Bad News [Archive] - TheDieselPage.com Forums

rjschoolcraft

01-12-2005, 08:53

Well, it happened...

Apparently, the near melt-downs that I had with this engine prior to getting the EGT and ECT in check have taken their toll. I have a broken #8 piston. I also found a crack in the second main web on the passenger side front of the web coming out of the outer main bolt hole. This is a common problem and unrelated to the broken piston. Here are some pictures:

Broken piston

http://www.schoolcraftpowertrain.com/Pictures_&_Data/IM000739.JPG

Broken piston close-up

http://www.schoolcraftpowertrain.com/Pictures_&_Data/IM000740.JPG

Galled cylinder wall

http://www.schoolcraftpowertrain.com/Pictures_&_Data/IM000741.JPG

Front view of cracked main web

http://www.schoolcraftpowertrain.com/Pictures_&_Data/IM000743.JPG

Top View of web with cap removed

http://www.schoolcraftpowertrain.com/Pictures_&_Data/IM000745.JPG

This engine went over 158,000 miles total (224,000+ on vehicle). 54,000+ were without EGT or Boost gages...I now know that things were getting extremely hot. After getting the gages, I just drove like I had been for a while... I saw EGT go above 1500F several times. :eek: I finally decided that I better let up when EGT started to get ridiculous and that I needed to do something to correct the design problems that GM left for me.

I'm assessing my options. More to come.

[ 01-12-2005, 08:19 AM: Message edited by: ronniejoe ]

moondoggie

01-12-2005, 09:12

Good Day!

Hard to say anything, really. Sorry about the bad news. Please keep us updated.

Blessings!

Brian Johnson #5044

arrowheadracing

01-12-2005, 09:18

What a drag. I dont really tow , and if I do its only a motorcycle or two. But I dont have egt or boost gauges yet. My heaviest load is taking my son to school the last couple of months ( 2 miles each way ). So I dont think I am too bad, but after seeing that piston, I ordered my gauges today.

I would really be interested to build a new motor, with some different stratgies in mind and see what kind of performance and longevity it would produce. I was always under the influence that diesel motors last a very long time. But it doesnt seem like the 6.5 is in that category.

Good luck
Todd

rjschoolcraft

01-12-2005, 09:26

Todd,

This is where I was performance wise...until Saturday night.

6.5 Performance Thread (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=006650)

There are ways to build these things to make them stronger, I had just hoped that I wouldn't need to do it. In fact, I'm of the opinion that these failures were unrelated to the performance gains I've made. In fact, I think this would have happened sooner without the mods to get the EGT in check.

Now, I'm hoping to better those performance numbers. Is that the silver lining? ;)

gmctd

01-12-2005, 09:59

Really bad news, rj.

But, on a lighter side, that sure appears to be the same #6 piston I saw in QM's block, last month, with the #4 a close second.

He did a SMOH (single-cylinder major overhaul) in that recovery................ :rolleyes:

john8662

01-12-2005, 11:04

What were the symptoms prior to your tear down? Looks like another member joins the blown up 6.5 sub club, bummer man!
I don't know what to do with my engine either, I really really miss driving that rig too!

eracers999

01-12-2005, 11:10

I decided to go with the splayed caps as my choice to shore up the bottom end, i couldent come up with a better solution.

With mine there was a whole section of block broken out of no3.

Its funny we are both down hard, at the same time. Kent

Bigg R

01-12-2005, 12:46

Sorry to hear about your bad news Ronnie! Just out of curiosity,what year was the engine in your Sub? Were getting ready to tear into my brother's 98 dually for coolant usage! I hope the main webs aren't cracked and it's just a head gasket!!

Bigg R

More Power

01-12-2005, 13:03

Is that a "D100" on the bellhousing flange? If so, its an April 10, 2000 block.

Sorry you had this problem..... Looks like the piston swelled, grabbed the cyl wall, then cracked as the rod was forcing it up/down. The crown may have also been softened a bit due to heat during the event.

