Blown Head Gasket
 

I was driving on the expressway today doing about 70-75 when the head gasket suddenly blew on my engine. I pulled over and the oil was about 5 inches too full on the dipstick and the radiator had nothing in it.

I'm wondering what damages I should be looking for. I plan on pulling the heads first then deciding on pulling the whole block or not. I feel that I may need to pull the whole thing as it dumped all the coolant in, lost oil pressure and then locked up from 3500 rpm's in less than half a second.

What do you experts think?

Yep, pull it. If it locked up I would be looking at the bearings. Not good!

Head gasket / Pontiac Gregg
 

You caught the motor in time, the bearings will be fine.Well, maybe not, I reread the post and saw the lock up part.
IF you are running 6X or 4X heads, they take a slightly shorter head bolt in a couple of places. Call me and I'll walk you through the details.

1-303-776-0877
Pontiac Gregg

Head gaskets don't 'suddenly blow'. Something caused it. From reading this , it seems you are telling the whole story.

how many miles since the heads have been off? were they retorqued?
Was the motor running hot?
Was it detonating?

First, I'd pull the plugs and then see if you can rotate the motor with a breaker bar on the crank bolt. It'll probably turn over. Do that first.
Then, depending on what happens above.
I'd pull the heads first and leave the short in the chassis. Drain the oil and look at it.
It is also hard to believe all that happend in under a half of a second.

1. The engine has just over 2000 miles on it. I honestly do not know if I ever retorqued the heads as I built this engine well over 3 years ago and I was only 15 at the time.

2. I only have the idiot lights that do work but the temp light was not on at all for the first 250 miles of the trip. Even while sitting in a gridlock.

3. I have never experienced detonation (not exactly sure what it would sound like), but I do not think this it was happening as the engine was running fine and making no odd noises.

I also thought that it was strange to happen so suddenly as from what I've read, usually people seem to lose coolant mysteriously or will have smoke out of the tailpipes. It never lost and coolant and I had nothing unusual until all at once I had loads of steam out the back and the oil light came on almost in the same instant the steam started. As soon as I saw the steam and the oil light, I pushed the clutch in and the engine stalled immediately and when I pulled over and popped the hood and checked the dipstick, it was already quite a bit overfull.

I'm running 7k3 heads on this engine. The bearings would not be too big of a deal but I'm more worried that the sudden nature of this may have damaged the rods or pistons as they were factory pieces(not too strong from what I read here). Thank you for the offer of help, I may take you up on that once I get around to taking it apart and see what damages there are. I guess I'll be making good use of the 3day weekend..

My timing cover corroded, which had a similar ending. You might consider this possibility before pulling the heads. Do you remember if your timing cover was pitted when you built the engine or is there a chance it corroded through? I hole there will fill up the crankcase with coolant very fast. Seems like a blown head gasket would look like a relatively small leak, and it does seem odd it would be able to fill the crankcase so quickly.

I also gave this some consideration but I do not think this was the case as I had all the smoke out the tailpipes which means it was getting into the combustion chambers somehow. Also add in the fact that it stalled out and the starter wouldn't turn it much at all which I think it could still turn over if just the oil pan had been filled.

Ya, the white smoke would only happen that way..

Maybe it didn't turn over just because it was hot... have you tried cranking it again cold?

Hope it has a good ending for you. Post an update when you figure it out.

With all the coolant getting into the engine it is quite possible the engine hydro-locked just as you shoved in the clutch. As Steve said, pull the plugs and see if it will rotate and how much if any water comes out of the plug holes.

Stewart

So far its only bad news. I pulled the plugs and tried turning the crank bolt. Will not turn either way, its locked up solid.

Also it looks as if there was a collision in #5 as the spark plug was damaged and hard to remove. Ill post a picture of it.

So now it seems that I'm going to be removing the engine for sure.

Valve came apart.
 

I started taking things apart today and I knew it was going to be bad when I removed the valley pan to see that the camshaft had broken into 3 pieces and one part is wedging the crank. I also noticed pieces of piston and rings up in the valley cover. Not good.

When I took the drivers head off, I saw that the #5 exhaust valve had broken (factory 2 piece valve I'm assuming?) It seems that when it came apart that the piston completly obliterated from the rpm's I was turning at the time, and all the coolant came in because the wrist pin dug a hole in the bore.

Complete destruction of the block. Looks like I'll be in the market for a new engine.:(

Picture 1 shows the broken camshaft

Pic 2 shows the valve head missing. (chunk of metal above the chamber is a piece of the piston that was stuck where the valve should have been)

Picture 3 shows how none of the piston was left on the pin.

Wow, that's the worst kersplosion I've seen in awhile. Do you think it dropped the valve first, or broke the cam first?

