searstractorfan
New Member
in my 93 6.5, How much is to much for EGT's? and how long can I hold a certain temp? I was told like 1100 degrees sustained but how long is sustained? Thanks!!!
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Max EGT and how long
- Thread starter searstractorfan
- Start date
Sustained 1100 till you run out of fuel. 1150 Aluminum melts. How accurate is your gauge, no really, how accurate? (Failure of the gauge as seen by black smoke and a safe reading will do damage.)
DB2's don't deliver much fuel, but, with boost issues things get real hot.
searstractorfan
New Member
The gauge is a bully dog and is prolly about 1 year old, its prolly been on for about 3000miles...the truck dont get drove much.... ive had 1200 degrees and sustained it for about 10 seconds and nothing funny happened, but i knew to back off cause i thought around 1100 was the safe zone..so somewhere around 1000 or so is the safe mark...ill try and shoot for that!!! thanks!!! boost issue will be resolved when I save enough up for the new ATT turbo!!!!
racer55
Member
Just to bring up an old thread.
Everyone uses these numbers as gospel and there is no reason not to.
But,though the majority of members live in the US-there are many from Canada and around the world.
Which leads me to-fahrenheit or celsius?
I expect the answer to be fahrenheit but almost no one adds that little detail when they post,and since most of the vendors of EGT gauges are over seas-the standard unit of measure is metric(noticed my gauge was marked out in celsius today).
I haven't run past the danger zone yet but could very easily have done so.
1100F=593C
Everyone uses these numbers as gospel and there is no reason not to.
But,though the majority of members live in the US-there are many from Canada and around the world.
Which leads me to-fahrenheit or celsius?
I expect the answer to be fahrenheit but almost no one adds that little detail when they post,and since most of the vendors of EGT gauges are over seas-the standard unit of measure is metric(noticed my gauge was marked out in celsius today).
I haven't run past the danger zone yet but could very easily have done so.
1100F=593C
great white
Well-Known Member
1100 Fahrenheit.
I keep egt's under 1050F.
My warning light is programmed to come on at 1050F and goes off at 1045F.
So I can drive all day long without looking at the guage, just make sure the little red warning light repeater stays off.
I only hit the light on steep or long climbs like look out pass, 4t of july, vantage, etc. Then, I just let my speed drop off. Never had to drop below 45-50 Mph to hold those temps.
Maybe push it to 1100 and a bit if I wanted to hold 50 ish mph....with the 34 foot bumper tow that is.....
I keep egt's under 1050F.
My warning light is programmed to come on at 1050F and goes off at 1045F.
So I can drive all day long without looking at the guage, just make sure the little red warning light repeater stays off.
I only hit the light on steep or long climbs like look out pass, 4t of july, vantage, etc. Then, I just let my speed drop off. Never had to drop below 45-50 Mph to hold those temps.
Maybe push it to 1100 and a bit if I wanted to hold 50 ish mph....with the 34 foot bumper tow that is.....
I may disagree with what I posted before. EGT may be a better use for load and combustion efficiency than 'protection'.
Combustion temps are hotter then exhaust temps. Air expanding cools it down so the peak combustion temp is higher than the melting point of aluminum. It cools off on the power stroke after combustion ends. So he melting point of aluminum is irrelevant. Timing, cooling, and altitude has a lot to do with how much EGT you can get away with. EGT is really to protect the turbo not a piston meltdown indicator. How much heat gets transferred to the piston without enough cooling is relevant. Too much timing can become pre-ignition and melt a hole quick.
After sustaining 1400 degrees EGT for 12+ min and still having a running engine I suggest there is no hard and fast number to use. Although the glow plugs sustained damage after repeatedly hitting 1400+ degrees the pistons were fine. (Glow plugs had surface texture of rusty metal.)
Combustion temps are hotter then exhaust temps. Air expanding cools it down so the peak combustion temp is higher than the melting point of aluminum. It cools off on the power stroke after combustion ends. So he melting point of aluminum is irrelevant. Timing, cooling, and altitude has a lot to do with how much EGT you can get away with. EGT is really to protect the turbo not a piston meltdown indicator. How much heat gets transferred to the piston without enough cooling is relevant. Too much timing can become pre-ignition and melt a hole quick.
After sustaining 1400 degrees EGT for 12+ min and still having a running engine I suggest there is no hard and fast number to use. Although the glow plugs sustained damage after repeatedly hitting 1400+ degrees the pistons were fine. (Glow plugs had surface texture of rusty metal.)
Edzzed
Member
I have hit 1400 on occasion and probably for 30-40 seconds each time if not longer. My engine is fine as far as I know. Maybe the water meth spray helps. I don't know for sure though.
great white
Well-Known Member
I find that if I leave my egt's too high for too long (1100 plus) it drives my coolant temps up to the 210-215 range without spray. Maybe a tick higher at times.