I like the idea of splayed main caps - especially for the post 599 & pre-11/2001 blocks.

MP

grape

01-12-2005, 13:13

we need a boom-bitch forum for everyone to post pictures of thier 6.2 and 6.5 engine failures. Mayber have a year end award for best explosion, or most destruction.

Jim P

01-12-2005, 13:22

Ronniejoe,

I would say that from the looks of that piston, that that was caused by more than just heat. It was also caused by running too much boost on an engine with stock compression.

Just a few months back you were saying that running 17 psi boost on a stock motor was not a problem. I believe this picture of your piston indidcates that it is a problem.

GMCHORSHAM

01-12-2005, 13:27

rj, sad to read about your piston failure.
After the 04 Rendezvous, I have been tracking your engines progress/performance, and must applaud your informative reports about the mod's.
What are your immediate plans??
Will you be doing a total engine rebuild or replacement.
Are we going to reading about an 18.1 comp engine that will boast an rj/jk combo tech rebuild, given the towing that you do(project motor).
Regards, Rod.

Mainous

01-12-2005, 14:09

Wow! My condolences. What were you doing when it let go? Please keep us posted as to whether this was the newer AMG block or not. It may make me go back and add that stud girdle as a bit of insurance.

rjschoolcraft

01-12-2005, 14:28

I really think that the damage was done three years ago... By this, I mean that I had several events where EGT was out of control...who knows what happened before I got the gages. I know that before gages, I would often downshift to direct thinking that this would keep the water pump and fan moving faster to keep the coolant temp in check. After getting the gages and driving in this same manner, I soon found out that this was conducive to extremely high EGT. The first engine (that was replaced under warranty) failed the #8 cylinder as well. The #8 seems to be the hottest running cylinder in this engine. I also ran the engine 100,000 miles before upgrading the cooling system. It ran hot a lot.

I've run at 15 psi and above for over 70,000 miles on this engine. All the other cylinders look great, so I really don't think this was associated with high boost. Besides, I've seen other pistons like this on other 6.5's running stock... I wouldn't be afraid to do it again, but since I'm here...

Plans are still sketchy, but I've been talking to Kennedy. I have ideas, we'll see what the future holds. Main caps, pistons... :cool:

The date code is D100 and as MP stated means April 10, 2000 (this is the casting date). This engine was installed under warranty in June of 2000. It must have just come off the assembly line when I got it. It does not have the Navistar logo.

I was towing my travel trailer when this happened. I had just entered I-57 in Southern Illinois. I accelerated hard up to about 65 mph...there was a semi coming in the left lane, so I held at 65 to let him pass. I then hammered down and moved over into the left lane. As I settled at 70 mph, I noticed a faint knocking, then a louder knocking sound. I let off and ducked back in behind the semi. When reapplying fuel, I looked in the mirror and saw lots of smoke. I knew I was in trouble.

My uncle and my 17 year old son came to retrieve me (and my two younger sons). My uncle has a 96 xcab long bed with 6.5...bone stock. He towed my utility trailer with my dad's 95 K1500 5.7 gas pickup on it. I used the K1500 to trailer my Burb home and my uncle towed my travel trailer home.

I was extremely impressed with that stock 96. It can do things that my Suburban couldn't do when stock. His truck is the reason I bought the 6.5 Suburban in the first place. He must have gotten a really good one.

rjschoolcraft

01-12-2005, 15:21

I've gone down and looked at the actual hardware again, and replayed the incident in my memory. I really think the piston broke before it galled the cylinder walls. EGT didn't get above 1150F on the accel and there was no prior indication.

When the first engine failed back in 2000, I'm convinced it followed the scenario of swelling then galling. It actually burned a hole through the side of the piston and through the rings. I drove this way for over 100 miles towing my travel trailer to get to the nearest dealership in Bismark, ND. It slapped and knocked the whole way.

