EOT meter for OEM oil cooler

[dsinned_imp]

Thanks Ferret. Yes, I am quite pleased with how this project finally turned out.

I forgot to mention one other thing . . . I lowered the fan slightly to be flush with the bottom of the EOC by offsetting it downward about half an inch from the EOC's center mounting point. I did this to prevent any fingers from accidentally touching the blades while the fan is operating. The rotational speed is over 6000 rpm!

The fan has a finger guard already, on the front side only. However, without this mounting offset, there was too much of an accessible opening at the back side above the top of the cooler. This potential safety hazard has now been avoided because access to the blades is no longer possible. The gap is greatly reduced, plus the oil return pipe along the top of the cooler blocks what little opening remains.

[Ulvetanna_imp]

With all due respect, and I hope not to be blacklisted, but I am not getting this at all. It's almost as if the OP is afraid the engineers at Honda (we're talking about HONDA, mind you!) know little about how to properly design an air/oil cooled engine, and that our bikes are just one sunny day away from disaster. If there's something I think all of us can agree on (except perhaps the OP?), it's that the engine in our CB1100's is a masterpiece on nearly every level. Has even one of us yet encountered engine damage related to the oil getting too hot, assuming normal usage and oil level? If the fine folks at Honda had seen the need for an oil cooler fan, would they not have included it in the design?
I will say, the OP is tenacious, extremely focused and imaginative in his approach to this problem. Too bad it's not actually a problem Truly, no insult intended here; I'm truly just baffled, astonished... imagine the fine engineers at Honda if they were to read of this, and what they would think...
Ok, I'll quit now and get ready to head out for a ride!

I strongly, emphatically recommend you make SURE the front fender has adequate clearance under maximum fork compression. The front forks have quite a bit of travel, around five inches, and if they were to make contact with this apparatus it could be problematic.

I've checked fork travel on my bike, and I am very light, 143 lbs. I can and have used every millimeter, right to the stop, under either heavy braking or when thumping into a nice road divot or pothole.

This measurement is done by using a ziptie on the forkleg as some folks know and I've seen mine move the full travel many times.

If you were to strike a pothole and bottom the fork, it could conceivably crush the fan into the oil cooler and make a mess, or compromise the steering.

Just saying that your bike can be a laboratory kit, chemistry set, or whatever you like but it's also a motor vehicle and was designed to work properly and safely as it came from Honda. There may not be adequate room there.

[dsinned_imp]

Ulvetanna, your point is well taken and you're absolutely correct. I completely forgot about a front fork compression issue with a fan now attached to the front of the EOC. The CB1100's front suspension travel is spec'd at 4.2" max, but with a fan, there is only ~3.5" of travel allowed before the rear fender touches the fan. Obviously, this presents a potentially serious safety hazard in a panic stopping situation or when riding over a large pothole/rut/bump on the road.

Thanks to Ulvetanna's warning, I no longer can recommend the installation of a fan to the front of the EOC as I have just done in this DIY modification. To do so, would be too risky due to insufficient front suspension travel clearance between the rear of the front fender and the front of the fan.

Unfortunately, the oil supply and return tubes that go to and from the front of the engine are located behind the center region of the EOC. There are also massive down tubes as part of the frame just behind the cooler on either side. These OEM obstructions are in the same area where ideally an auxiliary cooling fan could have been located.

As pointed out by other members here, Honda's designers apparently did not see any need for such a cooling fan, so they did not allow any space to install one.

In all frankness, after all the time invested in this project, I'll probably keep the fan, at least during the Summer riding season, but I will be doing so at my own risk! Fortunately, all the roadways around my area are well maintained, and I never ride off road. Nevertheless, any unforeseen panic stops could potentially damage my fan and EOC.

A big THANK YOU to Ulvetanna for the warning!

[flynrider]

One more thing to keep in mind is the amount of weight the bike is carrying. You'll use quite a bit more fork travel when braking hard with a passenger or lots of gear on board.

I learned this the hard way years ago when I attached some clamps to the upper fork tubes as part of a fairing installation. I thought I'd tested it thoroughly and that the clamps were plenty high on the fork tubes. It worked fine for 2 yrs., until I loaded up the bike with camping gear for a 2 week road trip. The extra weight compressed the forks much further under heavy braking and the clamps ended up destroying my fork seals in short order.

I also destroyed a perfectly good pair of jeans

[dsinned_imp]

I never have a passenger or carry any gear with me, but I weigh plenty at nearly 260 lbs. I always avoid bad roads and am continuously scanning ahead for dips, bumps, ruts and potholes (as well as all cars). My last panic stop (thankfully, without incident) was about 15 years ago, but no guarantee that my next won't be tomorrow.

I still wonder why Honda did not see fit to provide an engine oil temperature gauge, or at least a warning light that comes on way before 340F (can this really be true?) For this reason, I still "recommend" the use of a Trail Tech oil cooler temperature sensor and handlebar mounted monitoring unit ($43), fan mod or not. I find it important to KNOW how high my oil temp is getting under adverse riding conditions such as in stop and go and/or when OAT is already almost unbearable for a leisurely ride. I feel this add on EOC temp monitoring capability is still a very worthwhile mod.

http://www.trailtech.net/digital-gauges/...fin-sensor

[Ulvetanna_imp]

Ulvetanna, your point is well taken and you're absolutely correct. I completely forgot about a front fork compression issue with a fan now attached to the front of the EOC. The CB1100's front suspension travel is spec'd at 4.2" max, but with a fan, there is only ~3.5" of travel allowed before the rear fender touches the fan. Obviously, this presents a potentially serious safety hazard in a panic stopping situation or when riding over a large pothole/rut/bump on the road.

