Need help identifying a part that is on the side of the manifold. I know it has a sort of flat coil spring inside, that I believe is busted. What is this? Any idea on how / where to grab a replacement?
Thanks Rusty- Was this on every 207? It's from a 1933 Chevy 1 1/2 ton, but just learned my Carb was from a 37 - looks like The Filling Station lists this part starting at 1937 as well... beginning to think I may have a later engine...
The 1937 and up engines have the oil filler/breather on the right side, the 1936 and prior on the left side, The heat riser/manifold pictured was of a type used in 1933 and 1934,,,part of the (external) heat riser is on the other side of the manifold. The thermostatic spring fits 1933-36 models. It is behind the pictured cover.
Take a look in the Master Parts list. It will indicate which engines and models had them. My guess is that all 207’s had them. The design on the 216 is different.
Thanks Rusty- I know the image and Heat Spring is part of the manifold– was just noting I found out today my carb is a 37 model. So was wondering if my engine may not be original. I appreciate the help.
I found the spring on Filling Station- any recommendation on a whole valve replacement? I have found a bunch online, but none that go back as far as 1933.
Are you sure you need to replace the whole assembly? That will require you to remove the manifolds.
There are 2 primary failure modes. The spring fails or the flapper valve gets stuck and will not pivot. Both are easy to fix. Just Goggle "Unstick Chevy heat riser valve" or words like that.
Your manifolds are clearly of the 207 type. They are square(ish) and dump exhaust at the back. I can see the barrels of your cylinders so you do not have the 1936 engine which is the only 207 with a full length water jacket. If you can find a casting number on your block, many of us can help you verify which engine you have.
Unless you are experiencing some problem that you think is related to a stuck heat riser valve (flapper), Your truck will operate in a normal way with little or no noticeable affect. There are thousands of our old Chevys driving around with inoperable heat risers. Long term, it is a good idea to have this functioning, but short term, not something to obsess about. MY OPINION, others might disagree. If you decide to rebuild it, stainless parts are recommended.
Mike’s advice is good. If the valve is stuck in the “run” or open position,you might not want to bother with it.
What problem are you having that makes you think the heat riser is the cause?
Unless you have other reasons to remove the manifolds, I encourage you to avoid that work. I can pretty much guarantee that it will be way more work than you expected. Most likely you will deal with multiple broken studs. The other issue is that the manifolds will probably need “planed” or surface ground to get them flat enough to seal against the head.
This truck was given to me by my Father- who has been accumulating a list of known problems. This was one that he knew never worked. Good to know it isn't something we necessarily need to mess with. He knows there isn't a good seal between the block and manifold currently, so we talked about getting it machined already. Sounds like maybe we think about avoiding that too? Right now I'm getting the carb rebuilt, new gaskets on the fuel pump and re-arching the from leaf springs. I'm sure there are other items, but those were the immediate needs.
If the manifold is not leaking, I would leave it alone. If it is, it is not that big of a deal to get it planed flat. I just had to have the manifolds both milled flat on my 37 and 48 last year. I had my local machine shop do it. I never worry about the heat risers as long as they are not stuck in the closed position.
Rusty, I had the intake and exhaust planed as a unit, I didn't separate them. Are those the studs you are referring to, or the studs and bolts that hold the assembly to the head?
Thanks for adding that detail. Yes, the manifolds have to be bolted together to properly plane them.
I was lucky on my ‘37. The manifolds were not distorted so I did not need to have them planed. The one trick I learned was to attach them firmly to the head while the nuts that held the 2 manifolds together were just finger tight. Then I did a final tightening on everything.
I am referring to all the studs and nuts in the exhaust system. That includes the ones that hold the manifold to the head, the ones that hold the manifolds together, and the ones that clamp the exhaust pipe to the manifold. If you have to replace the heat riser valve you will have to take the manifolds apart.
No matter how many tricks I use (penetrating oil, letting the engine run to heat things up, a torch to heat the nut, 6 point sockets, try to tighten first, etc) my success rate is only about 90%. That is my overall experience doing manifold and exhaust system work on multiple cars regardless of their age. Those other 10% are always a pain to fix!
