#7 piston destroyed itself on start up today, what happened here?!?!

[merlot566jka]

ok well i did a new master cyl and hydroboost last night. This morning I looked at the resiviour and it needed some more fluid to top off. I get in the truck, crank and hear a god aweful noise and it fires up making a bizzare ticking/metal on metal noise. I shut it down and started investigating. I took off the air cleaner and looked in the manifold, nothing broken or stuck in there.... I check the oil, no coolant or metal. I checked the rad to see if it was smoking....nothing.
I pulled the intake manifold, looked in the ports with a flashlight....nothing. little oily but everything looked ok.
i fired it up with the intake manifold off, and to my suprise exhaust started coming out of the #7 intake port. it was loud and the knocking got softer. I thought ''what the hell could cause this? did I just loose a keeper or wipe a cam lobe?''
Knowing there is some serious damage and a long road ahead, I got a buddy to give me a ride to work for the next week or so. Then I started tearing it apart.
I got the injector lines off and the valve cover, #7 ex spring was a little loose and the intake wasnt as tight as the others aswell.
Time to rip off the head. I thought about an hr and Id have it off. Yeah right. exhaust unbolted fine from the manifold, but the cooler lines and rear vacuum port slipped by me. oh and the dipstick tube. after a back breaking battle I got the head off and this is what I found.
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0796.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0797.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0798.jpg

http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0805.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0800.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0806.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0807.jpg

Now what the hell happened?!?!?!? looks like something fell into the cyl. but the truck ran just fine last night and it sat in the garage all night. Air cleaner was on and truck was locked. I dont think anyone got in my truck, and put somthing in the air cleaner. Nothing appears to have broken off and fell in. Glow plug tip is still on there. precup is still there....what on earth happened? it was about 60 degrees on start up, and everything was just normal. I am boggled.

I got a line on an engine that came outa a hummer, 40k miles and looks decent in the pictures. Im gonna have a look at it this week and may take next week off work and pop it in if i think its ok. I just cant belive my luck, I got new wheels friday night, new brakes saturday, and sunday the damn engine eats itself. What gives?

[DmaxMaverick]

Looks typical of a glow plug tip. If you aren't missing any, it could have been from a previous incident, miles (or years) ago, staying lodged in the pre-cup until now.

From the pictures, unless you find actual cracks in the piston, valves or head, it should be OK. I'd clean it up and put it back together. I've seen many run with worse. Likely, you won't notice it. If the pre-cup is damaged more than just a crack (can't really tell from the pic), it may need to be replaced. Cracked pre-cups are normal, as long as the cracks don't run across the fire ring. Either way, the piston and head doesn't look too worse for the wear. If the bottom end of your engine doesn't look any worse than the top, it's a better bet than an unknown.

[merlot566jka]

Looks typical of a glow plug tip. If you aren't missing any, it could have been from a previous incident, miles (or years) ago, staying lodged in the pre-cup until now.

From the pictures, unless you find actual cracks in the piston, valves or head, it should be OK. I'd clean it up and put it back together. I've seen many run with worse. Likely, you won't notice it. If the pre-cup is damaged more than just a crack (can't really tell from the pic), it may need to be replaced. Cracked pre-cups are normal, as long as the cracks don't run across the fire ring. Either way, the piston and head doesn't look too worse for the wear. If the bottom end of your engine doesn't look any worse than the top, it's a better bet than an unknown.

Seriously? That thing was blowing exhaust outa the intake. Its hard to believe that this thing could be bolted back together and run just fine!

It has had some blow by recently, so I think now is as good of time as any to replace it.

[DmaxMaverick]

The exhaust out the intake was likely the piece you removed lodged in the intake valve (your sig says hummer intake, so no EGR). Your heads look good, so there's no reason to toss them. The entire top end, except for the piston dents, looks cherry, from what I can see. If you are having too much blowby, it may need attention. But, I wouldn't toss it unless it was serious. Some dents in a piston is no reason to throw out a good engine. How do the valves for that cylinder look (can't tell by the pic)? If they aren't damaged , run it. Also, check the pushrods for that cylinder. If they're straight, no harm.

Your choice. But I'd run it, unless you find something seriously wrong with it.

[merlot566jka]

The valves look fine from the bottom.

The pushrods are fine, they roll on glass without a wobble.

The precup has a huge chunk taken out and its port is a little funny shaped now.

The piston is really chewed, but I saw no cracks at all. I have duty today (military) and wont be home till tues night. I will pull the valves all the way then and have a look see. Maybe I can get away with just one precup and a valve. I hope the seat isnt banged up too bad

[merlot566jka]

anyone else have some input here? I am on the fence about just throwing it back together....

[john8662]

Tough find...

The bores don't look bad on your engine at all, the pictures are actually pretty good that you'd be able to see the wear ridge on the top of the bore.

