[jbranson]

Here's a pic of my solution to any heat issues on my 175. Almost a mini radiator...might even have to cover part of it on cool days. All "AN" fittings, braided lines. Should be able to beat the crap out of the bike with no worries.
JohnnyB

 

[jbranson]

Installation mock up.
JohnnyB

 

[jbranson]

Craig,
I started out with Mobil 1 coming out of the engine smelling bad and being too dark. Switched to Royal Purple...a similar synthetic with different additives...would smell bad..but because of the color I couldn't tell if it was burnt...noticed this at Mosport. Switched to Red Line ester based synthetic which is supposed be good to about 550 degrees. It's not burning so far. The engine comes back from a race hot enough to sizzle spit everywhere on the engine, everywhere...which means at least about 240 degrees. Ten minutes later...it still sizzles spit...which means overall engine temp is probably in the 300+ degree range...with hotter spots I'm sure.
The rocker pad end of the rocker arms turn BLUE....I'm thinking that's too hot. So far the chrome is not coming off of them, wear is what I would expect with the cam and springs I use. Cylinder walls show more scuffing than I'd like and the piston bottom is picking up more burn't oil than I like to see.
I compare my engine to Mary's engine which is much closer to stock and has run so far for 2 years and still looks new inside.

Believe me I was thinking about crashes when I set up the cooler. The supply lines are well protected where they enter the engine and the cooler is mounted such that I shouldn't have to worry unless I hit a wall straight on 50+ mph. I could drop the bike on either side and it wouldn't touch anything with oil in it.

I could probably have gone with a cooler a bit smaller...but I figure it's better to have one too big and have to cover it up with some tape on cool days rather than have one too small. I've changed the mounting from what is shown in the pics to a mounting where the ports are facing up..this will keep the oil from draining out of the cooler when the engine is shut down and will let air purge from the system easier. But it makes the lines a bit longer. The AN lines and fittings will cost more than the cooler did. I did some research on oil temps first and was impressed with the info on how much longer an engine will last if oil temps are kept in the proper range. It seemed to be the opinion of many engine builders that oil coolers are an absolute necessity on any type of race engine. I've noticed that just about every modern water cooled sport bike has an oil cooler.

Doug, send pics of your cooler setup...I'm interested in every setup I can look at.
And....Mad Max called.....he wants his bike back.
JohnnyB

 

[jbranson]

Bill,
See pic below. That's the main supply oil passage from the pump...goes through a passage in the side cover. I drilled and threaded the middle section of the passage and installed a plug. This forces the oil out the first oil...though the cooler...back into the same passage through the second hole...then on to the oiling system as normal.
The oil pressure on these engines is not particularly high at all...but volume does seem to be ok if the flow is fairly unrestricted. The oil cooler offers little or no restriction..although there will be a pressure drop through the cooler...it's moot because the down stream restrictions are greater than that of the cooler...meaning the resistance to flow through the cooler is way less than that of the downstream system.

I have changed the cooler mounting to point the supply lines UP, this will keep the cooler full of oil during shut down and prevent having to refill the cooler on startup every time. I have no worries about the pump making enough pressure to make the climb to the oil cooler...the reason these engines have low oil pressure is not the pump...but the type of supply system they have...many places for oil to just flow out of bearings and into the sump...the cam bearings are probably the only place in the engine where there is enough restriction in flow to develop upstream oil pressure.

It gets complicated....but, believe it or not...I have a couple of years of schooling on hydraulics, hydro-dynamics, heat transfer and fluid flow. Which means I know enough to really screw things up
JohnnyB

 

[jbranson]

Ken,
I don't KNOW that there would be any problems with the ports down...I've mounted them that way in the past on other bikes but most of those were tube and fin coolers...this being a plate and fin cooler it would probably like to gather air up top in the cooler and trap it there. With tube and fin all the oil flows through a single tube so it's kind of easy for the oil to flush out the air. With plate and fin you have two oil plenums on either side of the cooler with numerous thin plates that provide a passage between...since the oil can choose the easiest path to follow...it might just flow through the lower plates and leave the top plates full of air. Wouldn't be an issue on a high flow system like a car...might be on my bike though. Plus this type of cooler holds more oil...hence it would take longer to fill up on a cold start if it drained back...which by the way I don't know if it would do anyway. Figured better safe and than sorry.

