LDS-465-1A Exhaust Gas Temp Concerns

[SasquatchSanta]

I’m finding that the new LDS-465-1A engine in my bobbed deuce is capable of quickly producing dangerously high exhaust gas temperatures.

Call me naïve but I’m surprised! I figured that since the injection pump setting is stock and given that the LDS (5-ton) engine is in a bobbed deuce and therefore is pulling a truck that is thousands of pounds lighter that high EGTs wouldn’t be a problem.

I’m assuming that stock 5-ton military trucks are NOT equipped with pyrometers. Without a pyrometer, given the exhaust gas temperatures I’m seeing, I can’t imagine how the military keeps the engines from melting down in the “Much Heavier” 5-tons.

What am I missing here? As mentioned earlier, my IP pump settings are stock and sealed!
Could it be the five-ton gearing? Could it be the lower gearing allows more air volume and therefore keeps EGTs under arrest?

Perhaps it’s the lower CFM deuce air breather --- starving the LDS?

I’ve noticed that the engine runs warmer than the old LDT-1D. I made a 100 mile round trip to Hibbing MN yesterday. The ambient temperature was approx 10 degrees. With the stock military winter-front and no fan (the electric fan doesn’t come on until 200 degrees) the temperature hovered between 180 and 195 degrees. I was running @ 2,200 RPMs which equals 55 MPH. Exhaust gas temperatures were steady @ 600 degrees with approx 2 pounds of boost. It may have to eliminate the winter-front.

2,200 RPM seems to be a sweet zone for the engine & truck combination. The engine seems just as comfortable jumping up to 2,600. In fact, it’s so quiet and vibration free I have to be careful not to over rev it. The truck seems to handle better between 55 and 60 MPH (2,200 to 2,400 RPM)

I remember seeing a SS thread not long ago that discussed IP pump fuel settings, EGTs and air flow. I looked all afternoon but couldn’t find it.

 

[gimpyrobb]

600 is all your seeing? Thats nothing.

 

[SasquatchSanta]

No. If I put my foot in the pump on a hill EGTs can get to 1,150 PDQ.

 

[doghead]

FWIW I can't run an arctic grill cover(open or closed) on my deuce with the LDS motor. I tried it twice last winter(around 30-35 degrees outside temp) and it would run up over 210 and blow out the overflow(blow-off tube). I do have about 5 or 6 soldered over cores in that radiator(winch damage before I bought it), but the system was cleaned, flushed and refilled with new antifreeze before I tried to run the grill cover. I can run the cover(opened or closed) with no trouble on the LD powered truck in any weather(under 50 degrees).I have never tried it above 50.

I don't have a pyrometer installed yet, so I can't compare my exhaust temps to yours.

 

[SasquatchSanta]

Thanks for the comments and be careful until you get a pyro.

Last night when the temp got up to 195 degrees I pretty much decided that the finter-front would have to go.

What doesn't make sense is how young fire-pixxing GIs can abuse these engines in the much heavier 5-tones without a pyrometer and yet I have to keep a close eye on my pyro.

 

[EO2NMCB]

OTR trucks will push 1200-1300 temps on long pulls. At 600 you shpuld be fine.

 

[ken]

1150deg is no where near dangerous. IMHO. If you are worried about air flow to the bigger turbo. Take the intake tube off then test drive again. See how much a difference you have. If there is alot then you might want to put a K@N in the box or put a open aftermarket filter straight on the turbo compressor housing.

 

[jwaller]

installing the larger air filter will help a lot. you are basically overfueling it by having a restriction on the intake side. as ken said remove the intake tube going to the filter and go for a drive. should help a lot.

 

[m-35tom]

i fail to see how the air filter could be a problem, it is the same engine. the lds just has slightly better piston cooling and possibly more boost. (mine didn't have any more boost than ldt) i have long maintained i can turn up a ldt and have the same power. just because the ip is sealed doesn't really mean it is set correctly, how much max boost will it make? will the egt go over 1300 if you keep your foot in it? sounds like your ldt was set to the 'stock' fuel rate which is very conservative and will not make much power. my ldt turned up to safe level maked 14 psi boost and 1150 egt and lots of power..............

 

[cranetruck]

installing the larger air filter will help a lot. you are basically overfueling it by having a restriction on the intake side....

I agree with Tom, "overfueling" doesn't really apply to diesels.

600°F and a 2 psi boost sounds about right for level road driving.

 

[DaveP]

1150deg is no where near dangerous. IMHO. If you are worried about air flow to the bigger turbo. Take the intake tube off then test drive again. See how much a difference you have. If there is alot then you might want to put a K@N in the box or put a open aftermarket filter straight on the turbo compressor housing.

