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| Vacuum Advance https://slantsix.org/forum/viewtopic.php?t=61055 |
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| Author: | n4dxx [ Sun Apr 23, 2017 4:17 am ] |
| Post subject: | Vacuum Advance |
I have been working on my 1986 d-150 and noticed it has No vacuum advance on the distributor?Could it be electronic Or is it broken off?Has 2 wires going to it and this truck does not have the lean burn system..Any help appreciated...Thanks |
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| Author: | DusterIdiot [ Sun Apr 23, 2017 8:29 am ] |
| Post subject: | Ouch... |
2 wires and no vacuum advance. Sounds like you have the lean burn system distributor on a non leanburn vehicle, you can pull the distributor and look at the mechanism, if it has no weights or springs, you are going to need to get a normal EI distributor to replace it.... |
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| Author: | Reed [ Sun Apr 23, 2017 8:39 am ] |
| Post subject: | |
Are you sure it doesn't have lean burn? On trucks the computer was sometimes mounted below the battery tray instead of on the air cleaner. By 1986 it is much more likely than not that your truck would be equipped with some variant of the lean burn system. |
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| Author: | n4dxx [ Sun Apr 23, 2017 12:53 pm ] |
| Post subject: | Pics |
Just getting it together after a re-done head with 3 burned valves,Had 3 cylinders with the intake gasket was rotted completely off..I see No computer anywhere for a lean burn system.. http://i1319.photobucket.com/albums/t66 ... xizs18.jpg http://i1319.photobucket.com/albums/t66 ... ablubv.jpg http://i1319.photobucket.com/albums/t66 ... rfjvev.jpg http://i1319.photobucket.com/albums/t66 ... sk1voa.jpg |
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| Author: | Killer6 [ Sun Apr 23, 2017 1:14 pm ] |
| Post subject: | Re: Vacuum Advance |
Quote: I have been working on my 1986 d-150 and noticed it has No vacuum advance on the distributor?Could it be electronic Or is it broken off?Has 2 wires going to it and this truck does not have the lean burn system..Any help appreciated...Thanks
Well, it's not "lean burn" per se', but all '85 and up will have a controller& electronic timing control. Cali. models had feedback carbs, and O2's, the rest used a different fuel control system w/the spark control system. When You say "2 wires" You should actually have 2 PAIRS of wires & 2 2-wire connections at the dizzy. |
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| Author: | n4dxx [ Sun Apr 23, 2017 1:18 pm ] |
| Post subject: | |
Mine just has 1 two wire connection..seems to run great tho.. |
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| Author: | Killer6 [ Sun Apr 23, 2017 1:24 pm ] |
| Post subject: | Re: Pics |
Quote: Just getting it together after a re-done head with 3 burned valves,Had 3 cylinders with the intake gasket was rotted completely off..I see No computer anywhere for a lean burn system..
Easy, it would've been mounted on the air cleaner housing, which is missing from the photos, and it's hard to see, but the dizzy only appears to havehttp://i1319.photobucket.com/albums/t66 ... xizs18.jpg http://i1319.photobucket.com/albums/t66 ... ablubv.jpg http://i1319.photobucket.com/albums/t66 ... rfjvev.jpg http://i1319.photobucket.com/albums/t66 ... sk1voa.jpg one set if pick-up leads, someone probably "retro-engineered" Your ride. I suppose one could've switched out the dizzy & left the vac pot off, not advisable, esp. if the plate wasn't locked in position. The OE adv. would have been on the computer, the "before MAP sensor" pot/transducer type. |
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| Author: | Reed [ Sun Apr 23, 2017 2:13 pm ] |
| Post subject: | |
Your truck HAD lean burn. There are remnants of the system still present. Charge temp sensor on the #6 intake runner, coolant temp sensor in the head, idle stop solenoid on the carb, clear signs the wiring harness has been modified and re-wrapped. And on trucks the lean burn computer was sometimes mounted under the battery. Just like on vans the lean burn computer was mounted on the firewall. It wasn't always on the air cleaner. Are you sure whoever chopped up the wiring harness didn't just snip the leads for the start pickup on the distributor and leave only the run pickup wiring? Have you taken the distributor apart to see if it has mechanical advance? |
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| Author: | n4dxx [ Sun Apr 23, 2017 2:18 pm ] |
| Post subject: | |
Not yet but i will find out whats going on..Thanks for all the input.. |
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| Author: | afastcuda1970 [ Sun Apr 23, 2017 3:01 pm ] |
| Post subject: | |
That is a lean burn distributor. It has a hold down clamp similar to a RB engine instead of the slotted hold down like most slants. All you have for timing is the initial and no advance (mechanical or vacuum). I just converted mine to HEI a few weeks ago and had the same distributor. I had to put in a regular EI distributor. You may have to change the carb also to get it to run right. |
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| Author: | Reed [ Sun Apr 23, 2017 3:35 pm ] |
| Post subject: | |
I agree a carb swap may be necessary, but the distributor hold down mechanisms can be transferred between dustributor bodies and should not be considered a means of identifying the type of distributor. The later style holddown is superior and preferred because it gives more adjystability than does the older slotted holddown system. |
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| Author: | n4dxx [ Sun Apr 23, 2017 7:06 pm ] |
| Post subject: | |
So what would be a good plan?Just start from scratch and wire in a new HEI system..And why would this carb not work?It has a place to hook up a vacuum advance..I have no idea how this thing runs with all that disconnected..I don't see how it's firing i don't even see a Ballast resistor...Hummm |
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| Author: | afastcuda1970 [ Sun Apr 23, 2017 7:12 pm ] |
| Post subject: | |
Take some more pics of the fender wells (both) and the firewall area. It has to have some sort of ignition retro-fit installed if it runs at all. Someone will be able to identify the ignition source. |
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| Author: | n4dxx [ Sun Apr 23, 2017 7:16 pm ] |
| Post subject: | |
Will do in the AM..I really appreciate the help..i Want this thing to be right not trashed up.. |
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| Author: | DusterIdiot [ Sun Apr 23, 2017 7:24 pm ] |
| Post subject: | Sorta... |
Quote: distributor hold down mechanisms can be transferred between dustributor bodies and should not be considered a means of identifying the type of distributor. The later style holddown is superior and preferred because it gives more adjystability than does the older slotted holddown system.
The 'clamp style' noted is correct for about 1978-1979 until the end run of slants in 1987. The best way to identify the ESC distributor is to pull it and physically look inside... They have no springs, weights or "guts", just a solid plate with a pick up (early 80's version had 1 pickup, about the mid80's they went to the 2 pickup model with the start and run pick ups making it easier to identify).... The clamp style is much easier to make adjustments to your base timing, especially if you need "more" than 10 or 12. That being said, if you don't get the bolt down tight, you might end up with your static timing off qat the wrong moment... which makes the older style of bracket a bit batter as a safety catch... |
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