Compression testers

[LandRoverTom]

Afternoon.

I have a diesel compression test kit (admitedly a cheap version) that the non return valve diesn't seem to work anymore - the gauge pulses but drops back to zero after each compression stroke.

I keep meaning to connect it to the compressor to prove it off an engine but that involves making up adapters which until I'm back at work I dont have the facilities for.

So until then and pre-empting proving that the valve is indeed faulty, does anyone know where you can (if at all) source just the valve section from? the wonders of google just return full kits and all the adapters etc are fine so I'm reluctant to buy another set if I can get hold of the valve to fix this one...

 

[tom2207]

Afternoon.

I have a diesel compression test kit (admitedly a cheap version) that the non return valve diesn't seem to work anymore - the gauge pulses but drops back to zero after each compression stroke.

I keep meaning to connect it to the compressor to prove it off an engine but that involves making up adapters which until I'm back at work I dont have the facilities for.

So until then and pre-empting proving that the valve is indeed faulty, does anyone know where you can (if at all) source just the valve section from? the wonders of google just return full kits and all the adapters etc are fine so I'm reluctant to buy another set if I can get hold of the valve to fix this one...

It will only be a ball bearing and a spring , so its probably just a bit of carbon or the likes flake of rust maybe ,,, fiddle with it a bit , poke it with the straw off the wd40 tin , may just do the trick.

 

[123hotchef]

mine is new and does the same thing! I was going to fit a schrader valve into it

 

[tom2207]

mine is new and does the same thing! I was going to fit a schrader valve into it

my very old petrol one has a schrader valve in it , but I thought diesels having way more compression may have had a ball bearing ,,, either way its a good chance to poke it with something and see , if it has a schrader it could just be loose and need half a turn with a valve key ,,

 

[LandRoverTom]

No it's not a shrader valve its a quick release coupling type of valve.
Thanks for setting me back on the keep it simple track! A closer inspection and WD40/some light handed percussive mantainance might jsut do the trick!

 

[gordon stephenson]

I made one from a flexible brake pipe, spark plug and a pressure gauge, Tyre valve fitted into the spark plug, Works a treat, and still got it after all these years

 

[Melvyn Best]

I made one from a flexible brake pipe, spark plug and a pressure gauge, Tyre valve fitted into the spark plug, Works a treat, and still got it after all these years

For a diesel?

 

[gordon stephenson]

Oops I really must learn to read, Did not notice the "Diesel" Obviously mine was petrol, Sorry.

 

[RWD3M]

What sort of compression pressures do you get from a diesel?

 

[colnerov]

Anything up to 400psi.

 

[graffian]

I use the brass bit and valve from tyre valves.
Just epoxy or loctite the brass bit in.

 

[RWD3M]

Anything up to 400psi.

Really!!! Wow, didn't know that.

Thanks.

 

[LandRoverTom]

Oops I really must learn to read, Did not notice the "Diesel" Obviously mine was petrol, Sorry.

Haha, no problem. I did twig when you said spark plug that it must have been for petrol.
Not sure how well a tyre valve would cope with 30 bar plus...

 

[jpmillermatic]

I would not think a tire valve, like the shrader type were meant for anything north of 200psi.....but I dont know that for sure.

I did find this solution that might spark some ideas:

https://www.homemadetools.net/homemade-compression-tester-4

JP

 

[tom2207]

It will only be a ball bearing and a spring , so its probably just a bit of carbon or the likes flake of rust maybe ,,, fiddle with it a bit , poke it with the straw off the wd40 tin , may just do the trick.

If poking it with a stick , or hitting it with a hammer wont fix it


The problem was Electrical ...... hth.

 

[tom2207]

No it's not a shrader valve its a quick release coupling type of valve.
Thanks for setting me back on the keep it simple track! A closer inspection and WD40/some light handed percussive mantainance might jsut do the trick!

Thanks for setting me back on the keep it simple track! A closer inspection and WD40/some light handed percussive mantainance might jsut do the trick![/QUOTE]

If poking it with a stick , or hitting it with a hammer wont fix it


The problem was Electrical ...... hth.

 

[LandRoverTom]

I would not think a tire valve, like the shrader type were meant for anything north of 200psi.....but I dont know that for sure.

I did find this solution that might spark some ideas:

https://www.homemadetools.net/homemade-compression-tester-4

JP

Interesting link. I was begining to wonder about making a valve with a ball bearing just wasn't sure on how to release the pressure after. That said, I'd not given it much thought, more a passing 'humm... need to think about that later!'

If poking it with a stick , or hitting it with a hammer wont fix it


The problem was Electrical ...... hth.

Unfortunately as that's my trade, it doesn't help much

 

[LandRoverTom]

And after being a little less lazy, this pdf is quite intersting
https://www.schrader-pacific.com/media/pdf/Valve Core Brochure.pdf

 

[Morrisman]

Really!!! Wow, didn't know that.

Thanks.

25:1 compression. It compresses the air so hard it all but bursts into flame, then at TDC inject a shot of the deadly diesel poison, causes a massive explosion and rattle that sounds like the crank has broken, and the piston hurtles south at the speed of sound.

 

[tom2207]

25:1 compression. It compresses the air so hard it all but bursts into flame, then at TDC inject a shot of the deadly diesel poison, causes a massive explosion and rattle that sounds like the crank has broken, and the piston hurtles south at the speed of sound.

best demonstration of ''adiabatic heat on compression '' is just to put your finger over the end of a bike tyre pump and give it one pump , you will soon get a very practical demonstration .
Diesels basically work that way.

Its also the reason you should open oxygen bottles slowly , any dirt in the line or on fittings , and the high oxy content and sudden increase in temp is where you can get your oxygen fires from.