Extra 1/2 gear in coach

With the overheating problem you said your using thermo fans ?

Wow lots to reply to here so if I miss your post apology in advance.
Cooling:
I removed the huge Horton fan and fitted 4 14" thermatics with 16" motors to the original rebuilt radiator. Block was acid cleaned as well. Knew that would not be enough so added a ford AU V8 radiator with is own 12 v thermatics in series. Three thermostatic switches, so 3 staged cooling zones. Works great, apart from a really hot day, restricted to about 90 or temp starts to creep up. Having a larger custom radiator built to solve this one, will have 2 x 16" 24 V fans on it.
Reason for this move ? The original fan draws 12% of the HP just to drive it and most of the time it is not required. The extra load on the 240 amp 24 v woks out a 3.5% of HP draw.
We also moved the radiator to the side, louvred it to take advantage of us much ram air as possible.
Summary, almost got it right first time, but when towing all up weight of 21 tonnes, on a really hot day, just falls short, so correct it.
On a typical day under say 32 deg the third zone does not even come into play so system works well.

Engine Revs:
Seems to be 2 schools of thought on this one, the screamers and the gentlers. I don't wish to get into an argument but there are those that say if you don't want oil use or black spots all over the back, drive it between 1500 and 1900. So far that is what I have been doing but I am willing to try the higher revs on my next outing. I will let you know how I go.

Brakes
Have an issue with front brakes getting hot, even on highway can smell the shoe resin Cam had a look last time VP was at CPF but nothing was found. On the Bundy trip enough heat was generated to see some hub oil weeping from the filler plug, never done that before.
Booked into CPF on Monday for another look so hopefully that will be sorted. Pulled all the front brakes off today but cannot find any reason for this to be happening. Everything is new, spyder,shoes, drums, small parts, the lot.

Injectors
Nope no bigger injectors Cameron said was a small spec motor and it is fine for me. If I did put bigger in I would have an increased fuel bill and more heat to get rid of so am not going down this road.

Ratios
That is what I am finding, no worries lower down, bit far apart in the upper ones, thats where a 1/2 gear would be nice.

Skip shifting
Be nice, I am only at the stage of being comfortable with a crash box, I am sure clutchless shifting will come in time, maybe even skip shifting but I regard my self as still being on L plates as far as crash boxes go.

Thanks
William

busman, I am no expert on GMs but when I drove one the first time I was doing 1800 to 1900 revs and going no where fast so I stop to try to find the other gears to get going faster, then the boss came along and said after I told my problem, "well you have another 1000 rev yet" GET INTO IT MAN, ring its bl..dy neck. That's when it started to sing. All jokes aside mate it's your engine and you should drive it the way you see fit.
Colin

I have no knowledge of screemers but from experience of my little V the way to avoid boiling on long drags on a hot day is to keep dropping cogs until the revs are singing and not let her lug down.
Warm brakes may be due to faulty foot valve letting a little air past in the off position after gentle use, but with a hard stab in the workshop it returns normally and all looks normal. Had this problem on front circuit only, no one these days can (or don't want to) adjust or service them as a new one usually under $100.
my 2 cents worth

Mammoth, thanks for that tip, it makes a lot of sense, unfortunately after jacking up one wheel we could not detect any drag at all, no matter how we applied the brakes, or came off the pedal. (of course locked up when applied !)
Any other suggestions or ways to prove this may be the cause ?
Temperature is not going to be a factor, is it ?
William

endless rush hour traffic lights usually seems to bring on all sorts of symptoms you hardly noticed before. LOL

Only real way is to go through a long winded routine of substitution of each component - booster/dump valve/foot treadle valve/relay valves. Might also be worth checking that there is nothing funny happening with the way the wheel sits on the wheel bearings with/without weight. Just throwing it in there.

Busman, the following is just advice, based on my own opinions, experience and the laws of physics. I'm not "having a go" so to speak, but just making sure you have covered your bases for many years of happy busing. I think what you are doing is really overcomplicating the situation and will lead to further headaches down the track.

