Register or Log In To remove these advertisements. |
|
|
|
Thread Tools | Display Modes |
11-04-2008, 01:33 PM | #1 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Heat Riser for 250 ci. Straight Six
The heat riser on the exhaust manifold on my 1972 250ci straight six is shot. The counter balance is hanging and the spring is shot. I have two questions, is it even necessary, I run a manual choke, or can I just wire it to the manifold in the open position? Secondly, what is the open position? I take it it is when the counter balance weight is hanging down? I would rather not take the exhaust manifold off to find out.
|
11-04-2008, 02:01 PM | #2 |
State of Confusion!
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 47,216
|
Re: Heat Riser for 250 ci. Straight Six
I ran mine fior two years without it, although it does not get as cold here. You don't need it, it just makes the vehicle a little less cold blooded when you first start it up. After you are up to operating temps, it serves no purpose really.
I don't remember what position is opened, since I don't have the 6 any more.
__________________
Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! Last edited by Palf70Step; 11-04-2008 at 02:02 PM. |
11-04-2008, 02:37 PM | #3 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
My manifold has all the parts for an automatic choke, but the PO said he couldn't get it to work correctly so he installed the manual choke. I thought maybe the heat riser was to help heat the intake manifold so the auto choke would shut off quicker (since the coil is mounted to the intake manifold)? I don't plan on driving the truck as much when it gets colder anyway and it is always garaged at home, so I think I will just make it permanently open unless someone else chimes in with a reason why I shouldn't.
|
11-04-2008, 02:43 PM | #4 |
Out of the carpool lane.
Join Date: Jan 2000
Location: Clark Co, WA
Posts: 5,672
|
Re: Heat Riser for 250 ci. Straight Six
Like Palf said, you'll be fine without it but it'll take a bit longer to warm up the engine.
As far as wiring it open- you won't have to do anything. It will naturally hang in the open position. As long as it's not crusty and stuck and is freely moving, you'll be fine not using it.
__________________
1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten... |
11-04-2008, 02:49 PM | #5 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
I am more wiring it to keep it in position, right now it is falling out and just the butterfly is holding it in (the counter weight is hanging about an inch from the manifold). This also most likely is causing some exhaust leakage as well. Thanks for the input.
|
11-04-2008, 03:16 PM | #6 | |
Registered User
Join Date: Sep 2005
Location: Smith Mountain Lake Virginia
Posts: 1,537
|
Re: Heat Riser for 250 ci. Straight Six
Quote:
__________________
"A cat will almost always blink when hit between the eyes with a ball peen hammer" (you don't always have to state the obvious) Wear your PPE! You can eat with false teeth but you can't see with a false eye. 1959 Studebaker Silverhawk 350/400 1972 C10 L6 3OTT 2005 F350 - Built - whew! |
|
11-04-2008, 03:49 PM | #7 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
I will take a picture tonight. There is a (what I call) butterfly valve in the inside of the header (kind of like the choke in the carb) that closes when it is cold to keep heat in the manifold and then as the it heats up a spring on the outside lets it open. There is a counter weight on the outside that helps keep it open. These are both mounted on a shaft that goes clear through the intake manifold, but on mine there isn't anything holding the back side in so it is just hanging with just the butterfly keeping it from coming all the way out. Here is a drawing looking down the exhaust manifold outlet (once again, I am not an artist).
|
11-04-2008, 06:17 PM | #8 |
State of Confusion!
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 47,216
|
Re: Heat Riser for 250 ci. Straight Six
I do not know how much difference there is in the 72 vice 70 automatic choke on the 250, but you can have all the parts, but even when they were new the automatic (mechanical) chokes were know to be a pain in the *&^. Most of the time folks got tired of F'n with them and installed a manual choke. That is probably what your prior owner was talking about on the choke. I am keeping my 70 as a manual choke, even though I have the V8 now. I may convert to an electronic choke on the V8 later, but first I have to get all the pieces together to get it running again
__________________
Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! Last edited by Palf70Step; 11-04-2008 at 06:18 PM. |
11-04-2008, 08:03 PM | #9 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
Here are a few pics:
1. This is how it is, notice how it is hanging out. 2. This is how it should be (I think), pushed in. 3. Quick fix, I couldn't get wire around the manifold so I put a glob of quick steel in front of it to hold it in place until I come up with something better. I still don't know if it in the open or closed position, it seems to run okay. I am still looking online for a picture of it so I can be sure. |
11-06-2008, 10:23 AM | #10 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
I hate to continue to beat this horse, but does anyone have a 250ci straight six with a heat riser and, if so, is this the proper orientation for it to be in when open? Thanks for any help you can give.
|
11-06-2008, 04:42 PM | #11 |
Active Member
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
|
Re: Heat Riser for 250 ci. Straight Six
I took a pic of mine. I usually disconnect it in the summer and rehook it back up in the winter.
It moves counterclockwise as it warms up and when I rev it up but mine doesn' go all the way down like yours. The pics show it cold at first and almost completely warm on the second pic. I suspect yours is in the open position as it is. But if you're really worried about it, disconnect the exhaust pipe and look at it from the bottom. |
11-06-2008, 04:48 PM | #12 |
Active Member
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
|
Re: Heat Riser for 250 ci. Straight Six
Forgot to mention.
When I disconnect it, it falls downward counterclockwise. I'd say maybe 1/2 of the way from the uppermost position before it stops. This is a replacement exhaust manfold. The original heatriser was gone like yours so I just replaced the manifold. |
11-06-2008, 04:59 PM | #13 |
Out of the carpool lane.
