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914World.com _ 914World Garage _ Thermostate Bellows

Posted by: Joe Ricard Nov 29 2005, 06:17 AM

Up until it started getting cold the damn thing worked great. Engine cold flaps shut and would open fully as the engine reached close to 300. or so.

Now that is it cold here 50 this morning I got the heads up to 350 and pulled over to see whats up. Flaps only half open!!! wierd. I have all the tin including the warm air guides fully functional heater everything.

Confident the engine was warm I lossened the cable pinch bolt flaps sprang open and I drove to work. 1 eye on the road 1 eye on the CHT. Gosh these cars are a PITA sometimes.
I suppose there is some special german one of a kind tool to set the point of opening in relation to temperature. I don't got one!

Posted by: type47 Nov 29 2005, 07:05 AM

no special tool that i've ever seen. adjustment is just pull cable tight with one hand, hold flaps open with the other hand, tighten nut with cable under it with the third hand.

Posted by: Mark Henry Nov 29 2005, 08:03 AM

It's a combo of bi-metal material and most likely an inert gas. Heat makes the bellows expand.

Most times they will fail in the wide open position, but I've seen them fail half open.

Yours has failed.

Posted by: Joe Ricard Nov 29 2005, 09:04 AM

QUOTE (Mark Henry @ Nov 29 2005, 06:03 AM)
It's a combo of bi-metal material and most likely an inert gas. Heat makes the bellows expand.

Most times they will fail in the wide open position, but I've seen them fail half open.

Yours has failed.

Crap!
I think I got another one somewhere in by goodie box.
I suppose I can pull it clean it up and test it in hot water.

Hmm So how does the thermostate work with a 914 DTM? Not that I need one just curious.

Posted by: davep Nov 29 2005, 09:19 AM

While you are 'testing' it in hot water, consider cleaning it. Get it up to a high enough temperature to expand the bellows nicely so you can clean in between the pleats. Often, dirt will accumulate in there and prevent it from contracting completely. Besides, the dirt will often abrade the copper and cause a leak, then the unit is toast. A little Brasso won't hurt either.

Posted by: Cap'n Krusty Nov 29 2005, 09:34 AM

QUOTE (type47 @ Nov 29 2005, 05:05 AM)
no special tool that i've ever seen. adjustment is just pull cable tight with one hand, hold flaps open with the other hand, tighten nut with cable under it with the third hand.

Actually, you pull the cable taut and close the flaps fully, locking the pinch clamp in that position. As the engine and the thermostat warm up, the flaps open. The Cap'n

Posted by: Joe Ricard Nov 29 2005, 09:49 AM

Yea No shit really? Just never seen one do what this one is doing. I know how to set it. Just figured I would throw it out there and see if it rings a bell with anyone. As Mark pointed out these things can fail partially open. Didn' know that. Thanks Ya'll

My engine is fairly leak free. however the last time I raced it was raining like a bitch. then rained all the way from Tampa to Pascagoula. So I suspect it could be dirty. even with all the tin in place.

Posted by: Mark Henry Nov 29 2005, 09:55 AM

Sometimes just the flap can catch on something...make sure everything is working freely.

Also don't over heat the bellows, if it expands too far that will fuck it.
If it's bad when you put a bit of heat to it nothing (or almost nothing) will happen.

Posted by: tat2dphreak Nov 29 2005, 09:59 AM

good article in the classics about how the whole system works, too...
just my .02

Posted by: Joe Sharp Nov 29 2005, 06:43 PM

I took a belows up 300 Deg in the oven and got nothing then I chilled it the freezer and it srunk about 3 mm at 30 deg. It dosn't work untill it gets cold. Probably useless here.
:PERMAGRIN: Joe

Posted by: bottomend Nov 30 2005, 01:03 AM

If you drop it into hot water or the oven, MAKE SURE you leave it in it's bracket. If not ( ask me how I know...), it'll expand to about 7 inches long!

Posted by: bd1308 Nov 30 2005, 01:11 AM

QUOTE (bottomend @ Nov 30 2005, 01:03 AM)
If you drop it into hot water or the oven, MAKE SURE you leave it in it's bracket. If not ( ask me how I know...), it'll expand to about 7 inches long!

shocked[1].gif

Posted by: Mark Henry Nov 30 2005, 08:43 AM

QUOTE (Joe Sharp @ Nov 29 2005, 08:43 PM)
I took a belows up 300 Deg in the oven and got nothing then I chilled it the freezer and it srunk about 3 mm at 30 deg. It dosn't work untill it gets cold. Probably useless here.
:PERMAGRIN: Joe

It's fuched

QUOTE
If you drop it into hot water or the oven, MAKE SURE you leave it in it's bracket. If not ( ask me how I know...), it'll expand to about 7 inches long!

It's fuched

Posted by: Joe Ricard Nov 30 2005, 09:17 AM

SO if your woman queries "that all you got"? Just take it out the bracket and warm it up.
OK got it.

Posted by: maf914 Nov 30 2005, 12:29 PM

QUOTE (Joe Ricard @ Nov 30 2005, 07:17 AM)
SO if your woman queries "that all you got"? Just take it out the bracket and warm it up.
OK got it.

Are you saying she calls it a bellows? Never heard that before.