Add an Oil cooler to a Honda CB360

[mydlyfkryzis]

Some have asked about the oil cooler on my CB360. It was bought around 1980 or so and was made by Lockhart, now Lockhart Philips, but they don't make it any more.

I had to drill and tap (1/8 NPT) the clutch case, intall a rubber plug in the oil pump Idler gear shaft and screw in an aluminum spacer into the rubbur plug. The psacer blocked one of the oil passages so all oil passed through the cooler.

Here's apicture of the Cooler with the optional thermostat. (My wife was very nice to me, she bought the cooler and the thermostat for a gift)

this is where the oil lines tie into the right case cover:

Here's a shot of the case bottom showing the fittings. The RED nylon tie is on the supply line (Out of the case)

This is the screw/washer/spacer that is screwed into a rubber plug stuck in the oil pump idler shaft. This forces all the oil through the cooler.

This is the plug in the shaft. I couldn't remove it to measure it, but it is like a piece of rubber tubing. the screw is a tight fit and screws into it, retaining the spacer and plugging the passage

The spacer and screw and washer removed:

The next shots are the dimensions of the spacer and screw:

The oil cooler looks like a small car transmission cooler, JC Whitney Sells them. The thermostat is not available, but probably isn't needed. I know my NH 750 has a factory oil cooler and no thermostat.
The oil lines are oil resistant , reinforced lines, maybe similar to 1/4 i/d fuel line.

If I saw this, I would think about doing it....It doesn't require machining or complex parts.

So, here you go....how to install an oil cooler on the CB360.

Also, some have commented that an external oil filter would work. I've thought about it, but I can't figure out where to mount it.

Have fun.

 

[Kanticoy]

Very cool. Never knew they made one for the 360. Since you have gone this far, it should be stated that instead of a return line to the clutch cover, a feed line to the cam end on the right of the head/valve cover would be ideal to supply oil to the cam journals post cooler. I did something similar but used an electric scavenge pump for a turbo. Clean cool oil to the cam all of the time. Saves the 360 from it's Achilles heel.

 

[AlphaDogChoppers]

My problem with oil coolers is that they introduce complexity and a number of possible failure points while providing little or no benefit. Oil doesn't need to be cooled. It also means the oil will spend more time at sub-optimal temperature where the oil would tend to collect moisture rather than be hot enough to boil off any moisture that the oil may accumulate during engine warm up.

 

[mydlyfkryzis]

Couple of points.

1. My Honda NH750 has a factory oil cooler. So do a lot of modern air cooled bikes. Oil should be cooled...not too much, but oil starts breaking down much over 200 degrees. The oil cooler gets too hot too touch during normal operation. Oil is not just lubrication, but cooling, especially on an air-cooled motor. While the original design of this motor did not need an oil cooler, it isn't hurt by it at all. The oil itself last longer when cooled.


2. My CB360, if you look, has a thermostat. No over-cooling here.

3. The return from the cooler has to go to the clutch cover. The Cooler is in line with the normal internal passage that feeds everything, including the oil filter. The engine would have no flow except to the head if I returned that way.

4. Yes it is more complex, but not all that much. If the oil cooler or thermostat started leaking, I can just use a piece of the existing hose and bypass it all. A knife and a screwdriver would accomplish that. If I broke a fitting off, well, I'd be stuck. But the fitting is common hardware, and the risk of that is still low. If I hit something strong enough to break the fitting, in it's present location, I may of other problems, like crashing, to worry about.

5. I put this on my CB360 in 1980. Hasn't leaked or broken yet.

 

[Kanticoy]

Oh it's a great setup as is. And i should have expanded on my comment. The return line would have a tee off of it that runs to the cam end and the majority of it returns to the case. An incremental portion of it feeds the can journals however and keeps things lubricated up top. That's how my electric pump system is designed and it works well. I run it every time I ride. I also have a crankcase vent catch can and have never accumulated any liquid in it from condensation. I am a fan.

 

[mydlyfkryzis]

I think a separate feed like you said you had would be more "reliable" as I don't think there is much excess capacity in the oil pump. The oil at the cooler is unfiltered, and I'd rather not send that to the cam. Also, the oil needs enough pressure (which we know is little marginal) to send the oil up to the cam in the internal passages.

