Straight Vegetable Oil (SVO)Conversion for Diesel Engines

Mark Tinkerman

 

Suggested layout of system is

• 1. Fuel tank for veg oil, it can be original tank or new tank.
• 2. Fuel pump, using the mechanical pump already fitted to the engine for veg-oil is best as then the electric pump can be fitted to the diesel supply which makes clearing the veg oil out of the injector pump for cold starting easier.
• 3. Peugeot diesel filter with heater element on bottom, £5 from scrap yard
• 4. Pollack valve for switch over of both feed and return pipes from veg to diesel , it also switches fuel sender units so the fuel guage registers the tank you're running on and switches the fuel pump(s) on and of. £60 from Biotuning or a bit cheaper from ebay. Comes with wiring / plumbing diagram
• 4. Connection to heat exchanger for both veg and diesel fuel
• 5. Heat exchanger. See my design further down the page. The cost is minimal or free if you have 8 and 22mm copper pipe and bits in your scrap pile. NOTE: for my system you also need a 15mm stop tap to turn of the heat exchanger if veg oil is not available (ie. on long motorway journeys where time is of importance)
• 6. Short connection from heat exchanger to injector pump
• 7. Also suggest GPS navigator with POI (points of interest) download for supermakets to tell you where the nearest veg oil is available.

Weve discoverd that our engine 3.5 mazda tdi and merc 2.4 (OM616) both run quieter because of the slower burn time of veg oil and that we have a very slight power loss due to same, it is very slight. Could advance timing but like quiet engine.

Weve also heard there was an EU court ruling that duty should not be charged on biofuel. Checked http://www.vegetableoildiesel.co.uk/customs.html and that seems to say no duty on less than 2.500 litres per year. I have had a letter from customs confirming they don't want duty from me if I use less than 2,500 litres a year.

At present we are running as registered users after filling in an EX103 form ( which is mostly not applicable as it is designed for biodiesel producers) and have to tell HMRC how much we've used.

I've just finished converting my Land Rover 110 with Mazda 3.5 tdi engine will update page with running info as available

PICTURES at bottom of page

Conversion includes Land Rover under seat tank for SVO (straight vegetable oil), Puegeot 505 preheated diesel filter, Pollak 6 port valve, heat exchanger constructed from 8mm copper pipe in 22mm copper pipe. ( NO SVO pump as been told may not be necessary?)

Peugeot filter modified by having the thermostat removed by grinding of the flange and drilling out as large as possible and the hot water outlet drilled out slightly larger than original.

Land Rover tank mounted on wooden spacers and crossmember as we didn't have original mountings. The feed and return from the second tank is taken forward up to the mounting box for the brake master cylinder( space for SVO pump on bulkhead on o/s of box if necessary ) in which I drilled 3 holes on the near side top flange to allow me to bolt on a piece of angle iron as a mounting bracket for a Peugeot 505 pre heated diesel filter (£5 from scrap yard).

On the forward mounting bolt for this I added a strip of alluminium about 1 by 6 x 3/16 inch extending across front/top of filter which allowed me to mount the Pollak valve so that the inlet for svo lined up with the outlet from the filter. The outlet pipe from the valve continues across the back of the engine, tied on to the hot water supply, to the filter (3/4" id) and both lagged with 22mm pipe insulation.

At the near side of the engine these pipes are connected to a heat exchanger running forward below engine air inlet made from 22mm copper pipe with 90deg bends and short pieces of 22mm at each end.

The forward one linning up with the heater outlet from the engine the rear one pointing at and connected to the SVO filter.

The 90 deg bends I drilled on the outside radius with a 7mm drill I then used the same drill shaft to bend the holes until they lined up with the long 22mm pipe. I then used a pair of narrow nosed pliers as a mandrel (by pushing the closed pliers into the drill hole and rotating them) until the hole had opened up enough to just accept a piece of 8mm copper pipe which extended about 3/8 inch further at each end than the 90deg elbows this was then soldered in.

Onto these I soldered a 90 deg 8mm elbows (1 at rear 2 at front ) and short piece of pipe the rear one is parallel to the 22mm bend the front one at about 45deg to rear offside to allow for easy connection to the SVO filter and injector pump (ip) inlet respectiveley.

The whole lagged in pipe isulation and taped ( cutting holes in pipe insulation done with sharpened 22mm pipe and when soldering clean pipe and fittings with wire wool and use plenty of flux. I also found it helpful to have some thin flux cored solder ).

The heater outlet from engine connects to 22mm T piece with a 15mm reducer fitted to supply hot water to cab heater on T off (pipe running behind injector pipes) and straight through T to front of heat exchanger.

The hot water from heat exhanger exits to lagged preheater pipe across back of engine and through the SVO filter into house type 15mm stop cock then into 15 mm T piece and returns to engine. The other connection on the 15mm T is also fitted to a stop tap and connects to the outlet from the cab heater. The stop taps allow for turning on/off heat exchanger and cab heater.

I decided to fit the Pollak valve before the heat exchanger as I had seen some reports of valve failure when hot on biofuel chat forums.

