Checkmate

Well, after my truck sitting for over 3 months, I finally swapped out the #6 injector because I thought it was dumping fuel. Much to my dismay, it nSTILL knocked after I was done !!!

here's the run down in short.........

I was driving along with the cruise set at 64 mph. Oil pressure good, temp normal, no problems. All of a sudden it started knocking. No visible smoke out the rear tinted window. Lost power, stalled. Started back up rough and got to next ramp. Didn't want to start as if hydro locking slightly. Called AAA had it towed home. Got home, it started right up but rough and knocking. Still no real smoke except out the oil fill hole.

Hour later, start it up, still knocking AND now white smoke pouring out the stacks.

Loosened exhaust manifold and started it. Smoke coming from #6.

Shut off, pulled injector. Took it to a guy who said he could check it, but was an idiot.
Bought a used one from Greg at truckspecialties (very helpful guy) and installed. Started truck. SAME thing. GRRRRR

SO.... I pull the wires for the number 6 inj and the smoke stops, but the knocking still consistent. put the wires back on and smoke.


TELL ME what you guys think. Educated guesses welcome.
I have a strong feeling I know what the problem is, but I'll wait for responses.

A little background...Engine has 215,000 miles on it, but new rings and rod bearings at 205,000 and valves were adjusted then too.

CamperAndy

You lost a valve or seat. Check all your clearances and or do a compression check.

Checkmate

is this common?

Checkmate

I would do a compression check, but don't have and can't find the tool. BUT Since I'm getting fuel and air, would it not be safe to assume that I do NOT have good compression. Would a compression test tell me anything I don't already know.
Can you differenciate between valves, rings, etc by this test.
A few friends think rings, but I can't see bad rings causing a knock ???
Also been told to check for weak spring. ????

roughstock

Could be valve seat falling out and causing valve to stay open. Need compression check. Or pull head. I'd just pull head any way. You'll probably need to anyway.

BigIron70

Did you inspect rocker arms to make sure cup didn't fall off? I had a few that have done that. Usually the pushrod will come out of the rocker arm and cause a dead cylinder. If that's ok then you need to do compression test.
DIAGNOSIS AND TESTING - CYLINDER COMPRESSION/LEAKAGE TESTS
CYLINDER COMPRESSION PRESSURE
The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions.

Ensure batteries are completely charged and the engine starter motor is in good operating condition. Otherwise, the indicated compression pressures may not be valid for diagnostic purposes.

Disconnect the fuel inlet line to the fuel filter housing. Plug the fuel line from the fuel tank.
NOTE: Failure to plug fuel line will result in fuel leak.

Remove fuel transfer pump relay from PDC.
Start the engine and idle until the engine stalls (runs out of fuel).
FOR EARLY BUILDS Disconnect all three injector wire harness connectors at the rocker housing.FOR LATE BUILDS Remove the cylinder head cover.
FOR LATE BUILDS Remove the cylinder head cover carrier gasket.
FOR EARLY BUILDS Remove the breather cover and cylinder head cover.
Remove the high pressure fuel line between the cylinder head and fuel rail for the cylinder to be tested. Use tool# 9011 to cap this fuel rail on the cylinder being tested.
Remove the fuel connector tube nut and fuel connector tube.
Remove the exhaust rocker lever.
Use Tool 9010 to remove the injector and copper sealing washer.
Install the exhaust rocker lever and torque to 36 N·m (27 ft. lbs.).
Cover the remaining rocker levers with clean shop towels to prevent any oil splatter under the hood.
Place a rag over the compression test tool fitting. Crank the engine for 2–3 seconds to purge any fuel that may have drained into the cylinder when the injector was removed.
Connect the compression test gauge.
Crank the engine for 5 seconds and record the pressure reading. Repeat this step three times and calculate the average of the three readings.
NOTE: The minimum cylinder pressure is 350 psi. Cylinder pressure should be within 20% from cylinder to cylinder.

Combustion pressure leakage can be checked if cylinder pressure is below the specification. Perform the leakage test procedure on each cylinder according to the tester manufacturer instructions.
Upon completion of the test check and erase any engine related fault codes.
CYLINDER COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an accurate means for determining engine condition.

Combustion pressure leakage testing will detect:

Exhaust and intake valve leaks (improper seating).
Leaks between adjacent cylinders or into water jacket.
Any causes for combustion/compression pressure loss
Start and operate the engine until it attains normal operating temperature.
FOR EARLY BUILDS Remove the breather cover and cylinder head cover.
FOR EARLY BUILDS Disconnect all three injector wire harness connectors at the rocker housing.
FOR LATE BUILDS Disconnect injector harness connectors.
FOR LATE BUILDS Disconnect breather tube and breather drain tube from valve cover.
FOR LATE BUILDS Remove the cylinder head cover.
FOR LATE BUILDS Disconnect harness from injectors.
FOR LATE BUILDS Remove the cylinder head cover carrier gasket.
Bring the cylinder to be tested to TDC.
Remove the high pressure fuel line between the cylinder head and the fuel rail for the cylinder to be tested.
Install capping Tool 9011 onto the rail.
Remove the high pressure connector nut and high pressure connector with Tool 9015.
Remove the exhaust and intake rocker lever.
Use Tool 9010 to remove the injector and copper sealing washer.
Install compression test Tool 9007 into the injector bore.
Connect the leakage tester and perform the leakage test procedure on each cylinder according to the tester manufacturer's instructions.
Upon completion of the test check and erase any engine related fault codes.

Checkmate

Yup, I checked the rockers and such all looks fine. I'm gonna try and pull the head today.

BigIron..nice write up, thanks.

J BODY

.....of course cancelling cylinders with a scan tool would most likely pinpoint which cylinder has the issue.

CamperAndy

He took the exhaust manifold loose and the #6 was the one smoking.

Checkmate

Well.... The problem is worse than hoped. I pulled the head and there is nothing wrong there.
The I pushed down on the #6 piston and it dropped almost 1/4".
Gonna pull the engine today and see how bad it is.

Checkmate

Would this extra play cause that cylinder not to fire???

SAVOY1964

It would certenly lower the compression in that cylinder 1/4 inch is a lot.

JFlory

Are you saying the piston dropped a 1/4", but wasn't at TDC? If so it sounds like your rod bolts backed out. This would be a new one to me.

Hope things are salvagable. Sounds like you caught this before the bolts came all the way out. That would have made a heck of a mess.

Keep us posted with your findings. Some pics would be great.

Checkmate

Got it out and apart today. #6 bearing got chewed up and spit out. It was in the pan shredded up. No idea how or why. Bolts were still torqued and there is no discoloration to the crank or rod. The sides of the rod where the bearing goes was rounded off swome, but not bad. I'm gona take the rods and crank to the speed shop tomoro and see what they say.