V1902 fuel questions/help

[sheepfarm]

Well I'm new here. So I've been searching around on line and local places and can't really get the answers I'm looking for so I thought I would try here.
OK so I'm working on my bobcat x231 excavator that has v1902 motor. It does have a lot of hours it's not a new machine by no means.
So a short back ground I purchased the machine 4 or 5 years ago and motor had a lot of blow by. compression test showed number 1 cylinder bad so took head off rings was stuck replaced rings and piston in that hole and run it. This spring noticed blow by again. Recently checked compression and same hole bad again so this time pulled it apart and second ring was like shattered (question 1) what would cause that. This time again piston and rings ordered new head and sent off injectors and pump to be rebuilt thinking may had to do with cylinder problem. So now all back together and running . It seems to run what I think is normal. So I was looking over everything and noticed no return fuel going in tank. I removed the return line at last injector while running and no fuel from injector and motor died like it ran out of fuel (question 2 should you always have return fuel and why would I not is that saying the machine is not running like it should and i dont know. I never noticed the fuel return problem till now) so when i first bought the machine i cleaned tank and replaced all fuel lines and now I was thinking of a lift pump that I never noticed. I went thru my service manual and it never had any type of lift pump from factory is that common(question 3)should it is that my return problem. Do I need to add a lift pump or do I have other problems that a lift pump would just hide.
OK so I'll stop there for now sorry about being so long just trying to give a little history that I know about it so far. Thanks in advance for any help and advice

 

[CoreyM]

Well I'm new here. So I've been searching around on line and local places and can't really get the answers I'm looking for so I thought I would try here.
OK so I'm working on my bobcat x231 excavator that has v1902 motor. It does have a lot of hours it's not a new machine by no means.
So a short back ground I purchased the machine 4 or 5 years ago and motor had a lot of blow by. compression test showed number 1 cylinder bad so took head off rings was stuck replaced rings and piston in that hole and run it. This spring noticed blow by again. Recently checked compression and same hole bad again so this time pulled it apart and second ring was like shattered (question 1) what would cause that. This time again piston and rings ordered new head and sent off injectors and pump to be rebuilt thinking may had to do with cylinder problem. So now all back together and running . It seems to run what I think is normal. So I was looking over everything and noticed no return fuel going in tank. I removed the return line at last injector while running and no fuel from injector and motor died like it ran out of fuel (question 2 should you always have return fuel and why would I not is that saying the machine is not running like it should and i dont know. I never noticed the fuel return problem till now) so when i first bought the machine i cleaned tank and replaced all fuel lines and now I was thinking of a lift pump that I never noticed. I went thru my service manual and it never had any type of lift pump from factory is that common(question 3)should it is that my return problem. Do I need to add a lift pump or do I have other problems that a lift pump would just hide.
OK so I'll stop there for now sorry about being so long just trying to give a little history that I know about it so far. Thanks in advance for any help and advice

This is quite a coincidence. I just did a search on this topic and found your post so I registered. I'm working on a Kubota KX151. I'm replacing the tired V1902 with one that I purchased. The purchased engine was set up for a Carrier refrigeration unit. The engines are very similar but one of the differences is that the Carrier engine's injectors do not have a return outlet. I will probably swap injectors so the engine will be set up as close as possible to the Kubota engine but I'm very curious to know why one requires a return circuit and the other does not. Hate to answer your question with a question but I thought if someone can shed some light it could be helpful for both of us.

 

[sheepfarm]

I just assumed that they all had returns. I'm not sure how mine has fuel at injector and no fuel coming out the line barb.I checked that ring and washer on top and all was installed correctly
On that KX151 does it have a factory lift pump. I work on a KH90 often for the neighbor it has a aftermarket electric pump added to it

 

[Russell King]

I would assume the engine for a refrigeration would be similar to one on a generator unit. It probably is set to run a one speed and no throttle up or down. That is controlled by the governor and it would probably have to be changed out to one for varying speeds.