I think this event started with a stress crack in the center of the piston as a result of one of the earlier extreme heat events. I think the mechanical properties of the piston were compromised making it easier for a crack to form. This is common in mechanical failures. Furthermore, I think this crack has been there for a while... A few weeks ago, I noticed that vapor was coming out around the dipstick while it was in the tube. I took the fill cap off and it was breathing heavy out the fill tube. I didn't want to think about a problem and had gone over on my oil change interval... I thought maybe the oil was just breaking down. Changed the oil and switched to Synthetic Rotella T as I usually do in the winter and the breathing seemed better. I then began to think about the CDR valve...maybe it was bad.

I've put on close to 5000 miles (and done another oil change where it seemed my oil consumption was up) since I noticed the heavy breathing. It was running so well, that I just couldn't believe that anything was seriously wrong.

Thinking about it now, I think the crank case was being pressurized through this crack in the piston causing the observed breathing and the oil consumption. I also believe that combustion was occuring on the bottom side of the piston...burning the oil as the hot combustion gases leaked through the crack. This caused the already cracked piston to swell and gall the cylinder wall.

As JD always says, that's my story, and I'm sticking to it.

Kennedy

01-12-2005, 15:22

This build will be interesting for sure! Who knows, maybe by the time Kent gets his mind made up I'll have a batch of pistons done... ;)

MikeC

01-12-2005, 19:47

For Bigg R,

Make sure you look at the heads really well. When my heads were recently pulled for coolant usage it was thought to just be the gasket at the rear of #7. I drove over to look at it and by the time I got there the heads had been wire brushed and 5 of 8 cylinders were cracked after a closer look.

Mike

rjschoolcraft

01-12-2005, 21:31

Jim P.

I wrote this in the combustion chamber thread:

Originally posted by ronniejoe:
See my comments in the other thread.

One time, I calculated the overall cylinder pressure ratios from compression and boost for my 21.5:1 cr engine and 18 psi boost vs. John's 18:1 cr engine and 25 psi boost... His pressure ratio was higher than mine. I don't think it really matters how the pressure ratio gets there... but it does matter what it is.

MP wrote about peak flame temperatures and cr in an article for the Power Project Truck series some time ago. I would think that should be born out in higher egt. I guess my question is, what about high boost and high compression ratio is inherently bad, if the overall pressure ratio is less than another application? This came from my 6.5 Performance thread:

Originally posted by ronniejoe:
Kennedy's 96 had 18:1 pistons and the big Penninsular turbo. He ran 25 psi at the Pull-Off. I saw that much when driving his truck solo last summer. Figure that pressure ratio at 2.7:1. Multiply that by 18:1 compression ratio to get 48.6:1 total pressure ratio and ~700 psig cylinder pressure(before injecting fuel). My truck running 17 psi boost gives 2.2:1 pressure ratio. Multiply by 21.3:1 compression ratio to get 45.9:1 total pressure ratio and ~661 psig cylinder pressure (before injecting fuel). I may be crazy, but I'm fairly confident things will be ok. Time will tell. By comparison, some of these Dodges and Duramaxes are running ridiculously high pressure ratios. Yes, there are big differences in design, but if an 18:1 6.5 can run 48.6:1 pressure ratio, why can't a 21.3:1 6.5 run at 45.9:1?

In all honesty, I'm more concerned about your modifications to the heads than I am about high boost (with intercooler, of course). I hope that at some point in the future you don't face a bunch of cracks...then have someone like me remind you that you said it was OK. ;) I really hope that you don't have a problem down the road, and I promise that I will try to be nice if you do. smile.gif

On edit: This is tongue in cheek, here... Please don't be offended by my attempt at levity to ease my pain. :D

In retrospect, I'm surprised that this engine made it as far as it did. I was convinced that I had ruined it on the way back from Yellowstone...less than two weeks after it was installed. I also blew all the coolant out of it in 2003 climbing out of Salt Lake City on the way back from California and got it really hot. Countless other times it was close to popping its cork. I think that I was just too late in doing the mods to keep it cool.

