Blowby Problems, dead cylinder
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Junior User
Joined: Mar 2008
Posts: 64
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From: Montana City, Montana
Blowby Problems, dead cylinder
Greetings ... new to this forum. Been looking through the forum for the answer but still not sure.
Problem; Truck was ranning well until a pushrod broke. Replaced the pushrod and started truck. Engine has a definate miss on one cylinder. Number 6 is the suspect as it had the broken pushrod. There is enough crankcase pressure to blow oil up the dipstick when reved to over 1800 RPM. Exhaust has only a slight white smoke to it. Engine starts ok, idles rough, reves up, Fuel pressure is good 60#. Left bank air tube has oil in it that came from the CCV. Checked the CCV and it is working OK. Waiting for card for scanner so haven't run a scan on it yet. Want to do a compression test, what is the dia and thread of the glowplug hole?
Any Ideas? Hope it not a hole in the piston, could a dead cylinder cause an extreme amount of blowby?
2000 F450 PSD Automatic trans.
Thanks .... Ken Gardner
Problem; Truck was ranning well until a pushrod broke. Replaced the pushrod and started truck. Engine has a definate miss on one cylinder. Number 6 is the suspect as it had the broken pushrod. There is enough crankcase pressure to blow oil up the dipstick when reved to over 1800 RPM. Exhaust has only a slight white smoke to it. Engine starts ok, idles rough, reves up, Fuel pressure is good 60#. Left bank air tube has oil in it that came from the CCV. Checked the CCV and it is working OK. Waiting for card for scanner so haven't run a scan on it yet. Want to do a compression test, what is the dia and thread of the glowplug hole?
Any Ideas? Hope it not a hole in the piston, could a dead cylinder cause an extreme amount of blowby?
2000 F450 PSD Automatic trans.
Thanks .... Ken Gardner
Post Fiend
Joined: Mar 2007
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From: Texas
Welcome to FTE. If you've got a good scanner you can run a cylinder contribution test and injector buzz test without having to take things apart first. No point if fighting those valve covers off until you know for sure which side to chase.
Postmaster
Joined: Jun 2006
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From: Fulltime RVer
Do you have a stock CCV, or is it vented through a hose to the atmosphere? What do you see if you remove the oil filler cap and rev the engine? Put your hand over the filler cap hole and see if you feel repetitive puffs of blow by which might indicate ring failure, a holed piston, or some other distinct entry path into the valve cover/crankcase region of the engine.
Senior User
Joined: Mar 2007
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Take heart as all is not necessarily lost. If there is no physical damage to the cylinder wall or piston rings, engines have been known to heal themselves when the offending problem is fixed.
Quick like a bunny, check your oil for fuel contamination. If fuel is present in your oil that's a bad sign indicating mechanical damage(if all else in the fuel system is functioning properly). That would tell me the injector is still delivering fuel to an otherwise dead cylinder. More specifically, I'd bet a valve was bent when the push rod broke. It could also account for the extra blow-bye by washing away the lube oil that would normally seal the piston rings. A compression test will answer which cylinder is problematic, and a leak-down test will narrow it to specifics.
Quick like a bunny, check your oil for fuel contamination. If fuel is present in your oil that's a bad sign indicating mechanical damage(if all else in the fuel system is functioning properly). That would tell me the injector is still delivering fuel to an otherwise dead cylinder. More specifically, I'd bet a valve was bent when the push rod broke. It could also account for the extra blow-bye by washing away the lube oil that would normally seal the piston rings. A compression test will answer which cylinder is problematic, and a leak-down test will narrow it to specifics.
Butt-Head
Joined: Apr 2004
Posts: 9,448
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From: Reed Point, MT
Montana City, huh? I used to live in Jefferson City (about a year ago). Welcome to the boards.
The white smoke from the exhaust leads me to believe that you have unburned fuel. If you have no compression in a cylinder, the fuel will not ignite and you'll send raw fuel out of the exhaust. And yes, UNburned fuel is a white colored smoke.
