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Author Topic: 64 cad heat riser question  (Read 2424 times)

Offline caddyman20

  • Posts: 37
  • CLC Number: 18814
64 cad heat riser question
« on: April 25, 2015, 05:21:04 PM »
Hi. I have a 64 Cadillac and I just put a new heat riser exhaust valve were the y pipe hooks up to the drivers side exhaust manifold.  Well it seems like it's never open.  The car can be all warmed up and even after a short trip down the highway to make sure the engine is fully warmed up. When I get back the valve is still in the closed position. How terrible hot does this thing need to get to open up??  the choke housing on the side of the carburetor is in credibly hot. Even smokes a little.  I just feel like I got a bad valve or something.  If anybody knows when that valve should be open please help me out. Thanks.

Chris.
Clc 18814
C. Short

Offline 54 caddy larry

  • Posts: 91
  • Name: larry mandell
Re: 64 cad heat riser question
« Reply #1 on: April 25, 2015, 08:11:56 PM »
5 or 10 minutes at most before it opens i would think. Can you move the weight by hand, if not the bi-metal spring might be bad.
« Last Edit: April 25, 2015, 09:16:26 PM by 54 caddy larry »
Larry M

1954 series 62 coupe
1974 Harley Davidson FLH

My caddy is my never ending work in progress.

Offline caddyman20

  • Posts: 37
  • CLC Number: 18814
Re: 64 cad heat riser question
« Reply #2 on: April 26, 2015, 02:11:49 AM »
I can move the weight very easily.  But it's always closed even when running.  I don't know what's wrong. I bought it from a guy that sells only new Cadillac reproduction parts on eBay.
C. Short

Offline Glen

  • Posts: 2789
  • CLC Number: 727
  • Name: Glen Houlton
Re: 64 cad heat riser question
« Reply #3 on: April 26, 2015, 02:28:54 AM »
The bi-metal spring should lose strength when it gets hot as I recall, that allows the weight to drop opening the valve.  The weight should be up when cold and move down when the engine is hot.  It is possible to install the weight incorrectly. 
Glen Houlton CLC #727 
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Offline Scot Minesinger

  • Posts: 6004
Re: 64 cad heat riser question
« Reply #4 on: April 26, 2015, 09:39:24 AM »
Highly recommend that you wire the valve permanently open. 

This is designed to have the car warmed up a little faster, and otherwise in warm weather travel it is of little value.  Back in the 1964 when most Cadillacs were used regularly even in cold weather it was a nice feature.  The downside risk far outweighs the upside gain. 

Part of the reason your intake manifold is so hot is that the valve is not open.  This can do some annoying engine damage, such as but not limited to crack intake manifold, take out carb to intake manifold gasket, and other high heat related complications.

The problem probably is a faulty spring or spring mounting.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Offline russ austin

  • Posts: 819
  • Name: Russ Austin
Re: 64 cad heat riser question
« Reply #5 on: April 26, 2015, 11:05:22 AM »
Or the valve was put in upside down?
R.Austin

Offline Scot Minesinger

  • Posts: 6004
Re: 64 cad heat riser question
« Reply #6 on: April 26, 2015, 02:09:03 PM »
Either way, suggest you mechanically anchor valve open and enjoy your Cadillac!
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Re: 64 cad heat riser question
« Reply #7 on: April 26, 2015, 05:27:36 PM »
Chris,
I think Russ has the answer.  If you installed the heat riser valve upside down it would not open when warm, but the weight would keep it in the closed position.  The weight is supposed to "drop" when the spring warms up.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
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Offline Jay Friedman

  • Posts: 2536
Re: 64 cad heat riser question
« Reply #8 on: April 26, 2015, 09:21:03 PM »
Either wire it open or replace it with a spacer as I did on my '49.  Unless you use the car in very cold weather, the engine will run fine without it.
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
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Offline Glen

  • Posts: 2789
  • CLC Number: 727
  • Name: Glen Houlton
Re: 64 cad heat riser question
« Reply #9 on: April 27, 2015, 03:00:57 AM »
It’s not that hard to make it work as it should. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

