Testing tr6 injectors

[Ken F]

Hi,

I rigged up a testing kit to test my fuel injectors function. 
 

I’ve  seen posts where owners have tested for pop and spray pattern and leaking seals but they were a while ago. what have others done please. 
 

I put the end of my injectors in water to look for when they pop open but I can’t see much for bubbles. 
 

Air bubbles still come out at 30 psi and it’s difficult to know if they pop or are just not calibrated. 
 

I am only doing 2 and 5 which had a slight dribble, I fitted new seals after a clean. 
 

I would have thought I would see no air bubbles below 40psi.

 

Any advice before I give up and send them al for rebuild.

Thanks in advance Ken. 

[TR NIALL]

3 minutes ago, Ken F said:

Hi,

I rigged up a testing kit to test my fuel injectors function. 
 

I’ve  seen posts where owners have tested for pop and spray pattern and leaking seals but they were a while ago. what have others done please. 
 

I put the end of my injectors in water to look for when they pop open but I can’t see much for bubbles. 
 

Air bubbles still come out at 30 psi and it’s difficult to know if they pop or are just not calibrated. 
 

I am only doing 2 and 5 which had a slight dribble, I fitted new seals after a clean. 
 

I would have thought I would see no air bubbles below 40psi.

 

Any advice before I give up and send them al for rebuild.

Thanks in advance Ken. 

Did you lap in the Poppet Valve like you would when doing the Valves on a Cylinder Head.

[Ken F]

10 hours ago, TR NIALL said:

Did you lap in the Poppet Valve like you would when doing the Valves on a Cylinder Head.

Thanks Niall, no I didn’t as I wasn’t sure what to use, how to do it and if I might make it worse. That will be my next approach.

I was expecting a female cone shape corresponding to the poppet but it’s only a small contact area. The poppet cone must be only to direct the spray pattern.

If I dipped the end in a thin oil or similar it wouldn’t make so many bubbles obscuring my view. Do other people just do it by sound and sight without the dipping in liquid I wonder?

Regards Ken.

 

 

[TR NIALL]

1 hour ago, Ken F said:

Thanks Niall, no I didn’t as I wasn’t sure what to use, how to do it and if I might make it worse. That will be my next approach.

I was expecting a female cone shape corresponding to the poppet but it’s only a small contact area. The poppet cone must be only to direct the spray pattern.

If I dipped the end in a thin oil or similar it wouldn’t make so many bubbles obscuring my view. Do other people just do it by sound and sight without the dipping in liquid I wonder?

Regards Ken.

 

 

I don’t know how others do it but if it was me I’d take the Injector apart and devise some way of lapping in the Poppet Valve with a bit of Grinding Paste as for testing afterwards make up an airline connection to the Injector with a Compressor with the Regulator set to about 40psi as I think that’s what they are set at and try that way in jar of Petrol.

[TR NIALL]

This is what I played with before I’m not sure it’s the most scientific way of doing things and can’t remember if it worked as I had good set of injectors that I used but just made this up as a bit of an experiment.

[PodOne]

I blow mine out with an airline which will screw directly onto the injector body no need for the thin fuel line. They generally pop around 50-55psi.

[Lebro]

Many years ago I did this on a 2.5 P.I. I used brasso to lap it in, worked well.

Bob

Edited June 7 by Lebro

[Charlie D]

32 minutes ago, Lebro said:

I used brass to lap it in, worked well.

Do you mean "Brasso"? (Apologies if I got it wrong)

[Tom B]

Here are some notes that I posted some time ago. When looking for leaks from the poppit valve look for leaks past the small O ring on the stem of the valve. I have found that the interior bore can corrode. It is quite a therapeutic winter exercise refurbishing these devices....

Regards

Tom

2022-11 Notes on setting Injectors.pdf

[Lebro]

3 hours ago, Charlie D said:

Do you mean "Brasso"? (Apologies if I got it wrong)

Yep, corrected !

[Ken F]

Thank you everyone for your input,

I will try Brasso, saves me spending half a day searching for my diamond paste.

Tom B... your info was very helpful, the slot in the Allen key ingenious, I was going to try to cut one and drill down the centre to make a box spanner, without a pillar drill not easy.

I will try my electric pump, (similar to yours,) probably more accurate than my compressor regulator and gauge.

I spoke with Martin Giles ( Fred Milturn) and he confirmed that it's the nylon retainer adjusts the pop setting and agreed that if calibration can't be reached then screwing the threaded rod into or out of the spring will give more or less spring tensio

A warning to anyone playing with their injectors.... you must hold the threaded rod with a 1.5mm Allen key when turning the nylon retainer or you will ruin the spring as the nylon retainer/adjuster will squash  the spring or unfurl it. 

 

KMI rebuild Fred Milturn injectors and they fit new springs. They will rebuild customers own injectors too.  If I can't get a result myself when the enjoyment of tinkering has worn me down there is always the rebuild option. Incidentally the rebuilt ones have a Nyloc nut to replace the nylon retainer which makes adjustment easier.

 

Ken

[k_raven_smith]

Or you could send them to myself. I do all the work myself and have been for nearly forty years. A full set of six for under one hundred pounds.

 

[Ken F]

I tried lapping a poppet on one injector.... I adjusted the spring tension and got it to pop at 46psi, backed it off to 40psi  and could not hear for feel any air escaping.

I then put the point in a jar of petrol, air bubbles were evident to as low as 12psi.

Niall used the actual thin plastic hose from the car, could the volume of the apparatus I'm using have a baring? I have an 18 inch high pressure hose and coupled with that there is the stainless pipes to the gauge, the ball valve and the metre long hose from the compressor regulator to the ball valve.

I will try lapping  with some metal polish and try again.

If the spring has lost its recoil strength and only works on compression that would cause my bubbles through lack of sealing force.

Does anybody have any idea how much pressure there is in the injector hoses between pulses and how much is left after shut down? There must be a good enough seal of the poppet to achieve the one drip per minute.

Ken.