asdfghjkllkjhgfdsa Posted August 17 Share Posted August 17 (1986 Ford F-150, 300 I6, Rebuilt Engine, Heavy Cam, HEI Distributor, Offenhauser Intake, Headers, Motocraft 2150 2 barrel Carburetor. No electronics/emissions control, c4 automatic transmission) Restoring a previously owned Ford F150 that was being turned into a race truck. When I go to accelerate from a stop I get very little power/almost none until I hit 1700-2000 rpm and then the thing takes off. This means I can never ease into acceleration. Its always all or nothing. It accelerates great but I dont want everyone to think Im on some starting line at every stoplight. What is the primary cause of this? Is it timing and the module in the HEI distributor? Or is it entirely the heavy cam with a large degree and heavy overlap? I also believe the torque converter was replaced with a different one and a shift kit was put into the automatic transmission, but am unsure how that might effect drivability. I've messed with all the carburetor settings and dont think any of those effect this issue. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 18 Share Posted August 18 You already mentioned the timing in another thread. I would have to say that the combination of cam (and you don't know what the cam timing is) and perhaps too much carb are your big issues now that you have unlocked the distributor. The torque converter is just set up so that the truck has to be really wound up and into the cam before it starts loading the drive line. Don't be faint of heart in un-butchering this truck if you actually want to use it for it's intended purpose. Link to comment Share on other sites More sharing options...
1986F150Six Posted August 18 Share Posted August 18 You already mentioned the timing in another thread. I would have to say that the combination of cam (and you don't know what the cam timing is) and perhaps too much carb are your big issues now that you have unlocked the distributor. The torque converter is just set up so that the truck has to be really wound up and into the cam before it starts loading the drive line. Don't be faint of heart in un-butchering this truck if you actually want to use it for it's intended purpose. My gut feeling is that the low RPM performance has to do with that specific distributor. I feel like it may be defective. Link to comment Share on other sites More sharing options...
asdfghjkllkjhgfdsa Posted August 18 Author Share Posted August 18 You already mentioned the timing in another thread. I would have to say that the combination of cam (and you don't know what the cam timing is) and perhaps too much carb are your big issues now that you have unlocked the distributor. The torque converter is just set up so that the truck has to be really wound up and into the cam before it starts loading the drive line. Don't be faint of heart in un-butchering this truck if you actually want to use it for it's intended purpose. When you say "The torque converter is just set up so that the truck has to be really wound up and into the cam before it starts loading the drive line." Isn't this exactly what I'm experiencing with a lack of power until high rpm? Is it I have to get the RPM up to a specific amount before the TC cuts in and delivers power to the drive line? Im not very familiar with torque converters, but if this is an issue, would no amount of engine demodification I do make a huge impact on the ability to make a slow take-off speed until I also change back to stoke the TC? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 18 Share Posted August 18 When you say "The torque converter is just set up so that the truck has to be really wound up and into the cam before it starts loading the drive line." Isn't this exactly what I'm experiencing with a lack of power until high rpm? Is it I have to get the RPM up to a specific amount before the TC cuts in and delivers power to the drive line? Im not very familiar with torque converters, but if this is an issue, would no amount of engine demodification I do make a huge impact on the ability to make a slow take-off speed until I also change back to stoke the TC? Torque converters have what's called 'stall speed' A drag vehicle should be pushing redline from when it leaves the line all the way to the traps. You can't seem to differentiate between "The engine is gutless below X", or "It's not putting any power to the wheels below X". If your truck has a 2,800 rpm converter then it's not going to be friendly on the street, and you can't do anything but change it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 18 Share Posted August 18 My gut feeling is that the low RPM performance has to do with that specific distributor. I feel like it may be defective. David has a point. Has it been proven that the mechanical advance is working properly and starts pretty quickly off idle? I've not been following this very closely with all else going on at the moment. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 18 Share Posted August 18 My gut feeling is that the low RPM performance has to do with that specific distributor. I feel like it may be defective. David has a point. Has it been proven that the mechanical advance is working properly and starts pretty quickly off idle? I've not been following this very closely with all else going on at the moment. Have either of you read the OTHER thread where it was discovered that the dizzy was locked out, but it was put right? I mean, I doubt that this guy has a Sun machine, or anything, but if it's advancing and the static timing is okay what more can you do? Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 18 Share Posted August 18 Have either of you read the OTHER thread where it was discovered that the dizzy was locked out, but it was put right? I mean, I doubt that this guy has a Sun machine, or anything, but if it's advancing and the static timing is okay what more can you do? No, I've not. As said, things have been rather busy for me at the moment. But I'm glad that bit has been fixed. Carry on! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 18 Share Posted August 18 No, I've not. As said, things have been rather busy for me at the moment. But I'm glad that bit has been fixed. Carry on! This is what happens when the same problem gets spread across multiple threads. Link to comment Share on other sites More sharing options...
asdfghjkllkjhgfdsa Posted August 18 Author Share Posted August 18 This is what happens when the same problem gets spread across multiple threads. My original problem was an off-idle stumble. After unlocking the distributor and another fuel issue tweek, that has disappeared. What hasn't disappeared or what I'm trying to figure out now is why it's so under powered at a low rpm vs high. Hence the sperate thread because, being very new to this, I thought they were two separate issues. Sorry if starting a new thread messes things up. I'm just trying to figure stuff out best I can. I'm not going to stop asking questions either just because one person says "this is all that can be done". I've learned to many times there's more than one way to skin a cat, and I love hearing different people's ideas and learning how everything works. Please and honestly, give me a little bit of slack, I'm trying to learn something I've never done before. Link to comment Share on other sites More sharing options...
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