I'm thinking that the valve just broke first. I'm not really an expert though.

As my dad told me, when I break things, I know how to do it right..

At least you didn't blow the head gasket.
:eek:
:D

What brand of plug is that?

lol.

Its an AC Delco plug. the numbers on it say R45TSX

A very small consolation, is it not?

Stewart

The only thing I don't understand is that it made no odd noises at all. The smoke happened, then the oil light when I pushed the clutch and it stalled. Did not make any racket of breaking parts at all. Unless my exhaust is too loud to hear it? My radio was off at the time.

I'm very sorry to read of the loss of your motor. It having only 2,000 and no gauges means-

1. something was not put together correctly
2. things were not monitored correctly

I don't want to rag on you so do not take it the wrong way. I'm posting to help, not hurt.
This is something you need to learn from.

Valves do not normally come apart. Cast pistons will disintegrate and often take the motor with it when something hits it or during detonation. If you had forged pistons, the damage would have been minor.
Cast pistons act like glass. They are durable to a point,then, when pushed beyond their limits will shatter like glass as your did. A forged piston can absorb punishment. If your valve came apart, the forged piston would usually absorb it with damage but, would stay together.
Were these used cast pistons? If so, you were taking a big chance.

ALWAYS re torque head gaskets. The center bolts especially come loose over a short time. A few thousand miles was a good indicator.

Learn from your mistakes and do a smarter, better engine build. This has happened to me and , I am sure many others. It's a bummer to say the least but, you have to learn from it and move on.
Very sorry to see what happened to you.

sorry for the double post, not sure what happened....

Such a catastrophic failure is very uncommon and needs to be studied. I've hurt a LOT of Pontiacs in my years but, never broke a cam in 3 peices.
How much oil was in the motor? Study this teardown carefully. Something is very wrong for this to happen just chugging down the hiway. Are you sure you were not running it hard? how much rpm? etc.


From the pics I could not see much block damage but it the cam is broke it is probably too far gone. Otherwise, you could sleeve it and save it.
Here is your pic of your head. I circled some things.

First, what is that foil looking thing near where the push rods go?

Second, I circled the area where you and all others would be wise to drill a cooling hole at. Use the gasket as a template and it already has the hole there. Also add the hole in the deck of the block too. You need to practice because the bits tend to stick and break at the end. Do it slowly using oil and good quality drill bits. Use a center punch to start and practice on the junk block.
It will help cooling in this hot area between the 2 exhaust valves.

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That chunk of metal was the biggest piece of piston I could fine. It was stuck where the valve head used to be. I know I should have forged parts but all I could afford when I got this engine was a used original running engine to get the car moving.

I'm going to guess and say that you'll find another rod has come lose and caused all the carnage you're seeing now, especially with the cam being broke.

And just looking at the beating the head took, you're exhaust is WAY too loud to have not heard anything. In a vert with the top down, wind roar could've muffled it a bit.

I'm with Steve and the others. I've never seen such drastic failure like that so quickly. I would venture a guess that your exhaust may not be too loud, but if you were doing 3500RPM on the highway with the windows down it can be pretty loud. If a rod were to let go or valve were to just drop at high RPM, I can see the damage being quite catastrophic very quickly. I don't think a leak in the radiator\timing cover to block or head gasket would cause such drastic failure so quickly though. Likewise, if it was something that was happening over time (failing bearing) it may be difficult to have heard ("rod knocks" are often not very loud until right before they go) to someone who wasn't expecting it.

Top down, loud exhaust, and my trans that is grinding itself to death may have kept me from hearing the problem before it became this bad. Well there's nothing I can do about that now so I made a plan yesterday.

I search craigslist and found a 400 for sale that was running and driving in a car. I went and looked at it this morning and it was a 1976 2 barrel 400 out of a Catilina. It fired up and ran smoothly so I decided to buy it for $350. I'm going to clean it up tomorrow and put it in with the muncie that I was originally planning to swap in this weekend.

I know that everyone here would tear the engine down and get it machined with the good parts so I don't ever have a similar failure, but I can't afford to build an engine that would cost as much as I make in a year only working part time. I'm just hoping to be able to drive the car, I don't need it to be fast.

The only thing I would do is put a 4 bbl intake on it.

Did your other engine have a 4 bbl on it?

That's the plan. I have an edlebrock with a qjet on the old one, but I also talked the seller of the engine into "giving" me an oem 4bbl today because I've read here many times that the factory one is better than the low line edlebrock. I also don't like the look of the edle either. It was his discount because I had to help him pull the engine.

I was going to comment that if you were going to re-use the same intake on the new engine, be sure you clean out the manifold. I have seen bits & pieces of rings & pistons get sucked up into the manifold & cross cantaminate parts into other cylinders. That said, the price is pretty good for a complete running 400 motor. Make sure everything is clean before assembly. Make sure no old gasket material/dirt/debri gets in the mew motor. Go slow & double check everything & it will be fine.

