The QJet. Right now I have the secondaries set closed so I know those aren’t opening on their own, and the Woodgas inlet is capped off. I JB welded on a new throttle lever for the secondaries, so I know those are static.
It’s got to be some kind of an air leak or the carburetor is warped. I’m leaning towards the carb being warped because this was already a junky carb to begin with, but it ran sorta kinda before I rebuilt it and did the MEN modification.
If I close the choke my RPM goes down, or if I forcefully pull on the throttle linkage it will slow down somewhat.
I’m using a new gasket as well, and all the vacuum ports that I’m not using are plugged with silicone boots.
Edit: obviously this part of cars is out of my wheelhouse, I’m just glad I have an untouched working QJet that I know came off of a 350 SBC to fall back to.
I’m going to build the plenum out of some 2x6" heavy gauge steel tube and use my good QJet on top, I’ll essentially be copying what @Woodrunner did with his C10. I 3D printed a copy of a quadrajet heat isolator/spacer so I can make sure the holes are lined up well.
Thats what i did with my 73 chevy. Had two foot switched down there. One to switch from high/low beam and another momentary for the horn.
The horn switch was actually just another high/low switch i modified.
I hate horns. Especially if they are directed at me. I could count on my fingers how many time I used a car horn in my life and generally to alert someone about something. My middle finger has probably been a little overused though.
I’m assuming the venturi chamber before the throttle itself is important, maybe to impart turbulence?
I like that the air mix seems like it would act like an injector, to hopefully promote better gas flow.
I’ll need to see just how long I can make the plenum, it’s 2x6x(1/8 wall) steel tube. I’d like to have the carb and throttle body one in front of the other, but I can always bias the throttle body to the very front and make a new flange.
@Woodrunner do you think rivet nutserts would be a good idea to add threads for the carburetor and throttle body? It would be put into the steel square tube of course.
Hi Cody, rivet nuts work fine, i’ve used it myself on my old volvo.
It’s important to Countersinking them though, to get them flush for the gasket surface. (I didn’t and had to enlarge the holes in the gasket, but that worked good to)
Edit: there are available special “pressure tight” rivet nuts, which expands some more in the hole, could be good to use if gasket surface is limited.
I put my untouched QJet back on the truck for now, but I noticed a Dirt Dauber had started trying making a nest at some point at my carb’s PCV port. Punched that clean and put it back on the truck and now the Good QJet runs even better. Guess that happened when it was kept in the garage unattended for decades.
With the idle screw set to not touch the throttle, using only my air mixture screws I get a very healthy 600 RPM idle. I bumped it just a hair so the screw is barely touching and that puts me in the 650-700 range of RPM and it maintains a strong 500 RPM when put into gear. Should be great for sipping gas now. Before I had noticed the dirt partially clogging the PCV I actually had to up the Idle a bit and it only sounded healthy at 800 which is technically where it should be.
I ordered replacement valve cover gaskets, the fancy felpro rubber ones with some T Handle style valve cover bolts and some new spreaders.
I removed the Air Conditioning compressor because I noticed my plumbing for that was damaged anyway so it was dead weight and taking up room. I’m glad I didn’t try to put freon in it. I’ll definitely get around to fixing the air blower doors so I can at least get lukewarm air blowing out of somewhere other than the defrost. At least I have blowers that work and it’s set to defrost.
Got the new gaskets and bolts put in. They’re good and snug.
I’ve been noticing something odd lately with the exhaust mufflers, oil is weeping out of two of the bolts on the passenger side. It’s not coming from the valve cover area because the oil weeps out through the exhaust bolt holes.
Does that mean a cracked head? Or the bolts are just so old and worn they aren’t sealing oil in?
Forgot to take pictures of the rockers etc, driver side was just plain crusty nasty, passenger side was okay but dirty nonetheless. The PCV grommet was hard as a rock so I replaced it and the valve just to be on the safe side.
The breather will just get a regular standalone filter unit.
With how nasty the top end looks I might do a can of BG EPR on this upcoming oil change. It’s been running with MMO, 10W30 and a small can of that engine compression restore milkshake. My passageways look okay, I didn’t see any crap on those. Maybe I should just keep running MMO to slowly clean it so I don’t risk knocking a big flake of carbon and block it up.
I would put rags /or bolts ECT. down in the oil return places on the heads/crape as much carbon out while holding a vacuem hose to draw out the carbon as you break it loose/that should keep most from falling down to the oil pan area.
I did do that, got the easy stuff scraped off and sucked it up with the shop vac. Not sure why the driver’s side was so much nastier than the passenger side though.
