Autolite 1100 question

Hi. Curious about autolite 1100 differences before and after 1968. I understand this is the year they changed the advance on the distributor. Am I correct in saying that autolites prior to '68 had the spark control valve and those after did not, or am I way off? Also, I notice from looking at photos of 1100's online that the ones without the SVC seem to be missing the vent rod that runs across the body. Is there any connection here? Just wondering. Thanks

Another thought. What is the story with the diaphragms on these carbs? I'm currently running an 1100 with one diaphragm on drivers side. I have an automatic transmission. Someone told me that I should have the one with two diaphragms for an automatic, the second diaphragm acting as another accelerator pump. My car is a '65 200 ci. Did they even make 2 diaphragm 1100's on the '63-67 models or were they only present on the post '67 carbs? Puzzled. Thanks.

Howdy Back:

The two changes in the pre/post '68 1100s are no SCV after and the cfm was downsized to 1.1 from 1.2. The CFM in a '69 200 went down from 185 prior to 156. And no, the new distributor cannot make up the difference.

On the diaphragms you mentioned, one on standard transmission rigs and a second on carbs in an engine with an auto trans. The second is a dash pot designed to slow deceleration for the auto trans. If you don't have one it's not a big problem. If your engine kill on slowing for a stop you can remedy it by; 1. increasing the idle speed or 2. slip the trans into neutral.

On the bowl vents their design and function varied considerably over the years with different systems within the same year. The rod doubles as a backup. The brass vent pipe in the carb throat is the main vent. The rod vent stop does help the gas in the bowl from evaporating when sitting for a long time.

Hope that helps. Keep the questions coming.

Adios, David

X2 only thing I can add is that on the California emissions cars they made those changes a year earlier on the Autolites. Good luck

congrats on keepin it stock, nice to see a real piece of history movin down the road w/the rest…
8)

Hello. Thanks for info everyone. David, it's funny you mentioned increasing he idle speed. When I first got the car I was having stalling issues when I came to a stop. This caused me to increase idle speed. At the time I did it because it stopped the car from stalling. I had no idea I was compensating for a missing accelerator pump in carb. Eventually I want to switch over to manual transmission (I've been gathering up the parts) so it will be the right carb for that application.

HOwdy Back:

Hey '65 Mustang, are your sure that this is the original OEM carb for your car? Just a thought.

Adios, David

Well, since the car has most likely changed hands many times before I got it, I can't say for sure. It is definitely an autolite 1100 with an svc and one diaphragm. The car used to be manual but somewhere along the line an auto trans was put in. It seems likely that they just left the original carb not realizing you needed a slightly different carb for auto trans. I was just puzzled by the slight differences I was seeing in various pics of carb, especially the vent rod. Some have them, some don't. Didn't know if that was intentional or did the rod just get lost over time and people ran the carb without it with no noticeable difference.

mighta been what my garage buddies of the time named the carb "pull off" item ...

Any dead spots running the 1100? Does it run better on some day's when the air pressure is higher? I know ppl seem to push these carbs, and if you want to keep it all oem I understand that. But I'd be remiss if I didn't tell you what I thought. I think the scv 1100 is a pos and you'd be hard pressed to find a replacement that's worse than what you already have. The thing it's got going for it is that it's got to be one of the simplest carburetors ever made. But responsiveness is paramount with any carburetor imo. Some people have seem to have good luck with them

Glad 2 hear some 1 (U bro!) say that BUT don't 4get to add that the 2100 might also B da best ever made…
8)

Howdy Back All:

I have to give my opinion about the scat libiled lowly 1100. First it was designed to be cheaply made[FoMoCo problem], second it has a relatively weak accelerator pump. Other than that it is very similar to other one barrels in durability and reliability, but cheaper and easier to rebuild, and somewhat more tuner friendly than Carter YF and RBS, Holley 1940 and #1946 and Weber one barrel carbs.

My experience is that many of the so-called carb problems are more than likely ignition problems. The connection between the 1100 carb and the Load-O-Matic distributor is a source of many of the carb problems- from sticking or broken advance springs springs, a leaking or ruptured diaphragm and vacuum leaks, to bad OEM plug wires, to spark plugs. So, any time you might be assessing any carb start by making sure that the ignition system is in good shape and working as it should and that there are no vacuum leaks.

