[Rachelsdad]

Hi, all...

So, I've got a slightly weird issue with my heat riser not wanting to open quite all the way. The thing swings free, and when it's open (about 70% of the way?), it can be tapped/pushed the rest of the way with just a screwdriver, so it's not sticking. My thought is that the thermostat (which is what the coil spring is called in the parts manual) is just old and like the choke spring, not quite expanding all the way.

The problem I'm seeing is that while Ames has a spring for the 64-68, the one for the '63 seems elusive. I can't find a listing for it anywhere. The usual suspects have the anti-rattle spring, which is fine, but I need the bimetal coil.

The original part number for mine should be 9772543. I don't know how it may differ from the 64-68 spring. If mine is thinner (as in the ribbon being not-as-wide), I guess it could be ground down on a wheel. However, if mine is thicker, the later one may not have enough oomph to swing all the way open, leading to the same problem I'm having now.

Anyone with any suggestions or experience with these? There are outfits which make custom springs, but lacking proper specs, just having a spring wound with the correct outside dimensions may not be particularly useful.

Details, details!

TIA

[TXSTARFIRE]

Not sure I would worry about it. I believe that the flapper is offset on the shaft and the flow of the exhaust will open the valve when the engine is running. If the valve is not stuck I dont think you have a problem.

[Goatracer1]

Correct. The spring closes the valve. Exhaust pressure opens it. When the spring gets hot the valve could sit any place though not fully closed.

[mgarblik]

Ali Express is a source for bimetallic spring material. I could not find a domestic supplier. You could buy a coil of the stuff and wind your own spring. Would probably take some trial and error to get what your looking for. But for $20.00 might be worth the effort.

[Rachelsdad]

Thanks, Mike. I'm thinking I might try the '64 spring first, and see how it sizes up/works. If no joy, then I'll check into Ali Express, then.

I just want to be sure the crazy thing is opening all the way and not stopping along the way, as it doesn't seem to be getting to that fully open position despite being able to move freely.