Funny that you should say that. I had no idea at all how all the cylinders on the other bank had little bits of piston material in them when the pistons and rings were fine on that side. It would have been bad if you hadn't mentioned that and I wasn't going to use a different intake.....

Can you post pics of the valve?

I would like to see where the valve broke.

I second Steves cooling mod, adding the coolant holes in the heads and deck. I had excellant results.

Sorry to see your engine is destroyed.

I'll get pictures of the broken valve maybe today.

On the other hand I got the car running again on monday. It runs smoothly but I'm not sure how 170hp is going to suit me.:)

valve and camshaft pictures
 

I finally tore the engine apart today. I found that none of the rods had broken, just the camshaft. Anyone know what may have hit the cam to break it into 4 pieces?

But the valve broke right above the head. That's where I'm assuming they are welded together at?

Also should I just throw all the engine pieces away? Or could the crank or block still be good?

Well whatever happened,almost certainly the last thing that happened was the cam breaking,as after that,no way the engine runs for even a single moment more.

It can infact run with no piston in that one hole,but snap the cam and it's dead.

What did the valvetrain pieces look like,where were they found?

I seriously doubt the piston 2 valve collision caused the cam breakage,the pushrod would have twisted like a pretzel before that happened,that or the rocker arm or rocker arm stud would have broken.

So,IMHO,the cam broke for some yet unknown reason @ this point,like maybe a lifter somehow got out of it's bore and got wedged between the cam & the block somewhere.

But we need more intel on the valvetrain to deduce what the chain of events might have been,nothing is too superficial in this sorta deal.

We need to see ALL the debris,all the tiny bits and pieces.

Often the smallest pieces give the biggest clues.

:2cents:

BP.

You're secretly Gil Grissom, aren't you? Or wanna be? ;) :D

Stewart

I dunno,maybe? :confused2

But I sure do enjoy trying to figure these sorta things out. :Ithink:

And I REALLY like to check out engine carnage pics. :hooray:

It's just too bad that they all too often come at someone else's expense and frustration.

:o

I'm not sure if more pics could help as all the pieces are close to finely ground gravel but I can get more pics tomorrow maybe since you like them so much :D

You are probably right about the lifters breaking the cam.. The piece that fell into the crank, 2 of the lifters would up in the pan. Other lifters were damaged, physically broken, not wiped. Only 1 pushrod was bent and it came from the broken valve. Maybe the valve hit the piston to break it and that bent the rod?

Again, does anyone think the block or crank are any good? If not they are going to the scrap metal guy tomorrow night. He would love to have a few hundred pounds of metal from one house...

I thought "too bad" was when it happened to you. Isn't that what people say? Oh, wait, that's what you did. Sorry, my bad! :(

Stewart

Yeah,I dont care that much when I break my own stuff,not as long as I get the fun of doing so!!!

I expect to break stuff,I'm pretty hard on my cars by most standards.

Only time I dont like breaking my own stuff is when I break down somewhere unintentionally,and that turns into a major nightmare,but usually it just means a tow home,which is NBD to me.

:2cents:

When you guys say to re torque the head bolts do you loosen them first or just see if they will tighten back-up to the wrench setting? I've redone mine several times and not loosened them and they seem to all be at the spec ed setting. As in the wrench just clicks at 100. None of the bolts have moved at all. Should I loosen them and come back-up in increments?

I'm interested in this explanation also..

Charles

NO!! Dont loosen, just retorque to specs.

You obviously didn't see my post about the catistophic failure of my 455 last fall.

Wow, that looks very similar to my pile of parts except that I didn't break any rods.

I quizzed my local Pontiac engine guru who has been building race engines since the 60's about the scenario here. He said he has seen a few ponchos break the cam before, but it was "very difficult and rare". The few times he observed it, it was when someone forgot to install the eccentric on the front of the cam, and the cam walked around in the bore and caught another lobes lifter causing an immediate jam, cam failure, and then rod/piston damage due to cam pieces.

Just passing it on...

Knowing your location and such,the guru must be Barney Moravits.

He does know his pontiacs,been building 'em for years.

His observation is pretty on point,could very well be a part of what happened here.

:2cents:

BP.

Yep, good ole Barney! :)

The eccentric seemed to be on just fine when I removed it. It had gone those 2000 miles with no fuel issues ever, and I'm not one to be afraid to bury the go pedal.

I would be more inclined to believe the guess that maybe one of the lifters that came out jammed into the cam and shattered it.

Either way, the new engine runs great, but it sure is slow. That 170hp that is 33 years old is not as fun as the old engine.