Why no glow plugs?

[erniecarpet@...]

Good question. On my Detroit, if its' cold, I have to have the block heater
on or she will belch smoke for quite a while. Ernie-83pt40 in Texas-


[Non-text portions of this message have been removed]

[transit360]

Can someone tell me why domestic car and truck diesels have glow
plugs and large diesels i.e. buses do not? Just a thought that occured
to me as I was plugging in my two buses and Mercedes diesel today.
I've had four buses and none of them have had glow plugs. They just
start after a few turns of the starter whether air or electric.
However, every diesel Mercedes, Chevy, etc I've owned and have seen
has glow plugs. What gives?

[mrdonut12]

--- In WanderlodgeForum@yahoogroups.com, "transit360"
wrote:
>
> Can someone tell me why domestic car and truck diesels have glow
> plugs and large diesels i.e. buses do not? Just a thought that occured
> to me as I was plugging in my two buses and Mercedes diesel today.
> I've had four buses and none of them have had glow plugs. They just
> start after a few turns of the starter whether air or electric.
> However, every diesel Mercedes, Chevy, etc I've owned and have seen
> has glow plugs. What gives?
>
The only thing I can think of is maybe the glow plugs impair the
fuel distribution or airflow when the engine is running and they
figured they could get more power or economy with them out of the way.
This is pure speculation on my part.
If I have a shore line plugged in, I always pre-heat my engine
before starting, even in the warm summer months. Normal operating
temperature for the engine is 180 degrees, so if it's colder than that
outside, I heat the engine. ;o)
One of the reasons you should never let a diesel idle for an
extended period is the fuel doesn't burn completely and liquid fuel
washes the oil off the cylinder walls and that's bad for the engine.
I use the same logic for a cold start--if the engine is highly
inefficient, that means there's unburned fuel in the cylinders, so I
want to make the cold operation time as short as I possibly can.
My 3208 NA is one of the fastest starting engines I've ever had.
I only need to wave the key close to the switch and it pops right
off. ;o)

George Witt
81 FC 35
Lincoln, Nebraska

[guysmalley]

George,
I wondered the same thing. when its cold I use a little starting spray in the
little rubber nipple
on the air intake that is on my 86 v8 92 detroit. starts right up.
The generator has glow plugs just push the stop swith for 15 seconds then start

-guy smalley
86 pt 40

[transit360]

I am curious about this statement b/c I've been told that the
reason big trucks going OTR get such high mileage out of their engines
is b/c they never really cut them off. They just leave them running
and running... This helps b/c the engine nevers experiences
temperature changes like from starting, which we all know is when the
most engine damage is done.
Why wouldn't the fuel burn completely if the engine were just
idling...unless it was running to rich or something? I'm not arguing I
just haven't heard of this before. What would you say about trucks
idling like truckers do overnight at rest stops?

Steve
2 '98 Bluebird Q-buses

> "One of the reasons you should never let a diesel idle for an
> extended period is the fuel doesn't burn completely and liquid fuel
> washes the oil off the cylinder walls and that's bad for the engine."
>
> George Witt
> 81 FC 35
> Lincoln, Nebraska
>

[transit360]

I've also seen bad effects from using starting spray too much. The
compression is just way too high in a diesel for something as
combustible as starting spray.
I once bought a mid-80's Chevy with the 6.2. The guy said he had
trouble starting it and he just used starting spray. I don't think he
had enough sense to check his glowplugs first. Anyway, after I bought
it I investigated further. I took out one of the glow plugs (which I
absolutely had to PRY to get out of there) and the tip had swollen to
almost twice it's normal size b/c of the high combustion from the
spray. Two glow plugs were so swollen that I couldn't even get them
out and finally sold the truck to someone that wanted to pull the
heads off to get the plug tips out.
Now granted this guy probably used WAY too much. I've used it on
occasion to get my diesels started, but only a slight mist in the end
of the air intake it all it takes. Has anyone else had adverse effects
for the spray?

