Oil Pressure Orifice Size?

Ironflight · #1 02-20-2009, 11:01 AM

Quick question -

I am building up an AN816-4D as a restrictor to mount in Louise's engine for a new oil pressure sense line - I blocked it up with an appropriate sized rivet, and now need to drill a hole through it - any idea what a good orifice size is?

Paul

mburch · #2 02-20-2009, 11:04 AM

Paul,

According to their website, the restrictors Van's sells have a 0.040" hole.

mcb

Ted RV8 · #3 02-20-2009, 11:19 AM

Paul, Going from memory here so use at your own risk!

I was told by Bart at Aerosport to drill about an .020 diameter hole but he also said it's pretty tuff to do and he was right! It's also tuff to find a .020 drill which is #76 drill.

Again going from memory I believe I ended up drill an .032 hole which is a #67

These drills break really easy, even in aluminum!!

Good luck

Ted

vic syracuse · #4 02-20-2009, 11:40 AM

Paul, I just used the smallest one that wasn't broken in my box of numbered drills. 60 if you still have it, but anything in the 50' will work. Use a dremel on high speed to drill it. They break to easy if used in a regular drill.

Vic

scard · #5 02-20-2009, 11:42 AM

"Machine Screw" length drill bits also help. They are much shorter and hence stiffer across the entire size range.

Ironflight · #6 02-20-2009, 11:47 AM

Quote:

Originally Posted by vic syracuse

... the smallest one that wasn't broken in my box of numbered drills. 60 if you still have it, but anything in the 50' will work. ...

It's amazing how often I have used that criteria in drilling a small hole...

Thanks folks, I'll see what's left in the small end of the box and chuck it up in the Dremel.

Paul

Harold Lanfear · #7 02-20-2009, 04:09 PM

you can get them at any hobby store. I just bought a full set for about $4.00 after I dropped my old set and lost a lot of what wasn't already missing

David-aviator · #8 02-20-2009, 09:00 PM

I have the AN816-4D's from Vans, one for fuel pressure and one for oil pressure and I believe they are drilled out at .040.

A smaller hole would be better. The first time I pressurized the fuel system pressure should have been 25 psi but settled down at 8 psi. I had failed to tighten the -4 pressure line at the pump fitting and it sprayed fuel all over the firewall and aft side of the engine. What a stupid mistake that was.

It was luck, one more time, that the whole thing did not blow up with the master relay and battery right there.

Joe · #9 03-25-2009, 08:03 PM

Now that the hole size has been more-or-less specified, would someone please explain what size rivet is used and how? Is it pressed in or what? And which end of the AN816-4D?

Thanks,
Joe

Norman CYYJ · #10 03-25-2009, 10:06 PM

If you have a chuck that will close down small enough in your drill press use it the bits don't break so often.