SpartyGW

If this is in the ST12 then I overlooked it.

How are the heater controls supposed to work on a 61? I pull the "air" cable out and it seems if I pull the "temp" cable out it's warmer, but not significantly so. It seems no matter where the "temp" cable is the air is warm (which is fine by me).

I'm just curious how it's supposed to function. I'm guessing that the "temp" cable is supposed to operate some flapper that directs fresh air from air going over the heater core?

Eventually it gets toasty enough to keep driving in 50 degree GA weather with the top down.

One last thing...the "temp" cable is really difficult to move. Is this indicative of a problem?

Frankie the Fink

The "AIR" cable moves a flapper in front of the heater core at the firewall to allow air into the heater system via the 4" fresh air hose that goes to the front of the car. The "TEMP" cable adjusts the heater control valve under the dash to regulate the amount of hot water that flows through the heater core. This gives you fine grained control over both the air and water flow in the system so you can 'blend' things as desired.

If you find it too confusing just pull the air **** out 1/2 way and adjust the temp **** until you're warm.

The C1 heater system is one of the best in any muscle car I've owned. It'll roast your toes in freezing temps - even with the top down...

SpartyGW

Thanks for the excellent description.

AZDoug

IF your air box doesn't look like mine: multiple times wet (in the distant past) warped, torn and useless at directing air.

I really need to put on of those metal ones in., but I never use the heater.

Doug

SpartyGW

Doug, I didn't think I'd really need it in Georgia either but it helps. Guess I'm getting old.

I feel the need to throw the "because racecar" meme in here.

MrPbody

Not sure if all C-1s were similar, but my 62 also has what appears to be a thermocouple inside the heater box and connects to the water valve. it appears that it would override the temp setting under specific conditions?). what's the theory on that?

Frankie the Fink

Its called a capillary tube, and although needed for judging most modern repro heater control valves do not even include it. Its point was to do a finer regulation of water coolant temperature via the heater control valve by sampling the hot air inside the box.

Essentially a feedback loop to maintain the temperature more precisely at a fixed setting of the TEMP **** pulled out on the dash. It didn't 'override' anything but tried to regulate it more tightly. Pretty much proved an unnecessary example of "over-engineering" in the long run...

SDVette

So it would close the valve as the car warmed up to try to maintain a constant temp in the car for a given control position?

That's pretty cool... (says the guy who's entire heater plumbing is bypassed and ducting is in shambles!)

Frankie the Fink

Kinda, sorta. I think the operation was spotty and provided very minimal regulation of temp plus it is a very fragile device and once the tube is kinked or abused; its all over.

SDVette

Don't mean to hijack... but now that my gauges are working, I notice the temp fluctuates quite a bit (between 140 and 200) under normal driving conditions. I assume this is normal? I guess this device would have mitigated some of that swing in the cabin too?

Frankie the Fink

My '61 gets to 180 (at long stop lights in the summer) but cools down quickly when moving -- usually down to the 160 area (I have a 160* thermostat).

SDVette

OK, now it's an official hijack... I never noticed that the yellow zone on the high tachs goes all the way to 4K RPM.... The base tach yellow zone ends at 2K RPM..

I guess with my LT1 350 all bets are off anyway!

rich5962

okay, anti-hijacker here......

That capillary system shuts the valve if the temperature gets above a certain limit, whatever that limit is I'm not sure, but I tested one out for curiosities sake a while ago.

info here...
http://forums.corvetteforum.com/1584406064-post8.html

Maybe a safety so the passenger doesn't get burned if the heater core melted from getting too hot!

Rich

Frankie the Fink

I've heard it both ways over the years Rich - read down about 1/4 way on this page to "Function of Thermal Feedback" in this text on repairing heater control valves:
http://www.sw-em.com/Heater_Control_Valve.htm

I think if they were safety devices or "over temp" limiters the new valves would include them.
JMO though.

rich5962

That's great reading. Thanks for the link. When I tested that one here, I just used a lighter and saw the valve closing as the capillary got hotter.

Makes more sense now after reading. What's interesting is the old idea of turning on the heater if your engine is overheating.....
One would think it's helping dissipate engine heat through the heater, but with the capillary shutoff it closes the flow. Hmmmm, probably good that the replacements don't have it for that reason alone.

Rich

SpartyGW

My temp gauge is rock steady at 180*. I was going to comment on Frankie taking a picture while driving but I am not one to talk.

Here's a short video of my son and I out cruising, :48 into the video you can see the dash gauges:


A bouncing temp gauge is not normal. Either the wire connected to the gauge has some variable resistance (internally broken wire?), the sending unit is bad, or the gauge needs to be rebuilt. Using some wire and a variable resistor you can figure out which of the 3 is the problem.

Frankie the Fink

Several here have called me crazy but I put manual shutoff valves in BOTH heater hoses in the '61 and cut the heater core flow COMPLETELY off in the summer. The operating temp of the car is noticeably cooler when I do this. I can't explain it; its counter-intuitive, but I swear that's what I see.

The second advantage of this is that pulling the AIR **** out on the dash gives a tad more air flow without going past a hot (or warm) heater box in the summer.

SpartyGW - can't say if your cruising temp is normal or not - my car has an aluminum radiator that came with the 270hp cars and maybe that makes it run cooler. Also depends on what T-stat you have in there.

SpartyGW

Frank, I can't even tell you what t-stat is in there. I have never changed it. The radiator is about 6 months old from Dewitt. I feel good about it.

SDVette

This turned into a nice thread...

My temp does not 'bounce', (although I have been there too). It just seems to vary, slowly, with the conditions (stopped, moving slow, fast, uphill, etc.). I have a new aluminum radiator, my heater core is bypassed (hose jumped in to out) because I haven't gotten around to replacing the leaking core yet (and it's never cold in S. Cal!), and I have a 180 thermostat, but a guy drilled some holes in it (not me - long story).

Maybe the holes in the thermostat are enough to allow the system to cool off a bit even when the thero is closed?

SpartyGW

SDVette, I wouldn't worry about it then. I thought you meant bouncy-bounce like my fuel gauge used to do before I ran a new ground wire.

Besides, in SanDiego it's a constant 72* all year round you lucky *&^*&.