fuel line diameter?

[stephenellis]

I need your help again. Can anyone tell me the diameter of my fuel lines? I have a END672 diesel engine and the pipes from the rail to the injectors are corroded beyond repair and need replacing. I have lots of experience with 3/16 brake pipe and flaring tools but I would like conformation before I start removing the pipes. And does the length of the pipes matter? Any help would be much appreciated.

[farmer52]

Fuel injection lines are typically all the same length (all cylinders 1-6). Also the wall thickness of a brake line is not thick enough. Best to just go buy a set or have a fuel pump shop make them.

[stephenellis]

Thank you.

[h67st]

Fuel injection lines are typically all the same length (all cylinders 1-6). Also the wall thickness of a brake line is not thick enough. Best to just go buy a set or have a fuel pump shop make them.

Amen to that...very high pressure in these lines. Need to use material that's made for injection pressure.

[stephenellis]

thanks again guys.

[thomastractorsvc]

you can use ****STEEL**** hydraulic brake line for diesel fuel injection don't use anything that is galvanized as the coating comes off, don't use plain steel automotive fuel line unless it rated for injection. The flares on brakes vs fuel injection are different and you should be able to re use the nuts on the pump and injectors as probably only the lines are bad.

Make sure the diameter is similar and it is rated for pressure and you will be fine.

You can use hydraulic hose for fuel lines from the tank and back, just make sure it is rated for fuel, some are some are not so check depending on application or if you have them made just tell them they are going to be used for diesel.

Rob

[stephenellis]

thats great. Thanks. I have a flaring tool at home so will try to source some pipe. any ideas on what pressure the pipes are under?

[farmer52]

I am guessing older pump-line-nozzle systems are in the 7500 psi range.

[thomastractorsvc]

I am guessing older pump-line-nozzle systems are in the 7500 psi range.

I would say thats good guess on PSI, one more thing make sure the line is seamless. If you dont have the right flair tools make the lines and take them to a diesel shop and have them flair them. As you bend the lines write on them with a sharpy pen or use masking tape, it will make them go on easier when you are done messing with them.

[41chevy]

The injector line length is very important!! The lines ALL must be the same length... The fuel injection timing is based on pump to injector nozzle distance plus offset from TDC, and if the lines are not the same, the firing timing is different for each cylinder.This will result in low power and/or high exhaust temps, and higher fuel use.

One other thing, most all of the hard lines where the hose attaches have a small rolled "bead to prevent the hose and clamp from blowing off under stress and pressure. Here is one of the lines for my B mixer

Paul

[stephenellis]

I don't know what I would do without you guys. so in theory if I took one off and had 6 made the same length I would be ok?

[thomastractorsvc]

no what he is saying is each line needs to be the same length as the one you are replacing

[stephenellis]

cool. won't throw the old ones quite yet.

[farmer52]

Likely all the lines are the same length but you should make each new line identical to the old line.

[rsb502]

Its a good bet it will end up working out better in the end to have a Injection shop make them or get some from a Mack parts vendor. Injection line I.D. is very small its thick wall seamless steel pipe, they all need to be equal length as stated above, and the ends arent something youll have much luck flaring yourself(I havent) I would caution to get them done or buy them pre made since a bad line just leads to a blown line and fuel sprayed on a hot manifold and that leads to you crying in a ditch as you watch your baby burn to the ground. I just saw an E9 injection line with the end broken off earlier today it had about a 1/16" hole in the center of a line about 5/16" thick, the walls have to hold a lot of pressure and the wrong material will erode under pressure in the bends.

[41chevy]

Likely all the lines are the same length but you should make each new line identical to the old line.

The injector line length should be equal across the board. The flares are extremely difficult to make to the proper size. A good reputable diesel shop that does lines, pumps and injectors, will also use a "GO NO GO" gauge to insure the flares meet the specifications.

Paul

[stephenellis]

I am learning a lot from you guys. I am going to make sure I get the lines from a professional and reputable diesel shop. no point cutting corners and ending up crying in a ditch. I am just away to remove the old ones and start trying to find a good local shop to manufacture them.

[theakerstwo]

Forget making your own injection lines.

