Q-jets... some of us knew this for decades...

[SteveL]

Chuck turned me onto the q-jets wat back when. I think he ran into trouble with the 1st supplier and switched to jet performance.

 

[nvrstuk]

HUGE fan of both the Qjet and 2100 carbs. Like many I've learned some things the hard way with both. Been 4 wheeling longer with Qjets in my square bodies, didn't start with Broncos until 92 about a decade and half later. Never understood why people have used other carbs on either both with a touch of knowledge are excellent on and off road. Angles can be overcome.

Putting together the parts for my first Qjet Bronco and looking forward to the results. Moving to an Edelbrock manifold or I would be happy staying with the 2100. Ease of trail side repair is a major factor along with really nothing to break or fail are major reasons for me. A bunch of the places I go don't get much if any traffic with no service, to far of a hike anymore. Dependability above all else. The only downside is ethanol. I drive square bodies almost weekly and they can sit for weeks at a time before I get back to that particular one. I do find a electric primer pump on 1 of them reduces crank time after a long break. After, it's good to go, no issues the next day or so of sitting. Takes over a week of sitting to need the pusher pump. Switch off until the next time.

Same boat... also used an electric fuel pump to prime and then I also used it as a way to fill up all my gas cans around my property.

The simplicity of the carb, no sensors, no electronics, no sudden RFI issues, blah, blah, blah.

Nice thing about the carb besides its ultimate simplicity is if you pack a screw driver and a small crescent wrench you can almostr rebuild it on the side of the road.

The other fact is that they do not 100% fail and leave you stranded someplace.

When/if you have a carb problem you can still drive a 100 miles and get yourself out of those places where it sounds like both you and I love to go!

Who needs a fuel pump much less one that pressurizes your line at 43-65 psi??? I remember posting up yrs ago about a fuel pump/gas line problem as we were stranded on I84 along the Columbia River... coasted to the side. No gas getting to fuel pump... 10 pm, dark 8ft btw white line and guardrail... Bronco pulling 15ft camp trailer.

I drained gas from my NWMP tank into our foldable water jug, connected my 5/16" dia siphon hose from my carb inlet up thru the vent slots in the hood on the pass side, ran it into the water jug, had my wife hold it with 3 gal of gas in the clear plastic jub on the door frame (window down) and OFF WE WENT. lol What a trooper she is. Anyway, made it to an exit where death wasn't zooming by at 70mph literally a foot or two away.
Fixed the plugged line the next day when we got to our destination.


Back on topic more or less...

I have actually looked at propane again... tanks & over the top propane pricing are killers tho...

 

[gnpenning]

Similar issue on the Arizona strip with losing a fuel pump. We just had a gal jug. More stops to refill but got us home. This was in the early 80s. No traffic or cell service.

Propane has some advantages as long as you don't run out on the trail.

 

[nvrstuk]

Similar issue on the Arizona strip with losing a fuel pump. We just had a gal jug. More stops to refill but got us home. This was in the early 80s. No traffic or cell service.

Propane has some advantages as long as you don't run out on the trail.

Same pre cell days... probably late '80's or early '90's.

 

[ntsqd]

Similar issue on the Arizona strip with losing a fuel pump. We just had a gal jug. More stops to refill but got us home. This was in the early 80s. No traffic or cell service.

Propane has some advantages as long as you don't run out on the trail.

I wonder how far you could get on one of those fattie camp stove bottles? LOL.........

For propane to work well the engine needs to be built with that fuel in mind as their are a few things that should be different from running on gasoline. Not that a gasser converted won't work, just that there's stuff left on the table in the conversion.

 

[nvrstuk]

Leave about 20+% of power on the table. Torque mobile only... because if you are running 600-700 HP you need to run liquid propane & the price quadruples & the last decent propane build I was involved with we built it at 15.2:1 cr. Got a friend on the list here who runs propane & he's been doing it for decades.... Burns super clean as in -very little deposits.

 

[ssray]

Cold weather can be an issue. Depends on the tank though. We used a propane tractor on a corn auger with a 15 gallon portable bottle so we didnt have to unhook to fill the tractor. In fairly cold weather that bottle would frost up and lose pressure and kill the tractor. Needed something to warm the tank under those conditions. That was just a 60 hp tractor.

 

[ssray]

A mystery no longer.....pulled the QJ. Wondered about the steel gas line fitting going in but with a little tapping it came loose. I know I wouldnt get the vacuum lines back to emissions standards as there are 3 or 4 that go nowhere, probably the evaporative parts when the engine was pulled. 8 or more hoses connected various places. Anyway, the big screen question....something I've never run across, just the throttle plates themselves. If I'd thrown some light down there maybe could of figured it out. Double cross hatch pattern on the secondaries only. Opps...take that back, can see faint lines in the photo.

What big back holes those are! I think you could drive a truck.......


.......injector through there. Also interesting that they use two long pass through bolts on the front and studs in the back,

 

[nvrstuk]

What can I say... I love Q-jets. lol I've run the 800's and the 750's.

 

[56f100bbw]

Autolite 4100 is dead simple and better than fuel injection in my experience. I haven't looked at another carb since. My fuel injected motor is too fussy IMO.

I agree 4100 autolite a great carburetor I got 3 extras, plus a friend of mine’s gonna sell me two more hard in good shape

 

[DirtDonk]

I had an old 4100 that I was going to retrofit to my '71, but for some reason (maybe it was the larger size version?) I sold it on to someone that was desperate for one.
Summit Racing has their own house brand that looks an awful lot like a 4100. It actually won the "cheap 4bbl shootout" on Engine Masters a few years ago.
Pretty cool to see a new version. Can't remember what the CFM was, and I don't think they mentioned venturi size.

Paul

 

[nvrstuk]

They just can't supply fuel at 60 deg angles... that's what makes efi "better".

As always, it's the intended use for rhe individual & that part we put on our Broncos that makes one product better than the other IMO.

 

[phred]

Been running a a-jet on my 74 since o
09. Never had a minutes issue with it. Runs fantastic and makes good power. Average 14 mpg on the highway with a hot 306. Ive got a box of 4100’s. One is from a 289 hipo car with the offset jets to compensate for the intake runner lengths. I planted to install one over them on my 78 bronco. Just never seem to get to it since the truck runs so well with the Edelbrock.
The q-jet is mounted backwards in the typical hillbilly fuel injection method.

 

[ntsqd]

Oh Wow, I'd totally forgotten about the backward mounting!!

 

[Yeller]

I ran a qjet backwards for a few months while I gathered parts for TBI about 1999. Ran great up and down, side to side was a problem. Was running a lot of slot ravines in those days so we were always dragging the door handles lol. Been swapping FI since 1989 when everyone thought it was voodoo science, in some ways it still can be.