Pre-Filter Pressure Relief

Fingers

Fingers

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If any of you have a Curtis oil pump and try to drive your truck in the winter, you know all about the problem with popping the oil filters. Plus it can't be good for the oil pump or oil cooler to see those ugly pressures.

The problem is there is no pressure relief on the big pump. Unlike the OEM. So I whittled out a pressure relief valve on the lathe and installed it this last weekend. I would have used the plugged port on the top of the Filter Adapter to tap into the pre-Filter oil, but it was already being used for the fuel pump pressure switch. So I used a sandwich plate I had on the shelf from a previous project.

The setup takes the oil from just before the filter and dumps it back into the filler neck if it goes over pressure. The relief is set to crack open at ~100 PSI warm right now which seems to be about right to keep pressure post filter below 90 PSI cold (15*F so far) yet 70+ PSI while warm.

All in all, I am very happy with this setup so far. It is nice to be able let the truck get cold and not worry about popping the filters. If I was to do it over, I would make the whole thing part of a sandwich plate and dump the oil directly into a tap in the oil pan.
 
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Fingers

Fingers

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I would be happy to help anyone out that needs something like this. Not really looking at making a product out of it. The only thing that isn't off the shelf is the relief valve, and then only because of the machined in AN-12 fittings. I was having a hard time finding a big bore relief valve in the pressure range I needed anyway.

If I was to do it over, I would make it all part of a sandwich plate that would go between the filter and adapter. Then dump the excess to the pan directly.
 
IdahoRob

IdahoRob

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Nice job. I've blown off more filters than I care to talk about. What a mess! Amazing how fast those pumps can drain an engine!
 
minisub

minisub

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Fingers said:
I would be happy to help anyone out that needs something like this. Not really looking at making a product out of it. The only thing that isn't off the shelf is the relief valve, and then only because of the machined in AN-12 fittings. I was having a hard time finding a big bore relief valve in the pressure range I needed anyway.

If I was to do it over, I would make it all part of a sandwich plate that would go between the filter and adapter. Then dump the excess to the pan directly.
Click to expand...

How? Through the drain plug hole, use a bulkhead fitting or weld on a bung?

Nice bit of work BTW....:)
 
Fingers

Fingers

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Tapping the pan isn't too hard. The pan itself is easy to remove for the work. I would probably weld on a bung, but a two piece tap would work well too.
 
Fingers

Fingers

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IdahoRob said:
Nice job. I've blown off more filters than I care to talk about. What a mess! Amazing how fast those pumps can drain an engine!
Click to expand...

My driveway has several stains, as does the four lane near my house..... :(

Enough was enough, I HAD to do something.

As a follow up; I have had this on for a while now. I want to increase the pop-off pressure on the valve ~10 PSI when I get back home. At cruise, hot, I am just below 60 PSI. Just over 60 PSI at WOT. That would keep it in the "safe" range on the filter IMO.
 
Fingers

Fingers

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As a point of interest. The front seal does not like holding back the huge amounts of extra oil in the front cover that come from dumping into the filler neck. I am working on dumping directly back into the pan.
 
Fingers

Fingers

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Those don't dump volume out of the system prior to the gallery. Cold, the restrictions from the block gallery are just too high with the volume from the Curtis pump.
 
sweetdiesel

sweetdiesel

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Fingers said:
I would be happy to help anyone out that needs something like this. Not really looking at making a product out of it. The only thing that isn't off the shelf is the relief valve, and then only because of the machined in AN-12 fittings. I was having a hard time finding a big bore relief valve in the pressure range I needed anyway.

If I was to do it over, I would make it all part of a sandwich plate that would go between the filter and adapter. Then dump the excess to the pan directly.
Click to expand...


My pan is allready tapped I can get hose and fitting \i do however need a relief valve would you be interested in helping me out?

thanks simon
 
Dozerboy

Dozerboy

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Fingers said:
The front seal does not like holding back the huge amounts of extra oil in the front cover that come from dumping into the filler neck.
Click to expand...

Are you just saying that for those that might consider routing it there? I was just thinking how does the oil come down by the filler neck with your sandwich adapter. Thats where my Bypass filter return has been for 60K with no issues, but I'm sure it has no where near the volume.
 
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sweetdiesel

sweetdiesel

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Could you perhaps point me in the direction of a pressure relief valve please

igeuss you could almost just use a regulator and set it to DES press but that seems kinda of bulky
 
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