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Topic: Cracked Head (Read 5472 times) previous topic - next topic
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Cracked Head

Here's what I've been doing for the last couple of days (nights) instead of reading about audio compression.

http://as220.org/mobius/cracked.head/

I guess those few -9 degree nights have taken their toll on my poor engine.  It was actually running well right up until I started to rip it down.  Notice the thick mustard goo on the inside of the valve cover and intake manifold.  What a mess.  Watch out for those icicles hanging from your tailpipe.  It can only mean one thing.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #1 –
Nothing says fun like a pushrod V6  . What type of car / truck is that? There are no cars made in the US today that have 12 valve V6 engines w/ RWD if I remember correctly. Im guessing by the wheelwell in the mustard.jpg pic that its a truck....

Cracked Head

Reply #2 –
'89 chevy full size pickup with 185,000 miles.  The engine is a 4.3L V6.  GM calls it a "Vortec."  I would have considered looking for a new vehicle had I not just put a cat in and brakes/rotors/drums/cylinders three months back.  I also put the engine in last may.  Not ready to draw the line on it yet.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #3 –
Those old S10s are fun to drive  - I've driven my cousins (89' just like yours, 4.3L, RWD) - burned out across 4 lanes down in Flordia  - lot's of torque. Have you had any problems with a sticking throttle? I hear it's common on the older S10s. As for the engine, it shouldn't be a problem getting parts for it at a junkyard since the 4.3 was used in the Blazer / S10 / Silverado / base model Caprice among other cars. Good luck - that engine bay is a hell of a lot easier to work with than the one on my Taurus  .

Cracked Head

Reply #4 –
Number 5 is the bad one.

Actually, mine is a full size truck so even more room to work on them.  If it were a V8 I'd probably be less likely to do this kind of a teardown.  I don't know.  It's a friggan pain either way.

The astro/safari vans all have the 4.3s as well.  There are plenty to choose from.

Looks like I may have lucked out on the crack situation though.  These gaskets are TOTALLY shot.  They practically fell apart when I peeled them off.


edit:  number 3 to 5.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #6 –
parts should be beyond easy to get, it's just a chevy 350 with 2 cylinders chopped off, after all.  I think there are a few 350s around.

edit - well, except for parts of the block itself, obviously

Cracked Head

Reply #7 –
Uh, I gotta question for you guys.  Where did you learn your car knowledge (especially you ViPER1313)?  Cars are one of the things that interest me, but good online resources are difficult to find (which is how I often learn things, like going to Tom's hardware and Anandtech for computers).

I find it ironic that the same guys I know that know cars, envy my knowlege of computers, when I do the same about cars.

Anyways, to show off the knowledge that I have, I recognize the two valves per cylinder on the head face picture, but I have no idea what I'm looking at with the intake pics.  Also, WTF happened to your #5 piston?  I've never cracked a head so I'm not sure what a cracked head can do to a piston.

Sorry to be such a n00b on an off-topic post.

Cracked Head

Reply #8 –
what I think happened is the head cracked and the coolant got into the combustion chamber and that's what the rust is from. Also the 'mustard' is oil and coolant, if I'm not mistaken.

Cracked Head

Reply #9 –
Quote
edit - well, except for parts of the block itself, obviously

I was going to say...  I suppose if the bolts lined up I could cut the extra cyclinder off with a hacksaw.    Alas, the heads are fine, AFAIK.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #10 –
Quote
but I have no idea what I'm looking at with the intake pics.

The intake pic is of the underside of the intake manifold, which is aluminum.  I put that one up to show off the gunk.  Some of the stalactites hanging off were almost an inch long!
Quote
Also, WTF happened to your #5 piston?  I've never cracked a head so I'm not sure what a cracked head can do to a piston.

In most cases it steam cleans the piston head.  That is, before water destroys the rings due to its poor lubricating properties.  In my case I was lucky.  The heads weren't cracked.  The gaskets were seriously rotted.  Cyclinder #5 was lightly sipping antifreeze- enough to make a puff of steam come from the exhaust, but so little that all six were firing just fine.  Water in the oil can do harm if not properly vented.  I've heard of people destroying their main bearings that way.

The whole thing came to my attention when the engine suddenly started overheating.  It had plenty of antifreeze and the system wasn't leaking.  I realized that with each stroke of the piston a little bubble of gases would puff into the water jacket, and it would take a drink in the other direction.  The gases would build up in the top of the engine around the thermostat.  Gas doens't have the thermal mass of liquid so the thermostat wouldn't open and you'd sit and boil.  The logical thing to do was take out the thermostat, pop out the valve in the radiator cap so the system could burp, and put some cardboard in front of the radiator so that I could have some heat on those 0 degree mornings.  I drove it like that for three weeks until I could take it no longer.

