Bear 45/70 I beleive the vacuum is there for the advance to work. I don't want to go away from original. So something is either broken or not properly tuned or whatnot. Just trying to narrow it down. From whats been said here if I just do away with it I should be in the clear and I understand that. As I have said before. I am looking to stay original with everything working within reason. It's not my daily driver but I do try and take it out as much as I can. Real nice truck. I appreciate everyones input...just keep straying away from the issue of what is bad. In my mind....if it's original and worked foer some time and has gone bad or out of spec or whatnot...unplugging or disconnecting doesn't solve the issue in my mind. Could you imagine a doctor saying....sir..ur heart isn't functioning properly...we're going to disconnect it....lol Hope I don't come off the wrong way....I do appreciate everyones input. Just looking for a reason as to why I all of a sudden would have to disconnect it when it's been there it's whole life. I'd either like to replace/readjust/rebuild whatever is failing. But I am not looking to just throw parts at it. Thanks.
The advance will work just fine with only the ported vacuum connected. I did this with my 1969 428CJ until I replaced the dist. with a Ford dual point unit (yes, I was racing it and street driving it both, but gas was still cheap back then). Of course this was way back in 1970 but the dual vacuum units were thought up to placate Kaliforina CARB emissions board as a stop gap measure and did more damage to gas mileage to improve emissions. In this day and age, with the price of gas and if you don't have emmissions testing I'd either just run the ported vacuum off the carb only (which will give you your vacuum advance) and/or replace the advance unit with a single port model.
Bear 45/70 Thank you. That info really helped me understand a little more about how it works and such. We do not have emissions here and I can get areound 200 miles to a full tank of gas. Definately not great but considering the year it was made it's not so bad. I'll take the ported vacuum line and connect it to the port farthest away from the dizzy cap and cap off the other port and take her for a ride to see what happens. Even if she runs great afterwards I'd still like to know why all of a sudden the change. I'd just like to know...things like that interest me and in the process I can learn more. So, I'll give that a shot today right after work and try and post a pic in my gallery. Thanks for giving me a little more detail.
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
Yep, you have the manifold vacuum to the wrong port on the vacuum advance unit.
I think you were right. I went home and switched the vacuum lines around on the dizzy and it is doing much much better. But I think I have to retime it. I'll go back in a lil bit...retime it and drive it to work tomorrow since it isn't going to rain. I'll post my findings. Thanks everyone....especially Bear 45/70
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
Ok, so it runs great as far as power and smoothness and whatnot. Really a totally different truck. I checked the timing at idle and it was at 10 BTDC with vacuum lines pulled off and plugged. I read it should be at 6 BTDC for manual and 10 BTDC for Automatic. This is really a newbie thing here but...aren't you supposed to set timing at a higher RPM than idle...say 2-3000 RPM? Or am I mistaken. Reason i say so is I pulled the #1 plug out and it is white. It has been even before I changed the vacuum lines last night...just not as bad as now. Which would indicate a lean mixture. I know my carb (2 bbl) has both mixture screws set to 3 turns out. I usually start out at 2 1/2 turns out and go from there. Turn them in until it starts to stumble then back out till it stumbles. Then just divide that in half. I didn't set it this way but I figured 3-3 1/2 was a good point to start at. Any comments on this? I run Regular fuel with a lead additive (CD-2). I checked the compression when I got the truck and all were in the low 100's within 10 psi of eachother. Thanks.
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
Last edited by 77 Bronco : 05-09-2008 at 10:50 AM.
Reason: info
Checking timing and setting initial with the vacuum lines disconnected is an excepted way of checking. I prefer to check my total mechanical advance so I actually know what my dist. is cranking into my motor. Set up you timing light and rev the engine until the timing doesn't advance any more (a timing light with the retard feature helps with this as most damper only have 30° marked on them). Total timing on a street motor should never be more than 38° but I usually keep my street motors at 36°. It it needs adjustment change it and then check you initial again and use that as you base setting from then on. I also believe in re-curving the dist. advance so that total timing is in by 3500 rpm for a work/tow rig. and I prefer and advance curve of 20° to 26°.
Checking timing and setting initial with the vacuum lines disconnected is an excepted way of checking. I prefer to check my total mechanical advance so I actually know what my dist. is cranking into my motor. Set up you timing light and rev the engine until the timing doesn't advance any more (a timing light with the retard feature helps with this as most damper only have 30° marked on them). Total timing on a street motor should never be more than 38° but I usually keep my street motors at 36°. It it needs adjustment change it and then check you initial again and use that as you base setting from then on. I also believe in re-curving the dist. advance so that total timing is in by 3500 rpm for a work/tow rig. and I prefer and advance curve of 20° to 26°.
I so wish someone would make a uTube or other video on this so my brain could actually take it all in. Visual learner, what can I say??? Imagination impaired!! i guess LOL
Yeah. I feel the same way Redmanbob. I am more of a visual learner. Just nature I suppose. I'm definately going to have to do some reading on the subject. I know enough to get me into trouble...ha...and back out sometimes.
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
Here's a tutorial for redoing the advance curve. The dist. advance mechanics is the same, just that this one is electronic but removing the plate is the same.
If I was visiting my Mother-in-law in Battle Creek I could help you, but alsa I'm on the northwest coast and am on the outs with the crazy old broad, at least that's what my wife calls her.
So...I have a timing light that is adjustable from 0 and on up (advance). No retard feature. Am I correct in saying that I can have the truck at operating temp, idle set to factory spec (550-600 RPM), and set timing light to 0 and turn distributer until the timing pointer is pointed at 10 BTDC. Shouldn't the timing be checked also with the vacuum advance hooked up? I think this is why I'm running lean....the timing isn't correct. Sorry if I seem lost...like I said more of a hands on guy than a book guy.
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
Ok, been doing some heavy reading on timing and such as well as vacuum. I am going to pick up a new vacuum gauge this weekend. Pretty useful tool for testing. Does anyone know what the recommended vacuum should be? Maybe I should start another post. I have to fix this lean problem before I burna hole in a piston. I know a vacuum leak can produce a lean condition as well. Wish me luck.
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1968 Ford F-100 Custom Cab, 2WD, 8' Bed, 360 FE (5.9L)
3 Speed on the tree converted to 4 Spd Auto
Power Steering conversion
Bought 2/08 with 69,300 miles.
You never set initial timing with vacuum hooked up, always disconnect and plug it (I never plug it but that's becuase I know I'm using ported vacuum and everything is right). If the idle speed changes when you connect the vacuum hose then you need to find out why, as ported vacuum should be zero when idling. Oh yeah the knob is a retard feature on your timing light. If you crank in 10° on the timing light and check the timing you will see that timing is at 0° advance the light.
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