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www.itinerant-air-cooled.com

[Herbst '71]

I am in luck. I have a dual advance distributor timed at 5*ATDC. I do not have the flow through vents in the doors, but my vent windows never close all the way so I am getting some air entering the bus.

The recirculating idea may be pushed aside. Thanks for everyone's advice. I think we should end this thread before we repost everything that has been posted.

For anyone who is still looking for heat ideas, searching the posts will provide a wealth of information. Also, check Dunc's website for some ideas.

Thanks,
Rik
_________________
Rik
'71 Deluxe/1600 DP

"Fortunately my mistakes are serving as a warning for others."

[NASkeet]

[MrBreeze]

ALWAYS remember to check the ratwell site


http://www.ratwell.com/technical/Heating.html
_________________
-=Rob

WTB: Bay Shore or Queensboro VW Frames

HBB 1984-2009
RW 1943-2011
ER 1964-2023

[Wildthings]