Actually, I like the idea of a separate pump like you mentioned, and have it feed through the oil cooler. My NH750 has dual oil pumps, one for the engine, the other siamese'd off of it, which just sends oil through the cooler. An electric pump would be only an issue in that the alternator output is marginal too.

Maybe do like the old early 1900's bikes, put a hand pump on and give a couple of squirts before starting and a couple every once in a while..

Do you have any info on the electric pump setup?...sounds like a good idea though.

 

[Kanticoy]

Yes i have done it and am running it right now and have been for several years. I'm on my phone and can't post the link but look up project Gretta under cafe racers, it's in there. And the stock pump will work too, several have done it here. Crazypj for one did it with no issues.

Your setup is clean.

And I run a voltage meter on the bike always, at idle with the pump running and all lights on it maintains a steady 14.4 volts. It's minimal as far as accessories though.

 

[Sonreir]

I think a separate feed like you said you had would be more "reliable" as I don't think there is much excess capacity in the oil pump. The oil at the cooler is unfiltered, and I'd rather not send that to the cam. Also, the oil needs enough pressure (which we know is little marginal) to send the oil up to the cam in the internal passages.

Actually, I like the idea of a separate pump like you mentioned, and have it feed through the oil cooler. My NH750 has dual oil pumps, one for the engine, the other siamese'd off of it, which just sends oil through the cooler. An electric pump would be only an issue in that the alternator output is marginal too.

Maybe do like the old early 1900's bikes, put a hand pump on and give a couple of squirts before starting and a couple every once in a while..

Do you have any info on the electric pump setup?...sounds like a good idea though.

Actually, the pump on the 360 is quite good. It's the bypass in the right crank case that's the issue.

For the electric oil pump, the mod is fairly simply. Tap into the crank case at below oil level to provide and input line to the pump and then route the output through the cooler and to the cam journals. Depending on your charging setup, you may need to extra wattage to run the pump. Expect it to pull between 40 and 60 watts; about half of what the stock alternator is good for.

 

[mydlyfkryzis]

Actually, the pump on the 360 is quite good. It's the bypass in the right crank case that's the issue.

I've been checking the oil flow. This doesn't bypass the right crank case. The chamber the feed line is taking from is the feed for the right case cover to the oil pump. It locks the feed from this chamber to the case, instead, routes it through the oil cooler, then into the case where the original feed supplied it. So the oil is taking a slightly longer path to the filter, but everything that touched oil before this still touches oil except for about 1 inch of oil passage in the case itelf. the idler bearing is still seeing oil and the same volume is still going to the filter.

the troichoidal oil pump is a big improvement on the CB350 plunger pump, imo, and is good for it's duty. But I wouldn't want to divert any pressure/flow to the head under a separate path, as it may compromise the flow/pressure through the second path.

For the electric oil pump, the mod is fairly simply. Tap into the crank case at below oil level to provide and input line to the pump and then route the output through the cooler and to the cam journals. Depending on your charging setup, you may need to extra wattage to run the pump. Expect it to pull between 40 and 60 watts; about half of what the stock alternator is good for.

I did mention that the alternator has very little to spare in the way of watts. I understand where you get the oil from, and where it goes. But like the oil filter question, where the heck can you mount it neatly. My question was more about that, mounting it nicely,then about the technicalities of the source and destination of the oil.

I think a small, inline fuel pump might move enough oil to keep the heads wet, yet use very low power...something like this:

Being smaller, it may be easier to mount and less obtrusive...but I'd still like to see what/how kanticoy or CrazyPJ did it.

 

[tweakedlogic]

Nice, I just got my cooler and was tearing into an old motor to figure out what to do. Thanks for this.

 

[Dr.Jeff]

Hey Midlife (or should I start calling you 'crisis'? ),

Thanks for giving me this reference from the other forum, excellent report.

Wish I had caught it while you still had the cover off; I'd love to see a shot of the inside of the cover, where the passages are tapped into (though they may not be visible from inside?). Do I remember you saying there was some specific instructions for where to drill/tap the holes for the fittings?

Regarding the additional plumbing to route oil to the head/cam. I'm sure everyone has seen the stuff from Italy that does this on racing 350 engines:
http://www.cappellinimoto.it/index.php?option=com_djcatalog2&view=itemstable&cid=1&Itemid=4&lang=en

<<scroll down to see a couple different versions of their kits,, also a option for the oil pump>>

This is for 350's, not 360, and their stuff is extremely expensive but the concept is like you guys are talking about.