Headgasket Finally Went

[Dirk37]

I will be pulling it apart again to see what happened and I'll post pics here when I get it apart. I've been busy and have been kind of depressed about it so I haven't worked on it very much.

Here's the whole chain of events from start to end what happened:
-Got the car stock with coolant in it about 4 years ago when I was 17
-Heater core exploded shortly after and had a bunch of coolant leaks I couldn't track down
-Fixed heater core but coolant kept leaking from random places
-Kept adding water and eventually the whole system was water
-Added turbo to car
-Ran water in the car for about 2 years. Went through 2 water pumps and 2 heater cores before I realized I was being an idiot and filled it with coolant
-Still had some leaks and overheated the car moderately twice when it got low on coolant
-One night my thermostat stuck shut at 130mph and the car got really really hot, drove it home with coolant spraying out the overflow
-After I noticed any time I boosted I'd lose a bit of coolant out of the overflow
-Continued to get worse until it would eject all the coolant any time I got into boost
-Compression tested and cylinder 1 was about 70 psi, all other cylinders fine
-Pulled heads off and cylinder 1 was confirmed bad. Leak across the firing ring into a coolant passage as seen earlier in the thread
-Had heads pressure tested and decked at the machine shop
-Cleaned block off the best I could with a razor blade
-Brake cleaned block surface and wiped it down with a rag
-Blew everything off of it with compressed air
-Chased thread holes, brake cleaned them, then vacuumed them out and finished off with compressed air
-Put new gaskets on dry
-Used assembly **** on head bolt threads and washers - I did reuse the bolts
-Torqued the bolts to specification in 3 steps with a snapon digital torque wrench and reassembled the car
-Turbo still blown up at this point and leaked a lot of oil so didn't really get into boost
-Drove it for about 2 weeks with minimal boosting, it did seem to get a little hotter than normal a few times but didn't think much of it
-Rebuilt turbo
-Boosted around for a day, now that the turbo was rebuilt it would boost creep to around 9 psi
-Did a pull to 80 mph from 20 mph, left a huge white cloud behind the car and coolant went all over the engine bay
-Started misfiring really bad
-Flat towed it home with my friends truck
-Compression test showed 55 psi on cylinder 1, all other cylinders fine
-Its been sitting in my driveway partially disassembled since then


Unless I'm forgetting something that should be the entire story. Or to answer your questions directly:

1) how did you prep the block? Scraper? Sand paper? Check for flatness?
-I used a razor blade perpendicular to the surface to scrap it clean then wiped it down with brake clean. Did not check it for flatness

2) did you coat the cometic gaskets with anything?
-I used "rock" gaskets from shosource installed dry

3) did you clean the bolt holes before installing?
-Yes, very thoroughly

4) use a good torque wrench?
-Yes, I used a snapon digital one

5) did the machine shop check the head for cracks? Did they deck the heads?
-Yes and yes. Pressure tested and decked

 

[itwonder]

I'm slightly suspicious of the assembly **** used on the head bolts, but admittedly, that's a WAG.

 

[Dirk37]

I thought that might be an issue too, but it blew on the same cylinder even though I mixed up all the heads bolts which I think rules those out.

 

[SHOtime-95]

[QUOTE="I've personally been in, worked on, tuned, and driven [and owned] several SHO's over 520whp.[/QUOTE]

How do you guys achieve that much horsepower without the transmission exploding and killing somebody?

 

[Shamwow]

I would guess that you have a cracked block or a warped deck.

Hoping you pull it apart soon and post up

 

[Dirk37]

Started taking it apart the other day, and holy crap this gasket was blown. I literally dumped coolant out of the turbo up pipe. There was also a ton of coolant covering the transmission that I couldn't figure out where it came from at first (You can see the pool of coolant between the two wiring harnesses). When I pulled the downpipe off though, I realized it had leaked out of that. More pics to come as I get it apart.

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[TimboSHO]

I don't have permission to view your media

 

[Dirk37]

Oops, should be good to go now

 

[Devin]

Hope your turbo is okay!

 

[RJ-92]

If only you had used head studs...

But seriously, all other things being equal, sounds like your head/deck interface is not perfect. If the same setup worked for some time, no reason it would have mysteriously failed immediately this time.

What do you know, noob?







Not on here much anymore. It is pretty funny now to see the "kids" telling the veterans how things should be done. :thumbs:

 

[Dirk37]

Well, the mystery has been solved. One of the headgaskets was defective. The firing ring got all crunched up instead of compressing flat which caused it to blow. Also turns out it was a different cylinder this time. I guess the rings on the previous cylinder are bad from getting washed down which is why it had low compression.

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[luigisho]

This is the Cometic gasket? If so I wonder if this is something that may be an ongoing issue.

 

[zoomlater]

From his post 81 above, are these Rock Auto gaskets

2) did you coat the cometic gaskets with anything?
-I used "rock" gaskets from shosource installed dry

 

[Dirk37]

They were actually from shosource. The gasket brand is "Rock"

 

[luigisho]

Yeah that brand has been around for a few years that I recall. I wonder if they are related to DNJ? Again I also wonder if there is a production fitment issue

 

[Dirk37]

They fit the cylinder and head perfectly, no alignment problem as far as I could tell. My coworker said it looked like the pistons hit the gasket, but the piston isn't even close to the gasket at tdc. It looks like the firing ring just didn't compress right and warped

 

[Dirk37]

Well I discovered the real problem. I completely missed the WOT Spark table. So I was running 30 degrees of timing at 8 psi at WOT. I didn't usually go WOT, so this explains why the car was super fast sometimes lol. It lasted for 2 years this way though which is pretty amazing.

 

[Dirk37]

Also I discovered the piston on the cylinder the headgasket blew was broken. Some of the others were a bit melted but weren't broken

 

[SHOdded]

 

[Toolman]

That would do it