As for the blowing out of the dipstick problem. I think you have a broken/split/hole in piston concern. Pushrods CAN "just" bend, but usually it's due to other mechanical issues.
Good luck with this one, Ken!!
The white smoke from the exhaust leads me to believe that you have unburned fuel. If you have no compression in a cylinder, the fuel will not ignite and you'll send raw fuel out of the exhaust. And yes, UNburned fuel is a white colored smoke.
As for the blowing out of the dipstick problem. I think you have a broken/split/hole in piston concern. Pushrods CAN "just" bend, but usually it's due to other mechanical issues.
Good luck with this one, Ken!!
Thread Starter
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Junior User
Joined: Mar 2008
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From: Montana City, Montana
Bad News???
Do you have a stock CCV, or is it vented through a hose to the atmosphere? What do you see if you remove the oil filler cap and rev the engine? Put your hand over the filler cap hole and see if you feel repetitive puffs of blow by which might indicate ring failure, a holed piston, or some other distinct entry path into the valve cover/crankcase region of the engine.
When the oil filler cap is off there are obvious puffs of vapor coming out of it. When the engine is reved there is a lot of pressure here.
There ARE repetitive puffs,
Looks like a teardown is in store.
Ken Gardner
Thread Starter
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Junior User
Joined: Mar 2008
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From: Montana City, Montana
Quick like a bunny, check your oil for fuel contamination. If fuel is present in your oil that's a bad sign indicating mechanical damage(if all else in the fuel system is functioning properly). That would tell me the injector is still delivering fuel to an otherwise dead cylinder. More specifically,
I'd bet a valve was bent when the push rod broke. It could also account for the extra blow-bye by washing away the lube oil that would normally seal the piston rings. A compression test will answer which cylinder is problematic, and a leak-down test will narrow it to specifics.
Thanks for the info
Ken Gardner
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Fleet Owner
Joined: Jun 2004
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From: Rio Rico, AZ.
Real quick post, need to return to work.
Repetitive puffing like a steam engine=ruined piston/cylinder=need a rebuild.
At this point a compression check will only serve to verify your suspicions and tell you which cylinder is bad.
I am not sure on the glow plug thread size but I would hazard a guess at 11x1mm. Maybe 12x1mm.
Earnesteugene GREAT to hear from you, many many people here on the board have expressed regret at not being able to read your posts.
Repetitive puffing like a steam engine=ruined piston/cylinder=need a rebuild.
At this point a compression check will only serve to verify your suspicions and tell you which cylinder is bad.
I am not sure on the glow plug thread size but I would hazard a guess at 11x1mm. Maybe 12x1mm.
Earnesteugene GREAT to hear from you, many many people here on the board have expressed regret at not being able to read your posts.
Thread Starter
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Junior User
Joined: Mar 2008
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From: Montana City, Montana
Piston meltdown
Scanned engine and #8 showed up in the contribution / balance test. Pulled the glowplug and blew air into the cylinder and straight through to the crankcase. 
Pulled the head and found a huge hole in the piston. It had melted down around the 2-oclock position. Very little damage to the cylinder wall, thank God. Piston #2 is showing signs of burning out as well. Looks like a rebuild is in store. Ouch that hurts! At lease it happened now instead of during the Fire Season when the truck can be making money. Trouble is last Fire Season is so far away that I'm broke. No money but lots of time so I'll be doing the wrenching myself, no big deal. Any inexpensive tricks I should do while the engine is out of the truck? Just replaced the Tranny and transfer case, new breaks. Before long this truck will be like new but right now it feels like Fix Or Repair Daily!!
