glow plugs on deuce?

[ken326@yahoo.com]

Anybody know the reason why they didnt put glowplugs on the duce's?

 

[nk14zp]

No need for them.

 

[Heavysteven]

Maybe they were thinking "keep it simple"

My truck starts up fine even in the teens

 

[DieselBob]

Just wasn't a design feature back when they first produced. Back in the late 60's and early 70's you where lucky if you had a block heater even on a class 8 rig.

 

[ODdave]

They suck, lol. Your deuce should start just fine with your intake heater. If you already have a block heater or don't have a power sorce for one, try adapting a intake heater from a 5.9 (6bt) cummins. And if I forgot to mention glow plugs suck !

 

[Keith_J]

Compression ratio is very high for direct injected engines. A glow plug would cause issues with cold starting pressures in the cylinder head. At arctic temps, the air is very dense. The intake heater reduces this density by heating the air.

This is also some of the reasoning behind the coolant jacketed intake manifold.

 

[JasonS]

Waukesha used glow plugs in their diesel engines at least as far back as 1950. It is NOT a new technology.

 

[ODdave]

keith,......HUH? direct injected engines have a lower comp. ratio. The I.D.I. 6.2 & 6.5 engines have 20.5-22.5 to 1 ratio, where a D.I. 5.9 cummins has a ratio of 16.1.

"A glow plug would cause issues with cold starting pressures in the cylinder head. At arctic temps, the air is very dense"

i am a litle unshure where this came from. although i hate glowplug motors, when working properly they start great in sub zero temps, powerstrokes and duramax's use them and they work fine in the cold (sometimes better than the grid used by cummins)

 

[Tom_Statt]

I pondered the idea of adapting an intake heater from a kubota diesel (they were plentifull where I was working last), but I don't have much trouble cold starting mine. If I do on thoes 'teen degree winter days, a less than one second burst of starting fluid does the job just fine. The only time I had trouble cold starting my truck (30-20 degree weather) was when the in-tank fuel pump went out, and even then it would only take a few extra cranks it get it rumbling. I just don't think it's worth the trouble or cost trying to adapt and install an auxillary starting aid. Just keep it light on the starting fluid, and you should be just fine on thoes cold days, that and allways stay prepaired with an anti-gelling fluid, for thoes REALLY cold days.

 

[Keith_J]

keith,......HUH? direct injected engines have a lower comp. ratio. The I.D.I. 6.2 & 6.5 engines have 20.5-22.5 to 1 ratio, where a D.I. 5.9 cummins has a ratio of 16.1.

"A glow plug would cause issues with cold starting pressures in the cylinder head. At arctic temps, the air is very dense"

i am a litle unshure where this came from. although i hate glowplug motors, when working properly they start great in sub zero temps, powerstrokes and duramax's use them and they work fine in the cold (sometimes better than the grid used by cummins)

I am talking about THIS direct injected "diesel" engine. It it DI, most DI engines of this size will have a 17:1 to 18:1 compression ratio. Not 22:1. The ONLY reason it is that high is for use of gasoline fuels (although aviation gasoline with its higher octane index cannot be used). Gasoline has poor autoignition characteristics, that is the nature of octane index (anti-knock index, AKI).

 

[ODdave]

that still dose not support your reasoning as to why glow plugs cannot be used............. the 6.2 dose not have as "gracefull" of an injection system, but is multifuel capable, it has GP's.........

 

[mudguppy]

the 6.2 is multifuel capable? that's a new one for me.

 

[Tom_Statt]

Technically every compression ignition engine has multifuel capability, That’s one reason you get diesels "running away" on their own oil. If the temperatures are at a point for a fuel to combust, you can run it, although different fuels may cause damage to the fuel system or valves. It's hard to gauge the permissible amounts of alternative fuels, but the best thing to do if you are going to try running different fuels is to mix them with the diesel, since it has all the best properties for compression ignition, but by tweaking that mixture you may create an even more ideal fuel to use, but that is subject to differ between engines. But lets not stray away from the subject at hand, why deuces don't have glow plugs. my best guess is that it wasn’t necessary during testing, or through extensive field testing. if they needed any assistance, they used ether, as seen by the fire-wall mounted system, or they used the fuel fired intake heater systems. But seeing that they didn't install either system on all trucks, the military probably didn't recognize a need for all trucks to be equipped because the use of those trucks were spread across a wide range of operating conditions, and it would not be financially wise to spend money on all of their trucks to be cold weather equipped, if not all would be used in cold weather.

