using bus engine radiator for generator cooling

[Ray D]

For those of you that use the bus engine radiator for generator cooling, do you use an extra boost pump or will the generator pump push enough water by itself.  I have an 8KW deisel generator and it sets in the engine compartment right next to the 8V92TA?

Thanks,
Ray D

[Bob Belter]

Ahoy, Ray,

I cannot state that your generator coolant pump will supply sufficient coolant through the main bus radiator, but with good sized hoses (On my 12 KW genset, 1" ID) it probably will be.  I do know that you will need suplemental cooling air flow through the main bus radiator.  On mine, I use one MBZ fan on contiuous, and a second MBZ fan on a thermostat.  Works just fine.

As an airplane guy, by plumbing them together, I violated a basic premise of Aero Engineering ---  That is --- NO ENGINE should have even a notion that there is another engine in the vicinty.

I rationalized that:
A:  my genset need not run when the engine is running

[Bob Belter]

Sorry , Folks, I stumbled over a key and posted before I was complete.

Ahoy, Ray,

I cannot state that your generator coolant pump will supply sufficient coolant through the main bus radiator, but with good sized hoses (On my 12 KW genset, 1" ID) it probably will be OK.  I do know that you will need suplemental cooling air flow through the main bus radiator with the main engine NOT running.  On mine, I use one MBZ fan on contiuous, and a second MBZ fan on a thermostat.  Works just fine.

As an airplane guy, by plumbing them together, I violated a basic premise of Aero Engineering ---  That is --- NO ENGINE  -- EVER!!!  --- should have even a notion that there is another engine in the vicinty.

I rationalized my (terrible) act by the following:
A:       My genset need not run when the main engine is running.
B:       I have shut-off valves on the plumbing
C:      There is plenty of water aboard to re-fill the coolant.
D:      I have two different low coolant warning systems
E:      I can glide to a stop "with ease" if I loose coolant

Nhyah!!  Nyahah!!

Enjoy  /s/  Bob

[Tenor]

Great idea!  Has anyone done this on an MCI with the genset in the first bay or up front?  Would the idea be to plumb into the heater lines in the tunnel?  Or run separate lines to the rear to only one radiator?

[TomC]

I would highly recommend you NOT plumb into your engine-especially the 8V-92TA which is thee hardest engine to cool bar none.  It is better to have a separate radiator for the generator.  I have a squirrel cage blower with a 2spd belt driven (slower fan speed=quieter) motor on it.  I have to run my gen while driving if I want air conditioning since my 3 roof tops are the only A/C I have.  My gen is in the very front of the bus next to the drivers seat like a front engine.  Good Luck, TomC

[H3Jim]

DML had his eagle plumbed that way - using the engine radiator for the genset cooling.  Had to use an exterrnal fan for cooling when he was sitting and the bus engine fan was not drawing air through the radiator.

[buswarrior]

Further to Tom's post, you want to be sure you aren't creating a hot loop for the 8V92 through the generator when the big engine is running.

Once up to temp, the line through the generator could become a bypass to the radiators, and put a percentage of hot coolant right back into the big engine.

I am a supporter of "efficient design", but once the fail safe pieces are bought and installed, any efficiencies have been blown out of the water, both in cost savings and increased number of failure points.

You may also find yourself in some failure mode, (bus alternator fails?) having to run the generator in order to get home, and plumbed together might not work...?

Independent systems do have their advantages in redundancy?

happy coaching!
buswarrior

happy coaching!
buswarrior

[gus]

I agree with Tom, I can't think of even one good reason to tap into the bus engine system. If you do when you have one coolant problem you will also have two.

My Honda gas water cooled is completely self contained, when I slide out the gen box EVERYTHING, including the exhaust system,  comes out with it. This is as good as it gets!

[H3Jim]

The good reason to tap into the bus system is space savings.  The generator radiator and fan can take up a fair amount of space.

Dick Wright helped DML set up his, and I think DML was very happy with the way his worked - for years.

One point, is to use Y's not T's where the generator water goes into and out of the bus system.  It helps the flow get started in the right direction.

[Tenor]

I'd like to hear from DML about how his is plumbed.  I have never heard a bad thing about Dick Wright or about a bad plan of his, so my curiosity has gone up.

I'd love to save the space and avoid an extra radiator and there is plenty of room to install an electric fan behind the radiator on my MCI7.  It is a trick to avoid creating an accidental bypass for the DD, and to be able to flow coolant without running into the closed thermostats on the DD when parked.

[makemineatwostroke]

Looks like with the two systems tied into each other a heating problem with one engine you now have a heating problem with two engines go for the separate radiators and fan. One more thought you blow a hose on the bus engine in the desert at 120 and need to run the AC to keep your wife and dog cool not going to happen       fwiw

[DrivingMissLazy]

I'd like to hear from DML about how his is plumbed.  I have never heard a bad thing about Dick Wright or about a bad plan of his, so my curiosity has gone up.

I'd love to save the space and avoid an extra radiator and there is plenty of room to install an electric fan behind the radiator on my MCI7.  It is a trick to avoid creating an accidental bypass for the DD, and to be able to flow coolant without running into the closed thermostats on the DD when parked.

Well, I was trying to stay out of this, but really need to let everybody , again, know how it worked.

Initially I had some problems which were all based on the initial installation, which I did not do. I bought the bus already converted.

First let me say that it ended up being a great system and if I were doing another conversion I would do it exactly the same. Also the Webasto furnace was plumbed thru the engine coolant system so I only had one system. If the genset is running it is warming up the engine coolant so the Webasto does not have to run as much. If the Webasto only is running it is keeping the main engine and the genset warm. What more could a person ask for.

The output water hose of the genset is connected thru a 120 volt circulating pump (from Dick Wright) to a wye fitting on the top of the radiator. The input water hose of the genset is connected to a wye at the bottom of the main radiator. I am not certain the additional circulating pump is a necessity. I added it before I found a kinked hose leading from the radiator to the genset.

I also found that after about one hour of operation the genset would shut down on overtemp. That is when I installed an electric automotive 16 inch fan with a 180 degree thermostat. That solved that problem. In fact I installed two as I was having overheating problems withe the DD on some of the mountain passes.

Later I added six misters of the very finest mist that was available at that time. They were part of a drip mist flower watering system. That resolved my DD overheating.

So overall, after I solved the initial conversion problems, It worked great.

Richard

[H3Jim]

Thanks Richard, sorry for being so persistent about your input. Maybe in the future I should just be quiet and let you jump in only if you wish.  ) 

Jim

[DrivingMissLazy]

No problem Jim. I was hoping to find the old posts, but was not successful.
Richard

[Tenor]

Again, thanks Richard!  Always best to hear from one with experience.  So I do see makemineatwostroke that if a main radiator hose went, you could be toast for electrical unless a shutoff is put on the bus, which could backfire if not used properly. Definitely food for thought!