Author Topic: Exhaust heat valve question.  (Read 3108 times)

69Z28

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Exhaust heat valve question.
« on: July 24, 2013, 04:01:08 AM »
Is the heat valve the same for all 69 small blocks with 2" and 2 1/4" headpipes or are there two different valves? What about flanges? I don't have them and need them. Found both a valve and 2 flanges but need to make sure they will fit the factory manifolds and exhaust for a 69 DZ engine.
GaryC

'UNRESTORED' 1969 Cortez Silver X33D80 Z28

69pace

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Re: Exhaust heat valve question.
« Reply #1 on: July 24, 2013, 04:26:52 AM »

http://www.rickscamaros.com/1969+chevy+camaro+standard/camaro-exhaust-manifold-heat-riser-assembly-small-block-gm-1967-1974.html

This is the only one I know of for 1969 small blocks...though most of the ones I have seen were removed and an eliminator ring substituted or they just gutted and reinstalled the factory item by removing the flapper door and weights and a stove bolt inserted to close former axle pivot hole.
1969 Z-11 350/300 with 4 Speed

69Z28

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Re: Exhaust heat valve question.
« Reply #2 on: July 31, 2013, 10:50:01 PM »
This is the heat valve I have. Looks the same doesn't it? Something is either upside down or backwards on mine I think.

69pace

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Re: Exhaust heat valve question.
« Reply #3 on: August 01, 2013, 04:20:48 PM »
Yeah the bottom picture looks right side up as the weight should be installed on the fender side, weight pointed toward the front of the vehicle. Take the top one and flip it around and see what it looks like. Both Look in good condition considering age.

69Z28

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Re: Exhaust heat valve question.
« Reply #4 on: August 01, 2013, 05:14:07 PM »
Yeah the bottom picture looks right side up as the weight should be installed on the fender side, weight pointed toward the front of the vehicle. Take the top one and flip it around and see what it looks like. Both Look in good condition considering age.



Those 2 pics are of the same valve. Works perfect, just need to clean it up a bit. So as it sits in the second pic just rotate the valve 1/4 turn clockwise so the weight is parallel with the fender.


Is the Ricks pic wrong?

JohnZ

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Re: Exhaust heat valve question.
« Reply #5 on: August 02, 2013, 04:36:31 PM »

Is the Ricks pic wrong?

Nope, it's just shown upside-down; the flat side goes up, against the (flat) outlet flange on the manifold, with a gasket, and the chamfered side goes down, and mates with the top of the "donut".
'69 Z/28
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69Z28

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Re: Exhaust heat valve question.
« Reply #6 on: August 02, 2013, 04:43:29 PM »

Is the Ricks pic wrong?

Nope, it's just shown upside-down; the flat side goes up, against the (flat) outlet flange on the manifold, with a gasket, and the chamfered side goes down, and mates with the top of the "donut".


If you look at the pic of Ricks and mine the weigh mechanism is reversed or backwards or something. One of them is wrong it believe.

rich69rs

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Re: Exhaust heat valve question.
« Reply #7 on: August 02, 2013, 04:55:23 PM »
These things are problematic at best - I have not had
a good experience with any current offerings.  For what it's
worth, my two, cents is that they will eventually stick, and
probably in the closed or partially closed position.

I removed them from both my '66 Chevelke and '69 Camaro
and replaced them with the donut replacements.

Unless you absolutely have to have it original, to me
the problems far outweigh the benefits.  Both of my
cars start easily - and I give them a few extra seconds (10-15) at
idle when I first start them, but other than that you would not
know the heat riser valves weren't installed unless you physically
went and looked.
Richard Thomas
1969 RS

69pace

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Re: Exhaust heat valve question.
« Reply #8 on: August 02, 2013, 08:52:39 PM »
Is the Ricks pic wrong?
Nope, it's just shown upside-down; the flat side goes up, against the (flat) outlet flange on the manifold, with a gasket, and the chamfered side goes down, and mates with the top of the "donut".

If you look at the pic of Ricks and mine the weigh mechanism is reversed or backwards or something. One of them is wrong it believe.

No its the same valve - as JohnZ states there IS a top side and a bottom side of the valve.  And yes it was common practice to remove or to gut the valve, and close the hole from the removed flapper axle with a standard nut and bolt. That was what was done on my vehicle by the original owner when he removed the smog pump.

