Help! Drill/modify an oil filter for a pressure gauge sender?

Hi all,

I'm looking to fit an oil pressure gauge to my 950. After a chat with a KTM contact of mine, I arranged an order of a special oil filter cover with a sender line build in, apparently used on the rally bikes. Real neat piece of kit, except as you can see below (new cover on the left, stock on the right), the inside of the cover has a proud section of tube that looks like it should slot into an oil filter....except as you can see, the 950 normal filter has no hole. As such, the cover won't bolt on.



My hairbrained scheme is:

• salvage the rubber sealing ring from the old filter (which fits snugly onto the internal pipe from the new cover),
• drill a hole in the sealed metal end of the new filter
• install the sealing ring on that hole (fluid-tight with silicone sealant or something), making a 'straight-through passage to the sender line, allowing the new cover to fit on and 'plug in' to the oil system.

Assuming I seal the rubber ring properly, I can't see how this allowing dirty oil to mix with clean, and being right after the pump, it should give a good pressure reading, yes?

But if this is a terrible idea and someone can see any impending disasters (dashboard oil volcanoes?) with this plan, I'm all ears.

And thankyou in advance, but I do know about the other oil sender fitting locations, but I've decided to go with this one.

You just want to see an oil-cano, don't you?

To add to my last, the other ption would be to grind away the pipe on the new plug until it fits the profile of the stock one....but i dont kow if any oil would get through to it then.

If it was my bike I would modify the cover before I would drill the filter and risk getting metal shavings in the engine. Some could get caught in the folds of the filter and come out later.

If you cut the protrusion down to match the other you should be fine.

-John

+1 to this, but I think in addition to cutting the cover protrusion down to exactly match the stock piece (so that it holds the filter inward) you'd want to notch the protrusion so that some oil pressure could get into the pressure reading tube.

I had this in mind too - maybe leave a few mm of protusion proud, and drill holes around it.

The problem is that I think the filter comes up dead flush against the rest of the flat inside surface, leaving the hole in the middle of the cover 'sealed off', even with a notched protrustion.

Didn't think about swarf...good point. If I can drill it in such a fashion that none gets caught (hook up a vacuum next to the drill), do think the idea would still hold?

Does your ktm contact/friend know how the professionals use the cover. Do the pros modify the stock filter, or is there some "works" filter made but only offered to the pros?

If you drill the hole put some grease on the spot where you drill.

Another option, being that the metal base of the paper filter is very thin. Perhaps you could "punch" out the hole from the interior side. Might take some Jerry rigging and making your own punch, say maybe a screwdriver with its end sharpened to a point.

The latter - I think it's supposed to got with a special filter. According to him, it's originally for a 660 Rally Replic, but the filter port is identical to the 950.

I've emailed him too to see what he thinks.

I would take the new cover to my friendly local machinist and have him mill it to match the stock cover

Someone else had a similar thread, but maybe for a temp sender.

I think he ended up using the hole for the existing plug in the front of the oil filter housing.

Search part# 600.38.033.050 in the 950 parts manual.

Another way to do it, if interested..

http://ktm950.info/how/Farkels/adventure/oil_pressure_gauge/oil_pressure_gauge.html

The spigot on the new cover is designed to read the pressure on the inside (filtered side) of the filter.
With the spigot machined flat and a groove in the cover, the guage will only read the oil pressure ahead of the filter. If the filter plugs and reduces pressure/flow to the engine, the guage will still read the oil pump pressure on the outside of the filter.

Mill the new cover to match the old profile. Use a thin punch to pierce the filter from the inside out.

That should produce no swarf and still give the sensor a pressure source to read from.

+1 this is the final answer I believe

I had thought that the oil entered through the rubber grommet to the inside of the filter, and flowed outward into the filter chamber. The system diagram on page 2-2 in the repair manual, seems to show that flow direction.

Am I looking at this wrong? Is the flow actually inward from the filter's outer surface, and out through the rubber grommet at the inboard end of the filter?

Or, maybe am I just confused about your meaning?

Without a seal on the punched end of the filter there is direct path for oilto bypass the filter.

Oil flows from out to in. That is why the filter is compressed when the water pump seal shits the bed. Like someone mentioned earlier if the op uses the cover for oil pressure it will not show a loss of pressure when the filter clogs. It may show an increase but that may not register the needed enthusiasm to turn off the engine due to low oil at the bearings. If you really want to do this right OP, find an oil pressure source after the filter.

-John

Thanks John, VERY helpful post.

Sounds like drilling the oil filter is the way to go. With the protrusion plugged into the inside of the filter, I'll be reading pressure directly *after* the filter.

Actually the more I think about this, the more it seems like more trouble than it's worth (modifying every filter before use). I think I may just do what the HOW says and tap a thread into one of the chain tensioner caps....

I'm betting there is a filter out there that already has the other end opened and gasketed. And I would assume that is what the race teams are using with that cover.


Personally... I wouldn't go near the filter with any drill. The one little chip that is missed MAY be all that is needed to take out a bearing.

Punch it don't drill it. That said the metal form the end is softer than the bearings so it won't destroy a bearing. The bigger problem would be blocking one of those oil jets in the motor.