Engine/Transmission (1998.5 - 2002) Burned up my engine today

[ThrottleJockey]

1800 degrees must not be excessive heat then! EGT and piston crown temps aren't the same either.



When I crack this ATS or this PDR 16cm2, I'll let you know. Then it'll be time for a set of J. R. Adkins Twins. I wish this stuff WOULD break!



Brian

 

[Gary - K7GLD]

"1800 degrees must not be excessive heat then!"



WELL, maybe not in small spurts in Indiana - but hitch 12,000 lbs behind yer truck and head it up a few LOOOooong Colorado or Sierra grades at those temps, THEN get back to us as to how it does no harm to yer components!



And perhaps you've forgotten the lead post that STARTED this discussion?

 

[ThrottleJockey]

I work for Quality Drive Away specializing in Fifth Wheels coast to coast and I am well aquainted with every significant grade in the US including the Rocky Mountains.



And as I remember it it was YOU who ventured off topic. It was cylinder pressure that blew my headgasket from advancing the timing.



Not excessive EGTs! As a Hotshotter, I'll roll up to Vail every day at 1300 degrees. Iv'e only broken ONE part in 90,000 miles. a stock headgasket, which is what this topic is about.



Brian

 

[Cliffman]

Well boys, it doesn’t look good. Pulled the head last night and turns out the top of # 6 piston is melted . Cylinder is gouged pretty good also. Still don't know what caused it. At first I thought it was a bad injector that was over fueling but now I have a new theory. The day before our trip I pressured washed the engine. As always I covered all vulnerable components with plastic except the Pryo probe. I forgot to do that one . After I got finished I started the truck and all the gauges looked good but I think the pryo must have been off 200 degrees or so possibly due to water in the probe connection. Normally when there’s water in the connection I’ll get a fault code. Also, another little clue that the pyro was off; during the pull I noticed that the boost was 33 psi. I normally pull that hill at 29 psi. That’s the only thing I can think of. As always during a pull I watch my gauges very closely and I know I didn't hold it over 1350. I may have spiked it 1 or 2 times as high as 1385 but quickly pulled it down. We had only been pulling hard for 2 maybe 3 minutes. I know one thing. I’ll never pull over 1200 again, just for a safety margin incase of gauge error.

 

[Sticks]

Originally posted by Cliffman

Well boys, it doesn’t look good. Pulled the head last night and turns out the top of # 6 piston is melted

OUCH!



So now what, rebuild, or crate engine?

 

[Cliffman]

Not sure at this point. Still pondering the options. Most likley pull the engine and through another pistion and sleeve and call it good or maybe things just might get a little out of control.

 

[Ramafid]

The reason I run a Blue Box is so I have no timing advance. Not saying timing was an issue here but I read somewhere that a company with a fleet of class 8 trucks was having problems with engine meltdowns. EGT's were in the safe zone but it turns out too much timing advance was melting the engines, not high EGT's. Something to think about.

 

[barepa]

Cliffman, I tosted my motor in aug same mo as yours, #6 melt down I have a 99, this motor had about 90,000. I was 53rd in june

and replaced it with low mile j yard motor,then melt down. ok I bored and sleeved

only #6 put std piston back in. I had a great machnise help me. I didn,t pull the crank or 1-4 piston. find someone who know what there doing. I have put 40,000 on just fine, its working good. but it still sucks the big one when its you.

by the way the 2nd motor a #53 to, just my luck

Dave

 

[Gary - K7GLD]

"And as I remember it it was YOU who ventured off topic. It was cylinder pressure that blew my headgasket from advancing the timing. "



Not sure where the "off topic" comment comes from - the discussion is major engine failure, and suspected high EGT. The engine is now down, melted piston(s) - do we still assume it was not due to or aided by EGT? *I* doubt it...



As far as KNOWING what causes a specific head gasket to fail, hell, they fail for a number of reasons, and I'd sure hate to bet the farm on any one specific reason, without pretty definite proof!



MEANWHILE, I, for one, will be a little more sensitive to EGT with my truck - it holds at 1200 degrees under the heaviest load - but might need to keep my RPM up a bit further up the power band to avoid problems - and THAT is the main value of these discussions, recognizing problems others have had, and AVOIDING similar ones ourselves!

 

[ThrottleJockey]

Number six melted piston? Man, that sounds like too much timing advance!



I gotta agree with Ramafid. Injecting the fuel too early in the hottest cylinder during a hard pull.



Pull the block and bore it 20 over and put some of those steel crown 2 piece pistons in it and zip her back up!



Brian

 

[ThrottleJockey]

Number six melted piston? Man, that sounds like too much timing advance!



I gotta agree with Ramafid. Injecting the fuel too early in the hottest cylinder during a hard pull.



Pull the block and bore it 20 over and put some of those steel crown 2 piece pistons in it and zip her back up!



Brian

 

[bmoeller]

What kind of shape are the piston cooling nozzles in?

 

[Cliffman]

I'm curious . If advanced timing causes a hotter burning cylinder then isn’t it still measured by EGT's? Isn’t 1300 deg's, 1300 deg's no matter how it's getting to that point???

 

[Joseph Donnelly]

Well, it can be hotter in the cylinder, and heat also builds up over time, especially if there isn't much cooling of the piston to keep it from swelling. How about if you have cyl 4 and 5 at 1150 and cyl 6 at 1600? The average you are measuring is 1300.

 

[Cliffman]

Joe, I'm assuming this sceaniro is just to prove a point and not real world #'s. Has anybody ever bothered to measure each cylinder? What is the melting point of the aluminum our pistons are made of and, is the rule of thumb "1350 max EGT's" an average based on that higher (1500 maybe) melting point. Curious minds need to know Joe.

 

[Cliffman]

Originally posted by bmoeller

What kind of shape are the piston cooling nozzles in?

bmoeller, we won't know til we pull the engine and the pistion and check it out.

 

[csutton7]

Dang it--Blair and I were talking about this yesterday and were, of course, hoping for the headgasket--this sucks---I think it was the pyro misreading--if you had more boost than normal when pulling that hill then you probably had more heat and that's what did it--- it sucks that is the bottom line---chris

 

[CFast]

What's your turbo look like? Did the piston just melt, or did it send chunks of metal into the exhaust? Sorry to hear about your engine. Sounds, to me, like the timing was off.

 

[Cliffman]

Visual inspection looks good. I'm sending the turbo to Piers this week to have it "Piresified" and we'll soon know if there is any damage.

 

[Gary - K7GLD]

What temp thermostat do you run - seems there was a DC TSB concerning swapping to lower temp Tstats if lots of heavy pulling was planned - apparently hot spots and steam cavities can be generated in those circumstances that vastly aggravate cooling the rear cylinders...