 

[nk14zp]

Well said.

 

[mudguppy]

yes, i understand how the 'compression ignition engine' operates. however, the 6.2/6.5 engines were never classified as a 'multifuel capable engine', so i wanted to probe deeper as to how that was ascertained.

my theory:

since 6.2/6.5's don't start for jack-chet without their glow plugs functioning well, i'd say that the main differences between the two examples is the injection event itself: IDI vs DI.

the differences between these two designs is that the IDI needs high compression in order to operate, whereas, a DI engine does not. therefore, when it comes to cold weather starting, the IDI needs glow plugs. another example is the 7.3 IDI vs 7.3 DI: both engines have and need glow plugs for cold weather starting. however, the respective CR's are 21.5:1 (IDI) vs 17.5:1 (DI).


therefore, i believe the multifuel does not need the same starting aids (i.e. glow plugs) because it has an advantage: a higher-than-required compression ratio [for a DI design]. and it is this high compression ratio that makes the multi' a multifuel capable engine'.

 

[ODdave]

mud guppy,

they may not have been classified as multi fuel but they are definitely capable of it, i dont think uncle sam would have shelled out the extra coin to have all mil-spec stanadine DB2 pumps outfited with a hardend head and rotor if he wasn't expecting these trucks to be ran on something other than the standard No2 diesel with all of the correct lubricity additives. There are plenty of ppl around here running WMO and trans fluid through 6.2's and they run just fine. Just because they didn't tell you that you could, dose not mean you can't.


P.S. Im with TOM, gp's where not necessary on the multi.

 

[emr]

That is a total guess and opinion, absolutly no facts. and in no way in my opinion were those sub standard base trucks ever to support such operations,In my opinion they are not even tactical vehicles. not by a long shot, and may very well be the worst diesel ever made , they are a contract truck, from the factory, ...No where do they even hint of being a multi by design,and it would have to be stated somewhere for that to be true, that is just an opinion...sure may run on alternatives , but so do all diesels....randy

 

[m16ty]

yes, i understand how the 'compression ignition engine' operates. however, the 6.2/6.5 engines were never classified as a 'multifuel capable engine', so i wanted to probe deeper as to how that was ascertained.

my theory:

since 6.2/6.5's don't start for jack-chet without their glow plugs functioning well, i'd say that the main differences between the two examples is the injection event itself: IDI vs DI.

the differences between these two designs is that the IDI needs high compression in order to operate, whereas, a DI engine does not. therefore, when it comes to cold weather starting, the IDI needs glow plugs. another example is the 7.3 IDI vs 7.3 DI: both engines have and need glow plugs for cold weather starting. however, the respective CR's are 21.5:1 (IDI) vs 17.5:1 (DI).


therefore, i believe the multifuel does not need the same starting aids (i.e. glow plugs) because it has an advantage: a higher-than-required compression ratio [for a DI design]. and it is this high compression ratio that makes the multi' a multifuel capable engine'.

While some DI engines have them as a starting aid, IDI engines almost have to have them to get started even in the summer.

The multifuel is about the best starting diesel I've ever started. I think that has to do with the high compression it has compared to other diesels.

And yes, the mutifuel is a diesel engine. Some people will argue this but the diesel term has to do with the design of the firing process and not the type of fuel you use. The first diesel ran on peanut oil .

 

[ODdave]

emr, what proves fact? what you read in a book? (lmao) or what you have done/seen/heard/driven.......? i did not say that the 6.2 was DESIGNED to be a multi, i said it was capable. shure all diesels will run on alternates but the hardend H&R impllied something. i do agree with you on the fact they are crap engines for anything but civy transportation (this is what they where designed for!). (what part is guess & opinion?) I may be wrong about all this, im just a dumb mechanic fixin diesels for a living.

P.S. would you rather had a 6.9? and a ttb front axle? Uncle Sam picked the best suited of the 3

 

[trog]

Large cylinders favor good ignition because less compression heat is lost to the metal -- so direct injection engines usually have displacements greater than 55 cubic inches per cylinder. Smaller cylinders usually have precombustion chambers, glowplugs, maintenance misery, and much lower efficiency. On the other hand, I have little direct injection Yanmars that start with a hand pull very nicely!