Cold Start/Block Heater

rogo88 · 11-21-2012, 03:18 PM

This is the first of what I am sure will become an endless trail of questions...
Living in Vermont and having experience with diesel engines, I am familiar with block heaters. The manual for my Journey states that, when plugged in, the block heater is connected to both shore power and the generator. If shore power is unavailable "just start the auxiliary generator". Being, itelf,diesel powered, what makes the generator immune from the need of a block heater? What makes it more capable of starting than the engine in extreme cold?

clyon51 · 11-21-2012, 03:55 PM

I would say since the genny is much smaller which would use way less amps to crank is the reason. I have a 3 cyclinder Kobota tractor and it has no block heater. I've started it many times in sub zero temps. Same engine used in many gennys.

palehorse89 · 11-21-2012, 03:56 PM

The colder it is outside the longer the light flashs when I go to start my generator so if I had to take a stab at it ,I would say maybe glow plugs on a temp. sensor. Iam going to have to study up on this also or maybe someone will tell us. Happy turkey day!
Found it on cummins onan webiste

Push and hold the switch at

START until the
genset starts. The status indicator light on the
switch flashes during preheat and cranking. It
will come on solid when the starter disconnects,
indicating that the genset is running. (Depending
on how cold it is, preheat can take up to 15
seconds, extending the time that the light

blinks.)

dennis45 · 11-21-2012, 04:15 PM

Normally gensets do not have a block heater because of their size. Not to say you could not add one but as stated above, the colder it is, the longer the pre-heat has to be on to allow it to start.
The pre-heat is the same idea as the coach engine in that it heats the air going into the intake.
As long as you have a full battery, the genset will start. Make sure the block heater is plugged in. On my rig the blockheater cord and 110V receptical is in the Electrical Bay with a switch in the overhead cabinet above the driver to turn it on and off.
Best way to get around this problem is of course to be where it does not get cold enough to worry about it.

336muffin · 11-21-2012, 04:24 PM

Gen has glow plugs, most large diesels do not.

rogo88 · 11-21-2012, 05:59 PM

Thanks for the replies.
At 15 or 20 below, I usually plug in the block heater to avoid overtaxing the glow plugs, but I can see that the gen set is easier to turn over than the C7.

Thanks again.

KSCRUDE · 11-21-2012, 06:21 PM

If its 15 or 20 below I don't even want to be any where close. That's colder then a well diggers heine! We get some cold temps here, maybe zero to 5 below, and even the sticks and bricks don't like it. No place to be living in a RV if you can keep from it. Right now as I speak it is thanksgiving eve and the AC is running in the house at 7:17 pm. I just love global warming. And this is in north west Kansas.

Eaglesview · 11-21-2012, 06:29 PM

Quote:

Originally Posted by KSCRUDE

If its 15 or 20 below I don't even want to be any where close. That's colder then a well diggers heine! We get some cold temps here, maybe zero to 5 below, and even the sticks and bricks don't like it. No place to be living in a RV if you can keep from it. Right now as I speak it is thanksgiving eve and the AC is running in the house at 7:17 pm. I just love global warming. And this is in north west Kansas.

Some are chosen.

I use synthetic in the generator to assist with the cold weather start.

rogo88 · 11-21-2012, 07:57 PM

We have real men up here in Vermont...I'm just not one of them.

I'm not speaking of living in the coach at these temps. I'm considering the suggested winter maintenance of exercising the engine, generator, jacks, etc. periodically through the cold weather months when it is out of service.

grtharris · 11-21-2012, 07:58 PM

rogo88, Please add your Motorhome info to your salutation to help identify it.
There are 2 things that must be over come to start a diesel when it is cold.
First, the friction of the cold motor oil, the bigger the engine the more friction. The engine block heater takes care of that on big engines. Smaller engines just less friction.
Second, the temperature of the air in the combustion chamber, must be hot enough to ignite the fuel. On the big inline sixes like your motor home this is done with a air intake preheater. On smaller 3 cylinder engines like my tractor and your generator this is done with glow plugs. On V8 Ford and Chey diesel engines they us block heaters and glow plugs.
Sorry, more than you every wanted to know.