If I'm spraying, I can keep the coolant temps quite a bit lower and still hit the 1050-1100 mark. depending on how hard I push it.
Now personally, I prefer not to be riding along above 1100 and above 215 at the same time.
We all know how temperamental the 6.5 can be with temps, how hard it is for the cooling system to keep up and I'd rather not risk scuffing a piston skirt or worse.
Of course, each engine is a bit different and each driver has different comfort levels.....
If I'm spraying, I can keep the coolant temps quite a bit lower and still hit the 1050-1100 mark. depending on how hard I push it.
Now personally, I prefer not to be riding along above 1100 and above 215 at the same time.
We all know how temperamental the 6.5 can be with temps, how hard it is for the cooling system to keep up and I'd rather not risk scuffing a piston skirt or worse.
Of course, each engine is a bit different and each driver has different comfort levels.....
schiker
Well-Known Member
What they said a little differently .....
I have the philosophy of its a combo effect and you have to look at all 4 indicators (EGT, ECT, IAT, oil temp) to tell how much heat is being dissipated. Its hard to say what a hard limit is unless you know the overall situation. Loading and ambient temps play a big part.
For example 1100F EGT with ECT at 210F is worse than 1200F EGT with ECT at 195F. Still what is oil temp, IAT, and is radiator hot enough to engage the fan clutch etc?
You may be able to get away with one indicator high and sometimes 2 indicators but when all are high the limit is finer and could lead to damage if you push one just over the edge. While if 3 are cool 1 might be ok to push appreciably over the limit for a short time 1 -5 minutes depening on what other indicators start to do.
EGT is first to react usually and should key you to watch others more closely. Other indicators are telling you how well engine is shedding heat from combustion.
Sustained time would be long enough for other indicators to start reacting/changing or 1-10 minutes which ever comes first. Say if you are at 1100F EGT and ECT starts to climb from 195 to 205-210F then back out. If ECT doesn't climb (stays at 195F) and its cool and boost is ok then 1100F EGT is ok for a long grade of a couple/several minutes.
Does that make sense?
I have the philosophy of its a combo effect and you have to look at all 4 indicators (EGT, ECT, IAT, oil temp) to tell how much heat is being dissipated. Its hard to say what a hard limit is unless you know the overall situation. Loading and ambient temps play a big part.
For example 1100F EGT with ECT at 210F is worse than 1200F EGT with ECT at 195F. Still what is oil temp, IAT, and is radiator hot enough to engage the fan clutch etc?
You may be able to get away with one indicator high and sometimes 2 indicators but when all are high the limit is finer and could lead to damage if you push one just over the edge. While if 3 are cool 1 might be ok to push appreciably over the limit for a short time 1 -5 minutes depening on what other indicators start to do.
EGT is first to react usually and should key you to watch others more closely. Other indicators are telling you how well engine is shedding heat from combustion.
Sustained time would be long enough for other indicators to start reacting/changing or 1-10 minutes which ever comes first. Say if you are at 1100F EGT and ECT starts to climb from 195 to 205-210F then back out. If ECT doesn't climb (stays at 195F) and its cool and boost is ok then 1100F EGT is ok for a long grade of a couple/several minutes.
Does that make sense?
NVW
Well-Known Member
Makes sense to me.
Big T
Well-Known Member
Actually, pure aluminum melts at 1220 F and I thought that the type of aluminum alloy used in the 6.5 pistons melted at 1450 F, but nothing trumps the real world experience of War Wagon.
Combustion peak temps are what 4000 degrees F? Lots of factors prevent the piston from getting to the same temp as peak combustion temps. Like melting solder in a blowtorch - it takes time to do so. More time aka advanced timing the hotter the piston gets from exposure time.
Scuffing a piston happens when the oil gets too hot and fails (300 degrees conventional slightly higher for synthetic) the pistons run out of clearance and in my case directly caused when the defective radiator cap finally popped off and the colder but boiling coolant shock cooled the #1 cylinder. That scuffed and cracked the piston. It held up another 7000 miles before failing with oil samples in the red...
Lack of a TM, time to work on it, and a parts route to run all came together to push my EGT's through the roof. I would rather not have pushed it so hard. However in doing so we find the numbers are not fixed. Now the paint that turned brown under the carpet near the exhaust and heat coming off the firewall into the cab... Yeah we pushed the limits.
Scuffing a piston happens when the oil gets too hot and fails (300 degrees conventional slightly higher for synthetic) the pistons run out of clearance and in my case directly caused when the defective radiator cap finally popped off and the colder but boiling coolant shock cooled the #1 cylinder. That scuffed and cracked the piston. It held up another 7000 miles before failing with oil samples in the red...
Lack of a TM, time to work on it, and a parts route to run all came together to push my EGT's through the roof. I would rather not have pushed it so hard. However in doing so we find the numbers are not fixed. Now the paint that turned brown under the carpet near the exhaust and heat coming off the firewall into the cab... Yeah we pushed the limits.