_Shorty is correct about  the mustard.  It's emulsified oil.  You may see this under the oil filler cap.  That's usually normal.  If it's on the dip stick.. not so good.


Here is the new face:

http://as220.org/mobius/cracked.head/planar.jpg
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #11 –
lookin' better  I've got a quad4 here that's probably gonna give up the ghost in the next 6 months or so. Seen a little bit of that mustard up and down its long dipstick, it's either leaking or burning oil, and fairly certain it's got a cracked head, rocks, hehe. '89 Grand Am that I picked up probably a year and a half ago for $400Cdn, so cheap because the guy actually suspected it might have a cracked head, haha. Been running fine, just in the last month I started seeing that in the oil, after a cold spell in fact. So the head's probably gotten worse. At least it's just a second car.

Cracked Head

Reply #12 –
Back in action!  Though the rockers are troublesome.  Does anyone know a good procedure for adjusting rockers on a chevy?  I've had the covers off twice so far and still have the clackity-clack on a cold start.

I've got a quad4 here that's probably gonna give up the ghost in the next 6 months or so. Seen a little bit of that mustard up and down its long dipstick,[...][/quote]
Might be a good idea to check your PCV.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #13 –
PCV, hmm, yeah, good idea. It doesn't get driven much so I haven't put much thought into it, that's simple to go check though, thanks  Only thing I know about valve adjustment is you back it off until there's some play evident between the pushrod and the rocker, then slowly tighten it up while rotating the pushrod with your fingers. When you feel a slight drag on the pushrod, it should be pretty well adjusted.

Cracked Head

Reply #14 –
Quote
PCV, hmm, yeah, good idea. It doesn't get driven much so I haven't put much thought into it, that's simple to go check though

Pontiac Grand Am's 1988-1989 eat PCV's rather quickly, so much it's one of those things that should be changed just as preventative maintenance. They also like eating oxygen sensors on a regular basis.

When it comes time for a new head gasket on the 2.5 liter Grand Am's someone really has to know what they're doing to make a proper seal since they are known for leaking oil in copious amounts when done improperly, which is also contributed by the bolt pattern, nonetheless they are good 4 cylinder engines if kept properly maintained.

Cracked Head

Reply #15 –
thanks, I'll keep that in mind. It was already leaking a little bit of oil when I got it, heh, so maybe it was already serviced and put back together incorrectly.

Cracked Head

Reply #16 –
Quote
PCV, hmm, yeah, good idea. It doesn't get driven much so I haven't put much thought into it, that's simple to go check though, thanks

The PCV valve in mine was in great shape!  That was because the hose was completely blocked with crispy oil crap.  There was no venting going on.  I cleaned it out with ether spray and a drywall screw.  Breathing ok now.
Quote
Only thing I know about valve adjustment is you back it off until there's some play evident between the pushrod and the rocker, then slowly tighten it up while rotating the pushrod with your fingers. When you feel a slight drag on the pushrod, it should be pretty well adjusted.

I think they're being a pain in the ass because I disturbed them from their wear pattern.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #17 –
yeah, that's probably the case. They'll probably either simply quiet down on their own or do so after some readjustment after some new miles.

Cracked Head

Reply #18 –
Here is the rocker/lifter adjustment procedure according to GM.
Quote
Rotate crankshaft until No. 1 piston is on TDC of the compression stroke.  With the piston in this position, adjust the valves list in the VALVE CLEARANCE ADJUSTMENT table.  Loosen the rocker arm adjusting nut unil lash is present.  Tighten adjusting nut until lash is removed and push rod will not rotate.  When lash is removed, tighten adjusting nut one full turn.  Rotate crankshaft 360 degrees to bring No. 4 piston to TDC.  Adjust remaining valves.

Code: [Select]
                 VALVE CLEARANCE ADJUSTMENT TABLE
-----------------------------------------------------------------
|   Piston@TDC    |    Adjust Intake     |   Adjust Exhaust     |
-----------------------------------------------------------------
|   No. 1         |    No. 1, 2 & 3      |   No. 1, 5 & 6       |
|   No. 4         |    No. 4, 5 & 6      |   No. 2, 3 & 4       |
-----------------------------------------------------------------

Here's the valve arrangement:
Quote
Left Bank:  E-I-E-I-I-E (front to rear)
Right Bank:  E-I-I-E-I-E (front to rear)


Now this thread is complete.
Gur svggrfg funyy fheivir lrg gur hasvg znl yvir. Jr zhfg ercrng.

Cracked Head

Reply #19 –
should that have been 180 degrees?