Mr_D · 11-21-2012, 08:03 PM

Quote:

Originally Posted by rogo88

Thanks for the replies.
At 15 or 20 below, I usually plug in the block heater to avoid overtaxing the glow plugs, but I can see that the gen set is easier to turn over than the C7.

Thanks again.

On the RV diesels most have gone to the intake heater and no longer use glow plugs. That's why they say NOT to us a starting fluid sprayed into the intake. The C7 CAT definitely has the intake heater grid.

sdennislee · 11-21-2012, 10:16 PM

Quote:

Originally Posted by grtharris

rogo88, Please add your Motorhome info to your salutation to help identify it.

If you click on any users name it gives you the option of viewing their public profile. Typically I find if the haven't include their rig info in their signature as you suggest, it will be listed in their profile.

FIRE UP · 11-21-2012, 11:33 PM

Quote:

Originally Posted by rogo88

This is the first of what I am sure will become an endless trail of questions...
Living in Vermont and having experience with diesel engines, I am familiar with block heaters. The manual for my Journey states that, when plugged in, the block heater is connected to both shore power and the generator. If shore power is unavailable "just start the auxiliary generator". Being, itself,diesel powered, what makes the generator immune from the need of a block heater? What makes it more capable of starting than the engine in extreme cold?

rogo88,
The generator is not "immune" to cold start conditions. It is a smaller engine but, none the less, a diesel too. And, in that, it needs help in cold weather for starting. Now, if you have the 7.5 Quiet Diesel or the 8KW or even the 10KW, they are all the same. There ARE GLOW PLUGS in these little engines.

If your system is in proper working order, the generators that is, the gen will NOT CRANK OVER until a certain time frame is met, based on the outside ambient temp. There are certain parameters that the generator ECM fulfills prior to cranking. In short, based on just how cold the outside temp is, when you push the "start" button on the gen, the light in the switch will flicker and the fuel pump will prime the system.

The "flickering" of the light is indicating that the timer in the ECM is activated for a set amount of time to HEAT the glow plugs. If you have a manual for that generator, you can look up the set time for preheat of the glow plugs. There's at least three settings. And, each setting, teared from coldest to warmest, has a set time the glow plugs must heat, prior to allowing the starter to engage. The colder the outside temp, the longer the light flickers and delays the cranking of the engine.

Once the parameters are met in the time frame, the starter is allowed to engage. That way, you won't be cranking and cranking and cranking a cold little diesel, trying to get it to start. Once the glow plugs have heated to the set temps, that little engine will fire right off, within one or two revolutions from the starter.

As for the main engine, as has been stated, there are no more glow plugs for those. There is a heating element for the intake air. Again, when you turn your key on, and the ECM for the main engine is making preliminary checks of the entire system, it's also warming that heating element at the same time. Once the heating element has reached its set parameter, it tells the ECM to turn OFF the "Wait to start" light. Once you see that, it's OK to crank the engine.

As for your block heater, it's a 110VAC unit. It plugs into a 110VAC outlet someplace in your coach. Since the outlet is powered up by both shore power and gen power, you'd have to run your gen for quite a bit to really get the benefit of the block heater, if the rig's been sitting for quite a while in cold weather.

Whereas, if you're on shore power, you can turn it on the evening before you intend on departing and it will bring the engine up to a warmer temp for easier starting and running. They're all different so, it won't do any good to tell you where to look for the plug. Those block heaters draw a serious amount of watts/amps to do their job correctly. While they won't get it to "Operating temperature", it will heat the coolant/block to a temp that allows the engine to start easier and run cleaner due to it's not so cold on the start up. The intake heater is responsible for actually allowing the bigger diesel to start on real cold mornings/evenings. They both kind of work together. Hope this helps some.
Scott