 

[CoreyM]

I just assumed that they all had returns. I'm not sure how mine has fuel at injector and no fuel coming out the line barb.I checked that ring and washer on top and all was installed correctly
On that KX151 does it have a factory lift pump. I work on a KH90 often for the neighbor it has a aftermarket electric pump added to it

That is definitely odd. I'm not sure if you can close that barb off by rotating the ring on the injector that holds the barb. I'm pulling all my injectors off tomorrow and will take a closer look. My Kubuta has an electric pump inline. I'm not sure if you'd refer to it as a lift pump. It begins pumping as soon as the ignition switch is turned on.

 

[North Idaho Wolfman]

Have you ever used starting fluid or ether on the engine?
That will crack rings.
Also over heat can cause it.
If the cylinder was not bored properly that will do it too.

You may or may not have fuel getting returned, it just depends on how your running it.
If you removed a return and the engine dies as a result of that you have a bad injector.
A lift pump does not effect the fuel return from the injectors.

The V1702 and V1902 IDI engines were very problematic and had overheat and head issues.

 

[CoreyM]

I would assume the engine for a refrigeration would be similar to one on a generator unit. It probably is set to run a one speed and no throttle up or down. That is controlled by the governor and it would probably have to be changed out to one for varying speeds.

I'm sure you're correct. I'm transferring all the throttle mechanism from my original engine.

 

[North Idaho Wolfman]

I'm sure you're correct. I'm transferring all the throttle mechanism from my original engine.

It's not necessarily the external parts and linkages, it could be the internal governor that is different.

 

[CoreyM]

Have you ever used starting fluid or ether on the engine?
That will crack rings.
Also over heat can cause it.
If the cylinder was not bored properly that will do it too.

You may or may not have fuel getting returned, it just depends on how your running it.
If you removed a return and the engine dies as a result of that you have a bad injector.
A lift pump does not effect the fuel return from the injectors.

The V1702 and V1902 IDI engines were very problematic and had overheat and head issues.

Spoken like an expert. Running the machine full steam in the summertime was always an issue.

 

[North Idaho Wolfman]

Spoken like an expert. Running the machine full steam in the summertime was always an issue.

Swap it for a V2203 DI and all of your problems will disappear.
They start much easier (1000% easier).
They run cooler.
They have a real nice HP gain.
They are the same physical size and mount up!

 

[sheepfarm]

Have you ever used starting fluid or ether on the engine?
That will crack rings.
Also over heat can cause it.
If the cylinder was not bored properly that will do it too.

You may or may not have fuel getting returned, it just depends on how your running it.
If you removed a return and the engine dies as a result of that you have a bad injector.
A lift pump does not effect the fuel return from the injectors.

The V1702 and V1902 IDI engines were very problematic and had overheat and head issues.

No staring fluid
Never over heated and when I replaced piston and rings I just honed the hole. To have a lot of hours on it the cylinder walls looks good.
I was worried that I could have had a fuel problem that's why this time I sent injectors and pump to be rebuilt. I'll give the shop a call tomorrow and see what they think about the return.
Is it normal on these motors not to have a lift pump. And should I install one

 

[North Idaho Wolfman]

Does the motor bog down?
If not, then no reason to install a lift pump.
I'll bet the fuel tank is above the engine, so it's just gravity feed.

The only reason fuel could cause a ring issue would be if it went totally south and flooded the cylinder, and in that case it would smoke and more than likely bend the rod or break the piston.

 

[CoreyM]

It's not necessarily the external parts and linkages, it could be the internal governor that is different.

I doubt it. This is the second Carrier engine for my excavator. I swapped in a well used motor about six years ago and it functioned just like the original. The main difference is the fuel cam shaft. I'm once again performing the fuel cam swap. Most time consuming part of the swap.

 

[CoreyM]

Swap it for a V2203 DI and all of your problems will disappear.
They start much easier (1000% easier).
They run cooler.
They have a real nice HP gain.
They are the same physical size and mount up!

