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Bryan Irons
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Bryan Irons
Words and photos by Bryan Irons - @Bryanirons
If you have been following at 4WDrive, you know that our latest acquisition, Tim Toyota, a 1976 time capsule of a FJ40 Land Cruiser, has garnered squatter’s rights in Editor Irons driveway… Much to the chagrin of his lovely wife. While Tim not only runs and drives, it has even made a few road trips during its short tenure with, and given us some blatantly obvious areas to attend to. It runs like crap, drives like crap, and road trips like, well, it’s actually pretty fun for road trips… once you get it going. Basically, it needs some lovin’, and not the “Barry White in the background” kind.
Under the hood of our superman coloured dirt tank is a lowly Chevrolet 307 V8. Never heard of one? You’re not missing much as it was the base V8 engine in many late 60’s GM vehicles and has a reputation of being unexemplary. Local folklore has it that many moons ago, Tim was blessed with a rip-snortin’ 350 CI Chevy variant that would easily turn the 38” tires that the rig wore. At some point, the current smoldering turd was swapped in. The old Toyota was driven for a few years in its current disappointing state before being stashed under a ponderosa pine for a decade before our grubby paws acquired it, tree sap and all.
Cold starting was a feat of patience requiring a keen feeling for battery life, throttle control, and enough ether to cook a bison... medium well. Once warm, the motor would run OK, but black smoke out of the tailpipe during acceleration and some surging while trying to keep a steady speed told us something was awry. Off road performance was abysmal, as a quadriplegic tortoise with irritable bowel syndrome could make its way up a mild trail in better time, and less mess.
Riding atop the Chevrolet engine was a vintage Edelbrock 700CFM carburetor and a matching Edelbrock Torque intake manifold. This combination was not only too large for the vehicle, but designed for a much higher RPM range then the motor was capable of. Although we could have worked on the tune of the carb, we had to face reality - because the Toyota was unceremoniously mothballed in the past, who knew what was rotting within the original carb. On top of that, we knew some meddling had happened with the carburetor as the metering rods were mismatched, the electric choke was disconnected and out of adjustment. The carb had been mangled so badly that the back barrels were jammed closed. It had reached the proverbial point of no return.
We hit Summit Racing’s website and went shopping. A plethora of Edelbrock items were checked off our shopping list; Performer EPS intake manifold (EDL-2701), a 500 CFM Performer electric choke carburetor (EDL-1403), off road needles and seats (EDL-1465), a calibration kit for the carb (EDL-1486) and we splurged on a fancy air cleaner (EDL-41153). Gaskets and other pieces were picked up as well since the Summit brand gaskets we had used in the past were good quality and a fair price. While approaching our shopping limit we decided to upgrade some shop equipment, as we knew tuning was going to be required. We scooped an OTC vacuum gauge kit (OTC-5613) and a new Summit timing light (SUM-G1059) with adjustable advance.
We could have honed our grovelling skills and possibly gotten the green light for an EFI setup, but this would have killed the mojo and simplicity of Tim the Toyota. With a plethora of aftermarket carburetors available, we reached for the Edelbrock for its ease of tuning. According to Summit Racings Carb Calculator, even if we managed to get the old mill to 6000 RPM (HA!) we would have required less then 500 CFM. Unfortunately, Edelbrock does not offer an off-road version under 600 CFM that keeps fuel from sloshing around and flooding while at odd angles or bouncing down a washboard road, so we scooped the parts and pieces needed to retrofit our new one. A few other trick and mods were also made to ensure the old Toyota lasts another millennium.
With parts in hand we slipped away for another weekend in the shop. We knew the process of swapping the intake manifold and carburetor were simple ones, but the tuning process could take some time. Edelbrock supplies a handy chart to utilize the parts and pieces included in the tuning kit to get a good baseline. These are the results of our time well spend in our concrete happy place.
Summit Racing Equipment – www.summitracing.com
Edelbrock USA – www.edelbrock.com
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Lurking under the oily veil seen here is a sad example of late 60’s hot rod culture. This sad 307 Chevrolet has been suffering the automotive equivalent of waterboarding with high performance parts on a low performance engine.
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We called our buddy Darren over for some impromptu slave labour. With an engine sitting this long, take your time removing hoses as they likely have a good hold on the fittings. We brought our engine to Top Dead Center (TDC) before removing the distributor so that it could be replaced more easily.
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The first hour was simply nuts and bolts and no special tricks were required. Once the intake hardware was removed, gentle prying was all that was needed to remove it completely.
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One wheelers junk is another wheelers treasure. There’s no way we will recoup our costs with this pile of “useds” but I’m sure we can restock the shop fridge.
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Scraping the heads and block of old gaskets material is not a glamorous job, but it must be done. We stuff shop rags into the intake runners and line the lifter valley to keep any debris from getting into places it shouldn’t.
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Time to start our recalibration of the carburetor for our driving style and altitude. The Edelbrock manual is very useful for getting a good baseline.
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See that tiny clip holding the choke arm in place? Dubbed a “Jesus Clip” and not because it’s holy or divine, but because that’s one of the words you WILL use when you drop one of them on the floor while meddling with the carb internals.
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The old style needle and seat, which stops the flow of fuel to the carburetor bowls, is on the top, and below is our new “off-road” setup, which acts like a shock absorber when things start bouncing.
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The top of the carb had to come off to get to the components we needed to change (needle and seat, rods and jets). This can be done with the carb still on the engine.
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The needle and seats live under the pivot point of the carb floats. Once they are replaced with the new ones, the float level must be adjusted. We use a drill bit of the specified thickness found in the manual. Remember that with the spring-loaded needle and seats, you adjust the height when the needle just contacts the seat to stop fuel, not with all the weight of the float bearing down on the needle or the fuel bowl will never fill with fuel.
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Free hanging float level also needs to be adjusted but it is not as critical as the closing point above. This can be done with a tape measure. Make sure to keep the levels of the two floats on either side of the carb the same.
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Now that we have some fuel control when in bumpy conditions, we need to keep the fuel from traveling from one side of the carb to the other when at extreme angles. For this, some fuel safe nylon tubing was used to restrict the possible fuel flow from the 2 fuel bowls.
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We stuffed the nylon tubing (one piece of 10mm slid over a piece of 6mm) into the channel and made sure it would not move. You could block this channel off completely, but we prefer to leave a little breathing room.
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If your setup requires jet changes, now is the time. Jets are numbered and easily sourced. There are four of them in an Edelbrock carburetor located in the bottom of the float bowls and they are easy to change. No need to go all “Hulk angry” on them, just snug them down.
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Tuning will most likely require changing needles and springs. They fit into the jets and change how much fuel flows through them depending on the amount of engine vacuum. The springs are what resist the vacuum and depending on the combination, can tailor what sort of air/fuel mixtures are present depending on engine load and RPM.
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After carb mods, we started working on the intake manifold itself by plugging threaded holes that won’t be used. We prefer brass or aluminum plugs over hardware store steel.
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Mounting the intake on a small block Chevy is pretty simple with a quality gasket set. We like to use a little RVT around the water jacket for extra insurance and remember to use a torque wrench and the proper torqueing sequence.
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With everything together, lines connected, wires plugged back in, it was time to start Tim for the first time with the new top end. Remember to follow the included manual for choke setup, idle setup, and other tuning bits as the engine comes up to temperature. The needle and spring suggestions from the manual were dead on for our old rig and cold starting even in negative double digits is a breeze.
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