With regards to the cooling fans, it is a bit of a fallacy that electric fans are more efficient. In very simple terms, when you look at the energy required to move a certain volume of air, the electric and the mechanical fans (not the driving method) should use about the same amount of energy. The mechanical fan takes its mechanical energy straight from the crank and moves air. The electrical fan uses a very different energy flow path. First, the mechanical energy of the crank is transferred to the alternator, then it is converted to electrical energy, which travels through wires and batteries to end up at the fan motor. It is then converted back to mechanical energy. The energy path looks like this-

Mechanical fan- Crank pulley > Belt > Fan pulley/fan blades.
Electrical fan- Crank pulley > Belt > Alternator > Wiring > Fan Motor > Fan Blades.

So you can see that by the energy having to travel a much longer path, that more energy is lost along the way, most commonly as heat generated in the windings of the fan motor, alternator and wiring. This makes the mechanical fan, while it is running much more efficient overall.

The advantage of an electric fan is it doesn't run all of the time, so that is where it saves horse power. You will still use more fuel for the electric fan because you have to keep charging the battery after the fan has shut down. But you could always fit a clutch to the mechanical fan so it does not run all of the time either, and would make for a much simpler system.

Also, in regards to fitting a second radiator, I reckon you might just be treating the effect of a problem, the overheating, and not addressing the cause of it. How old is the bus? 30 years. So the original design of the cooling system has been doing an adequate job for 3 decades and now there is a problem causing the engine to overheat. If the cause, and we all do it, is asking too much of a 30 year old design, then you need to look at ways of improving the efficiency of the system. I would recommend such ideas as making sure that fans have their shrouding fitted (which electric fans don't have, another loss), fitting an air ram scoop to the side of the bus on the cooling air intake. You could also fit lagging to the exhaust system to keep the heat in it and not radiating back on to the engine or you could try fitting an oil cooler. You really need to look at improving what is there and not adding more radiators as its just another set of hoses or whatever, that can let you down in the middle of nowhere. Also keep in mind that hot air from the radiator is a hot gas which has now expanded and will now require a bigger area to escape than what it came in through, which is particularly important on ducted systems.

Is your overheating simply caused by too much load and not enough engine speed. An engine at full speed means a fast fan moving lots of air and a water pump moving lots of coolant. And you might not think it but you will use less fuel on a given load at full speed, than the same load at 3/4 speed. The engine simply isn't working as hard.

If the cause of the overheating is engine related, try to solve that first. You said that your burning more fuel? The only way you can do that on a Detroit is to put bigger injectors in, which would mean more power as you described, but not that much more heat. Detroits are timed depending on what size injector they have and what power they are rated for, so a 250HP 6/92 will have different cam timing and blower speeds than one that is rated for 500HP. So I was thinking that maybe bigger injectors where fitted but the engine wasn't retimed and maybe something funny was going on there.

Lastly, with the brakes, can I just ask how do you know that they are overheating? Is it just the smell or have you actually got a temperature reading off the drum? Now I am not being funny when I ask this, but is the odour you are smelling not the brakes, but actually an overheating and overloaded electrical system because of the fitment of too many high current fans?

I hope this provide so food for thought,

Regards DD

Now Im not real smart just a busted ass farmer but I do know that Diesel Dog is on the right track
a big old mechanical fan with a shroud fitted will shift a lot more air than electric fans right on the radiator
why ? because the fan back off the radiator and shroud draw air over entire radiator were as electric fans only draw air over the area that the fans against

just some thoughts

Paul

The Horton fan only uses power from the engine when it is locked in, so most of the time is only spinning the drive hub. It worked for years, you would be surprised how much air the Horton fan moves and some of that is over the engine itself to help with cooling.

I'd have to agree with diesel dog. Many moons ago when I was an apprentice, there was a huge sign in the workshop. " FIX THE CAUSE NOT THE COMPLAINT". Although I doubt that exists in many dealerships today.