Bill,
The 175's have the same large oil gallery in the upper case behind the cylinders. Feeds the top end, the main bearings and crosses over to supply the left side top end. Not sure if it's the same on the SuperHawk...but if you tap in on that gallery on a 175 it allows uncooled oil to flow up to the right side top end feed because that would be on the "hot" side of the cooler. The main gallery would have to be blocked or restricted in the middle to induce the pressure differential needed to drive any substantial amount of oil through the cooler. Fluid flow is almost identical to electrical flow...it chooses the path of least resistance...so if the main gallery was unrestricted then it would just flow through there without going through the cooler...since the cooler is mounted higher and has more "Head Loss"....a term meaning resistance to flow.

I wanted somewhat more than an oil cooler...I wanted to be as close as I could come to a "oil cooled" engine. So I wanted full pump flow going straight through the cooler before it goes anywhere else. I also carefully bored out all the oil passages between the pump and the main gallery about 15-20%. It should flow more oil after all these mods than it did before I installed the cooler.

Right now just waiting for some new fittings to come...I screwed up on the port fitting size. Just a little dremel work to do to the pump outlet area and I should be good to go.

BTW...I spent the last two days "splitting" my Cub Cadet garden tractor to replace a differential seal. Huge filthy pain the ass. But it's all back together and mowing again. I was about ready to start kicking it too.
JohnnyB

 

[jbranson]

Not really the 8 laps that concerns me much. It's practice, then an 8 lap race 20 minutes later, then a 20 min break and another 8 lap race, without time for the engine to cool off much in between.
My 175 is modified way beyond the typical CB350...so it gets much hotter, much faster, a it's running about 11,000+ rpm all the time. Even two laps with oil that's too hot is harmful to the engine.

I change the oil every event also...always a good idea.

JohnnyB

 

[jbranson]

Aaron...are you spooging in that oil too? Cause it works great!

How's the barn coming? I assume you are taking pictures so you can post progress pics.

I'll do the mods to your engine cover for $1000. In fact...I'll install an entire system on your bike for $1000.....+/- $2000.
JohnnyB

 

[jbranson]

I've updated my website with a complete summary of the oil cooler installation on my bike.

All the R&D is done for you...just follow the directions to have your own cool running 175.....assuming the freakin thing works that is. It's been pressure tested and oil is flowing to the engine...I'll test it for actual cooling in the next couple of weeks.

http://www.jrbranson.com/HondaRacer/CB175/Oil-system.htm

JohnnyB

 

[jbranson]

Craig,
Yep...weight. The stainless lines are pretty heavy and don't really offer any more resistance to heat since they are the same material underneath the stainless. The SS lines are mainly for high pressure and abrasion resistance.
I'm using Nyloc nuts on the long bolts right now, but now that you mention it I think I'll wrap some lock wire around the threads of the bolt that is past the nut and tie it off to something.

Fever,
Yep, main concern is top end heat in general, and specifically on my bike trying to keep the cam, rockers, springs and valves cooler.

The whole system would attach to a CB160 exactly the same as to this sloper 175.

Actually I'm after the CL175 sloper bottom ends, just the crankcase, crank and tranny. I've paid up to $150 for the bottom ends. I've got two spares now (three if I steal Aarons, but as they are getting harder to find I'm trying to pick them up.

George DeCamp recently picked up about a 1/2 $million in NOS Honda stuff, he's going to save me any NOS cases he comes across....assuming there are any.

I know where a couple are now, but I'm always looking to find one cheap like $50-100. So if you happen to come across any at bargin prices as Mid-O I'll take them off your hands with consideration to you for your trouble of course.
JohnnyB

 

[jbranson]

Eric,
I can't say for sure if it can be done to a CB350 I've never looked at one very close.
JohnnyB

 

[jbranson]

Ken...so the oil in a 350 flows in the opposite direction of the 175?
On the 175 it enters the clutch cover from the front and flows to the oil filter, then out towards the rear and up to the main oil gallery behind the cylinders.
JohnnyB

 

[jbranson]

Rosko, total oil capcity will be about 1/2 quart more than stock...or about 2 quarts.

