Small Block Chevy Heads

I'm not voicing ANY opinions here, but you need to show a close-up picture of both sides of the HEAD GASKET. You have the picture of the deck surface with 6 and 8, I didn't really see a close up of the head surface for 6 and 8, but most of all, where is the picture of BOTH sides of the gasket between 6 and 8. When questioning a blown head gasket, you also need a close up of the actual gasket. Thank you, TR

 

The photos clearly show a blown head gasket between #6 and #8 and the gasket was also leaking between #4 and 6 but not as bad...the black carbon shows it clear as day. Double check decks for flatness and use quality gaskets to re-assemble.

 

Darn Rocky, I was gonna go with #13 about the " high pressure intake check valves "

 

Shure it could the engine isnt running the carb butterflys are closed. if the intake valves where bad the air would take the path of least resistance Its possible. OldWolf

 

That intake valve is bent and the seat has been beat to hell also... There is also a tell tail flat spot on piston eye brow... Looks bigger than the other...

 

Looks like the flat spot is where the #6 intake valve encountered a massive carbon build-up in the piston eyebrow. That could bend a valve. Must have made a pretty good knocking sound.
I've seen that same problem [left unrepaired] actually ruin the rod bearing from the constant beating, not to mention cracking the side of the piston.
Ford 2.3, 4 bangers are prone to the bearing damage because of carbon build-up...don't ask me how I know.

 

I chuckle a little, but will add some close ups of the head gasket as requested, and cylinder. Nope its not the head gasket. With that much gap you can clearly see, its no wonder the air came right back out.

 

First picture...
Looks like the threads were pulled on the lower right head bolt hole... I could be wrong..

 

Huh, the head gasket was leaking between 6 and 8 and 6 and 4.
NOT blown, but leaking, big difference.
Use a short straight edge and a flashlight to check for warpage between the cylinders. A straight edge and feeler gauges will not show this warpage.
This is not a V2 engine people. The air will not pass through the intake manifold and out an intake, it will pass out the exhaust valves of the other cylinders or pass through the leaking headgasket.

 

Yep, the threads are pulled on the headbolt hole below #6

 

It does look like the valves was your biggest cause of problem.

BUT, that head gasket is blown(or as rick said leaking). It is black and has discoloration from heat as does the top of the block in your first picture set. The good news is those head gaskets are total crap and a good one will probably be fine.

I'd still check it for flatness. I think .003 is considered okay(someone chime in here), but anything over that is too much.

 

Pleez READ Post 28 !!! >>>>.

 

Within .002" tops!!!

 

I did read, and was we are on the same page, except, when I first dd the compression check and had no pressure in 6, I then went to 8. then adding air into the cylinder, it blew out in my face from #8. I did not check how much was coming out the carb but I assume some had to be. I knew nothing should be coming out the 8 hole.

I then called my machine shop buddy, and pulled the head. That is where I am at now. All cylinders held 130 psi except 6 and 8. gaskets are fine and everything else. It is at this point a intake valve issue. I am hopin to reassemble the engine this weekend.

 

After seeing those valves, regardless of what you pressure checked, I'd have BOTH heads off and getting valves replaced, seats put in and surface them both. Or better yet, a new set of heads with hardened seats already installed. Also check to see if you have a vacuum leak that may have caused those cylinders to run lean/hot and kill valves.
Forget about how you checked, and focus on what you see now that it's apart.

 

Kind of a moot point now but, when you were airing up the cylinders, did you have the valves backed of on both sides of the engine?

 

------ I was poking at old wolf. and yeah you need to get past all of the checking stuff and look at what's in front of you as badshifter says. Your original problem wasn't caused by cheap steel. Check the other head too. And do yourself a favor and check the fuel system, the cooling system, and the ignition system when you get this thing back together >>>>.

 

i dont know why people ask for help and then wont use it.

 

who asked for help? Iasked for what is normal. I figured it out.

As stated previously. This is an intake valve issue. I think everyone can learn from it, or put it in their experiences. This is unusual, however intresting as well.

AT this point heads are cleaned , Beaded, magnafluxed, and surface area checked and true. Spring seat preassure is 85lbs. SO I am waiting on valves to arrive.

As stated This is a 1986/87 350. It has hardened seats for those who dont know. I planned on going through the engine over the winter, but I would love to simply drive the truck for whats left of summer and fall. Over the winter I will be redoing the other head, and perhaps new springs, lifters and cam. Normal stret rod seat pressure, I would like to be 110lbs. although 65 is normal stock.

Once the head is complete I will post more pics.

 

The heads are done, no cracks, valves replaced. No warpage or less then .001 which isnt anything. I will post again when running.

 

This is the best the engine has run. WOW! all this from 2 leaking valves. She runs great!