Another Carburetor-Question

F

firewall

New member
Hi,

first of all I have to short introduce my Car and myself: I´m a 42 years old guy from Germany and happy owner of a 1968 T-code Mustang with C4 Trans since last summer. I bought the car in the area of San Diego and it is in quite good condition. After a few changes (Pertronix, Carburetor rebuild, non-Stock aircleaner) it runs well and economy is quite good with 20 MPG.

The carburetor is a Holley 1940, non LOM and similar to many Storys I´ve read here there is a stumbling and stalling when I want to accelerate fast with WOT even after the rebuilding.
So, I´m considering about another Carb and found a lot of Input here but there are still a few Questions.

If I am right, and my english don´t blame me I´ve understand that the Holley 1940 is not the best coice for the I6 and a little bit small. Better and bigger Carbs seem to be: Autolite 1101, Carter YF, Carter RBS and Holley 1946. The Holley and the Autolite should fit just like "plug&Play" or not ?
I´ve got the 1.5 bore so I will need a adaptor if I choice one of the Carter Carbs.
Will the Adaptor CA-200 from Enginequest fix the Carter Carbs on the 1.5 intake bore and could I use the stock throttle linkage with it ?

And finaly, I would like get mor torque in the lower RPM´s will a Carter RBS increase the performance in that way, or is one of the other carburetors the better choice ?

Thank you for reading and greetings from Germany
Helmut
 
Howdy Helmut:

And welcome to the FORUM. It's the best.

First, I must ask you some questions. Is your '68 Mustang a Calif/Emissions engine. It should say so on a sticker in the engine bay. If it is, it will have a good distributor, that has both vacuum advance/retard as well as centrifugal advance built into it. The down side is that the stock Autolite 1100 carb is downsized to a 1.1 venturi, which is flow rated at 150 cfm. 1968 is also the year that compression ratios started to become lower. A 48 state 200, in '68 was rated at 8.8:1. Calif/Em equipped engines were rated at 8:1.

Considering your current upgrades, linkage issues, and "Plug&play" plan, I'd recommend a carb upgrade to an Autolite 1101. It is rated at 215 cfm and looks like an 1100. Linkage, fuel lines, vacuum lines and air cleaner should all fit. You will have to modify the carb spacer that sits between the carb and the manifold. You will need to flair the top of the throat to clear the larger butterfly valve of the 1101.

The Carter RBS is a fine carb, but would require adapting the linkage, fuel line and possibly require a different air cleaner.

The 1101 should wake up your engines top end. To increase your engines torque characteristics you will need to increase the compression ratio to the 9:1 range, and/or lower the rear end gear ratio. What ratio rear end does your car have?

Enjoy the Forum and keep us posted on your choices and your progress.

Adios, David
 
8) helmut, your english is better than some here in america. welcome to the site. as for swapping carbs, my suggestion would be to go with a carter-weber carb from stovebolt engine co. it is a two stage carb with a small primary. classicinlines should ahve the proper adapter for the carb.
 
Welcome Helmut! I had a chance to live in Germany (1971-72) I still miss many things like the great food. Good luck on the T code
 
Hey
:thanks:
:nod:
that´s what I would call a very friendly "Welcome" - Thank you all very much!
I found a lot of suggestions and will consider about all the different ways - as I know:
Many roads lead to rome.
What I found for getting more Information is the Falcon 6 Performance Book - so I ordered it and hope to understand more about the I6.

@ David

I got the Distributor with both vacuum and centrifugal advance. But last time I tuned the carb I forgot to reconnect the vacuum hose and it seems to cause no Difference... so I examine the Vacuum canister at the Distributor and it´s ok - but I guess the plate in the dizzy is going not easy enough for the vacuum. I´ll try to find out if it works with a strobo lamp next days.
My rear end ratio is 2.83 that´s pretty ok, or is it not ?
The autolite 1101 is an interesting carburetor - but for me hard to find. Till now I have not found one at ebay or so. Are there any recommended Dealer which ship worldwide and will sale a 1101 without getting a core ?

I hope you all enjoy the Weekend, I will post how things going on.
Bye for now,
Helmut
 
enjoy the Weekend,
It's our "4th of July" /or/ Independence Day (250 yr old tradition).

You may trade for a core some 1 here wants to get rid of (send them the $ ) in a not-to-complicated, 3 party deal??? Seen it done on other sites.

Welcome to USA! Did U get ur shots when crossin the border? Got a stinefull a that great beer to share? :beer:
 
Hi @ all,

before I´m going to change the carb I decided to have a third look at my current one. And I remembered that the pump discharge ball and the discharge weight near the pump were not in place whe I opened it first. My Hygrade Carb kit contains the ball - but (no reason why) not the weight. So I decided to don´t install only the ball and let it as before.
After reading a lot of stuff here in the board, today I made a discharge weight from 4mm aluminum Bonsai-wire and install the ball and the Bonsai-weight :mrgreen:
After assembling the carb and doing the first ride I notice that the engine has a better throttle response and more torque... and additonally the exhaust sound has complete change - more like trumpets and even not so dull as before.... :hmmm:

Is this all the result of a simple ball and weight above it ?
My question shows that I don´t have a clue how this discharge stuff works... could anybody try to explain this for a rookie like me ?
Many thanks and greetings,
Helmut
 
Hello Helmut and a belated Welcome! to The Forum, as David says.

