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 Autolite 2100/etc. feeds&bleeds 
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
I have a cluster here from, I think, an Autolite 2100, and I can't find anything that resembles an idle air bleed. On the Holley 4010/4011 knock-offs, the idle bleed is located here:

Image

So where the heck is it?

Also, are there any good books or detailed info on the 2100/2150/4100 out there?

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Fri Mar 06, 2015 9:25 pm
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 375
Location: Phila. Penn.
Maybe these pics will help. This is Motorcraft 2150. I've never really mapped and written down the passages - so all I can offer is the pics. In the main body there looks to be a small bleed into the outer wells. In the back of the cluster looks to be a small bleed into the main well. Not sure how that connects into main well's tube.

Edit: Checked my bookmarked webpages - This fellow has pdf of a couple of Ford carburetor training booklets you can download.
http://www.carburetor-blog.com/free-car ... r-manuals/
I just downloaded the first one which cover the 2100. It looks to be from about 1965. If I read the correctly, the holes in the main body are the idle bleeds and the ones into the back of the cluster are anti-siphon bleeds.
Attachment:
File comment: back of cluster showing anti-siphon bleed
2014-Sept-1-MC2150_10-reduced.jpg
2014-Sept-1-MC2150_10-reduced.jpg [ 84.95 KiB | Viewed 598 times ]


Attachments:
File comment: idle bleed in main body
2150-2015-1-RebuildIMGP0111.JPG
2150-2015-1-RebuildIMGP0111.JPG [ 523.59 KiB | Viewed 598 times ]
Sat Mar 07, 2015 12:13 am
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
What's weird is, this cluster doesn't have the anti-siphon bleeds in the towers either. Only the two main bleeds beside the hold down screw. I don't know what this cluster is from. I don't even remember if I ever had the complete carb or if it's something I found by itself in a pile somewhere.

Thanks for the link! I'm going to try to use the Autolite design to 'fix' the jacked up calibration in the Holley versions. Their bleeds are way way too big (edit: and there are two idle bleeds, one in the base of the cluster, and one up high in the tower) and that means the idle feeds have to be huge... and their location way up above fuel level doesn't help any. I'm going to move it to the bottom/inlet of the idle tube where it should have been to start with.

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Last edited by cat herder on Sat Mar 07, 2015 1:08 am, edited 1 time in total.



Sat Mar 07, 2015 12:58 am
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
Image

Image

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Sat Mar 07, 2015 1:07 am
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 375
Location: Phila. Penn.
So what drove the need for two idle air bleeds?
I'm guessing there's a restriction at the top end of that inner tube, or perhaps the tips at the bottom are the restriction. My recollection of the i.d. for those tips is in the .020 to .030" range (eyeball measurement), but could have been a little bigger.

Also interesting is that these Ford carbs have annular boosters ( imagine that, all the way back to the mid 1960s or earlier!). I'm wondering if the large idle restriction and idle bleeds is because the boosters start pulling fuel at fairly low throttle openings. I've not had a Holley 4010/11 carb to play with or compare.


Sun Mar 08, 2015 12:17 am
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
The Ford carbs have normal-sized idle feeds, located at the bottom tip of the idle tube. This orphaned cluster has .025s.

The Holley (also Summit) version has the IFR way the hell up here:

Image

The Holley idle tubes aren't crimped/sized at the bottom, just plain straight brass tube. There's one .053" bleed on the angled pad just on the other side of the IFR, and a second .055" in the front of each tower, just below the crimped plugs. The total area isn't as bad as I was remembering it, .053 & .055 equal roughly a single .076". It's likely the high IFR location is what screws it up.

The main bleeds are where it gets weird... the Holley has two bleeds like the Autolite docs show. The main bleed is a nearly-reasonable .033", but the anti-siphon bleed in the back of the tower is .055"! Total area equal to a single .064" MAB. So it's a 'divorced main bleed' setup, unlike the 4150 where the emulsion & kill bleeds are both fed by the same external bleed. The design of the cluster is such that it's possible to block the rear anti-siphon hole and drill a new hole that connects the after-e-tube/booster leg chamber to the main air bleed chamber. Un-divorcing it, or something.

Image

The original emulsion tubes also have eight .040" holes each.

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Sun Mar 08, 2015 1:29 am
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