Vacuum tube fittings

[beeRS]

Has anyone ever used PTC (push to connect) type fittings for running vac lines? This is the type of thing I mean...

link

I know the easiest way would be to use a screw in hose tail and silicone vac tubing, but the PTC option would offer a nice tight 90 degree bend which would suit my application nicely.

[Miniliteman]

In my experience for best results do not use tight bends for anything that "flows" (air, water, petrol).

[alladdin]

i dont think bends would affect vac as you can use an accumulator anyway ?

they do work for vac but quality varys and good ones (smc festo etc ) are normally expensive. can you not get 90 deg barbed fittings ? try fish tank suppliers on ebay

[Graham]

I dont see an issue on vacuum lines they have very little if any "flow"

[beeRS]

Thanks for your replies guys.

The problem is that I went and drilled/tapped the four holes in my vacuum manifold too close together. I cannot screw in a ordinary 90 degree fitting as there isn't enough clearance to spin them around. I could screw one in, but not the one next to it . The banjo ones can be screwed in easily.

Yes - the PTC fittings vary in price considerably. SMC and Festo branded ones are really expensive. I might try a cheaper brand and experiment. I'm sure that in principle a PTC fitting should work for vacuum. If all fails, I'll have to re-think the manifold design or location.

[Graham]

normal vac advance pipes are tiny, presusmably to make faster response to any vac change, but its a closed system there is no flow to speak of you will be fine with what your proposing

[modifyitmike]

Hi beeRS.
sorry but you are wrong on that .
you can buy 90' swivel unions where the main body can be held in position and the threaded part tightened up. SO they would fit in such a tight spot.

uk.rs-online.com/web/p/pneumatic-fittings/1442612?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Pneumatics_%26_Hydraulics_Whoop-_-Pneumatic+Fittings_Whoop-_-1442612&matchtype=&pla-333922835479&gclid=CjwKCAiA_omPBhBBEiwAcg7smd0QVA0cJAXEYbupn1cxvMxdoVUyLAeaLjjOwDEq6qJ0eEi2UoMTeRoC8P4QAvD_BwE&gclsrc=aw.ds

[therealpinto]

I have used these push-in fittings for 20 years, actually also for fuel in some cases. I have had few problems until recently - it seems that now it is easier to be fooled into buying cheaper ones than necessary.

Good quality ones are usually fine, especially if you mount them somewhere not directly on the engine (vibrations can make them leak). Just choose a suitable line depending on what heat rating you need.

Gustaf

[stevieturbo]

Yep, I've used them for a lot of stuff. Only caveats are try and keep them away from extreme heat, and if attaching them to say an inlet manifold on the engine....get the metal bodied ones, not the plastic bodied.

But they make for very easy fitting and removal vs rubber hoses and clamps, plus the OD of the hoses will be small. Some stuff you can get away with 4mm OD, although for likes of say a BOV I prefer 6mm OD, as you're still moving a small amount of air to operate the valve.

I've seen people use them on actual petrol lines.....would not be keen on that idea myself. Even where some use them on water/methanol injection, whilst they do work...they do have a life span for that sort of thing before they leak, or maybe get blown off. But they're using much higher pressures than say a boost signal etc

[therealpinto]

When I started using these fittings back in 1998-99, I was working at a place that built truck bodies and we had fittings rated for pneumatic braking systems, that were also certified to use with the anti-freeze ethanol used in these. So backed up by the suppliers recommendation back then I felt OK using them for fuel/petrol.

But I am more hesitant to use "non branded" ones for that now.

Gustaf

[Forest_rallying]

You can get swivel brass unions that are used on commercial air systems that probably would do the job. The OP doesn't state the thread size what they need to be.