Diagnosing valvetrain issue
Thread Starter
|
Freshman User
Joined: Dec 2015
Posts: 49
Likes: 0
Diagnosing valvetrain issue
2005 F250
EGR Delete
FICM re-built
Injectors replaced
ARP studs
HPOP
EGT probe
Fuel pressure gauge
We've had. a "thump" that sounded like it was coming from the intake, started as an intermittent noise, had fuel in the oil and replaced a faulty injector and performed an oil change, noise went away.
Pulled the cab, did ARP studs put the truck back together and ran it for ~ 1K miles, lost HPO, replaced the HPOP and no change so we pulled the valve covers and found a destroyed injector, replaced it and we were good to go.
Bought a Ram for the business and started using it instead of the ford so we parked it for a few months, started it up about 2 months ago and noticed the "thump" was back along with light black smoke, no noticeable loss of power, jumped the starter and I can hear air being forced back through the intake when the engine is cranking.
Any other diagnosing I can do besides a compression test before I tear it down?
Video of the thumping.
EGR Delete
FICM re-built
Injectors replaced
ARP studs
HPOP
EGT probe
Fuel pressure gauge
We've had. a "thump" that sounded like it was coming from the intake, started as an intermittent noise, had fuel in the oil and replaced a faulty injector and performed an oil change, noise went away.
Pulled the cab, did ARP studs put the truck back together and ran it for ~ 1K miles, lost HPO, replaced the HPOP and no change so we pulled the valve covers and found a destroyed injector, replaced it and we were good to go.
Bought a Ram for the business and started using it instead of the ford so we parked it for a few months, started it up about 2 months ago and noticed the "thump" was back along with light black smoke, no noticeable loss of power, jumped the starter and I can hear air being forced back through the intake when the engine is cranking.
Any other diagnosing I can do besides a compression test before I tear it down?
Video of the thumping.
Fleet Mechanic
Joined: Nov 2008
Posts: 1,443
Likes: 9
From: South Alabama
I hear it woofing (Thumping). Bent pushrod, bad lifter, burnt valve? Compression test is the only way I know. You’re on the right track. Maybe Jack (toomanytoys) will drop in. He’s been thru this, I haven’t.
Hotshot
Joined: Dec 2014
Posts: 17,832
Likes: 3,119
From: Jersey Shore
The thump is there all the time. Mine was at startup due to the lifter hydraulically collapsed.
It could be a bent pushrod, collapsed lifter (mine) or the roller on the lifter gone away.
I pulled the oil rails down and used a dial indicator to check the valve lift. If it's a bent pushrod you might be able to find it just by bringing each cylinder up to closed valves and check for play. Somewhere there is a way to turn the crank to get each cylinder at the closed valve point. Once ou find the offending cylinder you can use a tool once you remove the injector to hold down the valves so you can remove the rocker and pull the pushrod to check for straightness. Mine were straight, Iowa the lifter that collapsed.
The rocker arm tool.
https://rotunda.service-solutions.co...x?SKU=303-1170
If you need the tool I can rent it to you, PM me.
It could be a bent pushrod, collapsed lifter (mine) or the roller on the lifter gone away.
I pulled the oil rails down and used a dial indicator to check the valve lift. If it's a bent pushrod you might be able to find it just by bringing each cylinder up to closed valves and check for play. Somewhere there is a way to turn the crank to get each cylinder at the closed valve point. Once ou find the offending cylinder you can use a tool once you remove the injector to hold down the valves so you can remove the rocker and pull the pushrod to check for straightness. Mine were straight, Iowa the lifter that collapsed.
The rocker arm tool.
https://rotunda.service-solutions.co...x?SKU=303-1170
If you need the tool I can rent it to you, PM me.
Thread Starter
|
Freshman User
Joined: Dec 2015
Posts: 49
Likes: 0
The thump is there all the time. Mine was at startup due to the lifter hydraulically collapsed.
It could be a bent pushrod, collapsed lifter (mine) or the roller on the lifter gone away.
I pulled the oil rails down and used a dial indicator to check the valve lift. If it's a bent pushrod you might be able to find it just by bringing each cylinder up to closed valves and check for play. Somewhere there is a way to turn the crank to get each cylinder at the closed valve point. Once ou find the offending cylinder you can use a tool once you remove the injector to hold down the valves so you can remove the rocker and pull the pushrod to check for straightness. Mine were straight, Iowa the lifter that collapsed.
https://www.youtube.com/watch?v=Jx7Oi7WHVwI
https://youtu.be/x0fSYCt9QDc
The rocker arm tool.
https://rotunda.service-solutions.co...x?SKU=303-1170
If you need the tool I can rent it to you, PM me.
It could be a bent pushrod, collapsed lifter (mine) or the roller on the lifter gone away.
I pulled the oil rails down and used a dial indicator to check the valve lift. If it's a bent pushrod you might be able to find it just by bringing each cylinder up to closed valves and check for play. Somewhere there is a way to turn the crank to get each cylinder at the closed valve point. Once ou find the offending cylinder you can use a tool once you remove the injector to hold down the valves so you can remove the rocker and pull the pushrod to check for straightness. Mine were straight, Iowa the lifter that collapsed.
https://www.youtube.com/watch?v=Jx7Oi7WHVwI
https://youtu.be/x0fSYCt9QDc
The rocker arm tool.
https://rotunda.service-solutions.co...x?SKU=303-1170
If you need the tool I can rent it to you, PM me.
Hotshot
Joined: Dec 2014
Posts: 17,832
Likes: 3,119
From: Jersey Shore
Agreed, you don’t have a hydraulically compromised lifter. Possibly a valve got rusty from sitting and the resistance bent a pushrod. A rocker fell out of place, it’s happened. That would be the least issues. Burnt valve next, and the worst an issue at the bottom of the lifter.
Start from the valve cover, you might get lucky with being all repairs without removing the head. There have been a fair amount of people who just replaced a pushrod. They are not that strong compared to other motors and bend with resistance that other rods would push through.
Start from the valve cover, you might get lucky with being all repairs without removing the head. There have been a fair amount of people who just replaced a pushrod. They are not that strong compared to other motors and bend with resistance that other rods would push through.
Thread
Thread Starter
Forum
Replies
Last Post
timbersteel
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
20
Jul 18, 2012 02:09 PM
twtcad
1999 - 2003 7.3L Power Stroke Diesel
13
Jul 28, 2011 08:47 AM