Thanks to Ulvetanna's warning, I no longer can recommend the installation of a fan to the front of the EOC as I have just done in this DIY modification. To do so, would be too risky due to insufficient front suspension travel clearance between the rear of the front fender and the front of the fan.

Unfortunately, the oil supply and return tubes that go to and from the front of the engine are located behind the center region of the EOC. There are also massive down tubes as part of the frame just behind the cooler on either side. These OEM obstructions are in the same area where ideally an auxiliary cooling fan could have been located.

As pointed out by other members here, Honda's designers apparently did not see any need for such a cooling fan, so they did not allow any space to install one.

In all frankness, after all the time invested in this project, I'll probably keep the fan, at least during the Summer riding season, but I will be doing so at my own risk! Fortunately, all the roadways around my area are well maintained, and I never ride off road. Nevertheless, any unforeseen panic stops could potentially damage my fan and EOC.

A big THANK YOU to Ulvetanna for the warning!

Dang, I actually did something useful!

What about a thinner fan? Seems like I've seen some designed for CPU cooling much thinner, maybe those would work for you.

[Magnus_imp]

Interesting project. I'm not particularly experienced in motorcycles but I do have a lot of experience with auto racing, even oil cooled Porsche race cars. One thing to note is that oil temps can generally get a lot higher than water temps without terrible consequences. For example if you saw water temps of 300F you'd be done for but an oil temp of 300F, while above optimal, is not going to destroy the motor if you have a good quality oil. But... as I said in the beginning... I have little experience directly related to motorcycle engines so don't take my word for it..

[dsinned_imp]

It's not so much the oil itself, but EXPOSURE to high temps by all other components in and around the engine may eventually take its toll. This is particularly true of less conspicuous "components" like rubber and plastic hoses, seals, gaskets, electrical wiring and insulation, etc. They may not withstand such high temperatures - including heat soak - as well as internal engine components made of metal.

ALL engines, over time, tend to literally "wear out" due to continuous high heat exposure. Reliability of engines as a whole can be extended by better thermal management, thus preventing high temperature excursions. With air (oil) cooled motorcycle engines, such excursions are all but guaranteed in very slow paced, stop and go, riding conditions.

This is why ALL other cars and motorcycles with water cooled engines have radiator fans. I don't know why OEMs bother to equip air cooled bikes with oil coolers, but leave out auxiliary cooling fans for just such worse case thermal conditions.

Btw, I already tried a thinner fan, which fit in front of the oil cooler much better. It's cooling capacity was just about the same as a fan in a desktop computer, but not nearly powerful enough to be of much added value in this application.

[the Ferret]

Nobody can say that you are not really into this stuff lol

[Ulvetanna_imp]

It's not so much the oil itself, but EXPOSURE to high temps by all other components in and around the engine may eventually take its toll. This is particularly true of less conspicuous "components" like rubber and plastic hoses, seals, gaskets, electrical wiring and insulation, etc. They may not withstand such high temperatures - including heat soak - as well as internal engine components made of metal.

ALL engines, over time, tend to literally "wear out" due to continuous high heat exposure. Reliability of engines as a whole can be extended by better thermal management, thus preventing high temperature excursions. With air (oil) cooled motorcycle engines, such excursions are all but guaranteed in very slow paced, stop and go, riding conditions.

This is why ALL other cars and motorcycles with water cooled engines have radiator fans. I don't know why OEMs bother to equip air cooled bikes with oil coolers, but leave out auxiliary cooling fans for just such worse case thermal conditions.

Btw, I already tried a thinner fan, which fit in front of the oil cooler much better. It's cooling capacity was just about the same as a fan in a desktop computer, but not nearly powerful enough to be of much added value in this application.

To me, I see these questions as a result of your being involved in a highly specialized field.

Air-cooled engines have been around a long time, aircraft engines, motorcycles, power equipment. Pretty much all aircraft piston engines are air-cooled, for example, except maybe some experimental stuff. These manufacturers have been doing this so long they've learned to make their engines so they will last a very reasonable lifetime.

In the case of the oil coolers, a large example such as that on the CB1100 or the earlier GSX-Rs qualifies the bike to be called "oil-cooled" or "air-oil cooled". These bikes have a much larger volume of oil than comparable liquid-cooled examples.

It may seem self-evident, but Honda, et. al. have been making these kinds of engines for many decades and if cared for reasonably (not necessarily even to the recommendations) they last a very, very long time. It is not unusual to see examples with over 100,000 miles.

Simply put, your concerns about durability and reliability are unfounded. You should enjoy riding the bike as it was designed and have no concerns as to its longevity.

The idea that the metal front fender could in fact come into contact with this modification would be of grave concern to me. It could very easily cause a serious accident. And the mod that could cause it will really do nothing to extend the service life or value of your machine.

Engines wear out but they can be overhauled. People cannot so easily be repaired or replaced.