The head is likely ok, but I'd straigten out the pointed spot on the precup, possibly replace it if it's in danger of coming off (look like it might if flexed). The best case is to remove the valves and inspect, or take to a machine shop that can inspect them for you.

The piston is pretty beat up, and there is quite a bit of shrapnel left on the piston and rings.

If this one was mine, I'd pull it and find one used correctly sized piston (D, E, C) clean everything up and then throw it back together, after you know that putting it back together is not a waste of your time.

But, this all depents on what parts you have around, or access to. Anyone who rebuilds these engines can probably send you a used piston in decent shape to install.

J

[merlot566jka]

here is what I am afraid of, pulling a piston and repairing a head just to have the blow by I had before. I have gotten next week off work and I have one shot to fix this. Not to mention limited funds. Taking the pros and cons here are tough.
I can use my new injectors, lift pump, balancer, alt, ps pump and timing chain on the next engine. The engine I found was a take out from a hummer as seen here... http://seattle.craigslist.org/see/pts/1137885724.html

Replacing just a piston seems like a lot of work. And also the time spent with these heads at a machine shop may be more time than I have...and I have never replaced just a piston before, its usually the whole engine. It bothers me to think that I may waste my time repairing this when I had the oppertunity to pop in a newer engine.
That said, whose to say this engine is perfect? Its a hummer take out with less than 50k on it. It looks a little different than the civy engine by looking at the coolant cross over, ip and oil neck. I will look at it this week and try to get a compression test on it while I am there.
I just wish I had the money for a rebuilt engine, I have had bad luck repairing and buying used engines.

I reall dont want to put this back together, the noise it made...the smoke...the poor piston...it just seems like its given up the ghost.

opinions? what would you do with these circumstances and thoughts?

[john8662]

Don't bet on the pull out engine being good, some are good, some are really bad, no good way to tell, you'd have to buy a couple to get something decent.

I've done the one piston swap before, well, not too long ago with the newly acquired '82 6.2L. Had a cracked wrist pin and lost a skirt on one side, didn't do any other harm. I replaced one rod (pin bushing more worn than others), and one piston of correct size, and year.

If you've had a hammering piston, chances are it could have further damage, like cracked pin bore.

Lots of work if the engines got a lot of blow-by though, the one I worked on didn't and was otherwise fine (still is).

For this scenario, I guess I have to agree with Dmax, just clean everything up really well, remove all fragments from that cylinder, put it back together, run it while you find a better engine to replace this one. Even save this engine to rebuild later, perhaps...

J

[merlot566jka]

I hope it didnt do more damage, Ill check everything a few times tomorrow when I get back home. Ill rotate it by hand and look, listen and feel for any potential pison problems. The metal I found in the precup was pretty flattened out and by the looks of the head, it wasnt a hard metal. So maybe I will be lucky.

I think im going to do exactly that, I will use the dremel and try to reshape the chamber on the piston, clean everything up, remove as much fragments as I can, check the valves and precup the put it back together. I may try to smooth out the top of the piston to remove any high spots that may catch the extra heat, maybe even a slight polish.

If there is damage on the seats, can the valves be lapped, provided there isnt any gouges?

[6.5 Detroit Diesel]

I had an old ford with the 300 inline six. i mounted a huge filter on it, and the kit fell apart dropping a screw into the engine. it got into the one cylinder and pounded around, making it look like your piston and head.

cleaned it up and bolted it all back together and ran it for almost another year before selling it to get the diesel

[BigGun J]

That motor has been listed a number of times. It is no loner in the shipping crate and has been sitting outdoors wrapprd in that tarp. I bought a military take out for my engine swap. When I pulled the pan to replace with standard style I found O' so small cracks starting on the innner webs. My motor was supposedly tested and repaired as needed by a second hand party. I would not trust purchasing it asis for a reliable drop in. If the price drops to 100 bucks I would buy it for rebuild parts.

Jim

[merlot566jka]

wow! thanks Jim, that made my decision a lot easier. I am just took a $70 cab to Marysville to get head bolts and a head gasket, I have until 4 am to get it back to running. Or else I have no way to work

[merlot566jka]

And of course, guess what they forgot to put in the bag, the damn head gasket. FML

[merlot566jka]

http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0809.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0812.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0819.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0821.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0822.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0828.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0824.jpg
http://i26.photobucket.com/albums/c134/merlot566jka/DSCN0830.jpg


bent intake valve. will repost later with more details, time for work!

[DmaxMaverick]

That's a much clearer pic of the pre-cup. It needs to be replaced. While I would not have gone to such lengths to clean up the piston, it looks fine, as long as the edge of the crown has no metal beyond the original circumference. However, if you were looking at replacing the engine anyway, you could just throw it back together (with a new valve) and run it until it quits. It may run fine for years.......or not.

[merlot566jka]

Where can I get a precup? (pretty quick...) and will I need machine work for it?