[ 01-13-2005, 08:57 PM: Message edited by: ronniejoe ]

eracers999

01-13-2005, 02:06

RJ:

Im curious to know if the rings were flaked out on the sides mainly the top one. All my pistons and cyl's looked good, the rings were flaked out on all 8.

Kent

ace58

01-13-2005, 03:05

As they say, I feel your pain, but the pictures came out nice. I am curious if the plates GM uses at the rear of the cylinder head, instead of a crossover connection, play a part in the rear cylinder over-heating issues. With so many others having problems, I drilled, tapped, and connected them with a tee and used AN fittings/hose to another tee in the rear heater hose. Good luck with the repair, I will be watching for progress posts.

markrinker

01-13-2005, 03:30

Bummer. Join the club... Good time to build another monster. Just don't tell the wife what you are about to spend!!!

eracers999

01-13-2005, 10:14

Couldent one in theory make the case that increasing cyl volume in a 6.5, like a 18:1, that creates the same cyl pressures via more boost as a 6.5 with stock compression say that it could be a softer blow, for lack of a better word??

Kind of like less of a hammering affect.

Kent

rjschoolcraft

01-13-2005, 11:31

I don't have the pistons out yet... I stopped after determining the condition of the block. I'll probably break it the rest of the way down this weekend. I've had other things to do and I have to install the updated front axle actuator on my dad's 95 K1500 tomorrow.

I've decided that at a minimum, I want to use Kennedy's splayed main caps and 18:1 pistons for the recovery. I also want the latest block... just don't know how to get one at this point. Any suggestions?

jspringator

01-13-2005, 11:51

I was hoping that you wouldn't need BOTH a new style block and splayed main caps. Since you apparently can't just buy a new style block, I don't know how you could do it, unless you rebuilt a rebuild! I was thinking about the "gold" rebuild with splayed mains from Diesel Auto Services. Has anybody used this rebuild? Would a new style block without splayed mains be a better choice?

Note that my block has not failed, but I have 177,000 miles and deem it prudent to plan ahead.

[ 01-15-2005, 04:44 AM: Message edited by: James Springate ]

gmctd

01-13-2005, 12:01

To expand on Kent's post - I believe it to be the space, or volume, between the piston crown and cyl head that is the determining factor for survival at higher Boost.
Lowering the CR, increasing overall area volume, allows the flame\pressure front to expand more rapidly, thus removing the main concentration of heat from that small Comet area, distributing it over the crown of the piston.

The cylinder-head bolt pattern would be the major cause for concern at high Boost, imo.

No such area is found in direct injection engines, where the combustion chamber is in the crown of the piston, allowing higher Boost and cylinder pressure.
The block, head(s), pistons, rods, and crank are also designed to accomodate the greater power output in those systems.

AndyL

01-13-2005, 13:09

Power by Design v2.0

With Ronniejoe and JK behind it, I can't wait to read it!

ronniejoe, sorry for your loss.

Jim P

01-13-2005, 15:24

Ronniejoe,

I kind of understand what you must be feeling right now. This past summer I had my flat bed trailer in tow with a tractor on it that weighed about 8,000 lbs. My son and I were headed to an antique tractor pull and this was going to be his first time to pull. He is 8 years old. We had to stop at a traffic light only a few miles from the pulls. Where I was stopped it is 1 lane but as soon as you go through the intersection it turns into 2 lanes. When we took off everbody was trying to get into the left lane to get around me because they thought I would pokin along. I just had to show them. After all I was headed for a tractor pull and the adrenalin was pumping. I was going through the gears and everytime I shifted I could hear the turbo make that sound that the semis make when they shift gears. (add a couple Tim the tool grunts here). Just about that time, I look in the mirror and I am leaving a huge cloud of steam. My first thought was that I had blown the motor. So I pulled over just a little ways up the road and the antifreeze was just pouring out from under the truck. I was going to call off the tractor pulls but the look on my sons face just would not allow that. To make a long story short, I called my wife and we went home and got the other truck and went to the pulls. The whole night all I could think about was my blown up truck. Even the whole next day, I still thought it was blown up. Two days later I checked it out and it turned out to be only the block heater had popped out of the block. What a relief.

