tx65coupe

I have an Edelbrock 1806 Thunder AVS 650 currently. I really think that it may be a bit too much carb for my engine. I am considering changing carburetors to an Autolite 4100. Is it possible to get one setup for having aluminum heads, mild cam, and intake that I have?

I also can almost never just get in the car and turn the key and have it start. The only time this works is if its been driven and sits for a short while. When its cold I have to pump it 5 or more times and attempt to start at least 2 if not 3 times. After its been driven in the warmer weather it floods extremely easily.

The average fuel economy is about 16. I was hoping for better than that. Not that this car was built for that purpose, it would just be nice if it were better.

Does anyone have any thoughts. Someone please chime in if this is a bad idea. I'm not looking for Holley recommendations, definitely not interested in that.

2+2GT

The larger of the 4100 was the 1.125 bore unit used on the 289HP, and 352/390/428 engines. Almost all of these were set up for the BB engine, so if you get one, make sure it's been recalibrated for your engine. The one used on the 289HP had a manual choke, on the Mustang.

The 4100 was the finest 4V carburetor ever made. Excellent response, easy to work on, no leaks, and with 4 annular discharge venturis, excellent mileage. I was getting up to 21 mpg highway on my stock A code 4V, which had the 1.085 version.

I know how you feel about Holleys. After 15 years of Holleys on my daily driver, I figure to go straight to heaven when I die.

tx65coupe

Thanks for replying to the other forum too.

Thats what I was hoping to hear. What info do I need to have one calibrated?

I feel dumb for having to ask, but can I use and electric choke on the 4100? I already have it set up that way.

It looks like Pony offers 2 different ones. One has 1.08 and the other 1.12. If I do get one, the one to get is the 1.12 I guess. Like you said, they are pricey at 599 and 744 dollars. I wish it was more like 400-500.

The Edelbrock is a decent carb, I'm not going to knock it, but I just want something more consistant.

I'm not entirely sure what CFM my engine really needs. Thoughts on that?

What fuel pressure do the Autolites like, will my Edelbrock fuel pump be fine?

Starfury

Tx, I think you need to tune your carb before dismissing it. Yes, it's probably on the big side, but you should be able to tune any problems out. The problems you're having aren't related to the size of the carb.

It sounds like the choke needs to be adjusted properly. You may also need to adjust your base timing. These should help with hard start issues.

What happens when the car 'floods' in warm weather? If it's running that rich, get yourself a tune kit and lean it out. The primary advantage to an edelbrock carb is the extreme ease with which you can make changes to the fuel supply. Rods can be changed in less than 5min, and jets can be done in under 15 if you know what you're doing.

kalli

i was jumping between carbs holley, edelbrock demon and figured that if you don't know how to tune them right none of them will work properly. The autolite 4100 1.08 stock is bang on for a 289 stock. simple manifold change and it was still perfect.
however once you start playing with cam and heads you need to start tuning the carb towards it. i found that a 570cfm street avenger was very good for a 289 with intake and headers but it just didn't cut it anymore (or I wasn't able to tune it anymore) once I added heads and cam.

I believe that if your edelbrock works fine for all driving and the only problem is starting we should starting to troubleshoot that.
I believe it should be as simple as
- adjusting choke
- make sure it's not running empty when sitting
- make sure it's not spilling when off
- maybe fiddle with the ignition.

we should at least attempt it. I would be very hesitant to spend 700 euro for a carb when EFI costs just twice that ?!

Kalli

tx65coupe

I don't really want to dismiss the Edelbrock carb, but I want one that is more consistant.

The choke has been adjusted and is functioning as it should.

I have adjusted the mixture for max vacuum and only get 15 psi.

The float levels have been adjusted.

I'm also tired of it having unpredictable starts when cold or hot etc.

The timing is advanced to 14 degrees. Where should I have the timing set?

If its cold outside like colder than 40 degrees the car is really cold blooded. It is happy above that and up to probably 90 degrees or so. It does fine when its hotter but doesn't like when its 100+ degrees all that much. It doesn't get that hot but it floods and or vapor locks often then. Especially after shut down and attempted restart.

It will sometimes flood even when its cold outside and it has only sat for a little while, but thats not that often.

tx65coupe

Your right, jumping around all over the place with carbs is not the best idea. I just thought that it would be a more predictable setup. Those Pony carbs are expensive. I was just thinking about it. I need to do more trouble shooting.

I'm not sure what you mean by spilling when off or running empty while sitting.

I do know that the boosters aren't dripping while its running.

JMD

I hate to admit it since they are made in China, but I am going to, between my son's and I we are running 3 of these carbs right out of the box. They have proved to be excellent drivers, and economical.

http://www.summitracing.com/parts/SUM-M08600VS/

Anyway, rumor has it that they are a copy of a Holley carb (now out of production), that was made very similar to a 4100 (kind of a 4100 copy), they do kind of resemble a 4100 apart from the accelerator pump which is not the same.

My Lincoln starts on the first turn of the starter practically every time, even when it is in the 20s outside, then idles cold without any help, gets me between 15 and 20 mpg, and it runs great.

I bought the first one because it was cheap, and I have to reluctantly admit to being impressed. Jim has one on his 66, it is a little cold blooded but it has a huge cam in it and would probably benefit from a good tuning.

Just another (cheap) option....

kalli

i'd say start in that order.
when car is cold and was standing for a while, best is over night:
remove air cleaner, the choke butterfly (front venturi top, not the AVS thing on the secondaries) is likely to be open. The rear one for secondary (has absolutely nothing to do with choke will be closed).

now without turning any keys simply look down the front venturis.
1. open the throttle plate (agitate the linkage to gaspedal at carb) and while opening you should see petrol spraying
2. When throttle is fully open close the throtte and latest now the choke butterfly should be fully closed (or pretty close to close)

if 1. results in: na, didn't see any petrol there. Then the first thing I'd do is add a phenolic spacer under the carb. Chances are very high that after engine shutoff the carbs starts boiling and fuel evaporates (common issue) so you will have to start the engine for lets' say 20 seconds to fill up the fuel bowls again

if 2. results in: na, that thing stayed open then pick up the owners manual and check for how the choke is supposed to be adjsted. can help here as well, just let us know the results.

if both 1. and 2. are ok (and only then) then don't spray a 2nd time. simply get in the car and start with no foot on pedal. doesn't start, press pedal half way. if you get it to start get it back to idle. if it cuts out there then you need to increase the fast idle screw.

let us know how you get on

Kalli


edit: after seeing JMDs post. yes, forgot to mention. this is a very very good alternative to the 4100s. seen a cut through, it's very similar design

eZ

your 650 is so close to being right. Going to something smaller is just not hot rodding. If your going to spend $300, is there anything you dont have yet that can help your car breathe a bit better? Headers, intake?