Yes, I think adding back the outlet weight and ball check to your accel pump system could make a big difference. The outlet weight and ball check not only prevent vacuum from unintentionally drawing excess fuel from the accel pump system, but also prevent the reverse flow of air into the accel pump system (best lay interpretation of the Ford Shop Manual description I can offer). I think the results of your ingenious repair also support that. Great job on identifying and resolving your issue :beer:
EDIT: Necessity being the mother of invention, innovation or even good ol' yankee engineering...congrats :thumbup:
 
Yes those little brass weights are a pain to locate.
I figured if I need one I might try a hobby or rc shop to find some brass rod.
 
@ Frankenstang
Thanks for your explanation - now I quite understand what for the ball and the weight is.

@ Jack Fish
It´s good to know that they originally were made from brass. I guess brass is nearly three times heavier than aluminum is... maybe this makes another difference. So I have to take a look for a brass rod.

:thanks:
 
And they are not round, in case you didn't know. They are hexagonal.

Come to think of it, a small piece of Allen wrench might work too.
 
Yes, I saw a round one here, and a hexagonal ohter where in the web...
Your idea with the allen wrench is very smart - unfortunately sometimes I´m to blind for such good&easy things :D
Thank´s a lot!
 
Okay,

now I´ve checked the Ignition Time and find out that both advances (vacuum and centrifugal) at the Distributor work well. Vaccuum is about 18 inches/Hg at the manifold.
The timimg is know at 14° and there´s no pinging or knocking. I tried to tune the air idle by using the vacuum but it was all the time a stable peak, so I turned it 2 + 1quarter out and that seems to be quite ok. Unfortunately, the stumbling & stalling in case of fast WOT is still present...

I found a carb (Autoline C844) for a 1969 250 and I think that must be a reman Autolite 1101. I know that the bore changes from 1.5 to 1.75 in midyear 1969. Will it be possible to mount the carb on my 1.5 bore even if it has a 1.75 or have I to use an adaptor in that case ?

Thanks for answering,
Helmut
 
Howdy Back Helmut:

ON the idle air screw, with the engine running and warmed up, turn it in until engine speed starts to decrease, then back out until highest engine idle speed is obtained. Go no farther then that. If you do you will be richening the idle circuit.

On adapting a 1101 to your engine, I'd suggest that you use your current spacer. It is made of soft metal and can be easily filed to flair the top of the hole outward. It will only need to be flaired out enough to clear the larger butterfly valve of the 1101. Be sure to verify that the carb is an 1101. The throttle bore should measure 1.69" inches or 1 11/16". 1100s measure 1.44" or 1 7/16".

Your engine vacuum and timing sound good. Did you check to make sure the advance plate, inside the distributor is moving freely? The stumble at WOT is most likely related to the accelerator pump issues and to the Holley 1940 carb.

Keep it coming.

Adios, David
 
Howdy David,

the advance plate in the distributor moves free, I checked it twice and by using an Ignition time lamp I could see that the centrifugal advance moves forward with increasing rpm - and moves forward a lot more by using both centrifugal and vacuum advance. So, I guess the Dizzy and the vacuum seem to be okay.
I will re-adjust the air idle screw like you suggest it, otherwise it seems that the engine starts better and the stumbling is bit less when the idle circuit is a bit richer... but I will check this.

The carb is tis one: http://cgi.ebay.com/ebaymotors/ws/e...0309194733&viewitem=&sspagename=STRK:MEWAX:IT

It must be an autolite 1101, or not ?

A few days before, I got your book from classic inlines...great stuff!
And, I ´ve to learn more things I would imagine... :D
Best regards
Helmut
 
Howdy Back:

Yup, That's the 1101. I'm glad to hear the handbook is useful to you. Keep us posted on your progress.

Adios, David
 
:beer: Hi guys AND gals.Just discovered something today when I was rebuilding my carb.(YF)
The needle and seat setup has a separate spring loaded thingy in the needle.Its BRASS.If you need a brass piece for the check ball setup,just clip the small diameter piece off of it and you`re good to go.(use the larger diameter piece)My carb was missing those pieces(the check ball and brass weight).
NOW,the truck runs really well.Recycling DOES work. :rolflmao: :rolflmao:
Good luck.Have fun.Be safe.
Leo
 
:cool:
:D
Hey woodbutcher, that´s really smart engineering!

I tried to make a weight from an Allen Wrench but however my 1940 Holley runs better with the weight from aluminum... :hmmm: Currently the engine runs very comfortable and the mileage is about 22,5 on highway at 70 mph.

Last days the autolite 1101 was delivered and I´ll try to make the swap in mid August. There is one new connector on the carb I couldn´t figure out what for it is...



I would be very happy if someone would be so kind an tells me his opinion about this.

Greetings from cold Germany,
we all think that our calendars are broken... they lost the summer 2011 :mrgreen:
 
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