Long story short, the head gasket blew a while back, and I finally got everything back together on Thursday evening. I believe the reason for the head gasket failure was air in the system in combination with a clogged air bleed pipe (steam crossover pipe). #7 cylinder was definitely the point of failure, as that cylinder was steam cleaned and also had a very dark exhaust valve (all other cylinders & valves looked normal).

I had the heads milled flat (removed .005" from each), valves back-cut, bowls worked a bit, and both the heads and the intake gasket matched. The machinist said all valve guides were good and he installed new valve seals. I put it all back together with the impala head gaskets.

Since Thurs night, I've put about 200 miles on the car, and it's been running fine. Then all of a sudden today, it starts pouring blue smoke out of the tail pipes. Also notice raw oil coming from the pipes as well.

I pulled the plugs, and #7 is completely covered in oil. The other's on the driver's side are fine. I'm thinking either a severe ring problem on #7, or the intake gasket let go and is allowing oil to be sucked in.

I ran a compression test 3 times on cylinders 1, 3, and 7.

• Cyl 1 = 155psi, 165psi, 155psi
• Cyl 3 = 170psi, 165psi, 165psi
• Cyl 7 = 155psi, 165psi, 155psi

I didn't do #5 because I was running out of time. To me, those #'s look fine, and it's making me lean in the direction of a bad intake gasket.

Any other ideas on what to check before I remove the intake? Could I still have bad rings on #7 and the compression test come out like this? I searched for a leakd down tool/kit, and could not find one at the local parts stores.

Another thought, would one bad ring on one cylinder be enough to cause raw oil to spit from the exhaust pipes?

Thanks for any assistance, this is getting really frustrating!

Thomas.

 

To answer your question regarding the compression test on cylinder #7, it is possible that you have a ring problem yet still seeing an acceptable gauge reading. Oil in the cylinder can help to promote the rings to seal when performing a compression test. A leak-down test would be a good idea.

 

Agreed, but I can't seem to find a leak-down tester anywhere. I suppose the real question here, is if one bad ring on one cylinder could allow enough oil into the combustion chamber to create a smoke screen out the back and spit oil out of the tailpipes. I'm thinking no, but have never dealt with bad rings before.

If my problem is the intake gasket, would the .025 difference in height (.005 milled heads and .020 thinner head gasket) be enough to cause an alignment issue between the intake and heads? Or am I just dealing with a failure of the intake gasket?

I suppose I'll be removing the intake either tonight or tomorrow to check it out and know for sure.

Thomas.

 

No, that shouldn't make a difference, and I'm thinking it's not an intake gasket problem. But, I hope it is something simple like that.


-Mike

 

Well, it appears you were correct. I finally had time to remove the intake tonight and it doesn't look like the gasket failed. There's also no sign of oil in the runner for #7.

Thurs I'll be replacing the valve seals on #7 and reinstalling the intake. Then Friday I'll start it up and see if it's still burning oil; if so, I suppose a short block is in order unless anyone else has any ideas?

Thomas.

 

Seems like a fairly good plan. I'm in Austin too. Let me know if you need a second opinioin.



Edit: Don't know off hand where to find leakdown tester. I'll ask around.

 

Just an update to this:

I replaced the intake gasket and put the intake back on, and so far so good. Very strange, as I did not see any failure in the gasket, and did not see any sign of oil getting into the head. I suppose it could have been leaking and I just missed it

Either way, I've got about 60 miles on it since the intake went back on, and no issues. Engine's pulling strong and no more smoke.

Thomas.