69Z28

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Re: Exhaust heat valve question.
« Reply #9 on: August 02, 2013, 10:07:38 PM »
Maybe your not seeing what I see. On the Ricks valve pic, the bevel for the packing donut is facing up with the weight mechanism pointing, lets say north and on the right. If you look at my second pic the flat gasket side is up with the weight mechanism pointing north and to the right. If I flip mine over 180 then the weight mechanism is on the left of the valve whereas the Ricks pic is on the right...OR...if you spin my first pic 180 either way, clockwise or counter-clockwise to match the Ricks pic the weight mechanism's are opposite.

Can you see it? I'm thinking one of these is wrong.

69pace

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Re: Exhaust heat valve question.
« Reply #10 on: August 03, 2013, 02:38:57 AM »
No I understand what you are saying but there are many repro valves out there some are flat and chamfered as original, others are chamfered on both sides. ANd they pictures are generic-interchangeable on catalog listings.

69Z28

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Re: Exhaust heat valve question.
« Reply #11 on: August 03, 2013, 07:48:49 PM »
No I understand what you are saying but there are many repro valves out there some are flat and chamfered as original, others are chamfered on both sides. ANd they pictures are generic-interchangeable on catalog listings.

OK, I think I got it now. That pic in itself is not a good representation of what an OEM heat valve would look like for a 69 Camaro Z28.

If that's the case does mine look correct? I think the guy said it was a take off of a 71 350 270hp Corvette.

69pace

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Re: Exhaust heat valve question.
« Reply #12 on: August 04, 2013, 02:41:09 AM »
Yes I believe that John liked your examples.

mickeystoys69RSSS

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Re: Exhaust heat valve question.
« Reply #13 on: August 06, 2013, 12:36:43 AM »
Any way to tell if this valve is stuck? The more I think about it, I noticed that at the rear tips the exhaust flows better on the drivers side than passengers. So I am thinking mine might be stuck?

janobyte

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Re: Exhaust heat valve question.
« Reply #14 on: August 06, 2013, 01:25:40 AM »
OE from my 68 Z

69Z28

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Re: Exhaust heat valve question.
« Reply #15 on: August 06, 2013, 12:28:08 PM »
Here is a pic of Jano's and the one I picked up for comparison. Note his valve weight on the left and mine on the right. So the valve weight on mine will point to the front of the car and his will point to the rear. Different for 68 and 69? Here's a question, how is the valve oriented when installed, with the arm on the engine side or the the fender side?

69Z28

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Re: Exhaust heat valve question.
« Reply #16 on: August 06, 2013, 12:46:21 PM »
Any way to tell if this valve is stuck? The more I think about it, I noticed that at the rear tips the exhaust flows better on the drivers side than passengers. So I am thinking mine might be stuck?

I always thought something odd was going on there. In the wintertime I noticed how steam would be coming out more on the driver side exhaust then the passenger side on a lot of cars when they were first started up and run in the morning. Would see it a lot with dual exhaust, not at all on single exhaust of course.

JohnZ

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Re: Exhaust heat valve question.
« Reply #17 on: August 06, 2013, 02:47:25 PM »
<<Here's a question, how is the valve oriented when installed, with the arm on the engine side or the the fender side?>>

Here's mine - if the weight is on the inboard side, it would probably interfere with the starter solenoid with the valve open.

69Z28

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Re: Exhaust heat valve question.
« Reply #18 on: August 06, 2013, 09:31:09 PM »
Thanks John...that's the shot I was looking for. The valve I have, looking at your pic, will be at 9 o'clock where yours is at 3 o'clock and the weight will be pointing the same as yours, towards the fender well. Can I assume that even these heat valves have differences in them? Or will/should they all be the same? I was looking at my survivor 69 Impala LM1 and the valve is installed with the weight on the left as well with rams horn (center dump) manifolds.


Reason I brought this up is because I took the headers off my Z to install the manifolds about a 1000 miles ago and noticed that the passenger head pipe was pushed up tight against the floor. I'm still wondering if I even have a packing donut in there. I'm sure I do since there isn't any exhaust leaks. I hate bring this up but I felt like I needed to. Always had headers on my cars so I have never seen what I need to connect UNCUT head pipes to manifolds before. At least now I know I need to get new studs ( short and long), 2 packing donuts, 2-2" head pipe extension tubes and a flat gasket. I should be all set then.

1968zee28

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Re: Exhaust heat valve question.
« Reply #19 on: August 07, 2013, 11:41:23 PM »
  FWIW , I used a small grinding wheel and cut/removed butterfly from riser assy.
    Re-installed  //  Looks, and functions (weight-spring movement only ) as original, and no worry about sticking in closed position!!