26ftcobraBBF Posted December 28, 2020 Share Posted December 28, 2020 I mentioned them and gave you a part number, because the thermactor crossover fits into the exact same holes on the back of the heads... If you want to get rid of that plumbing cap, and the pipe it's attached to, spend the $2.90 and buy two of those plugs. I would use the Edelbrock manifold that I mentioned ^^^ up there. Performers are ideal for a rig like yours. My opinion, of course. Bingo! You called it on fingering the flapper. That's what the problem was. It stayed closed tight till it started to open. So I'll need to make an adjustment to keep it cracked open. Do I do that by bending the choke pull off rod, or is there another way? I was racking my brain on how to seal the holes in the therm crossover, I almost cut the ends off the pipe, the bent them over, and welded them, but ended up just getting a pipe cap. I like your idea much better, I'm going to get some of those Welsh plugs. I'll go with your recommendation on the intake. You haven't steered me wrong yet, and I thank you for sharing your knowledge. Maybe you seen it, but I snuck a picture in of the plug that sits on top of the engine. It's kinda melted a little bit, and not to mention there are quite a bit of that type of plug around the engine bay. All look like they've seen better days. I'm big on preventive maintenance, and they look potentially problematic. Are they something to be concerned about? Should I cut them out and splice them back together, or leave them alone there probably fine? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted December 28, 2020 Author Share Posted December 28, 2020 Bingo! You called it on fingering the flapper. That's what the problem was. It stayed closed tight till it started to open. So I'll need to make an adjustment to keep it cracked open. Do I do that by bending the choke pull off rod, or is there another way? I was racking my brain on how to seal the holes in the therm crossover, I almost cut the ends off the pipe, the bent them over, and welded them, but ended up just getting a pipe cap. I like your idea much better, I'm going to get some of those Welsh plugs. I'll go with your recommendation on the intake. You haven't steered me wrong yet, and I thank you for sharing your knowledge. Maybe you seen it, but I snuck a picture in of the plug that sits on top of the engine. It's kinda melted a little bit, and not to mention there are quite a bit of that type of plug around the engine bay. All look like they've seen better days. I'm big on preventive maintenance, and they look potentially problematic. Are they something to be concerned about? Should I cut them out and splice them back together, or leave them alone there probably fine? You need to back off the cap. Look at the way I set the choke. It doesn't close all the way when cold. Gary baselines at .125".... I start a little tighter at .110 And, yes you can adjust the vacuum pull-off too. I'll go back and look. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted December 28, 2020 Author Share Posted December 28, 2020 Jim, I think cracking the chole plate open a bit is going to fix the issue it makes perfect sense. You mentioned a welsh plug in the front of the head, which is not a concern for me right? But you reference it size because it's the same size I'll need for the therm. crossover? I open for recommends for an intake. My research suggest a duel plane. What are your thoughts? It was tough trying to get a snapshot of what appears to be bent linkage possibly. I wouldn't be too concerned about that connector, but you should try to keep it off the exhaust manifold in the future. Most of those connectors are available as pigtails from Motorcraft. But just use the connector catalog (here on the forum somewhere) to get the numbers, then search eBay, Amazon, whatever... They are tooo much $$$$ through Motorcraft direct. Link to comment Share on other sites More sharing options...
LARIAT 85 Posted December 28, 2020 Share Posted December 28, 2020 You need to back off the cap. Look at the way I set the choke. It doesn't close all the way when cold. Gary baselines at .125".... I start a little tighter at .110 And, yes you can adjust the vacuum pull-off too. I'll go back and look. On my [Ford] Autolite 4100, the choke plate snaps completely closed with a bit of tension when it is very cold. As soon as the engine fires, the choke plate immediately cracks open just a tiny bit to let a bit of air in. As the engine builds up heat, that choke plate gradually opens until it has tension holding it completely open. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 28, 2020 Share Posted December 28, 2020 You need to back off the cap. Look at the way I set the choke. It doesn't close all the way when cold. Gary baselines at .125".... I start a little tighter at .110 And, yes you can adjust the vacuum pull-off too. I'll go back and look. On my [Ford] Autolite 4100, the choke plate snaps completely closed with a bit of tension when it is very cold. As soon as the engine fires, the choke plate immediately cracks open just a tiny bit to let a bit of air in. As the engine builds up heat, that choke plate gradually opens until it has tension holding it completely open. Rick - On carbs with a vacuum pulloff I set the choke to close fully and the pulloff to open it slightly, just like you said. But the Edelbrocks that I've mainly used don't have the pulloff so I set the choke to not quite close. Personally I like the idea of a pulloff as it is a feedback loop. Set the choke a bit rich for starting and then if the pulloff brings it too far off the vacuum drops and the pulloff lets the choke close a bit. Link to comment Share on other sites More sharing options...
