Three quick questions

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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Three quick questions

Postby zaca33 » Tue Jul 13, 2010 4:18 pm

Hi All-

Just few quick questions.

1.) The fuel lines after my Lift pump are harder than regular fuel hose and clear. Is there a reason for this? Do I need fuel line with a higher psi rating after the fuel pump?

2.) Do I need to replace the banjo bolt on the fuel filter? Doesn't in just essentially splice the two return lines (from the injectors and from the ip itself). Or can I just re-route the diesel return line after the banjo bolt?

3.) My veg. has a little diesel mixed in, maybe 5%, will that throw off a hot pan test?

Thanks
1979 W123 Mercedes 300D body and 300TD engine
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Re: Three quick questions

Postby John Galt » Tue Jul 13, 2010 8:32 pm

zaca33 wrote:1.) Do I need fuel line with a higher psi rating after the fuel pump?

yes
3.) My veg. has a little diesel mixed in, maybe 5%, will that throw off a hot pan test?

yes
in that case the vapor test would be more accurate, or one of the more sophisticated and expensive test methods.

Test methods are discussed in the Collecting, Filtering and Dewatering section of the forum.
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Re: Three quick questions

Postby SunWizard » Tue Jul 13, 2010 9:40 pm

zaca33 wrote:1.) The fuel lines after my Lift pump are harder than regular fuel hose and clear. Is there a reason for this? Do I need fuel line with a higher psi rating after the fuel pump?

Higher than what? If those are the stock lines, they are designed for the psi of the lift pump.
2.) Do I need to replace the banjo bolt on the fuel filter? Doesn't in just essentially splice the two return lines (from the injectors and from the ip itself).

Yes, yes.
Or can I just re-route the diesel return line after the banjo bolt?

No since it has a hole in it where air exits the top of the filter and goes into the return line. You need to tee the 2 returns yourself and cap where they used to go into the filter.
3.) My veg. has a little diesel mixed in, maybe 5%, will that throw off a hot pan test?

Yes.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby zaca33 » Tue Jul 13, 2010 10:55 pm

Higher than what? If those are the stock lines, they are designed for the psi of the lift pump.


Yes they are stock. I couldn't find the psi rating on them. I need to replace them when I re-route to fuel lines so I was wondering if I can use the same type of hose I have been using on the rest of the fuel system, or if it has to be rated for a higher psi now that its after the Lift Pump. The line I'm using now is rated for 50psi.
1979 W123 Mercedes 300D body and 300TD engine
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Postby John Galt » Wed Jul 14, 2010 1:10 am

I don't know what the lift pump pressure is on the MBenz. The older Toyota diesels with the inline pumps are similar. On those the lift pump / fuel feed pump pressure is 35 PSI.

I use Parker 801-6 hose. It's impervious to a wide variety of hot fuels and motor oils and rated to 250 PSI. I'm using it to connect the FPHE between the lift pump and the fuel filter. It's been in service for two years with no sign of any change.
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Postby SunWizard » Wed Jul 14, 2010 8:52 am

zaca33 wrote:The line I'm using now is rated for 50psi.

That's fine.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby David » Fri Jul 16, 2010 10:40 pm

I used standard braided/reinforced clear vinyl food grade line all over on my benzes. Its rated over 100PSI and is cheap as.
The OEM line is nothing special and being the pump is only a lift pump, the pressure is nothing to worry about or get carried away over.

It will sweat a little if you have a lot of bio in the fuel and it will harden if you use a lot of oil or have ULP in a blend. Once this happens though the line is in place and has found its position so I have had no problem.

I was replacing the braided line yearly but have now had some on my vehicle almost 2 years and it has not been any trouble. There isn't much line on a Benz anyway and to replace it probably costs less than $10.

I change the Hose over when I do all the yearly maintenance and replacing it also gives me the chance to inspect other parts of the fuel system and spot any damage from abrasion, impacts etc.

You can get this hose anywhere and I carry more than enough to replace all the line in the car but have never had to use it yet.
_____________________

I don't give a damn about what might or could happen until a significant group of people can tell me it HAS happened to them.
Until then, it's just more endless gloom and doom Veg folk law.
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Postby tinworm » Tue Jul 27, 2010 7:34 pm

lift pump pressure on a 617 and 616 is between .6-1.3 bar, or about 13-20 psi.
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