Your problem could have been caused by the previous over heats but I personally would not run that much boost on a stock 6.5.

I feel like someone else stated, the increased volume of the 18:1 combustion chamber allows a little more cushion for the explosion when the fuel is ignited. Pulling tractors typically run compression ratios down around 15:1 and even lower to keep them from self destructing. Most pulling tractors have to be started with ether because the compression is too low to start. I have seen some that require 4 cans of ether to get it hot enough that the engine will run on its own.

At any rate, if I were you, I would not put another engine in your truck that does not have reduced compression .

matt-max

01-13-2005, 15:57

hey ronniejoe,

so sorry to hear of your loss (geez, sounds like somebody died!), but am encouraged by your commitment to make it work again.

and a tad concerned about the 15psi plus that the stock motor in the tahoe is pushing.....

matt

eracers999

01-13-2005, 22:13

Talking about previous damage, ill bet a lot of members can subscibe to this. Ronniejoe said that early on when he put guages in he discovered that he had redicules egt's, 1500?? Ok so when the boost solonoid fails, (witch mine had 2 previous failures in the 35k the engine had on it before i bought it) does anyone have any hard no's on egt with zero boost at full pedal?? Ill bet it would scare the pants off ya. And ill bet it has taken the starch out of a lot of good 6.5's. Our fuel injection system is dumb , by todays standards. Someone should come up with a small plug and play system that monitors data and has the capacity to put these thing in a limp mode at the first glitch of trouble.

Kent

joed

01-14-2005, 06:17

Actually, the EFI 6.5's (at least OBDIIs, like mine) seem to have a safeguard built in related to no boost and high intake air. I have experienced this a couple of times while towing and blowing off an intercooler hose, dropping boost to 0. Naturally the EGT shot up to about 1300 but then I saw it clip fuel as the EGTs backed off without me decreasing throttle. I was able to limp along a ways to pull off and fix the hose,

Joe.

slagona

01-14-2005, 07:59

Actually, if there is no boost or very little, it is very common for IAT to be in check (nothing to superheat the intake air temp). This means that the system will not go into "limp" mode. This also means that there is way too much fuel. Therefore excessive black smoke and excessive EGT's. There is no sensor for EGT's, so engine damage can happen in this situation. It takes the engine coolant much longer to get overheated than the engine itself. It will self-destruct before the coolant overheats if the EGT's are allowed to continue to climb.

joed

01-14-2005, 11:27

Interesting. I think in my case it may have been due to intake air as the hose blew off the turbo outlet so hot underhood air was directly feeding the intake (through the intercooler piping, just not under pressure). Luckily my coolant temps didn't get that high.

Joe.

rjschoolcraft

01-16-2005, 22:10

Finished tearing the engine down tonight...

Pistons #4 and #6 were cracked as well as #8. The other two had not "blown out" yet. These three pistons show indications of being much hotter than the others... which stands to reason. All show heat discoloration on the underside of the dome, but these three are much more pronounced. Much larger area of discoloration and deeper shade of brown to black in color. #4 and #6 showed no signs of seizing or galling at all... which backs up my earlier claim that the crack in #8 came before it grabbed the cylinder wall. I'll post some more pictures later.

With this new information, I will argue that exhaust temperature...not boost...was the root cause of this failure.

I can see no other block cracks with the naked eye. It does not appear that the crack in the second main web has propagated any further than what can be seen in the photo that I posted earlier.

