OIL PRESSURE / TEMPERATURE

Don #6141 · Post by **Don #6141** » Mon Aug 11, 2008 4:19 pm

EMS wrote:Most of the heat generated by the internal combustion process is dissipated through the exhaust and the cylinder head. That is one reason most air-cooled engines have larger cooling fins on the head than on the cylinders.

All true of course

My point was that the amount of heat generated isn't something you need to worry much about unless you're asking the engine to make significant horsepower - On a motorcycle, it's hard to imagine a scenario where the engine is making lots of horsepower but isn't moving rapidly through the air and thus getting plenty of cooling from those large fins

At an idle, the head gets significant cooling from the engine oil, so trolling aroung town at low speeds is much more likely to overheat the oil than it is the head or the cylinder. If you had a cylinder head temp gauge, you would see it remain relatively low while the oil gets hotter and hotter

Don

twinegar · Post by **twinegar** » Mon Aug 11, 2008 11:24 pm

Geez, doesn't anyone play with toys any more. I like the look of a well laid out instrument cluster and I ran it by some old bikers at the biker breakfast Sunday and got a unanomous thumbs up. On a more technical note I just plain want to document the behavior of the engine under every condition I can think of. I will probably move the heat sensor to as many places as I can find to mount it including the oil drain bolt. Also after reading several articles and posts about the center two cylinders running hotter I want to confirm and document that compared to the other four. There is an exhaust temp gauge that I may add later just because I want to know. I ordered some black rubber tool dip and will dip the entire sensor array to create something resembling the original pressure sensor cover. That will keep moisture out and hide all the clunky looking joints. If I make my own sensor adapter from a block of brass and coat it the look should be even better.

On fabricating the turn signal case I will take one to a plastic injection company and see what they say. I may prepare wax replica's myself to save on the expense of them doing it. I would even consider having them cast in metal.

alimey4u2 · Post by **alimey4u2** » Tue Aug 12, 2008 4:26 am

Tinkering (for me) is just one of the great joys of motorcycles. It has held me in good stead over the years, as I could transfer that knowledge of tools & materials into my work place. In the old days my workplace could supply an endless source of chains but that's another story...

My kids, who were born of a privileged era where everything can be found on a screen, don't have a clue.
I have been following this thread & several others with great enthusiasm & interest. Wish we had more tinkerers sharing their experiences & zeal...

twinegar · Post by **twinegar** » Tue Aug 12, 2008 9:06 am

Thanks alimey4u2, I wish there were more tinkerers also. I get tired of figuring things out myself.................but I enjoy getting emails from people that visit my website and leave with a question answered or a part located. I have had the pleasure of talking at least a couple into starting their own collection and even talked a guy into pulling his Ebay auction of a nice 81 CB750 and keeping it.
Now I am off to mow the yard.............................

Don #6141 · Post by **Don #6141** » Tue Aug 12, 2008 12:42 pm

I'll read all your 'reports' with great interest - CBX oil temps have been a concern for me from day one and I find it interesting that the '79's got a 3 row cooler and all the others got a 5, so any actual on the bike 'real world' oil temperature info is always great to find and will be studied . . . . at least by me

I'm pretty sure you're right that the center two cylinders will get the hottest . . . . they don't have the extra fins that # 1 and 6 do and they are behind the front wheel so they don't get the air the others get so they have to get hotter - I don't see anyway around it. It will be interesting when you tell us how much hotter #3 is than #1

Luckily, the engine is so well designed that overheating is seldom a problem

Don't take my personal dislike of a 'fighter cockpit' look make you think I'm not interested - I'll read every word you publish and assume my bike is similar . . . . I just don't want a multitude of gauges ;)

Don

EMS · Post by **EMS** » Tue Aug 12, 2008 1:30 pm

Don #6141 wrote:I'll read all your 'reports' with great interest -

Don't take my personal dislike of a 'fighter cockpit' look make you think I'm not interested - I'll read every word you publish and assume my bike is similar . . . . I just don't want a multitude of gauges ;)

Don

This is why this group is so great

While we all have a common base to stand on, we all have different opinions and preferences - which we can express without being reprimanted, belittled or in any other way chastized!