26ftcobraBBF Posted December 29, 2020 Share Posted December 29, 2020 I wouldn't be too concerned about that connector, but you should try to keep it off the exhaust manifold in the future. Most of those connectors are available as pigtails from Motorcraft. But just use the connector catalog (here on the forum somewhere) to get the numbers, then search eBay, Amazon, whatever... They are tooo much $$$$ through Motorcraft direct. Breaker breaker, anyone got a copy, I'm boots on the ground at the Cobra Headquarters. Garagemahl we have a problem....ok ok enough with the funny business. I initially came down to adjust my choke pull off and while doing that today I hooked up my tach and I can't seem to get the idle down below 850 RPM. At 850 RPM my vacuum pressure is around 18-20 in Hg, the timing is @10° with the vac advance hose un- plugged, and capped, and is not changed when plugged back in. My vacuum advance is running off the spark port of my carb as said to do in the Holley installation guide. I can't get an accurate timing until I can get the idle down s little lower right? Also the curb idle scree is pulled all the way back not touching, and I pulled the accelerator cable off the carb just to verify that nothing was being problematic. What am I missing? Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 29, 2020 Share Posted December 29, 2020 Breaker breaker, anyone got a copy, I'm boots on the ground at the Cobra Headquarters. Garagemahl we have a problem....ok ok enough with the funny business. I initially came down to adjust my choke pull off and while doing that today I hooked up my tach and I can't seem to get the idle down below 850 RPM. At 850 RPM my vacuum pressure is around 18-20 in Hg, the timing is @10° with the vac advance hose un- plugged, and capped, and is not changed when plugged back in. My vacuum advance is running off the spark port of my carb as said to do in the Holley installation guide. I can't get an accurate timing until I can get the idle down s little lower right? Also the curb idle scree is pulled all the way back not touching, and I pulled the accelerator cable off the carb just to verify that nothing was being problematic. What am I missing? Sorry, but we've converted over to GMRS and away from CB. Seriously though, is your choke fully off? If not, the fast idle cam will keep the idle off the curb idle screw. But, if the choke is completely off, meaning standing up straight and the fast idle cam is out of the way, that would suggest you have a vacuum leak. However, when you say the vacuum advance hose is off and plugged/capped, you mean so that air can't get to the carb, right? There's no reason to worry about air getting to the vacuum advance on the distributor, but you don't want it going to the carb - although if the "spark port" is timed, meaning there's no vacuum at idle, it doesn't matter. Link to comment Share on other sites More sharing options...
26ftcobraBBF Posted December 29, 2020 Share Posted December 29, 2020 Sorry, but we've converted over to GMRS and away from CB. Seriously though, is your choke fully off? If not, the fast idle cam will keep the idle off the curb idle screw. But, if the choke is completely off, meaning standing up straight and the fast idle cam is out of the way, that would suggest you have a vacuum leak. However, when you say the vacuum advance hose is off and plugged/capped, you mean so that air can't get to the carb, right? There's no reason to worry about air getting to the vacuum advance on the distributor, but you don't want it going to the carb - although if the "spark port" is timed, meaning there's no vacuum at idle, it doesn't matter. Choke plate is straight up, fast idle cam I'll double check I'm thinking it was clear. Distributor vacuum advance was open to atmosphere,vthe hose that connects to it was plugged. I'm thinking the spark port is timed because i put my vacuum guage on it initially for simplicity, and only got about 5 in Hgwhitch I thought was odd . Could I have a defective distributor/ vac advance Link to comment Share on other sites More sharing options...
26ftcobraBBF Posted December 29, 2020 Share Posted December 29, 2020 Choke plate is straight up, fast idle cam I'll double check I'm thinking it was clear. Distributor vacuum advance was open to atmosphere,vthe hose that connects to it was plugged. I'm thinking the spark port is timed because i put my vacuum guage on it initially for simplicity, and only got about 5 in Hgwhitch I thought was odd . Could I have a defective distributor/ vac advance Is it possible to have a vacuum leak in the brake booster to but still have normal braking? Alos if the accelerator pump is adjusted to heavily, would that cause a fast idle. Fast idle cam confirmed clear I sprayed around intake and the base of the carb with brake cleaner, and had no difference in engine RPM. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted December 29, 2020 Author Share Posted December 29, 2020 Is it possible to have a vacuum leak in the brake booster to but still have normal braking? Alos if the accelerator pump is adjusted to heavily, would that cause a fast idle. Fast idle cam confirmed clear I sprayed around intake and the base of the carb with brake cleaner, and had no difference in engine RPM. The need to disconnect and cap the vacuum line is only if it's hooked up like it should be -stock- You don't have a 4180 and aren't using manifold vacuum, to a thermal vacuum switch, so none of this matters... If you can't find a vacuum leak one of two things might cause your problem. A) the secondaries might be cracked open. Either sticking on the EGR spacer or the stop screw (bottom side between the rear barrels) has them adjusted open. B) you have an internal vacuum leak, where one of the runners is sucking from the valley. You can usually see this as an oily plug Link to comment Share on other sites More sharing options...
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