When this engine was still stock, I would often cruise at 1350F EGT while towing my travel trailer. This was while only attempting to run 60-65 mph. I often saw excursions over 1450F... I admit, I stayed in it too long. This was my down fall. I did make it 160,000 miles, though.

rjschoolcraft

01-16-2005, 22:15

Kent,

The plating was coming off of some, but not all, of the top rings. I will post some pictures later. I also found plating coming off of the top half of the #3 main bearing... that is a puzzler. :confused:

Nearly all of the bottom halves of the rod bearings showed some distress or wear. Has anyone else seen this?

markrinker

01-17-2005, 05:02

Interesting.

I guess there is only one way to prove your theory, RJ. Build another one, crank up the boost as you like it, and 'let her buck'.

Only time will tell.

rjschoolcraft

01-23-2005, 18:03

Originally posted by ronniejoe:

Nearly all of the bottom halves of the rod bearings showed some distress or wear. Has anyone else seen this? Anyone?

By the way, the new GEP blocks are not available unless you buy a long block or short block. Turns out, GEP has an exclusive agreement with Franklin Power Products (Powr Bilt) to only sell to them. Since FPP is a remanufacturing business, they refuse to sell the block by itself because "it would put us out of business." I spoke with a gentleman from Powr Bilt and e-mailed a gentleman from GEP regarding this issue.

What a scam! :(

I will be using a block that Kennedy had on hand. It is a date code A100, so it is about 4 months older than the one that I just removed. The machine work is starting for splayed mains and other blue printing. Kennedy has some 18:1 pistons in the works and I will purchase a set for this build. I'm looking forward to the end product now!

Look for an article or two out of this. ;)

eracers999

01-23-2005, 19:19

Ronniejoe:

What ever you do when you send out parts for work, dont use usps. I sent my pistons to calico coatings in NC and they still dont have them yet, yes i am fumeing. When i get through this with my pistons i will be putting it all together, hopefully by sat. Im ready to get this done.

Kent

rjschoolcraft

01-23-2005, 19:25

Thanks for the heads up.

Sorry about your frustration! :(

Wheat Whacker

01-23-2005, 20:11

Your piston looks like mine only mine is stuck in the cylinder at tdc and the connecting rod tore away from the bottom of the piston on #5. When I disassemble it the bearings all looked good it had just turned 160,000 miles. And like yours I think my damage had been done before I bought it as the previous owner had pulled a fifth wheel trailer with it so I am sure the egt's an engine temps had been exceeded more than once.

dieseldummy

01-23-2005, 20:14

RJ, as for bearing wear when I took my motor apart the first time there was noticable wear on the bottom half of the rod and main bearings. Not sure why, but it was surely there.
Justin

john8662

01-23-2005, 21:00

RJ,

Out of curiousity, who is doing the machine work on your new block? I am mainly concerned with who is doing the work to modify the block for the splayed main caps. My 95 is dead right now, I am getting closer to pulling the engine and doing this too. I was considering a local shop for the main cap work, still have to contact them and find out if it's possible.

eracers999

01-23-2005, 21:08

John8662:

Cameron racing engines did mine, he has the tooling to do it, mine turned out real nice.
He does nice work, ive used him for years.

Kent

markelectric

01-24-2005, 06:17

Ron Do you want a block from Franklin power? I have a couple of inlaws working in management there. Might pull a string......

rjschoolcraft

01-24-2005, 06:35

If it can happen quickly, yes. As I said, John has started things in motion with the A100 block that he has, but if the work hasn't actually started, I'd be interested for sure.

I had planned to have Steve Schmidt Racing (http://www.steveschmidtracing.com/ssr_001.htm) do the block machining, but if I use the one Kennedy has, it will be done at his machine source in Wisconsin. I'm not sure of the name of the shop he uses. I will probably still use Schmidt for index grinding the crank and some other stuff.