The PCV flow pathway on a V-engine CodyT.
Fresh make-up air in the one valve cover.
Then all of the engines internal evaporations, and rings blow-by sucked up and out through the other valve cover.
Some four and inline six cylinder are even more dumb-dumb. Fresh air in one end of the valve/cam cover. PCV sucks out out the other end of the same cam cover.
Ideally the fresh make up air need to be introduced into the crankcase. Internal engine vapors removed up high under an oil flinging shielding baffle. Most small single cylinder engines do this well now.
S.U.
Makes sense, the PCV is currently on the Driver’s side valve cover.
I’m wondering if I should keep or delete this 70’s era EGR, it doesn’t have temperature dictated activation, it’s pure manifold vacuum actuated. I know more modern EGR is non-negotiable you must have it to maintain cool engine temps. Many people say to block it, and just as many say to keep it for fuel economy reasons. Some also say the older EGR systems dirty up the engine faster.
Trying to think of a way to make a Venturi chamber to insert in a pipe for a manual gas mixer. I really like the concept of the Finkbeiner mixer, it’s basically making a Gas Injector utilizing incoming air. The Venturi chamber after the mixer itself but before the throttle is meant to recover pressure.
I might try to heat up a PVC pipe and tighten a hose clamp around it to evenly smush down. I’m no good at 3d modeling, but the other idea would be to 3D Print a chamber and epoxy it into the pipe. I have some Carbon Fiber Nylon which is very heat resistant.
Going to start working a little on the gas plumbing. I’ve decided to have my woodgas line go over the roof and down the passenger A Pillar like I did with my Mazda, except I’ll cut a hole in the fender.
To protect the gas line I’m going to insert a Uniseal in the fender. I can just slip the pipe through the rubber bulkhead and that should protect it from being damaged via vibration. It’ll also prevent me from having to use a bunch of extra bends to travel along the undercarriage.
Cody,
Sounds like a great idea, if you have access to a printer. You could experiment with an inexpensive plastic until you get the shape you want, should not get hot enough there to melt plastic, unless the carbon soot catches fire.
I like the idea of the Finkbeiner design.
Oh yeah I’ve got a pretty decent filament FDM printer. I also have a resin SLA printer, but resin prints are fairly fragile. I think one burp from the intake would grenade anything SLA printed .
I just need to actually learn how to 3D model or find a modeller for hire. That’s more of a willpower issue than anything else.
Turns out I just needed to use Windows 3D Builder since it’s such a simple shape. Using my LS throttle body, and using 3" PVC’s 77mm ID as the OD for the cylinder, I then used simple cone shapes to cut out similar enough to the Finkbeiner venturi chamber. I set the tightest place as 50mm but I can always modify that to be a bit bigger. I think 50mm will be best because my gas pipe going in will only be 2", and I reckon I’ll use a 1.5" air inlet for woodgas.
The mixing chamber will use 3" pipe, with my gas inlet arriving at an angle like Finkbeiner has shown. Air will come inline with the venturi.
I wonder if there’s a good way to test the efficiency of this style mixer versus a T Mixer?
I was thinking of hooking up my charcoal gasifier to a series of blowers. Using no mixer as control, a T Mixer, and then the Finkbeiner once I finish making it. Not sure what the test would actually look like. Readiness of ignition? Or length of the flare? It’s hard to say.
Fixed one problem, headlight switch and pigtail.
Found a new problem thanks to the minty fresh scent of Marvel Mystery Oil. My oil pressure gauge line is leaking somewhere inside the cab, I can see it running down the firewall inside. Looks like a slow weep.
I guess I’ll have to find a new mechanical gauge to go in the cluster and replace the line with a new one. Old 1/4" copper line is probably stress cracking from age. Bummer.
Also a note from the oil change I did today, it was some of the nastiest oil I’ve seen in a while. No chunks of sludge but just dark from only maybe 250 miles of driving and idling. Replaced the oil with 10w40 conventional and 1/5 volume replaced with MMO to further the cleaning. It’s funny with all the weeping and seeping of oil I’m not noticing a huge loss over any length of time. Maybe the MMO is helping to swell up the seals again.
It’s definitely the oil line for the pressure gauge. I thought these were copper but apparently it’s steel. It rusted and finally broke through. I just barely touched the line and it came through the firewall.
I bet this means my oil pressure is a lot higher than it’s showing. Right now it’s saying I’m at 15-20 PSI at idle. Waiting on a new copper line to show up in the mail.
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