Aaannnddd POP!

[F-127]

Well, by the title of the thread can you guess what happened? Between the extremely loud pop and white smoke out the tailpipe it might be enough of a clue. I also had projectile mystery(well not really a mystery) material in the engine compartment, only found one piece, good chance its my problem.








Head gasket anyone?

[907DAVE]

Wow....had me worried there for a minute.

That sucks man, but its not the worst thing that could have happened.

Any coolant get into the cylinders?

[F-127]

Yeah I guess I could of had projectile engine block material, so its not the worst scenario. It blew out right at the back of the driver's side head. I'm kind of amazed at how that gasket made it from there up above the A/C line. Head is still on, but I'm guessing there was coolant that made it to the cylinder just from the smoke out the tailpipe, the rest of it just poured on the ground.

Engine kept running, it was a definite POP when it happened. It was the first real WOT run with the pickup and current setup, as I was usually satisfied with performance at half throttle or less. Comp 910s were waiting to be installed so I though I might have lost a rocker arm as well but they all checked out. I had just changed the oil after hauling a smaller tractor on a bumper trailer. I went to unhook the trailer and then only a few miles before putting it down. Probably about 10 minutes from the oil change... I did not even THINK of it being a cold engine with such a recent oil change and possibly cooler oil until after it happened. I'm not sure if that had an effect or not.

Pretty full day of work at the shop, so it'll probably be after hours before I dig deeper. Might hear from me late tonight.

[F-127]

Update time, I knew that headgasket at the back of the cylinder head had blown out, so that's the first picture, #8. Star pattern from some too advanced timing? Its really the only cylinder with a definite pattern.




Prior to head removal I had noticed that the gasket had also pushed out slightly on the front cylinder of the same bank, #2. There is a very minute star pattern, I can only see two "points."



Figuring I've been flirting with disaster running new stock springs(supposedly around 20k since replacement), yes its true. Everything looked fine in the valvetrain when removed, but I'll be taking a much closer look.





Figuring on stock headgaskets with new ARP or H11 headstuds, probably throwing on a 68/74 modded H2E and turning down, knowing the high HP that the sledgehammer would provide is kinda out of reach with fresh headgaskets and the local street diesel class is 2.8 anyway. Going to check piston protrusion on 2 and 8 compared to the rest. Had the 910s to install for a while now, just didn't think I'd be doing it with the heads off. YAY! Can't really justify a complete engine build quite yet. Need a few more $$.

[cleatus12r]

Originally Posted by F-127

Update time, I knew that headgasket at the back of the cylinder head had blown out, so that's the first picture, #8. Star pattern from some too advanced timing? Its really the only cylinder with a definite pattern.

That'll buff out....

Sucks to see it but as Dave pointed out, it could have been worse.

[F-127]

Picture time, once again. Despite have quite a few 7.3s in the family and working on several others as well, it's the first time I've had a cylinder head off. In the process of getting the head real clean I noticed some machining. Anyone know if this is an OEM head surface? Supposedly rebuilt about 20k miles ago, so it could have been resurfaced sometime. With all the tractors and other vehicle heads I have never really seen anything like it, in fact I can lightly feel the machining with my finger. I've been taught that if you can feel something on the head or the block, it isn't clean enough yet. Unfortunately I can't really scrape that off... lol. Probably going to call the machine shop in the morning to get an opinion too. Might post on a higher traffic site like PSN, but thought if any vistors here could chime in that'd be great.

[TwinTurbo]

That ain't normal. Must be a high performance setup for extra gripping power so you don't blow head gaskets Did you put a straight edge on it and the block?

[cleatus12r]

You shouldn't be able to feel the machining marks from the end mill.....

Looks like someone had the travel speed set a little too high when they set that up on the milling machine.

[amcguru]

Originally Posted by cleatus12r

You shouldn't be able to feel the machining marks from the end mill.....

Looks like someone had the travel speed set a little too high when they set that up on the milling machine.

Agreed. I spent two years working in a machine shop and we would never send something out the door looking like that.

[F-127]

Originally Posted by TwinTurbo

That ain't normal. Must be a high performance setup for extra gripping power so you don't blow head gaskets Did you put a straight edge on it and the block?

Yeah I was hoping I found the dark secret in 7.3 performance to keep headgaskets from blowing, unfortunately not.
Block and heads checked out true with straight edge.

Originally Posted by amcguru

Agreed. I spent two years working in a machine shop and we would never send something out the door looking like that.

Yeah I had a hard time believing it was normal. I have seen many head surfaces, and my dad many times of what I have, and it was a first... over on PSN someone called it corduroy... lol.



Here's the plans, heads were resurfaced(needed about .005" to clean up heads completely, valve recession still good), New H11s, stock head gaskets, Smith Brothers pushrods, shimmed Comp 910s. Honed cylinders and re-ring with rod bearings. Modded H2E will be going on with Bean's brass up-pipes(pretty sure they've been leaking some since I got the truck, spoolup should be near instant compared to the sledgehamer. Even though piston protrusion checked out, I changed out the connecting rods after reading this post over on PSN about a person who had a nearly identical situation I did.

Originally Posted by golfer

*I* wouldn't chance it...ever.

cause *I* have personally pitched a rod that checked out dead nuts tits, was shot peened, checked for bend/twist & magnafluxed ...came out of a cyl that had popped a HG...went back in the same cyl...then came through the block in 3 months...and have seen the same over and over w/ customers who pop a gasket...THEN do studs, LOL...

then pitch a rod.

and arp's aren't on my short list for head studs...

One somewhat of a budget and but doing a decent amount of work I'd be kicking myself immensely if a rod ever threw. Feeling a lot better after changing them out. Should be up and running by Wednesday night I'm figuring.