Thermostat Challenge

Manfreds78bay · Posted: Mon Oct 20, 2014 2:43 pm Post subject: Thermostat Challenge

Has anyone come up with a better solution to the standard VW thermostat? I would figure by now someone would come up with a neat-o way using tech-nalo-ogy and the interwebs to create something simpler and cheaper.

If you have, please sell it to me.

If not, I will accept this challenge.
_________________
1978 2.0L FI Campmobile

1982 AMC Eagle SX4 4.2L FI

Wasted youth · Posted: Mon Oct 20, 2014 2:49 pm Post subject:

I challenge you... Cool

I have seen these types of bellows used in steam heat condensate drain controls. They were made by Vapor Corporation in Chicago. But that equipment dated to the late 1960's, and I don't know if Vapor is still in business. They might answer the phone in Mandarin, for all I know.

merlinj79 · Posted: Mon Oct 20, 2014 3:19 pm Post subject:

You could install a solenoid to power the flaps closed. Several options for how to control it...

Simple: Manual on/off switch, turn the solenoid on from the cab to close the flaps for a cold start, and then turn it off when it's warmed up.

Less Simple: Same setup but with a safety timer that de-powers the solenoid after 5-10 minutes (depending on where you live and driving habits).

Not-so-Simple: Install an electronic thermostat in the engine compartment to control the solenoid. Challenge here would be locating and adjusting it just right to mimic the bellows performance.

I don't think you need to control the flaps to any intermediate position...I think they're mostly either all open or all shut, given the design of the bellows (fluid phase change) I don't think they linger half-open for long.
_________________
Rick
"Pumpkin II"
Stock 2L FI '77 Westy
CA Smog Stuff

Brian · Posted: Mon Oct 20, 2014 3:28 pm Post subject:

car-puter. have a thermocoupler on each cylinder and have an electronic solenoid control the flaps on each side with a failsafe that alerts you when temps get too high.
_________________
Wash your hands

'69 Bug
'68 Baja Truck
'71 Bug
'68 Camper

Only losers litter

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50351

How about a bellows and a rod or cable connecting to some flaps. Should run a hundred thousand miles quite easily between fairly inexpensive repair jobs. No wiring, vacuum hoses, dashpots, actuators or sensors of any kind needed. Wink

Air Cooleds Only · Posted: Mon Oct 20, 2014 10:07 pm Post subject:

Air Cooleds Only · Posted: Mon Oct 20, 2014 10:07 pm Post subject:

Manfreds78bay · Posted: Tue Oct 21, 2014 12:31 am Post subject:

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50351

I find that my flaps are halfway open quite often when the weather is cooler. Go down a long grade at near freezing and the flaps will pretty much close the whole way.

During the '70's there were dozens of different temperature controlled vacuum valves on various cars. One of them would surely have about the correct operating characteristics for the T4 engine thermostat when combined with a properly sized dashpot.

aerosurfer · Posted: Tue Oct 21, 2014 3:41 am Post subject:

Use a cheaper and more available type 1 t stat. Its a little cooler operating temp but the one im using seems more robust than the 3 stock ones I have come across in the last few years. Just need to swap to a different union nut to mount the cable
_________________
Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)

Wasted youth · Posted: Tue Oct 21, 2014 4:37 am Post subject:

merlinj79 · Posted: Tue Oct 21, 2014 7:47 am Post subject:

OK, so it needs to be variable...

Temp sensor on the engine, stepper-motor driving the flaps controlled by a PLC (programmable Logic controller).

Or instead of a PLC, a good science project would be to make your own custom digital controller. You could do it with radio shack parts but would probably want to locate it outside the engine compartment for durability reasons.
_________________
Rick
"Pumpkin II"
Stock 2L FI '77 Westy
CA Smog Stuff

Manfreds78bay · Posted: Tue Oct 21, 2014 7:50 am Post subject:

yea that's the real trick here, then and the genius of the bellows. It's able to self regulate based on the engine temp.

I'm looking at the new Mexican style thermostats. Looks like they are just a solid metal spring that elongates as it heats up. Nothing is going to leak and cause the failure. But what I just read about them says they are hard to find.

I want something easy to make that we can all get our hands on at Home Depot or something similar.

I was also thinking electrical that could attach to head temp sensor. AS the heads heat and cool the flaps open and close.
_________________
1978 2.0L FI Campmobile

1982 AMC Eagle SX4 4.2L FI

Manfreds78bay · Posted: Tue Oct 21, 2014 7:52 am Post subject:

udidwht · Posted: Tue Oct 21, 2014 10:52 am Post subject:

Don't bother trying to reinvent the wheel. Go with the following and it will be the last one you buy.

http://www.thesamba.com/vw/classifieds/detail.php?id=1036746
_________________
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

Manfreds78bay · Posted: Tue Oct 21, 2014 10:58 am Post subject:

udidwht · Posted: Tue Oct 21, 2014 11:07 am Post subject:

raygreenwood · Posted: Tue Oct 21, 2014 11:10 am Post subject:

Manfreds78bay · Posted: Tue Oct 21, 2014 11:31 am Post subject:

69BahamaYellow · Posted: Tue Oct 21, 2014 5:51 pm Post subject: Type 4 Thermostat

I got one of the NOS Thermostats from Bus Depot for the Beatle, since they were NLA for the Bus, and it failed really quick (6 months maybe), so I got one of the new Awesome Powdercoat ones, made specifically for the type 4 bus motors, and it has been working perfectly for the past 18 months, and they offer a 2 year warranty on them. I agree with a previous poster, their quality is excellent, so hope it lasts......

I can also share that just watching the flaps from a cold start and engine idling in 75-80 deg. ambient temperatures, it takes about 12 minutes for the flaps to go from full closed to full open, and it is a very gradual open (no abrupt movements.


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