Oh what the head gasket!

[Chevy305]

haven't read the replies, just the comp numbers.. the reason the # was higher the first time was cuz there was fluid in it.. once you evacuated the cylinder, the # goes down...

did it overheat bad at any point? you just put this together a while back right? new cam and stuff? where those aftermarket heads, Patriots or something?

No its never been hotter than 210 or 215. There's about 7k miles on the long block, and maybe 1k on the new roller cam and intake. Ya the heads are aluminum Patriot Performance brand.

Tomorrow I'm going to rent the leak down tester and coolant system pressure tester and post up the results. Regardless of how the tests come out, that head still needs to come off. So I'm going to just nut up and do it.

 

[ryoken]

yup, inspect it very carefully.... hopefully it's an obvious blowout and the head integrity won't come into question...

 

[dyeager535]

Ya the heads are aluminum Patriot Performance brand.

Plenty of people out there with a bunch more engine builds under their belt than me (would need 3 I guess lol) but are the gaskets you used designed for aluminum heads/iron block?

I checked the link, Summit makes it sound like they come in two varieties, but I didn't see where it said ok for aluminum heads. When I was looking at .015" gaskets for another motor, I started running into comments about fretting, depending on the design of the head gasket.

 

[Chevy305]

Plenty of people out there with a bunch more engine builds under their belt than me (would need 3 I guess lol) but are the gaskets you used designed for aluminum heads/iron block?

I checked the link, Summit makes it sound like they come in two varieties, but I didn't see where it said ok for aluminum heads. When I was looking at .015" gaskets for another motor, I started running into comments about fretting, depending on the design of the head gasket.

Patriot Performance recomends this gasket or equivelent:
http://www.jegs.com/i/Fel+Pro/375/1094/10002/-1

The Jeg's brand gasket I'm running is really the same thing when you compare them.

 

[Chevy305]

Ok results from the coolant system pressure test:
BAD...
Pressure drops slowly and coolant drips from the #7 plug hole.
While running, the pressure increased quickly to 18psi before I released the pressure and shut it down.

Going to start pulling it apart now.

 

[Chevy305]

Bad News

Bad news, I can't tell if the head gasket was the cause or not. There is one spot where it looks like it might have been leaking but I can't be sure. But what I did discover is multiple broken valve guides (where's the crying smiley when you need it?)

When I first pulled the intake and valve cover I found some milky oil. Now the oil had NO evidence of milkyness when I posted up so this must have been a result of the testing I have done on it.

The head gasket Top (head side):

The head gasket bottom side (block side):

The block:

The head:

A close up of the #7 cylinder:
What's with the pitting on the exhaust valve?

Onto the broken valve guides:

So obviously the heads need to be rebuilt, so I think I'm going to pull the other head too and send them both out to be magnafluxed and get a complete valve job.

This is really going to suck to have the truck down during the last weeks of this boating season. But at least I found the broken guides before the valves bent on my next 6000rpm redline shift and possibly grenaded the whole engine

 

[wasted wages]

My guess is you have some detonation going on....

you can see where the combustion gasses were blowing into the water port and bolt passage on the left side of the cylinder.... the pitting on the valve may also be caused by the hammering going on in the cylinder....

 

[80' 427]

You aren't going to get them magnafluxed. You can only do MT on iron heads. You need to have them penetrant checked. The pitting is from the steam cleaning that the water does to the camber. I can't see where the guides are broken but be sure to take the head gasket to the machine shop. those guys know how to id leaks. Good luck.

 

[Fordum]

I got some stuff going on right now, but I was wanting to check in and see what you found.

I know I'm a little distracted right now, but what are you calling valve guides?

Probably just a difference in nomenclature, but the things I have always called valve guides are bronze bushings pressed into the heads.

If they were broken, you would not be able to see them in those pics unless they have risen out of the heads.

But, maybe I'm thinking about something else......

 

[Chevy305]

Ya maybe I'm calling them something different but its that green part that should be at the base of the head.

 

[Fordum]

Ya maybe I'm calling them something different but its that green part that should be at the base of the head.

Gotcha. That looks like a valve stem seal. Not sure why it has ridden up like that.
Not familiar with that type, but they usually fit over a boss or something in the head to keep them in place.

Probably not as dangerous as it looks.

 

[Chevy305]

Gotcha. That looks like a valve stem seal. Not sure why it has ridden up like that.
Not familiar with that type, but they usually fit over a boss or something in the head to keep them in place.

Probably not as dangerous as it looks.

So then should I still rebuild the heads?

 

[Fordum]

So then should I still rebuild the heads?

Not necessarily. The most important thing right now is to determine why the coolant got where it did.
If those are just valve seals and they have moved up out of position, then they may only need to be replaced.

That can be done easily without any rebuild, and can be done on the other head without even removing it.
But, we need to find out why they moved.

Like I say, I'm not familiar with that type, but I'm very sure someone here is.

Unless there is something wrong with the gasket that is not obvious from the pictures, you are probably going to have to take that head in for a dye check, and the people at the head shop can probably tell you what is wrong with the seals.

It could be something as simple as the wrong seals for that size valve stem.

I have seen that before, but just in passing, and never asked why they were that way.

But, then I don't do a lot of GM rebuilds, or rebuilds at all anymore, so we need for someone here to chime in.

 

[Fordum]

Hang on, a thought just showed up in my head, and I am trying to be kind to it because its in a strange place.....

I was assuming those were positive type seals that stay on the head. Deflector types move up and down with the valve, but don't usually look like that.

Also, if I remember right, most of the positive type need the boss on the head to be machined so they can fit down over it and lock to it.

Again, we are getting out of my comfort zone, and my knowledge is not what it should be and is many years out of date to boot.

IF those are the positive type, then they should be down on the head. If so, then they were probably installed wrong or the head was not machined for them.
If they are the umbrella/deflector type, then they may be fine.

I was looking for some pics to post of the different types, but there are so many variations, I just gave up.

 

[ryoken]

valve seals don't move on a chevy....

how many did it? was it just the cylinder with AF in it?

 

[Chevy305]

valve seals don't move on a chevy....

how many did it? was it just the cylinder with AF in it?

At least 4 of them are like that.

 

[ryoken]

did they come preassembled?

 

[Chevy305]

Yup, they weren't like that when I got them.

 

[ryoken]

since they came assembled, might be worth a bitch call to Patriot..

 

[Chevy305]

Would my new roller cam have anything to do with this? I noticed the max lift says .575" hydraulic flat tappet, not hydro roller. My cam has a lift of .515/.530.
However, I don't know if the valves started doing this before or after the cam swap