Fuel heater, pipe size

[roylittle0]

Any one know if a 4mm diameter steel hydraulic pipe would be big enough to use for the liner of my home made fuel heater, I have made an aluminium block with 4 holes, 1 is for the water from the radiator and that is 15mm diameter with hose tails so I can clamp a pipe to each end, 2 are for glow plugs and the remaining 1 is for fuel but I would like to line it, instead of threading the block and fitting hose tails

It is made out of a 50mm diameter aluminium bar, by 100mm long.

Ill download some pics soon.

[MattF]

The I.D's of the fuel hoses are 8mm for the 2.4 and 10mm for the 3.0.

[roylittle0]

8mm it is then, thanks for the quick response, saved me bashing it in and having to drill it out again.

[roylittle0]

So this is the unit i have made, the large hole is for the water from the radiator, directly oposite is for the fuel pipe (i want to press in a steel tube, rather than tap it and fit hose tails) the other two holes are for glow plugs, they will be controlled by a thermostat on the machined flat area.

[MattF]

Why do you not want to tap and tail the block?

[POPEYE]

Well it's 10 to 3 and just woke up again so prob not quite with it but as he said why not tap it out to suit tails etc? personally i would't like to trust it "pushed in",
is it drilled right through? ie are the glow plugs going to directly heat the oil or the alloy block? if you see what i mean,
nice bit of machineing BTW

[roylittle0]

I want to push a pipe through the block for the fuel to cut down on joints, using a pipe i will have 2 joints and hose tails would be 4, less points to leak, also i have pipe and don't have the correct size hose tails.

The glow plugs are not rrilled all the way, they will heat the block, that way i will get all round heat as the block warms up.

[MattF]

I really wouldn't worry about it leaking. Brass tails and aluminium block bind extremely well. I had to remove quite a few from ally block so can attest to that. They use that method in fog/smoke machines, and I can't remember one of those ever springing a leak around the connections, and it is basically doing the same thing.

[roylittle0]

I really wouldn't worry about it leaking. Brass tails and aluminium block bind extremely well. I had to remove quite a few from ally block so can attest to that. They use that method in fog/smoke machines, and I can't remember one of those ever springing a leak around the connections, and it is basically doing the same thing.

Agreed they can be a pig to get out once they have been in a while, my main reason was that I had the pipe (4mm ID), I was going to fit the heater as the oil enters the engine (then the size I have would be fine, I think) but now I have read that it is better before the filter, is that correct do you know.

I’m hoping that the glow plugs, thermostatically controlled would be enough to heat the oil until the radiator kicks in with the heat, I don’t think ill need to control the heat from the rad as it should be about right.

I think ill be going the hose tail rout now, as I would have had to buy the 8mm pipe anyway so i might as well buy the hose tails.

[MattF]

Agreed they can be a pig to get out once they have been in a while, my main reason was that I had the pipe (4mm ID), I was going to fit the heater as the oil enters the engine (then the size I have would be fine, I think)

I get what you mean now. You were going to connect the fuel line directly to that pipe by having the ends protruding? Tails will be better.

but now I have read that it is better before the filter, is that correct do you know.

That's the place I would advise, before the filter. The filter is the main sticking point if the VO thickens, so you want that upto temp as quickly as possible.

[roylittle0]

Would a heated filter help.? or are they a wast of time ?

[MattF]

If you're wanting to do it properly, pretty much heated everything would be best, between and including, the tank and injectors. Otherwise, just heat what bits you can. How little or much is upto you. If you're mixing derv/VO, just keeping the ratio within reason negates most of the heating pitfalls.

[roylittle0]

So i have now fitted 3/8 bspt hose tails with 13mm outlet for the water, the fuel is 1/4 bspt with a 8mm pipe and the glow plugs are fitted into a m10 fine threaded hole into the ally block, do i need to fill any void left in the glow plug hole with something like heat transfer paist (glow plugs are 5mm and the hole is 5.5mm) could they over heat with being in free air or are they designed that way (can't think how fuel passes over them or how it heats the fuel) but it is getting late.

[MattF]

do i need to fill any void left in the glow plug hole with something like heat transfer paist (glow plugs are 5mm and the hole is 5.5mm) could they over heat with being in free air or are they designed that way (can't think how fuel passes over them or how it heats the fuel) but it is getting late.

They'll be fine as is.