Join Date: Jan 2000
Location: Clark Co, WA
Posts: 5,672
|
Re: Heat Riser for 250 ci. Straight Six
Yes, that's the proper orientation for it to be in when it's broken. I mentioned that in my previous post. GM designed it like that so it wouldn't block the exhaust when the spring broke. Like the last poster mentioned, if you don't believe us, just unhook the exhaust tube and look up there for yourself.
__________________
1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten... |
11-06-2008, 05:06 PM | #14 |
Out of the carpool lane.
Join Date: Jan 2000
Location: Clark Co, WA
Posts: 5,672
|
Re: Heat Riser for 250 ci. Straight Six
I don't see the point in doing this, any particular reason why you do it?
__________________
1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten... |
11-06-2008, 05:35 PM | #15 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
My issue was that since the whole thing "sprung" out of position, I didn't know if it had jumped a stop or something. According to 68gmsee (thanks for the pics) it sounds like there is a stop that holds it horizontally (not at the bottom like it currently is on mine). My exhaust is old and rusty (per my pics) and it is not easy at all to "just unhook the exhaust." Once again, thanks for the help 68!
|
11-06-2008, 06:47 PM | #16 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
Just for future generations, I found this picture online that shows the heat riser, it seems that the riser is only supposed to turn 90º. At straight up it lets exhaust get up to the intake manifold, and at 90º counterclockwise it shuttles air out the exhaust. I will break mine loose tonight and orient it to 9 o'clock.
|
11-06-2008, 07:53 PM | #17 |
Active Member
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
|
Re: Heat Riser for 250 ci. Straight Six
Where did you find that picture? I remember I looked a couple years ago for a pic and never found one.
And yes, you are wise not to mess with the exhaust manifold bolts if you don't have to right now. I broke a bolt trying to remove the exhaust nut and damaged the hole when I drilled it out. |
11-06-2008, 11:05 PM | #18 |
classic=of recognized value
Join Date: Sep 2008
Location: Wichita, KS
Posts: 317
|
Re: Heat Riser for 250 ci. Straight Six
I found it at Rockauto.com, just search for 72 c10 exhaust manifold.
|
11-06-2008, 11:52 PM | #19 |
A new C10 Addict!
Join Date: Oct 2008
Location: Vancouver, Wa
Posts: 105
|
Re: Heat Riser for 250 ci. Straight Six
Is my 327 supposed to have one of these because it has something very similar on the drivers side exhaust manifold. I don't mean to steal your thread I'm just curious
|
11-08-2008, 04:27 AM | #20 |
Out of the carpool lane.
Join Date: Jan 2000
Location: Clark Co, WA
Posts: 5,672
|
Re: Heat Riser for 250 ci. Straight Six
Just for the record, Stock72c10 I was wrong in what I said above regarding your heat riser weight and it's current position. I went out and checked tonight on an intact bare manifold I have and sure enough, it's exactly how 68gmsee described it! I'm sorry about the misinformation I gave you- that's a pet peeve of mine. I'll take some pics tomorrow of the butterfly and post them.
Now, I think your butterfly has broken away from the weight and it may very well be in the correct position for exhaust to exit but the only way to know for sure is to remove the exhaust pipe and check from below. I'm just wondering if you blindly secure the weight in the vertical position, will you know for sure that it's allowing exhaust to freely exit since the butterfly inside may still be partially closed? Because really, that's the main concern here, not the actual weight at this point. Since the weight and butterfly appeared separated, you could still have the weight glued like you have it as long as the butterfly is in the open position.
__________________
1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten... |
11-08-2008, 10:38 AM | #21 | |
Registered User
Join Date: Aug 2008
Location: Central TX
Posts: 393
|
Re: Heat Riser for 250 ci. Straight Six
Quote:
|
|
11-08-2008, 11:12 AM | #22 |
Registered User
Join Date: Aug 2008
Location: Central TX
Posts: 393
|
Re: Heat Riser for 250 ci. Straight Six
This thread has got me thinking about my setup. Here are pics of mine - 292 6cyl with butterfly held in closed position. My coil spring is long gone but the butterfly is in good shape. I recently did R&R on exhaust/intake gaskets and found that the PO put this Stanley L bracket on butterfly to hold it in closed position. I decided to leave it like this since I also have manual choke. My manual choke control (see pic) appears to be add on. I assume factory choke control would be on dash bezel although mine also has factory throttle control and I have never seen dash bezel with choke and throttle controls on it. This leads me to believe that my truck originally had auto choke. Is it possible that the butterfly did not work well to cycle auto choke off and PO installed manual choke? My SPID indicates oil bath air cleaner (also long gone) came with truck. I have seen many oil bath air cleaners for manual brakes and they do not have stove pipe assemblies. Maybe this lack of stovepipe assembly caused auto choke to not work properly? Maybe auto choke/oilbath ac was bad factory combo? I got the truck with aftermarket P.O.S#!@ air cleaner and have since replaced with factory offset air cleaner since I will be installing power brakes soon. The offset ac did not come with stove pipe so I am in the hunt for one and will probably go back to auto choke carb also. Didn't mean to ramble on with all these directions or grab the thread in the wrong direction!
Last edited by newbraunie; 11-08-2008 at 11:16 AM. Reason: upload pics |
11-08-2008, 11:38 AM | #23 |
Registered User
Join Date: Aug 2008
Location: Central TX
Posts: 393
|
Re: Heat Riser for 250 ci. Straight Six
On Inline 6 butterfly is above exhaust flow and does not restrict flow when open or closed, it only allows flow up to intake to heat it.
|
11-12-2008, 07:38 PM | #24 |
Out of the carpool lane.
Join Date: Jan 2000
Location: Clark Co, WA
Posts: 5,672
|
Re: Heat Riser for 250 ci. Straight Six
I hope this helps.
__________________
1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten... Last edited by Brad; 11-12-2008 at 07:42 PM. |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|