Fuel pump diaphram material

[Tony B]

Anyone know where I can get the rubber for a fuel diaphram from? I have just stripped the fuel pump for the fire pump, rebuilt engine 1961. Pump was a bit gunky. The diaphram had gone hard, but by a bit of serendipty I've found the 50/50 liquid paraffin /paraffin wax ointment that I use as emollient actually softened it. Lovley stuff, even if it does come with a warning 'Keep patient and clothing away from naked flame'. Another story. But  would benifit from replacement.  

[earlymb]

You might want to look for some modern material that can handle the nasty additives they put in fuel nowadays. It eats older membranes in no time.

[goanna]

N

10 hours ago, Tony B said:

Anyone know where I can get the rubber for a fuel diaphram from? I have just stripped the fuel pump for the fire pump, rebuilt engine 1961. Pump was a bit gunky. The diaphram had gone hard, but by a bit of serendipty I've found the 50/50 liquid paraffin /paraffin wax ointment that I use as emollient actually softened it. Lovley stuff, even if it does come with a warning 'Keep patient and clothing away from naked flame'. Another story. But  would benifit from replacement.  

Nitrile rubber might work . I used some for a carby gasket and its been fine .  https://en.wikipedia.org/wiki/Nitrile_rubber

Edited November 13, 2017 by goanna

[Tony B]

Thanks Guys. Seems easy enough to get in US, but not over here. 

[goanna]

The fuel pump diaphrams I have seen are usually laminated eg with many layers of a thin rubber material sandwiched together.

[Richard Farrant]

3 hours ago, Tony B said:

Thanks Guys. Seems easy enough to get in US, but not over here. 

Is it an AC lift pump? If so, don't frig about, just get a repair kit. I get kits for Land Rover 2a or 3 and they are suitable for most AC pumps on postwar British engines. Make sure it is not an old stock kit, best ones have a red diaphragm material.

[goanna]

I agree with Richard. Beware of old stock fuel pump kits.

Years ago I put a old stock kit in a Dodge WC fuel pump.  Everything seemed OK until the oil pressure went downhill . Yikes !

The diaphram in the kit was perished and the petrol just went into the engine sump and diluted the oil ! 

[MatchFuzee]

6 hours ago, Tony B said:

Thanks Guys. Seems easy enough to get in US, but not over here. 

If you can't find a repair kit, TYM supply Nitrile Nylon Diaphragm etc. material in gauges from 0.25mm to 1.5mm thick from a .5mtr x 1.2mtr sheet, although I suppose as you only need a small piece an offcut or sample would be better.

https://tym.co.uk/products/nitrile-nylon-diaphragm-material

Viton 100mmsq, 200mmsq, 300mmsq and 500mmsq pads

https://tym.co.uk/collections/viton-rubber

 

[Tony B]

The pump is of the Godiva pump engine. Thanks Richard. 

[Tony B]

Many thanks for all the replys. I'll mike the thickness tonight and see what I can get. 

[101 Ron]

Try a place that does LPG repairs.

Look at the different LP Gas convertor kits they stock.

LP Gas diaphragms ...the Yellow coloured ones can handle most hydrocarbons.(  the black diaphragms cannot )

Cut the fuel pump diaphragm from a LP Gas one .

I have done this and still working fine years later.

[CMP-Phil]

Hi

Often trying to find this type of matierials directly from the company or thier wholesalers is a lost cause because they want to sell you a entire sheet, large enough to make hundreds diaphragms or gaskets which costs maybe hundreds if not thounsands of dollars.   Try instead to find an end user of the matierial, as Ron suggests, that might have the matierial and be willing to sell small amounts.  Or as I have had happen the guy reaches in to the scrap bin grabs a chunk to small for their use and gives it to you. Carry a photo of what you are working on to peak their interest, works good on MV stuff, amazing how many veterans out there.

Cheers Phil

 

[Tony B]

Good idea Phil. 

Just had an odd thought. Years ago I knew a vetenairy anthstist who had patented a portable anathisia machine. He told me the main trouble was the diaphrams that control gas flow were expensive and need replacing every time the machine is used, apparently that is standard practice in any machine of this type. . So he went looking for an economic alternative. His claim was he had found a free supply. He just sent his wife down to the local birth control clinic and got standard Dutch Caps.  

Edited November 14, 2017 by Tony B

[sexton]

Viton rubber is very good stuff with good resistance to gasoline and its ethanol additives. Do a google search on its compatibility for more info. 

If you google nitrile, aka Buna N, you'll find it's good for gasoline but not good for ethanol. 

I  visited a sales rep at a local gasket company and he happily sold me some Viton offcuts for $30 which I have used successfully for fuel filter gaskets. (I volunteer at a military museum so I think he saw a potential market.)

But fuel pump diaphragms are a different kettle of fish, needing to be thin for flexibility, but also needing to withstand high stretching loads and also thousands or tens of thousands of cycles. As said by an earlier poster, I suspect that is why fibre reinforcement is critical. 

Have you looked at electric fuel pumps? They bring a whole new set of challenges but there are good ones out there with built-in pressure control, a critical factor when using with a carburetor.

Malcolm

Edited November 21, 2017 by sexton

[Tony B]

I'm off to my usual supplier of Landy parts for some bits tommorow, by good luck they also do LPG conversions, and are into MV's and know I'm nuts. A winning combination!