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Author Topic:   Jets for autolite/motorcraft carb
o5racer
Dirt Freak

Total posts: 402
posted March 06, 2005 07:26 PM  
Where can I get main jets for an autolite 4100 carb? its the one that looks like two twobarrels back to back. Right now it has a 48 front jet and a 68 rear jet. out on the road it runs real good but I would like to have a few other sizes on hand for test day. Thanks
Nick

ryan
Dirt Forum Champ
Total posts: 776
posted March 06, 2005 08:30 PM  
http://www.carbsonly.com/

Try them

o5racer
Dirt Freak

Total posts: 402
posted March 08, 2005 06:46 PM  
Any other suggestions?
Nick

dirtpoor racing
Dirt Full Roller

Total posts: 29
posted March 09, 2005 04:58 AM  
i got some different sizes from out of the two barrels. I think there are a few different sizes that came in them.I think I got some 57's out of one.Glad to hear another motorcraft is out there.

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted March 09, 2005 07:51 AM  
Here's a simpler answer: Cut the threads off the end of a Holley needle/seat assembly, skrew that piece in there with red loctite, and just use Holley jets which are easily available anywhere....the outside threads of a needle/seat assy are the same as Motorcraft jet threads, and the inside threads are Holley jet thread (1/4x32).

Hot tip of the day....

:-)
KP

o5racer
Dirt Freak

Total posts: 402
posted March 09, 2005 10:17 AM  
I will have to go home and check on that. That would be much easier. Thanks
Nick

o5racer
Dirt Freak

Total posts: 402
posted March 10, 2005 01:27 PM  
Hey KP, which style of holly needle and seat are you refering to? I just went out and pulled out one of the old ones for my 4412 and compared it to the motorcraft jet and the threads are larger on the needle then the jet.
Nick

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted March 10, 2005 02:00 PM  
Sorry, you must not have the same Motorcraft jets I am thinking of. They are a large thread, larger than the standard Holley or Rochester type jets (both of which are 1/4" with varying pitch).
Are your jets a 1/4" thread as well?
We've been putting "sleeves" like that in M'craft and Autolite 2bbls for years, because the OD of the standard commonly available needle/seat assy of a Holley carb has the same thread as those large jets. The ID of the Holley needle/seat assy is the same as the Holley jet threads.
Now, are you talking about the very SMALL Ford jets that are in 4cyl carbs? If that's the case, then that's an entirely different issue, and those little jets are available as blanks or in a few sizes still, and most of us carb builders size our own jets for that.

Sorry about the confusion and hope this helps some.

I think now that you mention it, the 4100 4bbls didn't have the same jets as the common Motorcraft 2bbls did...

Sorry about that...

KP

o5racer
Dirt Freak

Total posts: 402
posted March 10, 2005 09:22 PM  
The threads on the 4100 jets measure .306. is this the size you were thinking of? I would rather use the holley jets if possible because they are available here in town.
Nick

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