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What is this? Where does it tend to lurk? How do I dentify it, and then whether it works or not???????

So many questions; so few answers!

On the driver's side of the engine, it's located at the intersection of the exhaust manifold and exhaust header pipe. For starters jiggle the counterweight arm when the engine is cold and see if it moves freely - it should have some spring action and return to an upper position. When the engine is warm the counterweight arm should be downward.

When the engine is cold the valve diverts exhaust gases to heat the intake manifold (base of the carburetor) to help vaporize the fuel mixture and aid combustion in cold running. As soon as the engine warms a bit the valve opens and the exhaust gases resume their normal path.

Some day when you have some spare time you might just browse the illustrations in the parts manual to familiarize yourself with you car - the valve is pictured in both Plate 27 and Plate 29.

it is a valve that is directly after the driver's side exhaust manifold, inline with the exhaust tubing. it has counter weight arm on it with a spring. the counter weight should move by hand. if not its rusted shut or open.

jinx

Dear Pat:

Let me save you a boatload of heart ache.

If your car has dual exhausts then stuff a rag into the driver's side tailpipe during warm up. This will avoid the royal pain of fixing the heat riser if it is not working.

It sounds like you need a choke, choke pull off, and fast idle adjustment. Sometimes those Rochesters leak from the well plugs and the car will fire up and then stall.

A common symptom is that as the carburetor ages the pull off piston wears out and the only way to keep the motor from loading in warm weather is to lean the choke. Then in cold weather it doesn't run. This is one reason why new carburetors always work better than rebuilts. In this case the only way to live with the problem is to keep the motor on fast idle until it warms up.

Somebody I know found a brand new carburetor for their OHV V-8 Caddy. It was an absolute dream. You would think it had a computer control. If the motor had a balancer shaft you would not know it was running.

Drove the 54 Cavalier everywhere the past weekend. Started raining Friday night and finally slowed down Monday morning 11/25.

Our temperature in Phoenix is mid 40's for the weekend with a high of the high 50's.

We get no respect.

The Wiper Motor I got from WiperMan ran constantly and perfectly. Runs at idle, and under acceleration.

The Trico Mag-Numatic-Hydrostatic automatic windshield washer I rebuilt worked flawless (reminding me to get some antifreeze washer solution for the glass reservoir).

I was running both heaters on high (here in Phoenix we are comfortable at 100 degrees and freezing at 68 degrees).

Biggest issue is water leaks that end up on the driver door panel (original) and the back seat on the corner). I have added some foam weather strip on top of new door seals and in the wing windows. When the car is full of humidity the defrost takes a while to warm up and clear the windshield.

My other car is a Harley.

Tim Cole Quote:

Well, that's a "redneck" solution if I ever read one. And the "heat riser" is the path the hot gases take, whereas the suspect mechanism is known as the "Exhaust manifold heat control valve" in Packard parlance, but is a thermocoil valve to everybody else.

Nonetheless, I twice suggested to patgreen to check this because his symptons indicate that it is at fault. However, it also could be some part of the cold start mechanism on the carb.

Finally, after all that: the thermocoil valve and 4GC carb on my 55 Pat work perfectly. I've overhauled hundreds of carbs of various kinds over the years, so I'm confident I know what I'm doing. I usually do have to readjust the choke static setting between Winter and Summer since we get such extreme variances in temp here in Southern Nevada high desert.

This morning it started instantly even though the overnight temp was below 40F and was about 45F at the time and that was because I had driven it the day before. Still, I occasionally find that if I let my Pat cold soak for a week or more during Winter, I need to use some spray ether to get it started quickly, otherwise it just wears out the starter, although it will eventually start. My 1976 Firebird with a Quadrajet is even worse. Anymore, I don't even try to start it in the Winter without ether spray.

Craig

Here near the Canadian border the high temperature today was 28F with 15F overnight. Right now it's snowing.

The heading says Pat is having problems with running in 10F. 40F is downright balmy. I really don't think he needs to catch pneumonia fiddling with the exhaust manifold in the cold.

Heat Control Valve aka Heat Riser. If it's stuck open and he breaks the manifold bolts trying to get it to the bench he will wish he followed my advice. The manifold part is the crossover. It also serves to stabilize the manifold vacuum.

I don't know why he wants to drive the car in the cold weather. Once I was in Hirsch's 745 Phaeton when it was 5F out. The only thing colder than a touring car in winter is a motorcycle. It was terrible. Although that crashbox sure did shift easy.

However, I don't think he should risk his health over this problem. For all you know his problem could be leftover summer gas in the tank.

I don't recall the Packard company giving owners a can of Magic Start with a new car, but if they did no wonder they went under.

I'm not gonna dignify all this petty bickering over terminolgy with a response, but I don't believe for a NY minute that the manifold heat valve is at the root of this condition.

In the opening post, the owner advised that:

Quote:
The cold hard facts are that the exhaust manifold cannot make enough heat in such short time to have a significant impact on running so soon after a cold start.

THE PROBLEM IS WITH FUEL DELIVERY AND/OR IGNITION TIMING.

Use of starting fluid is nothing more than a band-aid - and a potentially dangerous one at that. Sure, that stuff makes cranking a lot easier - after it washes the oil off the cylinder walls, thus lowering compression. Guess where the rest of the fluid goes after it has compromised the seal between piston rings and cylinder? Keep on squirting enough of that stuff down the intake and you might get to see, first-hand, what a piston looks like with the top blown out of it - or worse.

I've only ever used starting fluid as a last resort, but I have never had to use it to get an engine running, no matter how long it sat, UNLESS there was a problem with FUEL DELIVERY AND/OR IGNITION TIMING. In fact, I have started more than one of my daily drivers, with a stone cold engine, in subzero weather and gotten them running - and more than once - here in Pennsyltucky, without a single drop of that stuff.

The real problem with this vehicle could be diagnosed in minutes with the laying-on of competent hands. It ain't rocket science.

Didn't I say a few adjustments?

The rag in the tailpipe is just a polite way of saying "Don't waste your time with that suggestion"

Once I had a situation where a Chrysler would run for 5-7 minutes and stall out. Then it would restart and run fine. But only when the temperature was 35-45F and wet weather. The rest of the time you could bury the tach at 6000 and it wouldn't miss a beat. The Chyrsler manual said that with 15inhg of vacuum applied to the pull off the linkage should be adjusted to a 3/16 drill bit clearance and the fast idle set to 2250 rpm. That solved the problem.

Whe I first imported my 55 400 back in 2003 I had very similar starting problems, the motor would initially fire then cut out and then spin over for ages before it would reluctantly start and once running it was better to leave it running as after stopping it would be the same story hot or cold. My tuning guy took a look and after hooking it up to his machine found the timing so far retarded it was actually firing after TDC... Once the timing was set correctly she would fire right up and still does once the gas eventually gets through after periods of inactivity.
Maybe something simple and worth looking at with just an inexpensive timing light...