My carb adjustments for Drivability

[edgewood bronco]

I'm putting this out here so that perhaps other folks can be helped by my experience.
I just got my 66 Bronco with a 170 and an Autolite 1100 carb on the road. I'd had some drivability problems: The truck would stumble when hot around town (25-35 mph), and did not start well when hot. It acted like it was flooded. Lots of cranking with the pedal to the floor would get it going finally.
I've made some changes and this is what seemed to help: I lowered the float about 1/16". I got this idea from my dad who runs old flathead v8s and found that leaning out the float adjustment beyond stock helped.
I also replaced both acclerator pumps. This was necessary because they were leaking so that the bowl would dry out after a couple days, but it also seemed to help the other problems as well.
I had about 200 miles on it since I got it back on the road. The three fillups during that time saw my mileage go from 17 to 16 then 15 mpg. Something was wrong. The plugs were really black and wet and otherwise fouled, and I cleaned them up and got them back to specs as best as I could. I'm driving it as much as possible now, and will re-post when I have an update.
Happy motoring!

 

[64Comet404]

yes, post your updates, i just replaced my carb, same as yours, and now i'm learning about adjustments, and seeing what others do with their carbs, their adjustments and tweaks for various issues, is helpful and educational...

 

[edgewood bronco]

So, finally an update.
With regard to flooding, I finally ended up asking on this forum about adding a pressure regulator between the fuel pump and the carb.
See
viewtopic.php?f=1&t=71341
for information on that (and sixes with overdrives in Broncos)

So far, the two times I've started it up hot after sitting a little bit, it has started right up and not flooded. I set the pressure at 3 1/2 pounds. It stalled a couple times at idle when I was driving it today when it was at 2 pounds. I'm cautiously calling this one a success.

I've not checked the plugs to see what they're doing, nor have I checked my mileage, but plan on putting a tank or 2 through it and will pull a plug and see what it looks like.
Cheers!

 

[edgewood bronco]

Keepin' on.
It was running pretty good today so I drove it all the way to the TOP of the Sandias today - 10,678 feet without incident. I was listening to it backfire all the way down the mountain (whenever the truck was pushing the motor), so thought I'd tinker on it and try out retiming it.
I adjusted the idle and ignition timing according to the classic inlines page...
http://classicinlines.com/Vacuum.asp
I also gapped the plugs to 40 thousandths since I was reading them anyhow. They looked a LOT better than the first time I read them. Some had a bit of carbon on them, but not full wet deposits like I had before.
Running better than ever, I can even accelerate a bit up the hill... against the wind this afternoon. Won't put you back against the seat, but at least I'm not holding up traffic.
I have this problem where now if it idles for a bit (like a minute) then I drive some more, It'll load up like it's flooded, and die. I set the float lower (thought I was over that), but so far to no avail. It Doesn't flood when I restart it though, so maybe that's progress???

The max vacuum I got was about 13 in Hg. I'm at 6500 feet here so that should be about the low side of right? Anybody else in the mountains have a vacuum reading they could share?

On setting the timing with a vacuum gauge, I advanced the heck out of the dist. I'm worried it's too much. It doesn't ping, so I guess all's well under there? I followed the directions at the link above. I've just never gotten that crazy with advance, so am looking for some reassurance that I did the right thing.
Thanks.
Andy

 

[67drewstang]

Do you still have the stock distributor? If so, manually advance it about 20 degrees and see if that doesn't fix the problem.

If both of those are true, you need to ditch the dizzy and go to a Duraspark. 1100 carb cars of that era ONLY have vacuum advance.

I chased "carb problems" for 37 years, before I replaced the distributor and fixed the problem.

 

[edgewood bronco]

That's probably about how much advance I have on it right now. I was beyond the timing marks on the cover. It ran pretty darn good today as I commuted 60 miles round-trip in it.
I'm assembling the pieces for a switch to a DSII. I bought a complete engine out of about an 81 car, thinking it was a low-mount block, but it wasn't. I was disappointed, but am now realizing that I have everything downstream of the ignition module, but don't have the module, or the pigtail upstream of the module to tie it in to the truck's original wiring. Need to call the local U-pull and see if they have a Fairmont lying around over there.

 

[xctasy]

.....I bought a complete engine out of about an 81 car, thinking it was a low-mount block, but it wasn't. I was disappointed, but am now realizing that I have everything downstream of the ignition module, but don't have the module, or the pigtail upstream of the module to tie it in to the truck's original wiring. Need to call the local U-pull and see if they have a Fairmont lying around over there.

Nah, there are donation 3.3 low mount blocks in some of these five Fox cars. This'll help ya.

X code 83 Fox LTD's
B code 81-82 X code 83 Fairmonts,
B and 81-82, X code 83 Zephyrs,
B code 81-82 Cougars (some two door Cougars were long wheel base Fox Thunderbirds)
B code 81-82 T birds

1981-1983 Ford Blue 3.3 Engine = High mount Ford US Toploader based RUC/Code 4 Mexican Tremec SROD/Code 6 US BW T4 manual, or Code BV French C3, or US C4
1981-1983 Grey 3.3 Engine = Code W Automatic only C4 or C5

If a Fox body is a stick shift, it will always be a high mount Ford Blue engine.

The engine codes on the engine decal are also an id point.

The low mount block comes with 164 teeth flexplate and numbers like CJ232 AA or CJ232 AB rocker tag gray X code 3.3 engine. The earlier low mount B codes greys won't have a blue rocker cover like the right picture below, and won't have the same IJ204AA code number as the B code in that picture.



Lots of them from 1982 to 1983, only Fox bodies. Just like any other 164, only zero balance and 2.75" spacing for the six crankshaft bolts

Some engines are repainted, or have rocer cover swaps, or early engines in later cars, but the above rule is an absolute more than anything else that FoMoCo did in those Maliase era Foxes

I've stated many, many times, that the 1981 to 1983 B and X code 3.3's are about 50% low mount, 50% high mount.

Blue engines have a 4, 6 or BV trans code for the non C4 transmissions. The BV was the 138 teeth flexplate C3 Bordeux transmission code, all cars with this on the buck code are Ford Blue high mount blocks. From 1978 to 1983, lots, and I mean LOTS of Ford Blue engines were found with high mount 136 teeth flexplate C4 gearboxes, using the same small bolts centers still cast in the block like every small since since 1960. The manual gearboxes on these engines used the large 3.03 trans bolt holes first cast in since 1967.

Grey ones are low mount, with large 164 flexplate, and C4, or lock-up clutch C5 transmissions for all 1983 X codes in LTDII's and Fairmonts/Zephryrs, B codes are from 1981 to 1982, and generally C4's, but C5's started in the Granada/Fairmont/ long wheel base early Fox Thunderbird. The 6 code 3.8 then became the D code 4.2 replacement engine. I'd say all 81-82 B code Tbirds were probably low mount C4's or C5's. They exist because the whole 3.3 line was to be converted over to large bell for the C5 and probably the AOD, but suddenly, the take up on 3.3's was so low that they just kept the old high mount starter as a DSO standard engine in various states from 1981 to 1983. So the Lima plant cranked out high and low mount blocks at the same time for 2 years.

 

[edgewood bronco]

Wow. Thanks xctasy for all the info. Great to have it available on the web when I start my hunt.