This meant I needed to fit a stop tap to turn of hot water supply through heat exchanger so that if SVO is unavailable the diesel would not be preheated and become to thin for injector pump and injectors. Also preheating diesel will also cause the input to warm up faster enabling earlier switch over to SVO hopefully.

Pollak switch mounted in cab wired as in supplied wiring diagram. SVO fuel tank sender unit wired one lead to earth. One through new warning light for low fuel to live feed on Pollak switch (use meter to find out which lead is which before fitting fuel tank!). Third to Pollak valve connection block.

Bought voltmeter with temperature sender. Fuel through heat exchanger running about 7 to 10deg C colder than water WITHOUT looping fuel return from pump but HAVE fitted about 0.75mm gas jet into return pipe (just pushed into) as a restrictor before T connection to leakoff pipe

Tried it and it does need fuel pump. bought Facet solid state pumps £30 each plus postage

Otherwise works well except getting used to fat smell

Above: Hole cut for filler neck

Rear tank mount made from wood and camping mat.

Front tank mount

The front tank mount is made of wood with a spacer block glued on outside end. This sits on the chassis (right end) and is bolted to the door sill.

This is bolted (visible bolt) through a very large washer, the footwell, the wood, a thick camping mat, the rubber bush on the tank.

SVO filter and pollak valve mounted on brake master cylinder mounting box.

Heat exchanger cut off tap (red handle) and heater cut off tap

Engine to heat exchanger

Connection to heat exchanger (at bottom) from engine (at top) and to heater (center). Fuel conection to injector pump is braided plastic pipe coming out from under heat exchanger

Heat exchanger core

The heat exchanger core is made from 8mm pipe with 1/16 brazing rod soldered at 45 deg angle about 1 inch from the end. This is then wrapped in spiral around pipe that isallowed to go slightly loose, then soldered where it touches.

The heat exchanger first bend

The heat exchanger first bend

Solder on a 90 deg 22mm bend and a short bit of 22mm pipe. Then drill 7mm hole on radius use drill shank to "bend" hole in line with long 22mm pipe.

Opening the bend for the core

Open the hole using closed end of some narrow nose pliers, which are rotated in hole until 8mm pipe just fits, then solder in.

Solder on 8mm elbow and extension.

For the second /third bend (for merc exchanger). Solder 90 deg 8mm bend onto heat exchanger core.

Cut it so that it is right length to come in middle of the 2nd 22mm elbow. Solder this on and then solder in 8mm 2nd heat exchanger core.

Then remove it so that elbow and pipe are left coated in solder.

Then solder on 22mm elbow and after that, refit/resolder heat exchanger core.

Solder on next length ot 22mm and repeat for third length

Heat exchanger 2nd bend

The heat exchanger for merc is almost complete. It still needs short lengths of 15 mm pipe soldered into a 15mm T piece, followed by foam pipe lagging and taping.

The angled 15mm T piece lines up with, and inserts into hot water supply to cab heater.

The 22mm end connects to the SVO filter.

The exit from the SVO filter runs across front of engine where it connects via stop tap to another 15mm T inserted into cab heater return pipe

Heat exchanger

The bottom connection (outlet) from jerry can/diesel tank.

Drill the tank at 7mm. Use drill shank to bend to a right angle for the pipe, then open using narrow nosed pliers to pipe size.

Note copper wire wrapped round pipe before soldering to tank to increase area for solder and strengthen joint.

Merc bottom connection

The T piece allows sight tube for fuel level (T piece is stuck to tank with Grip-fill to remove stress from soldered joint)

Merc top conection

Above is the top connection to the diesel tank. The sight tube top connection is visible going to left and the leak-off connection is going out top of picture

Merc tank

The fuel outlet is the red pipe, the leak-off is the white pipe, and the sight tube is clear plastic.

The white strip on the bottom of the tank is made from several strips of high density draught excluder stuck side by side and later taped over with strong gaffer tape to make cushion where tank sits on bulk head.

Three silvery bands on handle are clips that used to hang tent inner in frame tent and were just right to hold tank nicely in place but removable (leakoff pipe stuck to tank with Gripfill to remove stress on soldered connection to tank top)

Tank and filter in place

Clips are screwed into bulk head and the Peugeot filter is mounted next to the diesel tank and injector pump. ( It would have been better to mount it lower as heat exchanger goes across top of filter and makes it difficult to get spanner on bolt to remove filter).

Forgot to take piccy of heat exchanger in place will do so later.

Pollak valve will fit behind jerry can in center of heat exchanger.

Here is Pollack valve and Facet solid state pump fitted.

The remaining connector on the Pollack valve is the diesel return and the pump is for the diesel supply

Realised conversion on Merc is better than Landy as the longer more efficient heat exchanger means no need to limit injector pump return pipe and having the diesel on the electric Facet pump means that the system can be flushed of veggy oil without the engine running.

I think I will eventually add brazing rod finning to Landy heat exchanger and swop the piping on the pumps so the electric pump pushes the diesel not the veggy oil.

I DID GET ROUND TO SWAPPING THEM DEC 08

We've now run to vehicles for the whole season (May to September) and are well satisfied with how they've worked. Initial teething problems were limited to some fuel pipe problems as we dicovered which flexible fuel pipes didnt like vegetable oil.