Ken, in general it's best to put a cooler at the outlet of the oil pump, before the oil has to go through any other passages, filers or metering orifices. That way you get full flow through the cooler and provide cool oil to everything down stream. The cooler will usually provide less restriction to flow than any other part of the system....but it does provide some restriction. If for instance the oil filter passages are more restrictive than the oil cooler...then you have a flow decrease through the filter passages...then another decrease through the cooler. Whereas if it's the other way around....you have a decrease through the filter...(which flows more than the filter passages)..and then another decrease through the filter passages. Ok..that's not very clear.
How about this.... it's like water plumbing...you don't want to supply a large pipe with a small pipe. You want to do it the other way around. You want to supply the small pipe, with a large pipe. So, if the filter passages are the most restrictive, you want to place the less restrictive oil cooler BEFORE the filter. Typically the passages at the outlet of the pump are the largest, they should flow more oil than anything downstream of them. That's where you want the cooler. If the cooler is placed after the filter then you get a pressure drop at the filter passages...AND at the cooler.

Also...the filter passages on the Hondas go through numerous twists, turns and junctions....like the spinning junctions at the filter opening...and cooler downstream of this means a little bit more back pressure trying to force oil to leak at these connections.

To be honest...in actual practice...I seriously doubt if it makes much difference where the cooler taps are, as long as they are in a position where ALL of the engine oil has to flow through them. I have though seen people who have tapped into the main oil gallery in the crankcase...by the time the oil gets there it's already sent some oil up one side of the cylinders, and some to the tranny, so only part of the oil is ever sent through the cooler. They end up only cooling half of the engine.

I've also seen people install coolers between the crankcase supply and the top end supply...this is acceptable if you are concerned with bypassing the cylinder passages and providing cooled oil to the top end. Oil picks up a lot of heat going up the cylinder passages to the top end. Which will be the case in my setup...but I'm banking on the fact that if the oil is going into the cases at 40-50 degrees cooler it's going to be cooler when it hits the top end than if I didn't have a cooler at all.

So...while the direction of oil flow through the COOLER isn't important...the direction of flow through the engine where you tap into it IS important. Or more accurately...the LOCATION of the taps in the oil flow schematic is important.

Pump ---> Big pipe ---> cooler ---> big pipe ---> small pipes ---> filter ---> small pipes ----> metering orifices. Kinda like that.

JohnnyB

 

[jbranson]

Pressure will always be greatest at the outlet of the pump. Pressure decreases as you progress through the system due to "head loss" which is the natural resistance to flow in any fluid system. Head loss doesn't necessary reduce pressure in a particular part of a system though....the cooler will flow much more than the rest of the system will....when the cooler is up stream of smaller passages it's like having a large water pipe supply a small faucet....no matter how much you open the small faucet the large pipe won't reduce flow through it because it flows more than the faucet. In a engine oil system, pressure and flow will be determined by the smallest passage through which the entire oil supply must flow (with a given supply volume and pressure).

It's like having a 5 foot dam behind a ten foot dam. Yes the five foot dam holds back 5 feet of water...but it's moot because the next dam holds back 10 feet.
JohnnyB

 

[jbranson]

Ken...that is functionally the same setup I have. Components are in slightly different locations but the flow is the same.

I wondering about you plugging that last passage in the photos...that's where the oil enters the filter system....you are going to run a fitting in from the OUTSIDE that seals it off from the supply side of the passage right? That should work fine. For a minute it sounded like you were going to plug it from the filter access cover side...which of course would shut off oil to the whole engine.

Yeah, that setup should work good. Full flow through the cooler. That angled fitting shooting right into the filter passage would flow a bit better than my setup...the engine cover on the 175 isn't as beefy as the 350 and I needed to keep the fitting a little more out of harms way so it had to be mounted farther in where it couldn't get a straight shot at the filter passage.
JohnnyB