Back to the 1100 the most frequent problems are related to dirt and crud. A clean air and inline gas filters are a start to remedying those problems. But, in addition, remember that the choke is sucking unfiltered air through the exhaust manifold to the choke coil and into the carb. This happened with all one barrels until the advent of electric chokes. A regular and thorough cleaning, on the inside and outside of the carb goes a long ways to keep the carb happy.

The accelerator pump is probably the weakest part of the 1100s. It is relatively easy to diagnose and a standard part of any rebuild.

Lastly, the 1100 is an easy carb to rebuild. Caution, Do not over tighten any of the screws going into the soft metal of the carb body. Stripped screw holes is not an uncommon problem. That goes for the fuel inlet as well. Given that I'd have to say that another problem with the 1100 is human caused. I apologize, in advance.

Adios, David

Excellent info. Had no idea unfiltered air was coming in through the choke. Can the later model autolites (68-on) work with the load-o-matic distributer?

Howdy Back:

No. The LoM needs the modified vacuum signal from the SCV to function properly. Some have run manifold vacuum to the distributor, but that does not allow the LoM to function properly; and a '68 non-SCV 1100 would be down on CFM also. Not what you want.

Adios, David

That's what I figured. Since the bore size on these carbs are all the same and the Venturi size is determined by adjustable inserts, can you simply place a 1.20 v insert into an autolite meant for a 170 ci with a a 1.10 v insert? I ask this because I do have another autolite around but I suspect it came from a 170. It does have a SCV. Do they even sell the inserts anywhere? If I can't get them, I guess my question is pointless.

Howdy:

Q-"can you simply place a 1.20 v insert into an autolite meant for a 170 ci with a a 1.10 v insert?"
A- Theoritically, yes. The plastic inserts are attached some way that makes removing them intact and undamaged is next to impossible. And I have yet to find a source for replacement venturi inserts. A few years ago Pony Carburetors offered a "new" 1100 with a 1.29 venture insert. I inquired as to where they got their parts but never got an answer. They are out of business now.

It may be possible to carefully hone out the inner diameter of the venturi insert. I have not tried that. The best option is to find a 1969 1101 from a Mustang with a 250 engine. they are scarce but a great upgrade. If you need an 1101 with a SCV, find a 1963-64 Ford car with a 223 six. these carbs are rated at 210 cfm.

Adios, David

Alright. Thanks for all the great info David. The first thing I'll do is measure the Venturi size on the old carb that I have. Maybe I'll get lucky and it's a 1.20v. Now I have to go find my vernier calipers.

CZLN6.......I too, have a 200 with the 1100 on it. In reading all the post that I can, I have to ask why in some of your post that you say that the "exhaust tube" for the auto choke is unfilter air? Is that not air that's been pulled in through the carb breather and into the chambers , mixed with gas, compressed, etc, and is being exhausted out the "log"? In thinking....I guess your saying that because its been down the path of the mixture of gas and stuff. Would this be correct? Hope your think that there is no stupid questions.....only stupid mistakes
Thanks,
Hump

Humpster:
not 2 answ 4 him but (actually I guess I really am)…
there is a sm alu tube that extents upward frm the exh manifold to the choke housing (round black bakelite at back - external to carb) in oe situations. The tube was originally covered w/"white cloth" (asbestose) to keep hands frm getting burnt. This is NOT part of the atomization of fuel to combust in the chambers. It is a channel for hot air to drift up into the coil like 'flat strip' choke spring & heat it to draw open the choke as the engine warms up. Abt $10 bought as a replacement kit it interested. I use an ele 1 wired to my alternater's stator lug. This keeps the drawn up air clean cuz none is needed/used or even present. It's use is complicated (in a minor way) but the use of headers - so, gonzo! on mine...

Alternatively some models have a 'hot water' (rather than 'hot air') choke. Those have rubber hose which brings the same H2O as radiator/heater core use to underneath the carb. & back 2 maintain a 'closed system'.

HTH
Keep talkin...

Thanks Chad for your response. Check that on the tube to the choke. Mine was also a aluminum tube but over the yrs, it had broke off right at the exhaust manifold. So I took a piece 1/4" copper and redid it. As far as the warm air that travels through this tube, its exhaust gases. Correct? That being said....this is air that has traveled in from the carb, ( through the breather ) and when through the atomization process.
I guess what I'm thinking is that......this is air that started off as "filtered air", but becomes dirty as it goes through the combustion process. CZLN6 said that its unfiltered air....True to a point. It is unfiltered air as it travels "back" through the carb again after going through the choke.
Please don't think that I'm trying to stir anything up. Its just a play on words I guess.
Thanks,
Hump