Unless you decide to change ALL flexible pipes at the outset we suggest carrying some pipe with you (clear plastic with woven reinforcing) so that as leaks develop there's no panic about changing them.

If anything not understood please email and I'll try to edit/clarify.
marktinkerman@hotmail.com

Pollak, 6-Port Fuel Selector Valve

Incorporates six ports including return ports, designed for use on dual-tank fuel systems for selecting the tank from which the fuel should be drawn from (and returned to)

These motorized valves are driven into position by an electric motor and are stable in either position. They only draw power for a fraction of a second during transfer. A switch in the valve shuts off the motor when the valve reaches the selected position, it then does the same in reverse when power supply is reversed across the terminals using a suitable switch (DPDT On-On)

Complete with wiring connector, Changeover Switch and installation manual

Specification

Voltage	12vDC
Current	0.5 Amps
Recommended Fuse	10 Amps
Tank to Valve Fuel Supply Tails (2)	For 3/8 Inch (10 mm) ID Hose
Valve to Engine Fuel Supply Tail (1)	For 3/8 Inch (10 mm) ID Hose
Engine to Valve Fuel Return Tail (1)	For 5/16 Inch (8 mm) ID Hose
Valve to Tank Fuel Return Tails (2)	For 5/16 Inch (8 mm) ID Hose
Mounting Holes	2x 5/16 Inch Threaded Nuts, with 1 3/16 Inch Centers
Max Pressure	65 PSI
Material of Construction	Glass Reinforced Polyester

Pollak Fuel Selector Valve Installatiom For Two Tank Setup

1. All Wiring To Be 18G Or Heavier
2. Required Fuel Line I/O.			Fuel System Pressure MAX.(PSI)
Valve P/N	Fuel Supply	Fuel Return
42-149	3/B'	5/16'	60
42-149S	3/8'	5/16'	60
42-151	3/8'	—	60
42-153	3/B'	1/4'	60
42-159	3/B'	5/16'	65
42-1595	3/8'	5/16'	65

Attention installer

(1) Fuel system pressure not to exceed specified max. Valve pressure. (See table above)

(2) Note some late model fuel injection systems may exceed specified pressure.

1. General information

The Pollak 42-159 selector valve is intended for use only in fuel systems operating below specified max. valve pressure (see table above)and with:

• Vehicles with. One main and one auxiliary fuel tank.
• Vehicles with fuel return lines (except 42-151 valve).
• 12 vdc electrical systems (min. open-circuit voltage at valve connector, 11 vdc).
• Vehicles with in-tank fuel pumps or vehicles with a single fuel pump between the valve and engine.
• Ambient temperatures between -40°f and +180°f.
• Gasoline and diesel fuel systems only.
• Not for use in systems operating or having the potential to develop over specified max. Valve pressure (see table above)
• Do not allow valve to remain dry (no fuel) for extended time period.

2. Installation instructions:

The electrical and fuel systems should be connected to the valve as shown above.

Choose a protected location near the original fuel lines and using proper length 5/16-18 bolts, securely mount the selector valve to the chassis or other solid mounting surface. Orient. It such that the side of the valve with the four ports points towards the fuel tanks.

Route the auxiliary tank's source and return lines to the valve. Drain the fuel in the main tank and cut the original fuel lines. Be prepared to catch and safely store any fuel spilling from the cut line.

Using properly tightened 'worm' style hose clamp and fuel-approved flexible fuel hose, connect the fuel lines to the proper ports on the selector valve. Install fuel filters in the source lines as shown.

The fuel line routing should minimize the number of bends and have the largest possible radii to minimize the flow'restrictions.

Choose a position on the dash and mount the 34-592 toggle switch and 42-201 face plate. Cut the original wire from the fuel tank sending unit to the fuel gage and connect both ends to the 42-203 connector as shown.

Connect the new tank's sending unit to the connector. Install the toggle switch as shown connecting one pair of terminals to a good ground and the other pair of terminals to +12 volts through a 10 amp fuse. Connect the middle terminals on the switch to the connector as shown.

Maintain the orientation between the switch's key and the electrical connections. All electrical connections must be secure and the splices to the 42-203 connector should be secure, electrically insulated and sealed to prevent corrosion of the splices. Insure that the 42-203 connector locking tab is fully engaged with valve's mating connector for proper connection and moisture seal.

Double check the system to be sure all the electrical and fuel connections have been installed correctly. Then place a small quantity of fuel back into the fuel tanks to check the system for leaks. After it has been determined there are no fuel leaks, start the vehicle engine and switch the tanks to determine if the valve is functioning properly. Check the gas gauge when transferring between tanks for proper fuel level indication. After it has been determined everything has been installed properly refill the fuel tanks.

3. Valve operation

With +12 vdc to terminal E and ground to D the fuel will flow from the main fuel tank thru the filter, thru the valve, to the engine and return back thru the valve to the main fuel tank.

Reversing the polarity to terminals E and D will cause the fuel to flow from the auxiliary fuel tank thru the filter, thru the valve to the engine and return back thru the valve to the auxiliary fuel tank.