I understand this is only for a test drive but are you talking about running without filtered air?

 

[cranetruck]

Yes, it has been suggested in other threads, but simply by removing the filter element and making sure the canister is clean...

 

[DaveP]

no offense meant here but this is not somthing that should ever be done. at least it wont happen on my trucks.

 

[jimk]

Air filter restriction can reduce airflow into the chamber/exhaust. Excess air is basically inert and can be thought of as a coolant. Some [diesel] engines may depend on it for safe EGT /chamber temp. Like those running max egt...

Outboard motors are (or were?) designed to run a lifetime with no air filtration because they run in a clean environment, like the garage/clean roads during diagnostic work. JimK

ps
http://www.bankspower.com/Tech_whyegt.cfm

 

[m-35tom]

your air filter monitor should be of some use here. i put a very sensitive vacuum gauge on mine with a dirty filter and got no reading at all. i wonder if ernie is comparing a ldt with low fuel rate to a lds with high fuel rate, it would be a big difference.

 

[cranetruck]

I get about 5 inches (10 to 15 cm) of water during moderate acceleration with a filter element that's almost new....
The "dirty air filter" monitor by the steering wheel is full red at about 20 inches of water IIRC.

 

[SasquatchSanta]

EO2NBCB Wrote:

OTR trucks will push 1200-1300 temps on long pulls. At 600 you shpuld be fine.

I shouldn't have brought up the 600 degree part of the post as it only served to confuse things. The 600 degree part was brought up to give a exampleas to normal, conservative "flat land" cruising produced.

My real concern was that on a hill the pyro can reach 1,150 degrees in a heartbeat. I was under the impression that 1,200 degrees was the danger point. Now I see that 1,300 is the cut off. This "might" partially explain how the typical military 5-ton can get away without having a pyro.

I still can't help but wonder if the reason that stock 5-tons are able to survive without pyros is because their lower gearing allows more air flow through the turbo thereby lowering EGTs.

Ken Wrote:

......If there is alot then you might want to put a K@N in the box or put a open aftermarket filter straight on the turbo compressor housing.

What is a K@N?

m-35tom wrote:

...how much max boost will it make? will the egt go over 1300 if you keep your foot in it?

I'll be able to tell you tonight. I'm getting ready to make another 100 mile run. I'll also have some fuel economy (or lack of) numbers.


jimk wrote:

Air filter restriction can reduce airflow into the chamber/exhaust.

This makes sense ... If air flow ratios are restricted, for whatever reason, it stands to reason that EGTs would increase. I "think" this could also be brought on by under reving because of too much load at too little RPM. What I'm saying is that, from an EGT standpoint, under reving doesn't necessarily mean lugging at under 1,600 RPMs???

For instance, if I can climb a hill @ 58 MPH, @ 2,300 RPM, @ 1,250 EGT it stands to reason, (correct me if I'm wrong), that if I attempt to climb the same hill at the same speed @ (58 MPH), @ 2,000 RPM (300 RPM lower) the air flow will be less and therefore the EGTs will be appreciable higher????

But wait ... Will the added available torque at 2,000 versus 2,300 enable the engine to pull the hill easier at 2,000 thereby cancelling out, or at least partially offsetting an increase in EGTs??? (See Attached LDS HP/TQ/Fuel graph below).

jimk --- Thaks for the link --- very informative

 

[joec]

1300+ is the number to worry about. Then the piston starts melting! 600 is normal driving.

 

[Westech]

I have my temp prob after my turbo and i will run it to 1000* all day and have not had a problem. I have shot it to 1200* a couple times and you can hear the engine start to labor a bit but i get off the gas and she cools right off. I would say you have nothing to worry about. I did install a huge K&N air filter and that seamed to help some on dropping the temps.

 

[jimk]

After upgrading the LD with a D turbo I found the high EGT at lowest rpm. The 9??AM post (below) expressed the findings/reag then, and some adjustments.

http://www.steelsoldiers.com/index....pic&t=11992&postdays=0&postorder=asc&start=20

I have been driving commercail big rigs a long time, mostly Mack. The old U models had pyro gauges. They would also show the high egt's at low end of operating range, like climbing a hill. And -Only- then.

High egt can also be caused by fuel burning outside(beyond) the chamber. The exhaust system/turbo don't benift from the cooling jackets the chamber has. Jimk

ps
I have been using K&N filters for a long time. I currently have them on a Ram Air GTO and KZ650 (both stock replacement types). They are supposed to out flow everything. Unfortunately it seems( with some recent research) to be at the expense of poor air filtration. Poor, even when oiled as recommended. That is worring. I will be making some changes back to paper in near future. JimK