Doomsday Dually Project

[IDIBRONCO]

My opinion? I wouldn't do that because it sounds like a lot of re-engineering. Better known as trying to reinvent the wheel. I won't say to not do it. I can't think of any issues other than the one the you've already mentioned. I just won't be trying to do that myself. I'll have the regulator along the frame, close to the Holley black. My separate return will go from it straight to the tank. The engine return will still keep it's original routing.

 

[Lumberjackchuck]

My opinion? I wouldn't do that because it sounds like a lot of re-engineering. Better known as trying to reinvent the wheel. I won't say to not do it. I can't think of any issues other than the one the you've already mentioned. I just won't be trying to do that myself. I'll have the regulator along the frame, close to the Holley black. My separate return will go from it straight to the tank. The engine return will still keep it's original routing.

My issue is that I’ve got 2 tanks so I’d imagine I’d have to tee the2 returns up before the FSV somewhere. I will try tee’ing them together along the frame and run a larger line for the regulator bypass and see what kind of pressure I have.

The 1/4” line I had coming off the regulator bypass is definitely too small and causing excessive pressure.

 

[asmith]

Since you have two tanks, to keep it more simple, take the regulator return and tee it into the supply side of the pump. The pump wont know a difference and all that fuel stays out of your return system to the tank. There are a lot less parts that way too.

 

[Lumberjackchuck]

Since you have two tanks, to keep it more simple, take the regulator return and tee it into the supply side of the pump. The pump wont know a difference and all that fuel stays out of your return system to the tank. There are a lot less parts that way too.

Interesting. I don’t see why that would be a problem. Definitely a better option than to put the injector return into that spot, i won’t get any air drawn in this way.

Just wondering how that may affect the pressure regulation if the inlet pressure to the pump is higher than the outlet pressure I’m trying to regulate too.

I’ll have to try it and see, if I can get the bypass pressure low enough it shouldn’t be a problem

 

[Lumberjackchuck]

Update on the doomsday motor, it may have had its own doomsday .

Fired it up and timed it, and the thing was sounding really great. Took it down the road and made it a mile before I heard a loud rattling/knocking noise.

Turned around and made it home, couldn’t really pinpoint the noise. Ended up draining the oil to see if there was any carnage, I didn’t see any metal in there so my hopes are high.

Tomorrow I will pick up a compression test kit and hopefully find out more.

My worst fear is piston to valve contact or maybe a glow plug broke. We shall see. Stay tuned for some possible carnage.

 

[Lumberjackchuck]

So I haven’t had a minute to look into yet, but I’m thinking there’s a possibility it could be injector knock.

At idle or high rpm when not moving the knock isn’t that present. But when hitting the gas under load, like driving on an incline it’s pretty bad

It really sounded like rod knock to me, but when I brought that up to the machinist he said it’s most likely an injector issue and he thinks it’s verrrry unlikely it’s rod knock. My oil pressure is good and the motor was started up only after I had already primed it.

I also had fuel in the oil and a lot of smoke coming out the tail pipe.

In the case that it is an injector knock, how likely is it that it caused any damage to the engine, cracked piston perhaps?

These are brand new injector from R&D by the way

 

[Duke57]

Or just go w/ a real 6x6 oil burner and avoid the roads where all that clutter is.

You must be registered for see images attach

What engine is in that 6X?

 

[asmith]

So I haven’t had a minute to look into yet, but I’m thinking there’s a possibility it could be injector knock.

At idle or high rpm when not moving the knock isn’t that present. But when hitting the gas under load, like driving on an incline it’s pretty bad

It really sounded like rod knock to me, but when I brought that up to the machinist he said it’s most likely an injector issue and he thinks it’s verrrry unlikely it’s rod knock. My oil pressure is good and the motor was started up only after I had already primed it.

I also had fuel in the oil and a lot of smoke coming out the tail pipe.

In the case that it is an injector knock, how likely is it that it caused any damage to the engine, cracked piston perhaps?