Good Day .... Ken Gardner
Pulled the head and found a huge hole in the piston. It had melted down around the 2-oclock position. Very little damage to the cylinder wall, thank God. Piston #2 is showing signs of burning out as well. Looks like a rebuild is in store. Ouch that hurts! At lease it happened now instead of during the Fire Season when the truck can be making money. Trouble is last Fire Season is so far away that I'm broke. No money but lots of time so I'll be doing the wrenching myself, no big deal. Any inexpensive tricks I should do while the engine is out of the truck? Just replaced the Tranny and transfer case, new breaks. Before long this truck will be like new but right now it feels like Fix Or Repair Daily!!Good Day .... Ken Gardner
Post Fiend
Joined: Jul 2005
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From: 21791
Since it's a work truck, i wouldnt do much to it. If it was a toy that you are thinking about modifying beyond 450hp in the future, it would be wise to put push rods (chromoly), valve springs and headstuds in (about 1200 or so total)
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
Scanned engine and #8 showed up in the contribution / balance test. Pulled the glowplug and blew air into the cylinder and straight through to the crankcase. Pulled the head and found a huge hole in the piston. It had melted down around the 2-oclock position. Very little damage to the cylinder wall, thank God. Piston #2 is showing signs of burning out as well. Looks like a rebuild is in store. Ouch that hurts! At lease it happened now instead of during the Fire Season when the truck can be making money. Trouble is last Fire Season is so far away that I'm broke. No money but lots of time so I'll be doing the wrenching myself, no big deal. Any inexpensive tricks I should do while the engine is out of the truck? Just replaced the Tranny and transfer case, new breaks. Before long this truck will be like new but right now it feels like Fix Or Repair Daily!!
Good Day .... Ken Gardner
Pulled the head and found a huge hole in the piston. It had melted down around the 2-oclock position. Very little damage to the cylinder wall, thank God. Piston #2 is showing signs of burning out as well. Looks like a rebuild is in store. Ouch that hurts! At lease it happened now instead of during the Fire Season when the truck can be making money. Trouble is last Fire Season is so far away that I'm broke. No money but lots of time so I'll be doing the wrenching myself, no big deal. Any inexpensive tricks I should do while the engine is out of the truck? Just replaced the Tranny and transfer case, new breaks. Before long this truck will be like new but right now it feels like Fix Or Repair Daily!!Good Day .... Ken Gardner
.
One reason I always tow the trailer with stock only tune.
Posting Guru
Joined: Jul 2004
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From: Buckingham, IA
For what it's worth, the dealers usually raise the cab off the frame to get to the engine. Makes the job a lot easier and actually saves time. If you have access to a two post hoist, that would help. Others can give you advice if you have to pull the engine the "normal" way.
ernesteugene, good to hear from you. Sure miss you on here.
ernesteugene, good to hear from you. Sure miss you on here.
Postmaster
Joined: Jun 2006
Posts: 2,647
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From: Fulltime RVer
Regarding burned pistons and elevated EGT, I've read several places (Bank's web site among others) that holed pistons are usually due to repeated insults (operating at marginally elevated EGT) rather than due to a single event at very high EGT. It seems that the aluminum metallurgy changes and weakens over time, and a work truck seems to fit this category of failure mode.
Also, an over-fueling injector can elevate EGT in a single cylinder to over 1350 F, but since an EGT probe averages over 4 cylinders, the gauge will still indicate an apparent "safe" reading.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
I thought you towed with a DP 40 TOW? However, I agree with a stock tune being safer. When towing a long steep grade I found that I couldn't use all of the fueling from my DP 40 TOW without exceeding 1250 F, and I always had to keep a close eye on the EGT while modulating the throttle accordingly. In stock tune, I could stay at WOT and remain well below 1200 no matter what the grade was, so that I could just watch the scenery go by and glance at my gauges occasionally.
You and I have a lot in common. I love to just set the cruise control and watch for geese migrating, or interesting viewpoints to pull over and enjoy.
The 4.88 axle won't let me go any faster, no matter how much HP I have under the hood so the only difference between stock tune and tow/haul is elevated EGTs and 1.5 less mpg.
So it's stock tune from now on.