Curious JP3 feature since changing injectors

[starman]

I've just replaced my very dirty injectors with a set of cleaned and checked ones (also done an oil change).

The engine runs fine but there's a new resonating noise which turns out to be caused by fuel pulsing through the longer 2 & 3 pump to injector pipes making them resonate. (If I hold the pipes gently the noise stops). The pulsing through the pipes seems much stronger than when the old injectors were in - maybe they were just dirty?

The short No 1 pipe does not vibrate or throb anywhere near as much.

Should I be concerned and should I lightly tie the pipes together to stop the resonance?

[bizzard]

I've just replaced my very dirty injectors with a set of cleaned and checked ones (also done an oil change).

The engine runs fine but there's a new resonating noise which turns out to be caused by fuel pulsing through the longer 2 & 3 pump to injector pipes making them resonate. (If I hold the pipes gently the noise stops). The pulsing through the pipes seems much stronger than when the old injectors were in - maybe they were just dirty?

The short No 1 pipe does not vibrate or throb anywhere near as much.

Should I be concerned and should I lightly tie the pipes together to stop the resonance?

Restrain them with some home made bolt on clips with rubber grommets, or they could fracture.

[Timleech]

Strictly speaking, the pipes should all be the same length

 

I'm not convinced how much difference it make in practice, though.

 

Tim

[BEngo]

Strictly speaking, the pipes should all be the same length

 

I'm not convinced how much difference it make in practice, though.

 

Tim

 

 

Bugger all, IME, but it does make it easier to just hold one straight spare pipe on board and bend it to fit when needed.

 

Bizzard is right that they njeed to be restrained from vibrating or they will break. Had that happen once on a Foden FD4 off the Needles at night in a SW gale. Diesel everywhere. Squeaky bum moment! Fortunately the other FD4 was OK and kept going.

 

N

 

N

[Albion]

I've just replaced my very dirty injectors with a set of cleaned and checked ones (also done an oil change).

The engine runs fine but there's a new resonating noise which turns out to be caused by fuel pulsing through the longer 2 & 3 pump to injector pipes making them resonate. (If I hold the pipes gently the noise stops). The pulsing through the pipes seems much stronger than when the old injectors were in - maybe they were just dirty?

The short No 1 pipe does not vibrate or throb anywhere near as much.

Should I be concerned and should I lightly tie the pipes together to stop the resonance?

More likely that the cracking pressures on your reconditioned injectors are now up to the correct pressure. The old ones would have been weaker and lower pressures. The increased cracking pressures required are the likely cause of the changes that you have seen.

Ideally, as the others have said, if the pipes are actually vibrating, as opposed to resonating, then they should be restrained with brackets and rubber inserts.

Roger

[dave moore]

Bengo,

 

We have had to replace one of our high pressure pipes on Resolute several years ago but it's not a job I'd want to look at on board unless there's a fully equipped workshop. 6mm steel pipe isn't easy to bend to precise contours and the ends had to be silver soldered to the pipe. It's a job I left to one of the engineers at the yard. We have spare pipe, just in case, obtained from a local injector servicing specialist in nearby Wolverhampton. If you have the gear and skills , it's a different matter....

 

Cheers

 

Dave