What size orifice would you get?

[Hurst89]

I just won this filter housing on ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200375253142

And am going to make a bypass filter out of it for my Allis Chalmers 7000 4.9 L turbo diesel. I was wondering what would be a good size orifice to use for this engine. The oil pump is rated at 4 gpm at idle, and 14 gpm at 2200 rpms. The pressure is about 20-25 at idle, and quickly rises to the 45 psi where the relief valve cuts in. The sump is 16 quarts.

Hurst

 

[Hurst89]

Also, where do you put the orifice? Should it be on the inlet of the filter or outlet? Or does it matter? I was thinking of maybe doing away with an orifice and using 1/8 inch outer diameter copper tubing to feed the filter, which is .06" inner diameter.

Hurst

 

[Jim Allen]

The "store bought" unit I bought for a similar application has a 0.40" orifice. It's built into the filter outlet port on the filter head.

 

[Hurst89]

If I were using 3 ft of really small copper line, wouldn't I get the same restriction with a slightly larger diameter than an orifice? Just thinking about resistance through the tubing, as the orifice is only a few mm's, where with a tube we are talking a few feet.

Hurst

 

[labman]

Small changes of diameter mean huge changes in flow. A 1/4'' line will flow 16 times as much as a 1/8''.

 

[Hurst89]

I understand that, it's exponential. I was thinking a .06 ID copper line in place of a .05 orifice? I have seen on powerstrokes and cummins that the norm is around 1/16" orifice, which is just over .06, but I want to be a little on the conservative side.

Hurst

 

[Gary Allan]

Just run a pig tail "curlicue" if you're not happy with the flow out when warm. You're right, run the skinny tubing long enough and you should be okay. I have no idea how long that will be.

Amsoil puts the restrictor on the outlet. The thought being that the restrictor passage (on the BP80A it's a drilled .030 hole in a brass nugget insert). will not become varnished or otherwise subjected to anything but the cleanest conditions. The restrictor on the Motor Guard is much bigger.

You would also want the restrictor on the inlet side if this was something like a Luberfiner CT 750 which holds a number of gallons of oil. If you put it on the outlet-the run time to pressure in the whole system would take too long.

 

[Colt45ws]

Hmm, You could do a double restrictor in that case. Put a too large restrictor on the inlet and the true restrictor on the outlet.

 

[Gary Allan]

The one on the inlet attenuates flow, somewhat flattening out the flow curve over a broader time span. Putting two restrictors on it (finer one on the outlet) would have the potential for rigging a gauge to tell you filter condition. Even an idiot light.

Put "metering valve" into the ebay search engine. If you put one of those on the outlet, you probably could put a gauge or idiot light that would tell you when the filter was shot.

It might take a little R&D to get it where you're changing them out without wasting too much money or getting too little filtration.

 

[Hurst89]

Here is another idea, Since the problem would only be at idle, could I not put in a 25 psi pressure valve, so therefore the bypass filter would be cut off during start up and hot idle (if the oil pressure is below 25psi at hot idle). Here is what
I am thinking. Maybe I should design the ultimate cartridge bypass filter and get rich selling them??? lol

http://www.grainger.com/Grainger/items/6D915

Hurst

 

[sdan27]

The LF777 bypass and filter head I use on my Powerstroke has too high a flow rate and dropped my oil pressure more than I wanted it to. What I found out worked real well was a flow control valve on the return side. You just open the valve to get enough flow through the filter but not too much that it drops your pressure too much. It's infinitely variable so you don't have to be concerned with having just the right size orifice.

 

[Gary Allan]

Originally Posted By: Hurst89
Here is another idea, Since the problem would only be at idle, could I not put in a 25 psi pressure valve, so therefore the bypass filter would be cut off during start up and hot idle (if the oil pressure is below 25psi at hot idle). Here is what
I am thinking. Maybe I should design the ultimate cartridge bypass filter and get rich selling them??? lol

http://www.grainger.com/Grainger/items/6D915

Hurst


That might work. You can get a check valve that has a specified cracking pressure to your desired level

http://www.checkall.com/PDFfiles/BU.pdf

It will probably cost more.

You would probably want a BUDBRVT25.0SSXX

That would be a reducer BUshing 1/2x3/8 BRass ViTon seat 25.0lb cracking pressure SS sprung valve with no other options.

http://www.checkall.com/PDFfiles/BU.pdf
http://www.checkall.com/valvestyles/BU/BU.htm

 

[Hurst89]

Ok, well, I ordered some of the parts from McMaster and picked up some from Ace this afternoon, so hopefully everything will be here on Monday. I got 2 needle valves, one to fill oil samples from and the other to limit flow at the inlet of my bypass filter. Is there any problem with having the valve on the inlet? I was going to put 1/8 inch tube on the inlet (1/8" ID) and 1/16" tube on the outlet (1/16" ID).

Hurst

 

[Gary Allan]

I don't really see a problem. The valve would stay cleaner on the outlet side. It may require periodic readjustment if anything builds up on it. Not that it's likely, it's just what I ran into with needle valves in the environments that I used them.

 

[Hurst89]

Sounds good, I will be sure to post the end result when I get it all put together. The filter housing will be the last thing to arrive, and that will be tuesday afternoon most likely. I will try to get it all put together by the end of tuesday night. I won't be able to do any UOA until winter probably. I am, however, planning on doing a UOA of the JD break-in 10w30 oil, which I think may be the first analysis of this oil if I get the results back before I leave for Philadelphia... if not, it may take me a while to get them up.

Hurst

 

[Gary Allan]

If you have the means, take some images of the setup.

 

[Hurst89]

I will try to do that. I have the means, it's just if I have the memory to remember to bring the camera and charge the batteries the night before lol. I will definitely get pictures of the finished set up, and try to get pictures of the installation and parts as I go.

Hurst