Any advantage to longer oil cooler lines?

I’ve seen a lot of bikes in Japan on Instagram with oil cooler lines that wrap around the engine before connecting to the oil pan. Is this just an aesthetic trend or is there an actual benefit to routing the lines like this vs just running them straight down from the cooler to the pan like my stock gpz550? I mean I suppose since you’re increasing the volume of oil in the system that it would run cooler but would this really make any kind of difference? It does look pretty rad. 


 

There's no advantage using longer lines, they should be as short as possible especially if no thermostat is fitted.
Many bikes such as the Z900/Z1000 etc didn't come with a stock oil cooler so aftermarket kits took the oil supply from the rear of the block and sometimes through a thermostat hence the need for a longer hose path.
Later factory equipped oil coolers like your 550 took the supply from the sump and ran the lines the shortest route direct between the headers.
The 400 pictured should ideally have gone straight up from the sump to the cooler like your 550 but for whatever reason they chose to loop them around the block for as you suggest aesthetic reasons or maybe they ran them through a thermostat and the only room for it was under the carbs.
The only way to gain a little more oil capacity in the system is to position the cooler with the fittings at the top so that the cooler holds oil and doesn't drain down when stood.

I have never understood why the Japanese owners prefer this "look". I am with Zed1015 on this, the shorter the better.

The shortest path back to the stock oil feed behind the barrel is up and over the motor hidden by the fuel tank.

Shorter lines may also be slightly cheaper and that routing above protects the lines more. I don't believe you would gain any extra cooling from them "flapping" in the wind, those lines are smooth, no fins on them There is also a slight danger of them being damaged out in the opened.

The longer lines will add pressure drop in the system, and slow oil delivery to bearings on start up because those long lines all need to fill with oil before the system stabilizes. 

I don't see the point in a huge cooler, like that 400 has, either.  Racing maybe, but not for the road.  Also realize that a large cooler like that blocks air flow to the engine.

wrote:

The longer lines will add pressure drop in the system, and slow oil delivery to bearings on start up because those long lines all need to fill with oil before the system stabilizes. 

I don't see the point in a huge cooler, like that 400 has, either.  Racing maybe, but not for the road.  Also realize that a large cooler like that blocks air flow to the engine.

Ness,
   I'm not sure I put much faith in the first half of your opening statement.  Oil pressure is traditionally measured in pounds per square inch. By adding longer lines you are absolutely increasing the square inches of the area, but there are still X pounds per square inch.

The second half of your opening statement is absolutely correct. A bigger volume will take longer to fill given the same flow rate.

So most likely just for looks. Kinda what I figured. I just saw it on so many bikes I was wondering if maybe I was missing something. Thanks guys.

I think that look is either a love it or hate it kind of thing.

Those built bikes are mostly "eye candy" and there is a cookie cutter aspect to that "look"  - Note the ridiculously large expensive carbs with velocity stacks, way too big for that cylinder head even if it was heavily modified. They all look the same to me.

Maybe its just me but I would rather own a POS that goes fast rather than looks fast

wrote:

wrote:

The longer lines will add pressure drop in the system, and slow oil delivery to bearings on start up because those long lines all need to fill with oil before the system stabilizes. 

I don't see the point in a huge cooler, like that 400 has, either.  Racing maybe, but not for the road.  Also realize that a large cooler like that blocks air flow to the engine.

Ness,
   I'm not sure I put much faith in the first half of your opening statement.  Oil pressure is traditionally measured in pounds per square inch. By adding longer lines you are absolutely increasing the square inches of the area, but there are still X pounds per square inch.

The second half of your opening statement is absolutely correct. A bigger volume will take longer to fill given the same flow rate.

The pressure loss I'm referring to is a result of the extra length of hose, and the friction and turbulence of the oil running through that hose.  I don't know how much loss there would be, but it's there.  Guys on the Suzuki GS site use high spin pump gears as compensation.

I'm planning to put a small oil cooler on a KZ440, replacing the OEM hard line. One braided hose will go from the banjo fitting under the oil pressure sensor, run up the right side of the engine to the cooler, then the return line from the cooler will go along the left side of the engine to the fitting on the aft part of the head.

The z400 in the initial picture seems to use the oil pressure sensor connection too, but both lines appear to go to the same place so not sure what's happening there.

Someone mentioned mounting the cooler with the connections at the top to keep the oil from draining out when the engine is shut off; that seems like a good idea. I've been looking for a one-way check valve to put on the right-hand line, as close to the connection from the pump as possible to ensure the lines and cooler remain full after shut-off.

EDIT: that someone was zed1015.

That 400 4 cylinder sure looks cool.  

My original rubber lines on the GPz550 oil cooler started to leak so I had to have braided SS lines installed.

wrote:

I'm planning to put a small oil cooler on a KZ440, replacing the OEM hard line. One braided hose will go from the banjo fitting under the oil pressure sensor, run up the right side of the engine to the cooler, then the return line from the cooler will go along the left side of the engine to the fitting on the aft part of the head.

The z400 in the initial picture seems to use the oil pressure sensor connection too, but both lines appear to go to the same place so not sure what's happening there.

Someone mentioned mounting the cooler with the connections at the top to keep the oil from draining out when the engine is shut off; that seems like a good idea. I've been looking for a one-way check valve to put on the right-hand line, as close to the connection from the pump as possible to ensure the lines and cooler remain full after shut-off.

EDIT: that someone was zed1015.
 

Mounting the from the top of the cooler is the way to go if you can do it. Its much easier/quicker to get the oil level correct on oil changes. If you are fussy about getting the old oil out of the cooler it can be easily accomplished with gentle air pressure on a unhooked fitting.

I would avoid any check valves or thermostats etc. - Just extra connections that can leak and unnecessary in my opinion.

I am not sure what oil pressure the 440 runs at (check FSM) but you need to size your line ID's accordingly. The Z1 engines use a high volume low pressure oil system, the 650/750 uses a high pressure system so the lines are a smaller ID.

The longer hose will likely cause a drop in oil pressure where it's needed.  The oil pump has to push more oil with longer lines - and that will cause the oil pump more work and some of these older oil pumps struggle without an oil cooler to start with.