[39 Baby Mack]

Forget making your own injection lines.

That's about the truth Glenn

Wasn't going to say anything but I'm glad you brought it up.

The fittings on the ends of the lines aren't flared, they're separate pieces, and I think they are somehow welded to the ends of the lines.

Not to mention the wall thickness of the tubing that was already stated above.

Ron

[BC Mack]

as the other guys have said..... get a pump shop to make them.... nowhere near a car brake line flare... but go ahead and make supply lines from tank to pump yourself.

I had some made for a 1940's AEC (CAV-Simms) many years ago in the UK and they had a pre-made nipple sweated on each end, not a formed flare....so would the Mack flare ends of that era be similar?.... anyone got a close up of the injector pipe end??

I thought the usual injection pressure for a direct injection engine was 175 atmospheres in that time ( x 14.7 to get psi) so that would bring it to 2500psi.

BC Mack

[farmer52]

I thought the usual injection pressure for a direct injection engine was 175 atmospheres in that time ( x 14.7 to get psi) so that would bring it to 2500psi.

BC Mack

2500psi is the injection pressure for a pre-chamber engine. Most early DI engines were in the 5000 to 7500psi. Later DI P-L-N engines were pushing 15K psi. Today's unit injector engines are in excess of 30K psi. Higher inejction pressure and finer atomization of the fuel promotes complete combustion for more power, better fuel economy, and lower exhaust emissions.

[rsb502]

I think the flares on the end are crimped and silver soldered on the tubes, I've heard of heard of a die for a press to flare a line but never seen it. I was hanging out at Taylor diesel in Nashville today talking upgrade turbos for my E9 and we ended up talking injector lines for a while. I think I'm gonna get some bigger lines and injectors made up when we get the turbo sorted out. Anybody know a p/n for bad ass E9 injectors to save me some research?

[BC Mack]

2500psi is the injection pressure for a pre-chamber engine. Most early DI engines were in the 5000 to 7500psi. Later DI P-L-N engines were pushing 15K psi. Today's unit injector engines are in excess of 30K psi. Higher inejction pressure and finer atomization of the fuel promotes complete combustion for more power, better fuel economy, and lower exhaust emissions.

Yes, agreed, I was refering to period engines that I used to work on with CAV injection with pop pressure set at 175 atmos... one of my jobs as an apprentice was to clean injector nozzles and run BPE6B CAV in-line pumps and injectors on a Hartridge test bench... 1940's technology in the 1970's..

some earlier AEC engines had Ricardo heads with a pre-combustion chamber and Pintaux injectors.

today, I play with the Cummins ISL in buses.... 29-36,000psi and given the egr and dpf problems I think I would prefer the 1940's Leyland and AEC... no laptops needed...

in all the old CAV books I have, I found a document "nipple forming tools", got to be 40's or 50's... it shows the tool and process for forming pipe ends on 6/8/10mm pipe... if anyone wants to see it I can try and scan for posting here.... but, it looks pretty straightforward, all you need is the right pipe, right tool, right dies... hence, get them made at a pump shop..!!!

BC Mack

[theakerstwo]

That right, all you neds is the proper tools and parts and nipples and dies and press so who has them and also 40 years ago those lines was custom built in pump shops but I have sen them last somes a few days and some never have a problem. The virbration that goes along with the pressure is something else. You see enough broken injector lines from factory lines.If I remenver right whn the pump shop made those lines the end was formed in a press with a die and cant remember any nipple being installed.And don't remember any heat being used.

[41chevy]

That right, all you neds is the proper tools and parts and nipples and dies and press so who has them and also 40 years ago those lines was custom built in pump shops but I have sen them last somes a few days and some never have a problem. The virbration that goes along with the pressure is something else. You see enough broken injector lines from factory lines.If I remenver right whn the pump shop made those lines the end was formed in a press with a die and cant remember any nipple being installed.And don't remember any heat being used.

No nipple or heat, the lines have AN fittings. . . a "collar" that fits up to the back of the "flare" that the line nut fits on. It is an early high pressure Aircraft hydraulic design. These are lines I'm making up for one of my projects.