Steve
2 '98 Bluebird Q-buses

--- In WanderlodgeForum@yahoogroups.com, "guysmalley"
wrote:
>
> George,
> I wondered the same thing. when its cold I use a little starting
spray in the little rubber nipple
> on the air intake that is on my 86 v8 92 detroit. starts right up.
> The generator has glow plugs just push the stop swith for 15 seconds
then start
>
> -guy smalley
> 86 pt 40
>

[guysmalley]

Steve I agree using the spray too much would be a problem. I found in temps of
18-25 it
helps and also it doesn't take much. Do you know how to activate the glow plugs
on a v8 92?
-guy

[transit360]

Have no idea...

--- In WanderlodgeForum@yahoogroups.com, "guysmalley"
wrote:
>
> Steve I agree using the spray too much would be a problem. I found
in temps of 18-25 it
> helps and also it doesn't take much. Do you know how to activate the
glow plugs on a v8 92?
> -guy
>

[Robert Johannesen]

Hey Guys,
According to the Detroit Diesel Service manual, there are no glow plugs
in the 8V92 Series engines. Page 1-57 in the engine section shows a head with
four exhaust valves and an injector in the center of each cylinder - nothing
else.

Bob Johannesen 91 WLWB 40 "Seldom Blue"

transit360 wrote:
Have no idea...

--- In WanderlodgeForum@yahoogroups.com, "guysmalley"
wrote:
>
> Steve I agree using the spray too much would be a problem. I found
in temps of 18-25 it
> helps and also it doesn't take much. Do you know how to activate the
glow plugs on a v8 92?
> -guy
>






SPONSORED LINKS
Recreational vehicles Wanderlodge Automotive maintenance
Recreational vehicle dealer Used recreational vehicles Automotive radiators

---------------------------------
YAHOO! GROUPS LINKS


Visit your group "WanderlodgeForum" on the web.

To unsubscribe from this group, send an email to:
WanderlodgeForum-unsubscribe@yahoogroups.com

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


---------------------------------






---------------------------------
Yahoo! FareChase - Search multiple travel sites in one click.

[Non-text portions of this message have been removed]

[Neil & Pat LeKander]

You observation is quite correct. The primary reason for glow plugs (or
heated intake grids) being used on small consumer diesels is because of the
market where they are offered for sale. Can you really see the little ole'
soccer mom trying to start the family Mercedes via spraying ether down the
intake? But for the truck driver, bus driver, or equipment operator it is
all in a days work.

There are also technical reasons for the difference. Most small diesels
utilize a different type combustion chamber design than do the large
commercial truck engines. They are equipped with a pre-combustion chamber
located in the head or top of piston, when so equipped the amount of heat
required to raise the temperature to the degree that will aid cold starting
in minimal and can be provided by the battery system in the form of glow
plugs or heated grid. In contrast to heat a very large combustion chamber
such as used in 9-14 liter diesel would be immense, certainly well beyond
what could be provided by a battery. Note, that virtually all-large diesel
engines come with block heaters, which apply external heat to the combustion
chamber area of the engine. This of course serves the same purpose as does
the glow plugs or heated intake grid but has a 110 VAC electric source to
provide the required energy. On my own DD 6V92 I can assure you that all of
the above is correct and works quite well.

I did read another response to your inquiry in which it was stated that
trucks have glow plugs but buses do not. I am quite certain that is not the
case as truck and bus engines are generally identical excepting for the
cooling system and a few other components.

Neil
Author, "The RVer's Ultimate Survival Guide"
http://www.rvsafetyinfo.com
author@...

Can someone tell me why domestic car and truck diesels have glow
plugs and large diesels i.e. buses do not? Just a thought that occured
to me as I was plugging in my two buses and Mercedes diesel today.
I've had four buses and none of them have had glow plugs. They just
start after a few turns of the starter whether air or electric.
However, every diesel Mercedes, Chevy, etc I've owned and have seen
has glow plugs. What gives?