Lister 6/1 Diesel

[HobbyNut]

http://www.youtube.com/watch?v=zXzqGHn0CDY
Dave, have a look at the link there. That is the engine running. You may notice that you do not see him starting it.

[steamer]

Thanks for that Pat! 

funny he states in the video that the injector pump has a 4 mm bore.?

Dave

[HobbyNut]

My mistake, it is 4mm....that is why I picked 3/16", come to think of it.
I emailed him re my problems, and he said that he was having similar problems. He pulled the spring out of the injector. The only way he could get it to run "slow" was to restrict the inlet to 1/8" dia. I asked him if he heated it to start it, but there was no reply to that yet. He has a needle valve on the return line to adjust the fuel volume going to the injector. he said that it is too coarse and a small movement makes a too big change. said he was going to fiddle with the taper on the needle. I couldn't get that working at all, it was either too closed, or too open.

[Maryak]

Hi HN,

Thanks for the link.

The main thing I found interesting was the fuel used was model aircraft diesel fuel. The exhaust is a bit of a give away with the white smoke which leads me to believe castor oil is present. In turn this suggests that the fuel is more viscous than ADF and allows for a less precise fuel pump in terms of fit. His by pass system puts high pressure fuel back to the suction side of the fuel pump, also reducing the need for micro sized fits within the pump. Probably why a bigger bore fuel pump is required.

Just my thoughts and observations from afar.

Best Regards
Bob

[dieselpilot]

I'm considering a 3mm plunger for my project. The scale of these parts is a problem and probably the reason we don't see much in the way of model diesel injection. The only other functional model injection I know of is Find Hansen's work and unfortunately he doesn't talk about the pump. I wish I could work on my project, but at the moment all my diesel injection drawings are on a crashed HDD.

If the viscosity of the fuel was enough to get the pump working it only proves that the fit is that critical. Castor oil is approximately equal to SAE50 in viscosity. White smoke is generally indicative of poor atomization of fuel in a diesel.

[HobbyNut]

His by pass system puts high pressure fuel back to the suction side of the fuel pump, also reducing the need for micro sized fits within the pump. Probably why a bigger bore fuel pump is required.

Just my thoughts and observations from afar.

Best Regards
Bob

Bob, the bypass does go back to the inlet, but what I found was that it is at greater pressure than the incoming, so it tends to go to the tank as well. you may be right, in that the backflow takes care of the overvolume.
Like my wife says to me at times," it can't be that hard to do"!!!! It bugs me that this is so difficult.

[steamer]

My Dad was a Master Mechanic for the local Fire Department.    Every once in a while they would order a new truck and he would go visit the company that built the trucks..well, while in the bid process for one, he was invited to got to the Detroit Diesel factory,  and while there, he toured some of the manufacturing area's

He was a big fan of Detroits and called them" Detroit drippah's " 

He said this technician showed him some injector assemblies, and showed how they went together.   He then held the plunger in his closed hand for a few seconds, and then tried to assemble them and they wouldn't go.   The Tech stated that the tolerance was .000033"  (33 millionths)    He was stunned.

Now we're not making hundreds of thousands of injectors....just one......so

Now 3x that tolerance is .0001" or 1 "tenth"....WE  MIGHT be able to do that in a home shop....but I think it won't be easy, and we'll need to think about that for a bit

Dave

[Maryak]

Bob, the bypass does go back to the inlet, but what I found was that it is at greater pressure than the incoming, so it tends to go to the tank as well. you may be right, in that the backflow takes care of the overvolume.
Like my wife says to me at times," it can't be that hard to do"!!!! It bugs me that this is so difficult.

Hi Again,

Is there any reason not to fit a non return valve on the pump suction or as part of the filter to prevent fuel returning to the tank?

Maybe another email to George to clarify what's his setup in this area.

Best Regards
Bob

[steamer]

My mistake, it is 4mm....that is why I picked 3/16", come to think of it.
I emailed him re my problems, and he said that he was having similar problems. He pulled the spring out of the injector. The only way he could get it to run "slow" was to restrict the inlet to 1/8" dia. I asked him if he heated it to start it, but there was no reply to that yet. He has a needle valve on the return line to adjust the fuel volume going to the injector. he said that it is too coarse and a small movement makes a too big change. said he was going to fiddle with the taper on the needle. I couldn't get that working at all, it was either too closed, or too open.

Pat, 

What size orifice is specified for the injector?

[stevehuckss396]

he was invited to got to the Detroit Diesel factory,  and while there, he toured some of the manufacturing area's
He was a big fan of Detroits and called them" Detroit drippah's " 

I was working at the detroit Diesel factory doing some electrical upgrades. While there i made a friend named Guy. I talked with Guy about an idea I had to build a 1/4 scale Bugatti engine that really ran. Instead of laughing Guy brought in a cardboard box full of stuff and told me i was going to need this. It had 1-2-3 blocks, V-blocks, 6 inch caliper, ect. About a week after that I bought my lathe and mill. I think you guys know where this is going but Detroit Diesel is where modeling began for me.

[steamer]

I know EXACTLY where that's going........."Bubba"!

Those who know us ....know where that came from!...

Sounds like Guy was a heck of a guy!

Dave

[steamer]

And you know....I had a similar conversation with a man about my dream of building a steamboat....His offering was lots of kind words and encouragement...when EVERYONE ELSE was laughing.

His name was Ray.   Thanks Ray!

[steamer]

OK   Pat, I'm going to get a 4mm ball bearing ball...and see if I can run an experiment this weekend

Dave

[steamer]

OK.....purchase made.

[dieselpilot]

Now 3x that tolerance is .0001" or 1 "tenth"....WE  MIGHT be able to do that in a home shop....but I think it won't be easy, and we'll need to think about that for a bit

Dave

.0001" or 2.54 microns is possible with a lap. But it's the 3-5x bore that is tough and I certainly don't have any way of checking it, and not even a pin gauge set. My approach was going to be plunger from hardened and ground drill blank, tool steel pump body lapped to fit. I have no idea how many attempts it would take to get it right. I think in the real world a hone would be involved prior to lapping.