Details, details and hybrid running

Spark advance was originally controlled by a basic computer and manifold pressure sensor (MAP) I expect manifold vacuum will be variable on woodgas so replaced the distributor with an earlier one that has centrifugal advance and a transistor ignition module, it's the finned box on the spring tower.

I added the simple LPG mixture controller pictured along with an exhaust oxygen sensor, and ran the 5 volt feed wire from the removed MAP sensor to the forward throttle position sensor (TPS)

The front and rear gas locks and the LPG computer are wired to the ignition circuit, via a safety relay, and are now always on while the engine is running

The yellow inline lockoff will allow a small amount of LPG to the intake for hybrid running, and should regain the power loss expected with woodgas.
It picks up gas after the LPG mixture controller and is switched on/off by the rear throttle position sensor (the rear TPS has a 12V reference voltage)
The blue vapour lock at left switches LPG to the mixer ring on/off, and is switched together with the converters' forced idle solenoid

Air leakage past the two large throttles gave a high idle speed, throttle stops are backed right off and idle air bypass passages have now been blocked

The glass vacuum bottle in the rear corner lifts water from the trap at the bottom of the firewall.
The inline lockoff on the firewall above it switches manifold vacuum on/off and gives a controlled bleed of woodgas for idling.
This lockoff and the rear TPS are switched together

Woodgas Ute - intake revisited

I induced several backfires by leaning the LPG mixture and snapping the throttle open. The stubby holder did its job of protecting the throttles and intake hoses but would sometimes split and blow off, this could leave me stuck in traffic with no fuel so I'm filling those three holes and adding a spring loaded valve that will reseat every time

Woodgas ute - under floor and valves

Stubby holder and 3 by 30mm holes for backfire relief

Gate valve and flare tube

Heavy bolt, welded washers and silicone seal

All steel piping is 2 1/2"

SS hot water jacket over short piece of 2 1/2" SS pipe

SS pot scrubber at outlet

All tucked out of harms way

80mm riser pipe and water trap

Clamped and sealed - elbow from water trap to vacuum bottle above

Woodgas Ute - Intake

Click any picture to enlarge
"Cut and shut" two and a half inch mandrel bent "U"

Cut 3 flanges from 5mm plate

Two Ford throttle bodies

LPG mixer ring on front throttle inlet

Air inlet behind headlight, woodgas inlet at rear of motor

Early GM V6 inlet tubes give reasonable clearance all around

Sliding link on woodgas throttle at left for cable to increase gas flow

Woodgas Ute

Inlet pipe and filter barrel (ex speedway rim)

Filter lid showing pressure relief valve and tap for generator takeoff

Latches and seals

Mocked up and ready to plumb forward

I'm in the middle of moving shop and may be offline for awhile
cheers

Woodgas Ute

Woodgas could be fed into stock intake but not efficiently

Removed stock exhaust and intake manifolds, carby and associated sensors, hoses etc.

Fitted EFI intake (optional in the late 80s) extractors and high torque starter - note the tuned length runners that are perfect for gas

Rubber inlet hose, pod filter and LP gas ring are temporary - this is still my daily driver

Gas cooling

Hot gas enters from bend at top right, note hole sizes

Hottest parts are in airflow

Cyclone filter and gas cooling

Wedges cut from 4" exhaust pipe

Cyclone filter welded in place

Gas cooling system taking shape

Loop on left is removable for cleaning

Spring Locking Lid

Most leaf springs have a locating hole near the centre, line this hole up with the centre of your lid as a starting point (it beats drilling in to spring steel)
Heat and bend the leaf to follow the curvature of your lid then shape the ends as shown, (a gas axe or forge will be needed)
The "eye" was forged over an old head bolt using a vice, heavy locking pliers and a hammer

Adjust the distance between the two lower pivot bolts as needed to clear the spring when opened and to give a firm seal when closed, the valve spring can be pulled down tighter if needed but must have enough "give" to allow the over centre latch past it's locking point

Keep the handle longer than the upper bars for ease of use, it stops them from getting tangled
A wooden shifter knob on top is absolutely essential for the "cool" factor - happy fabricating y'all

Rob