5.4 Triton Intake Valve Failure - Leading to timing rebuild and plugs
08-03-2015, 09:35 AM
#1
5.4 Triton Intake Valve Failure - Leading to timing rebuild and plugs
2004 NBS F150 Lariat 4x4, 197,500 miles.
Bought used with 143k, seemed very well taken care of. Changed oil with Pennzoil Platinum 5w-20 or 5w-30 every 5 k miles religiously. Had a RH exhaust leak that seemed to be getting worse. Had VCT noise at hot idle. In the past week, the ticking got a lot louder, which I now realize may have been a sticking/failing valve.
Driving to work the other day, let off the gas at a stop light and heard a nasty noise. Engine started stumbling, and wouldn't idle without giving it gas.
A week later, I now know the front most intake valve on cyl 3 failed. Valve is still in the guide, so I'm hoping there's no cylinder wall damage.
Can't get the exhaust manifold off the head - that's all that's standing between me and being able to assess the extent of the damage. I'm going to chisel the two bolts holding the header to the cat, and pull the head and header out at the same time. I had an exhaust leak on that side, so I don't mind replacing the header anyway.
So after I took the timing cover off, I found that the RH timing chain was slack. Guides are still intact and looked very good actually. But as I rotate the crank, the RH chain goes from tight to loose. I assume the Cam Phaser is jacked.
So assuming I get the head off, and there's no cylinder wall or piston damage, the plan is:
Truck is up there in miles, could be a fluke.
Bought used with 143k, seemed very well taken care of. Changed oil with Pennzoil Platinum 5w-20 or 5w-30 every 5 k miles religiously. Had a RH exhaust leak that seemed to be getting worse. Had VCT noise at hot idle. In the past week, the ticking got a lot louder, which I now realize may have been a sticking/failing valve.
Driving to work the other day, let off the gas at a stop light and heard a nasty noise. Engine started stumbling, and wouldn't idle without giving it gas.
A week later, I now know the front most intake valve on cyl 3 failed. Valve is still in the guide, so I'm hoping there's no cylinder wall damage.
Can't get the exhaust manifold off the head - that's all that's standing between me and being able to assess the extent of the damage. I'm going to chisel the two bolts holding the header to the cat, and pull the head and header out at the same time. I had an exhaust leak on that side, so I don't mind replacing the header anyway.
So after I took the timing cover off, I found that the RH timing chain was slack. Guides are still intact and looked very good actually. But as I rotate the crank, the RH chain goes from tight to loose. I assume the Cam Phaser is jacked.
So assuming I get the head off, and there's no cylinder wall or piston damage, the plan is:
- Replace with a reman head
- Replace cam phaser with Motor Craft part
- Replace VCT solenoid with Motor Craft part
- Replace timing components with Cloyes kit from rock auto
- Replace the LH plugs (going to use the extraction tool, if it fails, the head is ready to come off
- Replace RH exhaust manifold with cheap-o dorman
- Clean throttle body
- Decide whether to sell it, or try to get some more value out of it. It's a gorgeous truck in excellent condition, so it'll sell quick. Would make a good down payment on a lightly used 2013 3.5 EB.
Truck is up there in miles, could be a fluke.
Last edited by dyeguy1212; 08-03-2015 at 02:53 PM.
08-04-2015, 08:34 PM
#3
Update time. Didn't even attempt to get the exhaust manifold bolts off, as they looked horrible and from what I've read here, it's not worth taking on. Figured for the price of a 60 buck dorman ex. manifold, I'd just replace it. I had a slight exhaust leak anyway.
So after TWO hours of fighting with the TWO nuts that hold the flanges of the exhaust manifold and cat together, the head was ready to come out.
Pulled the head, and there's no cylinder or cylinder wall damage. The valve bent in an S shape, keeping it in the head when it failed.
Cylinder walls look great, no unusual wear patterns or scoring. They'll live to see another day.
Having a spare cylinder head will be a great opportunity to practice removing the spark plugs before removing the passenger side. I'll try different methods, namely PB blaster, impact gun, slow removal with a ratchet, and I also want to try hitting the plug with MAP gas, then quenching with PB blaster to wick it into the threads.
So after TWO hours of fighting with the TWO nuts that hold the flanges of the exhaust manifold and cat together, the head was ready to come out.
Pulled the head, and there's no cylinder or cylinder wall damage. The valve bent in an S shape, keeping it in the head when it failed.
Cylinder walls look great, no unusual wear patterns or scoring. They'll live to see another day.
Having a spare cylinder head will be a great opportunity to practice removing the spark plugs before removing the passenger side. I'll try different methods, namely PB blaster, impact gun, slow removal with a ratchet, and I also want to try hitting the plug with MAP gas, then quenching with PB blaster to wick it into the threads.
08-04-2015, 08:55 PM
#5
FYI, the oil in the cylinders was from me wiping with a sopping oily rag to avoid corrosion while I wait for parts.
Pistons and cylinder side of the valves have a ton of carbon build up. But the intake side of the valves are spotless.
Pistons and cylinder side of the valves have a ton of carbon build up. But the intake side of the valves are spotless.