These are brand new injector from R&D by the way

do you still have a mechanical fuel pump? Those failing while rare can lead to fuel in the oil, it happened to me.
If you dont have a mechanical fuel pump then maybe you have an injector sticking open and washing down a cylinder.
If you can try to figure out what cylinder the noise is coming from. Then swap that injector with a different cylinder. If the noise follows then you know it is your injector.
If you are worried about it being an injector sticking open I wouldnt drive it too much and try to get it fixed as soon as possible. Diesel fuel is not a good lubricant and can cause issues being in your oil.

 

[Lumberjackchuck]

do you still have a mechanical fuel pump? Those failing while rare can lead to fuel in the oil, it happened to me.
If you dont have a mechanical fuel pump then maybe you have an injector sticking open and washing down a cylinder.
If you can try to figure out what cylinder the noise is coming from. Then swap that injector with a different cylinder. If the noise follows then you know it is your injector.
If you are worried about it being an injector sticking open I wouldnt drive it too much and try to get it fixed as soon as possible. Diesel fuel is not a good lubricant and can cause issues being in your oil.

Nope, I’m running an electric fuel pump

 

[LowTech]

What engine is in that 6X?

The multi-fuel, this one in particular was built by Continental.

 

[The_Josh_Bear]

Since you have two tanks, to keep it more simple, take the regulator return and tee it into the supply side of the pump. The pump wont know a difference and all that fuel stays out of your return system to the tank. There are a lot less parts that way too.

Looping the fuel like that will heat it up as it's supposed to be cooling the IP. Same problem as before but without the leaks. Hot fuel flows great but affects timing and maximum fuel delivery. Wes did some tests on it a while back here on OBN. He was gonna sell a fuel cooler for performance engines, if you can believe that. I don't think he ever did make a kit.

 

[Lumberjackchuck]

Update on the motor, I took both valve covers off, everything looked great. Then I did a compression test, all cylinders were between 470-490 psi! Great news!

However, I observed a strange phenomena on 2 cylinders. When ever the engine cranked over I had air blowing out of the return lines!

I think this may confirm that the problem was a bad injector, if they were stuck open then I’m sure air could make it back into the return lines. Well actually, it looks like I have 2 bad injectors. At this point I think I want a new batch, they were R&D stage 1. I think I may try another brand.

I know if I got any dirt in them they could get stuck open, but I was super clean installing them, and any lines after the filter I thoroughly flushed.

Any recommendations for injectors? I don’t want to take my chances with these again.

 

[The_Josh_Bear]

That's crazy. Never heard of that before, though it's possible. I'd call R&D and see what they say, maybe they send you 2 good ones? They are a good outfit, shouldn't have quality control issues.

That said, if you want to switch it up, @typ4 Russ Repair Injectors has injectors and he pop-matches them, does a great job and stands behind his work. I don't know if he does anything performance-wise like a stage 1. I've pop-tested my last set twice from him over the 5+ years I've had them. All are still within 50psi!

Last I checked Wes over at classicdieseldesigns.com does a stage 1, same with Moose Diesel but I haven't looked in a while.

 

[asmith]

Looping the fuel like that will heat it up as it's supposed to be cooling the IP. Same problem as before but without the leaks. Hot fuel flows great but affects timing and maximum fuel delivery. Wes did some tests on it a while back here on OBN. He was gonna sell a fuel cooler for performance engines, if you can believe that. I don't think he ever did make a kit.

You think it will heat the fuel too much? Wes was who I got that idea from. But that is something to think about, it may not be able to shed enough heat that way.
If that is the case then he will have to come up with dedicated returns for both tanks. I am no help with that. I only have one tank.

 

[The_Josh_Bear]

I do. That IP will burn your hand when it's getting cooled actively, I can't imagine how hot it would get if the majority of the fuel going through it is just looping. Now maybe it doesn't cause any issues at all-- but I thought I'd throw it out there.