Motorcraft 4100

[Crush]

Whats the best source for a new one?

 

[tirewater]

New? Supposedly the Summit branded M2008 carburetors are the spiritual successor of the 4100. It doesn't look like anyone has spun up a Chinese foundry to cast any 4100 replacements as they have done the 2150/2100s - so a questionable rebuilt used one is your only choice.

 

[spap]

Do you have to old one to rebuild. Pretty easy unless the carb is all jacked io

 

[MarsChariot]

I got mine from Poney Carbs. But since they are no more, your best bet would be to head over to one of the Mustang forums and see what they are doing for a Autolite 4100 source these days.

 

[B RON CO]

Hi, there are no new 4100s, only new aftermarket carbs.
Good luck

 

[blubuckaroo]

New? Supposedly the Summit branded M2008 carburetors are the spiritual successor of the 4100. It doesn't look like anyone has spun up a Chinese foundry to cast any 4100 replacements as they have done the 2150/2100s - so a questionable rebuilt used one is your only choice.

Agreed.
The Summit carb looks like the closest knock-off.

 

[broncodriver99]

As mentioned I haven't seen anyone repoping the 4100 but the Summit carb is pretty close. I have heard that it is best to go through the summit carb as they seem to be a "starting" point that should be tuned for your specific application.

I have picked up a couple of decent 4100s over the years on ebay but it is a crap shoot. Decent ones go for decent money and there is a lot of garbage on there. I will look around, I think I have a decent core and I know I have one good one in really nice shape if you are interested.

 

[cs_88]

I'm running the Summit 600cfm carb and have been happy with it.
It looks like now they're offering a 500cfm version as well.

 

[Joe473]

I'm running the Summit 600cfm carb and have been happy with it.
It looks like now they're offering a 500cfm version as well.

I haven't tried the summit carb yet but did do a good amount of research. They appear to use common holley jets and power valves similar to the 4100. They also use a common secondary control spring. 1 clear advantage is they do have the ability to resize air bleeds for the idle circuits. This was not the case in the original 4100 and why some look to change the boosters from one carb to another. They are more tunable than a 4100 but not a quadrajet.

The also make a mechanical secondary version that was not factory on the 4100 but kits were offered to modify 4100s to mech secondaries.

I was not able to find any info on float springs in the summit to control fuel during offroading like some 4100 have. I'm sure other would love to hear feedback on off road performance of the summit carb vs 2100 and 4100.



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[cs_88]

I don't have much feedback to offer yet as far as off road performance with the Summit carb.
Makes me realize how long it's been since I've done any wheelin'.

 

[blubuckaroo]

4100 or Summit, I can' understand why anyone would expect any carb to work to its prime without tuning.
You would be leaving a lot on the table.

 

[laserfish]

I have been running the Summit carb for a couple of years with 0 problems. Started and ran with minimal tuning right out of the box.

 

[phred]

I took three 4100 cores and built one. I took the best of all three and still ended up with a carb that will not idle clean. I think ithas a cracked emulsion tube or something. It’s a beautiful piece of shop art now.
One of the three I used was from hipo 289 because it had the staggered primary jets.


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[DirtDonk]

...and still ended up with a carb that will not idle clean.

One of the three I used was from hipo 289 because it had the staggered primary jets.

Could it be that those go hand in hand? Maybe the cam that the hipo engine used is enough different, or that the timing and idle speed specs were enough different, that on your engine it just doesn't want to idle nice?

I don't know that of course. Just that those two statements somehow seemed related.
By the way though, what is a staggered primary jet?

Thanks

Paul

 

[blubuckaroo]

That's where tuning comes in. If you have more cam, you'll have lower vacuum. Tthe power valve thinks you're on the throttle and feeds it more fuel.