Ray Cecil Posted October 7, 2019 Author Share Posted October 7, 2019 Nvm, I'm on my tablet now and see it is used for the bypass valve. So, I think you should probably keep the thermal vacuum switch that provides manifold vacuum to the distributor in case of overheating. If this is just a toy, no need, but if stuck in traffic it's nice to raise the idle (increase fan and pump speed) Jim. Ive installed a 3 row Aluminum radiator to keep things cool. I daily drive the truck. Ive been stuck in traffic in 100 degree weather and the needle never moves. That radiator does a great job. I dont think I need to keep anything fancy to increase idle. Ill get the new choke in the mail Thursday. Ill get it hooked up then. Also, what pulls the hot air up the tube into the choke? Is there supposed to be a second line drawing air through the choke housing? Is there an internal orifice pulling the hot air in? Or does the heat just rise in the tube because hot air rises? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 7, 2019 Share Posted October 7, 2019 Jim. Ive installed a 3 row Aluminum radiator to keep things cool. I daily drive the truck. Ive been stuck in traffic in 100 degree weather and the needle never moves. That radiator does a great job. I dont think I need to keep anything fancy to increase idle. Ill get the new choke in the mail Thursday. Ill get it hooked up then. Also, what pulls the hot air up the tube into the choke? Is there supposed to be a second line drawing air through the choke housing? Is there an internal orifice pulling the hot air in? Or does the heat just rise in the tube because hot air rises? Ray, I'm not sure with your Cali emissions factory carb. Some carbs have an internal passage that provides vacuum. Afaik, all electric assist, thermal choke carbs use vacuum from some source to draw heat across the spring. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 7, 2019 Share Posted October 7, 2019 Ray, I'm not sure with your Cali emissions factory carb. Some carbs have an internal passage that provides vacuum. Afaik, all electric assist, thermal choke carbs use vacuum from some source to draw heat across the spring. Yes, there's a small orifice in the carb that provides a little vacuum to the port where the tubing fits. The intent is that you'll have a line from the clean side of the air cleaner, down to the exhaust, and then back to that port. The vacuum pulls the hot air across the bi-metallic spring. Link to comment Share on other sites More sharing options...
Ray Cecil Posted October 7, 2019 Author Share Posted October 7, 2019 Yes, there's a small orifice in the carb that provides a little vacuum to the port where the tubing fits. The intent is that you'll have a line from the clean side of the air cleaner, down to the exhaust, and then back to that port. The vacuum pulls the hot air across the bi-metallic spring. Gary, the clean side of the air cleaner is under vacuum. So, is the vacuum from the choke housing orifice greater than the vacuum on the clean side of the air cleaner? Do I need to run my copper back up towards the air cleaner? Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 7, 2019 Share Posted October 7, 2019 Yes, there's a small orifice in the carb that provides a little vacuum to the port where the tubing fits. The intent is that you'll have a line from the clean side of the air cleaner, down to the exhaust, and then back to that port. The vacuum pulls the hot air across the bi-metallic spring. Gary, the clean side of the air cleaner is under vacuum. So, is the vacuum from the choke housing orifice greater than the vacuum on the clean side of the air cleaner? Do I need to run my copper back up towards the air cleaner? There should be a port on the carb that just goes into the air horn, where the air is clean. Probably the one in the pic below from the FSM. That air will be cool so you can run a vacuum hose from it to the copper tubing. And yes, the vacuum in the choke will overcome any vacuum in the air horn. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 7, 2019 Share Posted October 7, 2019 Yes, there's a small orifice in the carb that provides a little vacuum to the port where the tubing fits. The intent is that you'll have a line from the clean side of the air cleaner, down to the exhaust, and then back to that port. The vacuum pulls the hot air across the bi-metallic spring. Gary, the clean side of the air cleaner is under vacuum. So, is the vacuum from the choke housing orifice greater than the vacuum on the clean side of the air cleaner? Do I need to run my copper back up towards the air cleaner? There's no appreciable vacuum above the carb unless your filter is a filthy oily mess. It's fine going there.. Link to comment Share on other sites More sharing options...
1986F150Six Posted October 7, 2019 Share Posted October 7, 2019 Nvm, I'm on my tablet now and see it is used for the bypass valve. So, I think you should probably keep the thermal vacuum switch that provides manifold vacuum to the distributor in case of overheating. If this is just a toy, no need, but if stuck in traffic it's nice to raise the idle (increase fan and pump speed) On my truck, when I switched to the YF from a 1970 F350, I went with a manual choke kit. It was less than $15 and easy to install. It also acts as a security system since many of today's drivers do not know how to set a choke! Link to comment Share on other sites More sharing options...
Ray Cecil Posted October 7, 2019 Author Share Posted October 7, 2019 On my truck, when I switched to the YF from a 1970 F350, I went with a manual choke kit. It was less than $15 and easy to install. It also acts as a security system since many of today's drivers do not know how to set a choke! Good idea. I think Ill get the automatic thing going first. I might upgrade to a Fitech 2 barrell setup eventually. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted October 7, 2019 Share Posted October 7, 2019 There should be a port on the carb that just goes into the air horn, where the air is clean. Probably the one in the pic below from the FSM. That air will be cool so you can run a vacuum hose from it to the copper tubing. And yes, the vacuum in the choke will overcome any vacuum in the air horn. http://forum.garysgaragemahal.com/file/n40247/YFA_Clean_Air_Port.jpg Did you miss my post back on think page 27 with pictures of how the hot air path works? Yes, you can run heat to the carb with a header. Use some of the soft tubing Jim talks about for brake or fuel line, and wrap it around the header two or three turns. That'll warm the air up in the tube quite nicely. You might want to put some insulation on the return, but it'll work. Copper tubing is better, it will not rust out and is easier to bend. Poor man headers ... EFI manifolds http://forum.garysgaragemahal.com/file/n40066/20180916_131830.jpg http://forum.garysgaragemahal.com/file/n40066/20180916_170816.jpg http://forum.garysgaragemahal.com/file/n40066/20180916_170737.jpg http://forum.garysgaragemahal.com/file/n40066/20180916_170802.jpg If you need to run pre-heat to the air filter you can make the tin from sheet metal and/or tin cans to catch the heat and use the paper hose up to the filter housing like stock. I have not done this and don't know if I will have to only time will tell. Dave ---- Dave ---- Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 7, 2019 Share Posted October 7, 2019 Copper tubing is better, it will not rust out and is easier to bend. Poor man headers ... EFI manifolds Dave ---- Dave, it's copper/nickle brake line. Bends by hand and reverse flares without collapsing. EFI manifolds with the Walker -non catalyst- Y pipe. 2 1/4 to the collectors and 2 1/2" out. We did this on a CT members truck when he mounted my 465 Holley on an Offenhauser intake Link to comment Share on other sites More sharing options...
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