Sounds simple and I wish it was. I had the 2203 but ended up selling it because the conversion was problematic. It would be a much easier swap into a machine that doesn't have a hydraulic pump driven by the fuel cam shaft.

 

[North Idaho Wolfman]

I didn't realize that that has a pump off the fuel cam.
Most EX's do not, so the fuel cam is not normally an issue.

 

[CoreyM]

I didn't realize that that has a pump off the fuel cam.
Most EX's do not, so the fuel cam is not normally an issue.

I wish it wasn't with my machine. It would be a one day swap if it wasn't for the fuel cam. Too many hours and $50 for the timing cover gasket Still beats $6K for a reman engine.

 

[CoreyM]

Have you resolved your issues yet? I took another look at my replacement engine and of course it has the same return circuit on the injectors. The person I bought the motor from had removed the the

Well I'm new here. So I've been searching around on line and local places and can't really get the answers I'm looking for so I thought I would try here.
OK so I'm working on my bobcat x231 excavator that has v1902 motor. It does have a lot of hours it's not a new machine by no means.
So a short back ground I purchased the machine 4 or 5 years ago and motor had a lot of blow by. compression test showed number 1 cylinder bad so took head off rings was stuck replaced rings and piston in that hole and run it. This spring noticed blow by again. Recently checked compression and same hole bad again so this time pulled it apart and second ring was like shattered (question 1) what would cause that. This time again piston and rings ordered new head and sent off injectors and pump to be rebuilt thinking may had to do with cylinder problem. So now all back together and running . It seems to run what I think is normal. So I was looking over everything and noticed no return fuel going in tank. I removed the return line at last injector while running and no fuel from injector and motor died like it ran out of fuel (question 2 should you always have return fuel and why would I not is that saying the machine is not running like it should and i dont know. I never noticed the fuel return problem till now) so when i first bought the machine i cleaned tank and replaced all fuel lines and now I was thinking of a lift pump that I never noticed. I went thru my service manual and it never had any type of lift pump from factory is that common(question 3)should it is that my return problem. Do I need to add a lift pump or do I have other problems that a lift pump would just hide.
OK so I'll stop there for now sorry about being so long just trying to give a little history that I know about it so far. Thanks in advance for any help and advice

Found this on a different forum. If you've had the same issue twice in only one cylinder this could be the issue. Broken rings can be a result of excessive heat.

"Bad injectors can cause a bad spray pattern that causes too much fuel to reach the combustion chamber walls (on the piston) instead of atomizing first. Whole different scenario. Another scenario is that the injector doesn't close properly and dribbles fuel into the cylinder through the intake and compression stroke, leading to a cylinder that's running too hot."

 

[sheepfarm]

Have you resolved your issues yet? I took another look at my replacement engine and of course it has the same return circuit on the injectors. The person I bought the motor from had removed the the

Found this on a different forum. If you've had the same issue twice in only one cylinder this could be the issue. Broken rings can be a result of excessive heat.

"Bad injectors can cause a bad spray pattern that causes too much fuel to reach the combustion chamber walls (on the piston) instead of atomizing first. Whole different scenario. Another scenario is that the injector doesn't close properly and dribbles fuel into the cylinder through the intake and compression stroke, leading to a cylinder that's running too hot."

 

[sheepfarm]

No I was waiting to report back at my findings. I spoke to the shop that rebuilt my fuel stuff and of course they said I had a blockage somewhere else but it's mostly all new fuel line and can blow thru all of it. My next step over the next couple days Is put all clear fuel line on it and run it from a bucket of fuel just to physically see all the fuel flowing in and out. I just can't see it using all the fuel that's going to the injectors all the time I'm still thinking that somethings is not right with my rebuilt fuel parts.
Like your finding i guess is what I was wondering that might have happened to my piston ring in someway I just didn't know what or how