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SU fuel pump mounting

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I am trying to mount an SU pump onto my S3. The previous owner had replaced the original SU pump with a cheap Chinese made alternative. As a result, the mounting bracket (no. 12) is now missing.

 

I have to fabricate a new mounting bracket, but cannot figure how it mounts onto the chassis. Would appreciate greatly if someone could snap a pic of the bracket and pump mounted onto the vehicle. TIA.

91471283_Screenshot2019-09-05at10_13_30AM.png.784e10ec59fe829e4f2cda1306cf5f35.png

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9C095009-2B5A-4D06-8B75-EEBFD435DDEC.thumb.jpeg.a34796e64cc66a2744807531245b3f5e.jpegI don’t know how it’s on an S3 NA Eric but on a turbo it’s a rather simple bolt on bracket


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The bracket bolts onto the body, not the chassis, behind the passenger seat (RHD).

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48681932936_cb7d8c992b_c.jpg

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Pete '79 S2

LEW Miss September 2009

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Thank you all for your instant responses. 

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4 hours ago, peteyg said:

The bracket bolts onto the body, not the chassis, behind the passenger seat (RHD).

 

48681932936_cb7d8c992b_c.jpg

Small wonders. I was looking for screw holes in the chassis to mount the bracket. 

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On 5 September 2019 at 09:40, peteyg said:

The bracket bolts onto the body, not the chassis, behind the passenger seat (RHD).

48682104802_1ed2f381b6_c.jpg

48681932936_cb7d8c992b_c.jpg

@peteyg My late S1 has the SU fuel pump is located in the same position as the S2. When I disassembled it in October 2016 the carb-side fuel tank hose was routed over the top of the rear of the chassis, in front of the cabin bulkhead. Though broken up, and with the fuel pump in a box of assorted parts. Fitting SJ Sportscars replacement fuel line I followed the same principal, although suspicious of its practicality, since the pump has to draw fuel out of the tank, then up and over the chassis.

On a recent road test, now that the car is restored and working, I ran out of fuel, but found that the carb-side tank still had 20L of fuel. Filling the cam-side tank solved the problem.

On inspecting this problem further I spotted a circular hole in the chassis adjacent to the pump. It's shown in your lower photo I think. However, in the same photo your line appears to come in from above. Indicating the same route as mine. With the copper pipe also returning along the same path and to the carbs.

I've looked to see if there is a hole in the chassis that would take a rubber grommet and fuel line across the car, presumably below the water cooling pipes, and out to the pump. However, the lower airbox obscures the view and access.

I've been meaning to contact @Lotusfab about this, as his S1 has the same fuel pump positioning.

Regards,

David.

Edited by Fridge

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Hi David @Fridge,

The fuel pipe should go from the right hand tank, into the chassis tray underneath the water pipes. I see no reason why it shouldn't exit through that hole in the chassis next to the fuel pump but mine pops over the rail just above that hole to keep it as far away from the road and debris as possible. The main point is that the majority of the hose sits below the bottom of the tanks. It definitely should not go over the chassis by the bulkhead. The copper fuel pipe that connects to the braided pipes into the carbs runs forward along the chassis rail just behind the water tank and across the bulkhead above the water pipes then down into the fuel pump. Hopefully these photos make it a little clearer. I can try and get some more if you need. Ignore the very cracked fuel line, these were taken as I was replacing it.

Pete

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Pete '79 S2

LEW Miss September 2009

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Thanks @peteyg that makes a lot of sense! I don't know how mine was set up like it was. Possibly a PO fix, though like yours, the fuel lines looked original and came away in bits. I still have them as momentoes.

I'll look to make this change next spring. I'll have to drain the tanks before undoing one of the pipes (carb-side).

Has your car got a lower airbox, as I can't see it in the above photo? Mine sits inboard of the driver side body shell, suspended from the chassis below the seatbelt mounting. UK RHD car.

I think the fuel line will just go straight across, and above the lower airbox intake.

Thanks once again. A lot of help.

David.

Edited by Fridge

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@Fridge

No lower airbox on an S2, don't think I've ever seen one. At the end of the day the fuel pump should be pumping fuel so even if part of the fuel line is slightlyhigher than the bottom of the tanks you should still get fuel being sucked along until the tanks run dry.

Pete


Pete '79 S2

LEW Miss September 2009

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1 hour ago, peteyg said:

@Fridge

No lower airbox on an S2, don't think I've ever seen one. At the end of the day the fuel pump should be pumping fuel so even if part of the fuel line is slightlyhigher than the bottom of the tanks you should still get fuel being sucked along until the tanks run dry.

Pete

I suppose the S2 doesn't need a lower airbox as it has the air inlet "ears".

I've found a photo of my bare chassis which has the two holes in view directly opposite each other. I think I already have rubber grommets to fit.

The fuel pump is only able to bring fuel across the higher route until the fuel drops to a certain level. Leaving 20 or litres still in the tank. Yes it's a lot, but it's simple physics I suppose.

I'll sort it next spring.

Currently investigating rear wheel alignment shims.... My S1 goes in on Monday morning.

Edited by Fridge
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