Offline Scott Halver

  • CLC #24920
  • Posts: 133
  • 1960 Eldorado Seville - Sienna Rose
  • Name: Scott Halver
Re: 64 cad heat riser question
« Reply #10 on: May 01, 2015, 06:40:51 PM »
I just replaced my heat riser valve (1960 Cad) with a modified valve..........  went to salvage yard, got a replacement valve, took it to a good welder, took the guts out but left the outside spring and weight, painted-   installed with 2 new gaskets.    The car runs significantly better, has to be at least a 40 hp gain.   My valve was obviously closed or partly closed.    I live in Arizona so warming up is not a problem.   If you are not driving the car in really cold weather I would consider just getting rid of the valve or doing what I did. 

Note:  Part of my motivation is that I've been having vapor lock problems.   I don't know if I've solved the problem but it has to be better-   did a bunch of other things to help with the vapor lock issue, no problems so far but summer is not fully here.   SHalver #24920
1960 Eldorado Seville, Grandfather Bought New
1970 Corvette Convertible 350/350

Offline Glen

  • Posts: 2789
  • CLC Number: 727
  • Name: Glen Houlton
Re: 64 cad heat riser question
« Reply #11 on: May 02, 2015, 02:08:53 AM »
The big problem with these valves is that someone oils them.  The heat burns the oil and that causes the valve to freezes up.  Rust is a second problem.  Ether way the answer is to work it free by exercising it and spraying it with a cleaner like electrical cleaner.  It must not leave a residue.  After it is clean and free use a graphite base lubricant. 

I did mine in the late 70s and have never had a problem since. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

Offline Jason Edge

  • Posts: 1177
  • CLC Number: 14225
  • Name: Jason Edge
Re: 64 cad heat riser question
« Reply #12 on: May 02, 2015, 01:49:03 PM »
Check out this video I just posted on Youtube and our 1963/64 Cadillac Website: I planned to post some new 'From Jason's Garage' videos and thought I would start with one regarding the left exhaust manifold heat riser which has been discussed on the 63/64 Cadillac Site and main site recently. Here is the link: https://youtu.be/uOIhsVz_EPg

If the heatriser is installed correctly and working properly, the weight will be pointed directly to the right when closed, and turn clockwise and point straight down when fully open.  The manifold in the video came from a 41K mile car and was stuck partially open, meaning you would get a bit more than normal exhaust pushing across the intake manifold center exhaust channel after engine was warmed up.  This would in turn speed up the decay of the internal choke tube and eventually allowing fire hot gases leak out of to the choke assembly on RH side and out bottom of intake on LH bottom side; tend to make engine run hotter, cause additional exhaust backpressure on LH side and affect performance across the board.  With the heat riser in the video, it was relatively easy to break loose with some WD40, and washout with Acetone and blow any residue out with air gun. I also hit it with some dry high temp graphite spray.
« Last Edit: May 05, 2015, 10:05:44 PM by Jason Edge »
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Offline 35-709

  • Posts: 5363
  • The most valuable antique is an old friend.
  • CLC Number: 4719
  • Name: G. Newcombe
Re: 64 cad heat riser question
« Reply #13 on: May 04, 2015, 10:37:09 PM »
Highly recommend that you wire the valve permanently open. 

This is designed to have the car warmed up a little faster, and otherwise in warm weather travel it is of little value.  Back in the 1964 when most Cadillacs were used regularly even in cold weather it was a nice feature.  The downside risk far outweighs the upside gain. 

Part of the reason your intake manifold is so hot is that the valve is not open.  This can do some annoying engine damage, such as but not limited to crack intake manifold, take out carb to intake manifold gasket, and other high heat related complications.

The problem probably is a faulty spring or spring mounting.
Wholly agree, I wouldn't have a heat riser on any of my cars, or if I did it would be wired open or soon removed.  In cold weather just let the car warm up a few more minutes.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

 

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