Oil Cooler Situation

Hello Team:

I have been doing quite a bit of research. Some say "Tomato" and others say "Tomoto".

I am adding a Earls 13 row oil cooler on my '78 z1R. I see some old Kaws mount the cooler with the fittings UP and others with the fittings DOWN.

I know the oil level will be different now that the lines and cooler are added! When the bike is shut off does the oil drain back into the engine? I haven't measured the amount of oil I will need to add in the lines and the cooler, but I intend to once I am done with the brackets, and before final mounting.

What are YOUR ideas of mounting with fittings UP or DOWN?

Does that extra quart or so of oil hurt when you first crank the engine after it sits a while? THEY SAY NEVER TO OVERFILL?

Just Curious...

Thanks, CwiseGUY

I always mounted my oil coolers with the fittings on the bottom. Kawasaki did the same on their customer race bike the KZ1000S1. One difference that I do is run the oil cooler lines up over the top of the motor. That way the cooler never drains of its oil. So my motors never really had any chance of running any length of time before the top end of motor had a steady flow of oil. The S1 ran the lines under the motor to the cooler. Which means the cooler was drained of its oil every time you shut the bike off!!!

I don't like the look of the oil cooler lines running along the side of the motor to the oil cooler myself. That is why I run my cooler lines over the top of the motor. You have to watch where you end up mounting the oil cooler. If you mount it outward from the frame, you then have to make sure when the forks are compressed the front fender doesn't crash into the cooler!!!! If you mount it too high it gets hit by the lower tree when you turn the bars. It gets even worse when you have the fittings on the top of the cooler.
Earl's Supply oil coolers like to be mounted in rubber to keep the vibration reaching them to a minimum. I some what copied how Kawasaki mounted the oil cooler to the S1. You can see it in the one photo below.

The S1 oil cooler setup


My own oil cooler setup


Photo of my oil cooler mounting setup.


Photo of oil cooler mounted in place.

If you install your oil cooler Fittings up or down no oil will flow back into the oil pan. The oil Level in the oil cooler lines will stay on the cylinder head level. The oil flow from the cooler must flow through the oil port gallery up to cylinder studs into the head cam bearing ports = syphon effect = hydro lock = same level as the oil cooler!!!

I have checked the turning radius of the triple tree. I would not have enough room for the fittings on the top of the cooler, unless I moved the cooler down, then it would affect/effect the tachometer cable. The fittings have to be on the bottom side. I don't care for the hoses along the side either. I don't really care to run them under the motor either. I plan to run them over the top of the motor, which would also allow shorter hose length.

Hopefully there are NO issues of having too much oil in the motor when you first crank it for the day. I would NOT think it would be a problem as the S1's and others have the extra oil capacity in their motors.

Thanks for the pics and the advice...

This is my latest project. Ground Up. This is for the cooler I am asking about...

Thanks, CwiseGUY

As I recall, the factory service manual calls for an additional 4 ounces of oil on the GPz 1100, compared to its non-oil cooled brethren.

Probably about right. I would guess it would hold more than that, the cooler and hoses? I would guess at least a pint or two extra? Some of the oil may NOT drain back in the crankcase? I have a Gpz1100 81 model. Looks like a ELR. It has a factory oil cooler. It is about a 4 row or so cooler with thin cooler lines. It is pretty small. The one on the z1R I am doing now has I think a 13 row Earls (EAR 41300A). Once I measure the ounces and the fill for the hose length I would guess around a quart and maybe a touch extra.

The parts I am using:
EAR 41300A - 13 row oil cooler
2 - EAR AT809108 - 90 degree -8 female to -8 hose (Option to use on motor fittings - for hoses to go up between carb boots)
2 - EAR AT800108 - Straight -8 female to -8 hose (Option to use on motor fittings - for hoses to go straight out under carbs)
2 - EAR AT812008 - 120 degree -8 female to -8 hose
10 - EAR 350008 - 10 foot of pro stock black hose (probably use 6 to 8 feet, if going over top of motor)
2 - EAR AT985081 - Adapters that attach to the oil cooler that attach the fittings
2 - Also, the blocks on the motor have fittings on them, on one end -8 hose, and whatever the thread is on the blocks..

Thanks, CwiseGUY