Any good advice? Will be doing it with the motor in the vehicle. Hope that I didn't bend a rod. It was leaking water into the cylinder(s) and was having no prblms starting and the leak evidently got worse and I tried to turn it over and it stopped dead when it was cranking. Just left it and walked away. Got a little time today and am going to start on it. Help?

david,

in my experience, the starter will self-destruct before it bends a rod. On my boat, I had a bad experience with exhaust manifolds that leaked water. I filled the back 2 cyl up with water maybe 5 or 6 times. The starter would not crank the motor over at all. Once it broke the nose right off the starter, and another time the sprag clutch in the pinion gear busted.

You should be alright. Best of luck!


Tim

Probably the cylinder full of water put you into a hydraulic lock; water can't be compressed, not being able to spin the engine over means at least you don't have leakdown on one or more cylinders that kept the engine from cranking over with water in the cyl.

Take a good look at the pistons and cylinder walls while the heads are off. Are you going to have the heads tested?

got a chance to start tearing into the motor. Got all bu the 2 head bolts closest to the firewall on the passenger side ou. I have to find my break bar. Now that the bolts are out, how do I seperate the heads from the block? Don't want to tear the heads up.

DavidW

Cherry picker and definitely a second person to operate it while you guide it out.

I did a set of heads on a 6.2 once in a parking lot without it, never again.

I highly reccommend pulling the hydraulic lifters out for inspection/replacement.

Have a good look at the pushrods and rocker arms too, and keep in mind the pushrods do have a top and a bottom so don't put them in upside down, mark them before you take them out with a felt tip pen or something.

good time to replace those stupid plastic rocker retainers too.

It is possible to just lift it up and out, but hard on the back. I'd take all glows and injectors out before removing the head.

Cherry picker?? Just to lift off the heads? What am i missing here? If the heads are stuck to the block just give it a couple of whacks with a rubber hammer or block of wood from the intake side, they'll come free.

I didn't mean to free them from the block, it just makes the job of manuevering them in and out a LOT easier.

Had no obvious(at least to me) blown gasket, but around #7 cylinder tore when I popped the head loose. Piston top is pitted? or something unlike all the other pistons. No cracks in the walls that I can see. Cylinder head above #7 has some pitting from ? any ideas. Just new gaskets, bolts and install? TIA.


http://www.hunt101.com/img/298214.JPG

#7 pistonhttp://www.hunt101.com/img/298219.jpg

http://www.hunt101.com/img/298220.jpg



http://www.hunt101.com/img/298222.jpg

Cylinder head above #7
http://www.hunt101.com/img/298223.jpg

Cleaned up
http://www.hunt101.com/img/298216.JPG

Your gaskets may well have been pooched if it came apart like that. Did that thing smash up a glow plug tip at some point in time?

coolant hits the top of the hot hot piston and erodes it away like that.

The pitting looks heat induced but possibly only cosmetic. If you're feeling good about those heads and deceide not to have them bench tested, there's nothing left to do but clean it up and bolt it back.

In case no one mentioned it, there is a proceedure for torquing the bolts to help seat the gasket and bolts right.

In case no one mentioned it, there is a proceedure for torquing the bolts to help seat the gasket and bolts right.

What would that be? I thought that you started from the middle and worked out equally on both sides. How tight do you torque them? and what order?

Looks like the gasket might be sucked into the chamber just beside and below the exhaust valve. (?) The pock marking looks like a dozen or more early 6.2's I've pulled after a glo-plug tip went through the engine.

14 . 10 6 . 2 . 3 . 7 11 15
17 . . 9 . . . 1 . . 8 . 16
. 13 . . . 5 . . 4 . . .12

Bolts are tightend in three stages: 20 ft lbs, 50 ft lbs and retorque to 50 again and then a 1/4 to 90* turn to streach them.

What do I need to have checked and done to the heads? Gonna take them to get checked just in case. Resurface, mill a little? Any ideas?

Have them tested to make sure the valves/seats arn't leaking and there's no hairline cracks between the valves.

TDG
which end is which on the pushrods? I just changed my heads and was about to put the valve covers back on and saw your post regarding pushrods. How do i check to make sure they are correct. i did not mark them when they came out. :help:

The hardend end looks like it is somewhat gold-orange in the metal and the other tip is silvergrey.

And the hardened end goes...up or down?

Mine looked identical on both ends, but i did put them in the way they came out.

Hardened end goes up, it rotates the most against the rocker arm, the 'softer' end goes down to the lifters.

From the factory there is a paint mark near the hardened end, or so this manual says, never seen one that was marked.

I hate to be a spoilsport but don't they need to go back on the exact same lifter and rocker that they came off of? Don't all three wear in together? :confused:

When last I did mine, I laid them out the in order they came out on a table to make it easier to get them back in the same spot.

Was loading the heads up to go to the machine shop and n the bright sun I saw a CRACK in between the valves on #7!!!!! It doesn't go all the way across but about half way. Will this work? Do I need another head? Will this run like this for awhile? I need to get this thing going even if I have to tear into it later. I need my truck.

http://www.hunt101.com/img/299236.jpg
http://www.hunt101.com/img/299240.jpg

David
I just replaced my heads and will be finishing up this week, i hope. I was able to see cracks between valves on about 6 of 8 cylinders and cracks at the edges of the precups on all 8. I had them tested anyways and I was told they are gone beyond repair. I have read that cracks in the precups and between valves are not necessarily bad news, it depends on if they continue into the cooling passages. I am assuming (based on machiine shop testing) mine did. I did not want to play the guessing game so i just replaced the heads. Good luck with your project
Doc:o:

I haven't even taken them to the machine shop yet. Anyone else seen these cracks this small. These are the only ones that I can see.

Most any machine shop familiar with 6.5 heads will be able to sleeve the coolant passage for you, so even if the crack does spread, it won't leak coolant.

Small cracks in the precup are nothing to worry about either.

So put it back on and run it and see if it will last?

Most machine shops (well the ones that are not trying to rip you off) will say that some cracks are normal, I can't say for the Chev, but I've rebuilt 3 VW & 2 Toyota Diesels and all of them had "cracks" at least 4X larger than yours and every one of them were between the valves, they were pressure checked and turned out fine, in the case of my VW this was 25,000Kms ago and my toyota 18,000KMs. No issues and I don't even think about it. I think the cause for concern is more how 'WIDE" the crack is

All that being said there are always exceptions to the rule. I'd say have them tested by a good shop and go from there.

My 0.02$

The sleeves are cheap, if they tell your they're not available or expensive your shopping at the wrong place.