[DmaxMaverick]

Any machine shop that services 6.2/5 heads/engines should have one. Be sure to replace the cup with the same series (according to the stamped markings on the face), and remove/measure yours for comparison of the replacement before you buy. If you don't find one local, several TDP Advertisers (http://www.thedieselpage.com/vendors/main.htm) can source one (and overnight it to you). Machining may be required, but not always. Depends on how it seats. I've been lucky, never having to machine a fit. A bit of lapping is all that's been required. If your head has been surfaced before, you'll will likely need to, again. If you are having a machine shop replace/seat your bent valve, they should be able to handle the pre-cup replacement.

[merlot566jka]

You're an incredible help! Thank you very much!

I am having trouble finding a pre-cup through the typical parts stores and gmpartsdirect.com. I had planned on putting the valve in myself, as the seat looks perfect, and the valve doesnt look like its ever been cut before...I was going on luck that I could buy a new valve and pop it right in with a little bit of lapping and call it good. Same for the pre-cup. I will call a few local diesel shops and see what they can do, even if its just throw me the parts and wish me luck.

Again, thank you and I will update when I get somewhere.

[merlot566jka]

Found a local shop, they gave me a used valve for free, we discussed the precup and piston, they said it looks fine. Just might want to take the sharp edges off. So I did just that, all I replaced was the intake valve.

This was yesterday at about 5pm. (I finished at about 7pm today, no sleep, lots of caffeine and nicotine!!) I went back to the parts store that forgot to put my headgasket in the bag, the manager argued with me and said he would have to verify that it was left out of my bag that night and that I would have to wait until his employee came in, because he wasn't going to call him at home. Needless to say I was furious. I called their cooperate office, they said I can go to the store and they will give me a gift card for the price of the head gasket. I told em to F' off. I went to napa and got the only other head gasket I could find, made by Victor Reinz.... It had a felpro part number, but Ive never seen that brand before. Who cares, it worked.
While I was in there, I added a new 6.5l valve cover with the cdr opening and used it as an additional CDR port. It seems the hummer intake doesn't pull enough vacuum to vent out the crank case at idle (well and that's with an open air cleaner too) I painted the valve covers with some red caliper paint I had laying around. Looked great! Until I got my grimy hands all over it.
I also re did the entire wiring harness and replaced the glow plug wires.
I got rid of the cruise control (temporary until i figure out if i can use the digi one with out an ecm)
I removed the EPR flapper in the exhaust manifold, And eliminated the EGR and EPR sol's
I cleaned my K&N filter
Flushed the coolant
replaced all the belts
painted some of the accessory brackets and the p/s res and a/c pump.
replaced the leaky oil cap.


When I picked up the head ad crawled into the engine bay i was pretty sure my back was going to give, and finagling that thing in there with the exhaust mani connected was not easy, i smashed my hands like 5 times and I am pretty sure I am going to need a wheel chair!
Things went well putting it back together, EXCEPT a bolt for the drivers valve cover broke in the head and i left it there thinking it would be fine. Guess where its leaking oil from now?!

When I fired it up, it took some time to get fuel back in the lines and get the air purged, but once It fired up, it was smoking bad from the side I had just replaced the head on. I was thinking ''Great, I didn't fix a damn thing!''
I used my hand to feel the manifold to see which cyl it was causing the smoke, it was 3 of them, they were really cold compared to the other side and adjacent one. I cracked the fuel lines a few times and got some hissing out of them, but it didnt fix it completely. I was going to let it warm up to operating temp while in the garage but the smoke was killing me. So I took it for a drive. Once the truck warmed up and was in stop an go traffic, the white smoke stopped and when i put the pedal down I got a little black smoke.
I then went home, found the leaking valve cover and said 'screw it, I am done for today' (anyone know how to take off the valve cover without oulling the injector lines/? ( it would be easier if I didn't have the hummer intake manifold....that thing just doesnt bolt up easily.)
The truck feels more smooth and is a little more responsive. The headgasket I removed were aftermarket, so maybe those are newer heads

anyways, its up and running, just a few little tweaks

and I am exhausted. I am getting old when I cat pull a 48hr working on cars shift!

Thanks everyone for your help!

(oh and It started to pour rain as I went for a test drive, and the valve cover bolt....you guessed it, ended up in my tire. So it was raining cats and dogs and I was trying to stab the tire with plug and keep trucking.

well I am going to bed folks.

[DmaxMaverick]

Wow. Thanks for the update. Sounds like you've had a week worthy of a TV sitcom. I've had a few of those, so don't feel like you're completely alone.

You can remove the valve cover after "tweaking" the lines out of the way. I don't recommend this as a normal course, but I've done it out of necessity (and lack of time). If at all possible, loosen the nuts at the injectors to give a little more flexibility (then, don't forget to tighten them, after). Just be sure you don't bend them more than necessary, or at tight angles. Make sure the fittings/nuts are properly lined up (absolutely square) with the injectors when it goes back together, and it should be fine.