Mopar 440 exhaust manifold heat riser return spring!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[gpnavar]

Hello all I have a 1968 440 and am looking for a heat riser return spring for the right exhaust manifold if anyone can tell me where I can purchase this part I would greatly appreciate it. I look forward to hearing from you soon. Thanks Gary

[8WHEELER]

I have not found them yet, The new YO Manifolds have them, so why can't the people that repro these manifolds
sell the other parts we need like the valve, rod and spring  I wish they would.

Dan

[histoy]

I'm looking for a heat riser spring that actually works like Mopar designed it.   I bought a new set of the YO manifolds, because they had a heat riser installed, where my old one had it missing.  The bad news is that the spring doesn't work.   As supplied, it won't close the heat riser valve when the engine is cold, so I might as well not have one.   I wrapped the spring around 1 more turn, and then it closes the valve when cold, but it won't open the valve when the engine warms up.  That sends exhaust gases under the carb all the time, which is even worse than not having a heat riser.  I tried robbing a good spring from a GM heat riser that I knew worked, but it wouldn't fit my manifold.   Does anyone know a source for heat riser springs that will work on our cars?

[ricksresto]

I looked every where - couldn't find anything.  So I removed the flapper and spring - drilled and tapped wholes - plugged them with alen head plugs.  Then I ground them and filled holes with JB weld and used a manual choke.  Works fine unless your going 100% original. 

[8WHEELER]

I am looking for some myself no luck, I did see a NOS setup on ebay last year, rod and counter weight
and springs sold for over $300 this little hobby is out of control. And no I have not used my YO units yet.

Dan

[resq302]

I recently installed a set of the YR1 repro HP manifolds on my 383 HP motor.  The thermal spring was too tight so even when it did warm up, it kept it most of the way shut.  What I did to correct the problem was undo the hook part of the thermal spring and cut it down just a tiny bit, maybe 1/4" from the curved original part.  I then rebent the thermal spring to the original shape.  Now the spring has less tension when it is cold and when it heats up, the spring functions as normal.   Just be careful as if you cut too much off, there is no going back to make it tighter unless you wind it around one more time.  Then you will need to chop more of the thermal spring off.

[4402tuff4u]

8WHEELER and I had the same conversation a while back when I was looking for one too. I ended up fabricating a spark plug heat shield that keeps the flap open. I wanted to keep the stock look with the flap mechanism intact, but I did not want to use a wire like many wire it up open. The heat shield I made keeps the flap open and protects the angled spark plugs that come out of the INDY EZ heads towards the riser on the manifold. The 440 does not even miss the flap! I also did not want to invest in another set of manifolds just for the spring. The heat shield blends right in and it's not that noticable. Looks like a OEM part!

[hemigeno]

Has anyone tried to totally remove the coil spring from the slotted shaft, and re-index it 180 degrees around from where it was? 

When you wind it back up to the comparable position, that should give you 1/2 of a turn of additional spring rather than a full turn.

 

Might be worth a shot to try.  My 440's manifold still has the old spring in place, and I didn't want to pry around on it and break it, but it seems like it would work to me.

[histoy]

I thought the idea of removing the spring and indexing it 180 degrees made sense, so I tried it.  Winding the spring about 1 1/2 turns using that method closed the heat riser, but it wouldn't open when hot.  I tried cutting off the spring at the original bend in the tab, then I rebent it at 1/4".   I installed it in the original position, but that wasn't strong enough to close the heat riser.   I removed it and cut off the tab, and bent it at 5/16".   When I installed it in the original positon, it just had enough tension to close the heat riser.  I thought "now I've got it".  Wrong!  When I warmed up the engine to normal operating range, the heat riser wouldn't open.  If I push on it, then it will drop.  It's like the heat in the manifold has absolutely no impact on the spring tension.  I'm beginning to wonder if this is really a bimetallic spring, or just a spring made out of spring steel and stuck on there for show....Brian

[hemigeno]

Is the thermostat/spring really supposed to open the valve all the way up and hold it there?  Or is your spring tension so tight that the valve isn't opening at all when you hit the throttle?

I dug out the '69 Service Manual, and here's what it says:

Operation of the manifold heat control valve should be inspected periodically.  With engine idling, accelerate momentarily to wide open throttle.  The counterweight should respond by moving counterclockwise approximately 1/2 inch and return to its original position.  If no movement is observed, shaft is binding due to accumulation of deposits or thermostat is weak or broken.

Based on that, there is still supposed to be tension on the spring even when hot.  I looked at the picture (Figure 21 on page 11-14) and it shows the "free position" of the spring at about 1:00, and the "installed position" on the stop pin at about 4:00.  In other words, it's supposed to get about 3/4 of a turn of tension.  So much for my idea of re-indexing the spring!

I have no idea if newer springs are still thermostatic, or if they're just spring steel as you've suggested might be the case.  On my Hemi, I installed all the counterweights, springs, etc. but I cut the valve off the shaft.  Heck, I even have non-functioning Intake Manifold Heat-tubes also.  It's all just there for looks.  I think I'm going to do the same (cutting off the control valve flap) on the Daytona's 440, unless there's some visible/tangible evidence that the valve has been removed.