Vilter 440 Help

[Huskerseth]

Does any one know how to convert a Vilter 4412 with gas unloading to oil unloading? we took one of our spare 440's from our main system and installed it in to our low Temp system. The problem we found after moving it was it is set up for gas unloading and our low tem system only operates at about 10psi so we need to convert it to oil unloading. I know that the heads for gas unloading have a small hole drilled in to the side to vent the gas. Is there an easy way to plug these holes so we can use oil instead of gas. one suggestion we came up with was to drill and tap the hole but the small bleed hole is so close to the edge of the head i am afraid we will crack the head if we try and drill it out. Anyone ever done anything like this before?

[NH3LVR]

I have converted them, but only in the reverse direction. Should not be too hard to find heads used. If you cannot find any I might know someone who has some, but they would be on the west coast.

[RANGER1]

I can't see why you can't drill & tap hole!

It only has to be a grub screw to block it off, the hole you have now may even be suitable or close to something.
Just use a drill bit to gauge the size hole(probably 1/16") & go from there.
You obviously have to vent back into crankcase from unloader piston as currently would go to suction.

What type of 3 way solonoid are you going to use, Vilter?

[Huskerseth]

I only have 2 issues with trying to drill it out, 1st we dont have a small right angle drill to get to the vent hole. 2nd the vent hole is like 3/32" and maby about 1/16" from the edge of the head. so to drill it out i would have to use a bit bigenough to go over the orginal hole but be started in a different spot, like 1/4" from the edge of the head.

[RANGER1]

I only have 2 issues with trying to drill it out, 1st we dont have a small right angle drill to get to the vent hole. 2nd the vent hole is like 3/32" and maby about 1/16" from the edge of the head. so to drill it out i would have to use a bit bigenough to go over the orginal hole but be started in a different spot, like 1/4" from the edge of the head.

Huskerseth,
It may not be easy but whats the alternative!

Remember its only cast iron, very easy to work with.

Even if it is close to edge of the machined head face, can't see how it matters as long as gasket can seal this area.

Is there a machine shop that you use & trust to do the job with the right tools?

You could even put a dab of weld on it with cast iron electrode.

Can you run a 1/2" line from highside close by after blocking holes)to give higher pressure for unloaders to work.
If it has traps or is to long it may condense liquid in it though so keep it short & slope back to point of exit.
Line to each head would have needle valve to adjust pressure onto unloader, otherwise it might smash unloaders.

[RANGER1]

Out of interest I just saw a right angle drill attatchment at hardware store for $15

[Huskerseth]

Thanks for all the help! i have a guy from our local machine shop coming out next week to look at the heads and see if they can drill them out for us.

[RANGER1]

Thanks for all the help! i have a guy from our local machine shop coming out next week to look at the heads and see if they can drill them out for us.

Hope I don't sound to harsh!

Let us know how you get on with modification.

[arliefarley]

We have done this many times it is not as hard as many think, use a torch tap cleaner so you will know the angle of the hole. We use a #7 drill bit, and a 1/4-20 starting tap and do not tap all the way then use a 1/4" bolt put red lock tight on it, and install with impact wrench and break it off. Works fine. If you want we may have replacement heads I will need to know model.

[danod]

I have done this on 2 machines using silver solder. You have to clean the holes very well, use flux for silver solder, heat the area up till the flux flows and the metal is hot enough to melt the silver solder then fill the hole till the solder stops flowing and wait for it too cool