Engine/Transmission (1998.5 - 2002) How long can you hold 1250 degrees?

[MHagen]

How long can you hold 1250 degrees? I thought you could continually pull that but now Im getting mixed mesages from people, so i come here to the experts. :-laf



I was driving up the rockys a couple weeks ago and I held my egts at 1250 for at least 10 minutes at a time multiple times over the coarse of 3 hours. Is this as safe as I thought it was? I thought that 1300+ was where I needed to be concerned.



Mike

 

[Vaughn MacKenzie]

I'm probably one you've heard saying be careful with 1250 but it depends on what engine you're talking about. 3rd Gen 600 series can take higher EGTs than 12v and non-HO 24-valves because of better piston cooling.

I've known of a couple guys with 24-valves melt #6 down at 1250F towing up grades. The first guy was Shooter and he was around 1200F when it happened, and figured it was because his gauge was off. Another guy (don't remember the handle) melted down on one particular grade he'd towed up many times. He always went up at 1250F, everything was always fine, but then one day he got bit at 1250.

1250 is probably OK if your pyro is very accurate. But at 1250 your margin of safety is almost nonexistant. If you have a non-HO or 3rd Gen I'd say 1150 is the highest temp to safely sustain indefinitely.

 

[WDimig]

that is the max. egt that cummins says you can run continously, i personally would be very weary of running such high exhaust temp for a sustained peroid of time, 5 minutes is more than enough to cause engine damage, and aluminum melts at 1220 deg. , something to keep in the back of you mind while watching that temp gauge, im sure you engine was getting really hot if you were running that temp for such a long time, i would not do thay on a daily basis, you engine is not going to last that long if you do, that is a really high heat cycle to be running all the time, something is going to fail sooner than it should.



wes

 

[chuckwilson]

Were is your pyro sender, in the manifold or after the turbo?????

 

[MHagen]

Were is your pyro sender, in the manifold or after the turbo?????

Its in the manifold.

 

[chuckwilson]

In the manifold before the turbo, 1350 Deg. for 60 seconds max. anything under that it will be fine. 1200 Deg. if at down pipe!!!!!!!!

 

[DCreed]

as i understand it the pyro reads all cylinders together mostly the last three and if u have a unmatched or leaky or rich injector especially on six which gets the least air. time to step to a bigger turbo or boost cooler

 

[RustyJC]

A stock HO engine can hit 1300 degF when towing, and most of them are running without gauges. I haven't heard of a lot of failures on these engines.



If one is running a box or programmer that advances timing, however, that's a different story. Advancing the timing will lower EGT but put more heat into the combustion chamber components. That's because injection and combustion starts earlier (in terms of degrees of crankshaft rotation), so more heat is extracted from the combustion event before the exhaust valves open. With the timing advance from the Edge EZ, I limit my EGTs to 1150 to 1200 degF when pulling heavy up long grades and haven't had a problem, but I'm an old man and don't like the thought of having to walk home! :{



Rusty