Autolite 2100 1.02" C3TFH for stock 292 V8

Decided to get into this rebuilt carburetor a little closer before the summer driving season is upon us. "Should" have inspected it closer before installation. Thought it was running lean.

Spec size main metering Jets according to the manual are:
48 for 0-5000 feet
46 for 5-10000 ""
44 for 10k-15000 ""

Installed? 43 ! Yeesh. These older Autolite jets are supposedly tough to find, because up until 1963, they were 1/4" thread size. This is the same thread size currently used by Holley.

So.. What's the deal there, what am I missing? Why can't I order #48 Holley Jets, and call it a day? Or Holley #48s don't correspond or?? I have some Holley jets laying around and they physically fit fine, but 73s may be a little rich.

Next. The power valve selection according to the shop manual is a little confusing (to me anyway)

There is "Green" listed for 0-5000 feet, and "Yellow" and "Black" listed for the higher elevations, yellow is also listed as #65 and black as #55, sounds a lot to me like they are 6.5 Hg and 5.5 Hg, no? But I dunno. So is "green" power valve a 7.5?

Finally, to confuse things more the manual says on the next line
"Power Valve Timing Opens @ Inches Of Mercury"
C3TF-9510-H, J, and K ....... 8

Tells me that all V8 292 engines and trucks need a power valve that opens at 8 inches? So, I'm just a simple guy trying to do a simple job. Can anyone translate these old specs into new part #s?

 

Just something in the back of my mind and thats pretty cloudy these days but I seem to remember that Holley and Autolite jet sizes aren't equivalent, like a Holley 48 isn't the same as an Autolite 48. Seems I read that somewhere after I had all my jets in the same bucket . So when I needed to up the jets in my new Holley I just ordered new ones from Holley, not sure if you can get new ones for the autolite. I know most of my jets are Autolite, what size do you need?

 

Well I want to install a pair of the 48 (stock) for 0-5k feet. Hope I didn't roast a valve running 43

I'm pretty sure Holley jets drill size correspond directly to their number size, until they get up in the 80s or somesuch, but that's not to say they cross direct with Autolite.

 

ND has weighed in before, sounds like the "green" is equivalent to: ??

COAZ-9A565-A .. Economizer (Power) Valve ~ 0-5,000 ft. (Motorcraft CE-74) / Obsolete

 

Wondering if any of you have number drill sets. Be interesting to see if a #48 drill fits a # 48 jet for comparison. Posted this link below just for a look at. Many links covering jet drills with pros an cons

20 Piece Carburetor Tuning Drill Bit Set Holley Rochester Carter Mikuni Walbro - Drill Bits Unlimited.com

 

I tend to run on the rich side to be safe and usually go up two sizes from stock running this crap ethanol fuel and California blend.. Want me to look and see if I have any 48's?

 

These are the ones I just bought for my C3TF-H carb, they are the smaller 1/4" thread size and worked fine... They are considered Holly #48 jets...

1/4" Holley Jets

Power Valve

If you go on that Mikes Carb site, he explains what each piece is, like the power valve, and which ones you SHOULD buy as opposed to what they say in the book written 40 years ago and also how to test them to see if they even need replacing.

Hope this helps

 

Sure do appreciate this! See if you have any 50s, stock is 48, already ordered a set from Mike along with a 7.5 power valve. Good point about today's fuel, it's not the same!

The fuel bowl when I opened it, it looked just like somebody whizzed in it. I thought I remember as a little kid, gasoline had a reddish tint, not urine? "Your horse has diabetes". Hm.

Best smell ever was that 5 am mixture of worms, outboard motor boat gas + lake water. Oh well.

 

I'll get out to the garage and check in the morning. What size did you order, the 48's?

 

Yep, I have 48s on the way. No rush, when you get a chance. The 43s will work if I ever get out to Leadville. Thought it was runnin' a little lean here. Didn't ping or surge though? Lots of messed up stuff on this "professionally rebuilt" carb going through it. *******s. Think I'll check everything. When I read that jets are tougher to find for pre-64 Autolites I figured some clown would install "whatever", turns out that might have been it. The accelerator pump arm (at the front of the carb) should have been installed on the "inboard side", the power valve isn't quite the right size, and of course the Jets weren't even close.

Since I'd never disassembled one before didn't notice this clip was missing - figure I can make one out of a paperclip. Shouldn't the needle be able to freely rotate where it wants, while it hangs off the float arm? Mike in the videos on the 2100 sez the little clip is to keep the needle jet from sticking.

Well my OCD kicked in and disassembled the carb completely, removed the annular discharge assembly, cleaned that up. There sure are a lot of holes in that thing, rodded them out with some fine twistie wire from loaf of bread, and ensured the checkball and rod were installed for the accelerator pump.

The accelerator pump itself is a little different than later models. The little red rubber umbrella deal apparently hadn't been invented yet. Good thing I have the Shop Manual, and better, even read it a little bit. There's a checkball in that, too. Coulda been trouble there. Got them both out safely.

 

Thanks, I have never looked at that site before so I was glad he recommends going up two jet sizes also for the crap gas.

 

I'll see if I have one of those clips for the needle when I get out there, it's just 5am here LOL. I don't know if the needle actually rotates or not.

 

Mike has quite the webpage for Carburetor Parts.

He stocks those clips. Takes .19c for em too. I can't wait.

There's also supposed to be a damping spring on the float arm, to keep float from flopping around when on rough trails, and a splash guard that goes around the needle seat, and a fuel filter screen at the inlet. Sure glad I paid top dollar for a rebuild to do it all over again.

 

Good you can order the clip, I did find one but no luck on the jets. No matching pairs in the 50's and all the other pairs are in the 60's. I don't know who you got that carb from but I wouldn't deal with them again. Some didn't have that spring but a spring was built into the needle, I still have one of those.

 

Good you can order the clip, I did find one but no luck on the jets. No matching pairs in the 50's and all the other pairs are in the 60's. I don't know who you got that carb from but I wouldn't deal with them again. Some didn't have that spring but a spring was built into the needle, I still have one of those.