LPG converter noise when cold

[dom14]

LPG converter noise

Hey Guys,

This is Impco model L converter on Nissan Patrol RB30 engine.
The noise you hear on this video happens when the engine is cold started. Once the engine(coolant) is warmed up and the LPG converter is warmed up(few minutes) the noise goes away.

I'm wondering what this noise is and whether I need to fix this?

https://www.youtube.com/watch?v=iqMUDmavbH4&feature=youtu.be

Thanx

[4bye4]

Hi Dom, its possible that there is a film of oil on the valve inside the unit. Sometimes there is a distalate of oil from the gas and this can make the valve sticky. As ite warms up the oil becomes less tacky and the noise goes away. A couple of things, oil companies will tell you that there is no way there can be distilled oil in the gas so I don't know what Im talking about, and this if it does happen, which it can't, would happen in cold weather. I am only talking from 25 years as a gas fitter. I wouldn't wprry about it but if you want to check, a licensed gas fitter could take the top cover off and check the valve and diaphragm for you by undoing the screws around the circumfrance of the cover and carefully removing the cover, but a licensed gas fitter would know that if you see what I mean.
Cheers Tony.

[mudski]

Yeah i remember one of my old v8 Kingswoods doing this exact thing. I just turned the radio up and drove harder. Lol.

Sent from my GT-N7105T using Tapatalk

[dom14]

Hi Dom, its possible that there is a film of oil on the valve inside the unit. Sometimes there is a distalate of oil from the gas and this can make the valve sticky. As ite warms up the oil becomes less tacky and the noise goes away. A couple of things, oil companies will tell you that there is no way there can be distilled oil in the gas so I don't know what Im talking about, and this if it does happen, which it can't, would happen in cold weather. I am only talking from 25 years as a gas fitter. I wouldn't wprry about it but if you want to check, a licensed gas fitter could take the top cover off and check the valve and diaphragm for you by undoing the screws around the circumfrance of the cover and carefully removing the cover, but a licensed gas fitter would know that if you see what I mean.
Cheers Tony.

Thanx Tony.
The reason I decided to ask is that the original Impco model L LPG converter(vaporizer) died a while ago, and this is the replacement one.
This is a used one. The original one started making the same noise before it died completely.
I tried to rebuild it without much success.
I've dismantled this particular converter couple of times, so I'm bit familiar with the internals.
The reason my rebuild/repair job didn't work 'cos I think I used silicone on diaphragm gaskets.
I probably gummed them up by oozing some of the sealant into the diaphragms.
I know they build up goo inside from the stuff they add to LPG since I opened up one of them.

I thought an experienced fellas can tell me about the exact reason of this particular noise.

I think I'll try another rebuild and if that doesn't work, i will stick with a new one.
I like the idea of recycling things, when it's not too dangerous to do so & when it's economical to do so.(or when it's fun for me to do so).

The previous converter died fairly suddenly after making the same noise for a year or so.

[dom14]

Yeah i remember one of my old v8 Kingswoods doing this exact thing. I just turned the radio up and drove harder. Lol.

Sent from my GT-N7105T using Tapatalk

Yeah, I pretty much do the same thing and if it shytes itself suddenly, I'll have a spare one handy and besides I'll have petrol as a backup anyway. :)

[mudnut]

Contamination causes a lot of problems. Another reason I won't run LPG. Has your LPG system got a strainer in line at all? I'm interested to see if there is any solid pieces that have come through.

[dom14]

Contamination causes a lot of problems. Another reason I won't run LPG. Has your LPG system got a strainer in line at all? I'm interested to see if there is any solid pieces that have come through.

There's a filter in the lock off valve, and I remember cleaning it while ago after opening it up(not much to do anyway).
I keep a spare lock of valve with me all the time, just in case.
I think there's filter at the tank end, near the tank lock off valve as well(I might be wrong on that as I haven't opened it up to check).

Contamination is a problem with both fuels.
Just like carbies, fuel filters need replacement, LPG fuel filters inside the lock off valve need cleaning/replacement I think.
LPG converter is way too critical to open up and clean it by a regular backyard guys I think, but I've already done that, and it looks like I'm about to
do that again.
I think the reason for LPG converter failure is that they don't get serviced/cleaned but replaced.
If we can safely clean them once every few years, I think they can last for a long time without dramas.

[dom14]

Contamination causes a lot of problems. Another reason I won't run LPG. Has your LPG system got a strainer in line at all? I'm interested to see if there is any solid pieces that have come through.

LPG is better with dedicated LPG throttle bodies. When we use the carbies to do the job, carby usually end up worn and torn over the years, 'cos of no petrol getting through it for longer periods. With EFI it's not an issue. EFI throttle body can be shared with both petrol and LPG without any excessive wear to the throttle body afaik. All the good reasons for me to consider EFI conversion. :)

[mudnut]

Yeah,yeah. We all know the real reason you want EFI is so you can fit a turbo.:icon_victory:

[dom14]

Yeah,yeah. We all know the real reason you want EFI is so you can fit a turbo.:icon_victory:

:D
The only reason I haven't done it yet 'cos of the worries about turboes with long solo trips.
Reliability is an issue. EFI conversion is fairly cheaper to do though. It's just PITA of sorting out all the wiring stuff.
Mechanically it's not that challenging I think. :)