Don #6141 · Post by **Don #6141** » Sun Aug 17, 2008 9:30 pm

For anyone considering just replacing the voltmeter with a 'real' gauge (oil temp or pressure or cylinder head temp) here's a couple of neat voltmeters you can use in place of the stock voltmeter

http://www.customdynamics.com/LED_battery_gauge.htm

The first one with the 10 LED's is very small and very thin and could easily be mounted on top of the fuse cover with no visible wiring

The second one is the one I like and it could be put in the unused square next to the high beam indicator - Maybe replace that black square with a clear plastic one and mount the 'display' under it

Both are bright during the day, automatically dimming at night and actually give you MORE information than you get with the stock meter

I'm thinking more and motre that the VDO oil temp gauge would look very nice in place of the stock voltmeter . . . . .

Don

twinegar · Post by **twinegar** » Sun Aug 17, 2008 10:01 pm

The led volt panel would allow replacement of the oem volt meter with the temp gauge without losing anything. Cutting or drilling the fuse cover is no biggy either because they are available and cheap in case someone wants to put it back later. They do amazing things with leds. I would like to have a digital clock readout in place of the black idiot lense but I have never seen one that shape that could be modified.

I replaced the 150 psi VDO pressure gauge and sender with a VDO 80 psi gauge and sender to better cover the CBX range. Mine is running about 68 psi cold and 55 hot at speed. Because 300 seems to be nearing the seizure temp I will probably stick with the current temp gauge. I am going to contact VDO to see if they have solved the problem with their cylinder head temp gauge. I am anxious to post some readouts and comparisons between the cylinders. I would like to have Honda's data when they were developing the engine as I am sure they had temp sensors all over it. If the center 2 were getting all that hot they probably would have installed something on the fork to vector the air onto them.

I wish more people would check in with gauge ideas. There are many possibilities and it is fun stuff to think about.

cbxtacy · Post by **cbxtacy** » Mon Aug 18, 2008 1:56 am

Here's where the oil temp sending unit is mounted on my '82. Next time the fairing is off, I'm removing the guage and at the same time I'm removing the sending unit. I've had 4 different guages and sending units over the years and I pretty much know what the engines are doing as far as temp goes. I also have 13 row stacked plate oil coolers on all my CBX's so I'm not worried about temp.

Don #6141 · Post by **Don #6141** » Mon Aug 18, 2008 9:26 am

I was just looking at all of those caps under there last night, George

Did you remove the cap and then drill and tap it . . . . or did you do it on the bike?

Don

cbxtacy · Post by **cbxtacy** » Mon Aug 18, 2008 10:03 am

I bought that bike used and already had the package installed. I've installed them in plugs and drilled and tapped my own and, once, bought a cap already drilled and tapped from TIMS when Tim Ware was the proprietor. If you drill and tap ypur own hole, you have to be very careful, the plugs are very brittle. If you need a plug, I have 4 spare engines with spun bearings, bent rods, rusty cylinders etc. I can probably make one good engine out of them. Email me with a pic of the plug you desire and I'll mail it to you. That way your bike isn't down if you crack the plug. That's for anyone.

EMS · Post by **EMS** » Mon Aug 18, 2008 11:35 am

Aren't the plugs threaded? It would be easier to make your own brass plug. I have one in the right side oil gallery plug.

Don #6141 · Post by **Don #6141** » Mon Aug 18, 2008 11:42 am

That's a thought . . . . if you could buy a metric threaded brass plug which would just screw into the block then you could drill and tap it for 1/8th pipe to fit the gauge sender - But most brass plugs are tapered pipe threads and I don't think the threads those caps screw into are pipe threaded . . . .

Any ideas George?

I guess we need to see what threads are on the caps . . . .

Don

alimey4u2 · Post by **alimey4u2** » Mon Aug 18, 2008 11:53 am

I "think" they are parallel threads with an O-Ring seal..

EMS · Post by **EMS** » Mon Aug 18, 2008 11:58 am

alimey4u2 wrote:I "think" they are parallel threads with an O-Ring seal..

I think so too!