A new twist in my ongoing saga after losing an oil cooler. If you have been following my travails you know I have been struggling with this engine. After losing the oil cooler I decided to do the ARP studs while we were tore down. I was having trouble with low power and extreme smoke after reassembly. After too many questions I purchased the Autoenginuity software. The initial scan showed cylinder 5 with low contribution. We removed the valve cover and oil rail and discovered a bent push rod in cylinder 5. We replaced it. When we restarted the engine it sounded much better but still some low rpm sluggishness and still some smoke. I ran it for a while and drove it about 30 miles. Still the same issues. It ran pretty good above 1200rpm. We rescanned and discovered a cylinder 4 low contribution. We had not seen this before. Tear it down, another bent push rod. Installed new one and bumped the engine over to see what would happen. It bent the new one too. If you push down on the other valve push rod there is some give. There is no give in the lifter that is bending the push rod. Help please.
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Ricatic
04 F250 CC SB FWD PSD
First Coast Diesel EGR cooler delete, ARP head studs, MBRB Turbo Back/no cat and SCT X3 tuner
stuck vale is the only thing i can think of.when i worked at the dealership i heard that some techs ended up getting heads that set on the shelf to long and the valves where seized in the head.
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ASE MASTER TECH FORD SENIOR MASTER TECH
I remember you had the heads machined....do you know how much was taken off? Someone please correct me if I'm wrong, but I seem to remember .008 as being the maximum that should be removed.
Maybe the pushrods are too long now, and they're bottoming out in the lifters.
Heads were machined at a very reputable machine shop. They do work for Roush and on Red Bull Racing Lycoming aircraft engines. They have done many 6.0 cylinder heads. When I got them back he said they were not too bad, 003 to 004 milled off.
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Ricatic
04 F250 CC SB FWD PSD
First Coast Diesel EGR cooler delete, ARP head studs, MBRB Turbo Back/no cat and SCT X3 tuner
I had a 6.0 once that would idle okay initially then start to miss on one cylinder. After a long process of tear down. I found a lifter that was pumped up too much and would not bleed down. Even after I took it out, i had to compress it in a vise to push the oil out. Before you get to pulling heads back off again, I would take a real close look at the rocker arm assemblies.
go to the http://www.powerstrokehelp.com/fubar..._part/1of1.asp and look at the video on 6.0 failure. it was due to a lifter failure and he goes over the required process to replace a lifter. Sorry for that in advance.
I also would think that it is a lifter issue. Could be trash in the oil flowing into the lifter and locking it up.
IF that is the issue, you MAY also have had a valve contact the piston. (Hope that I am wrong!)
Yes, it is required to remove the head to access the lifters and if its either of the back two cylinders on either side then you have to remove the trans and rear backing plate to remove the branch tube to access the lifters.
This is my first post; just want to say hi to every one. Now I am reading about this problem, and I am not sure is this common or not but I just had same problem. After replacing head gaskets and installing head studs I have bent push rod on cylinder number 4. Heads were machined in reputable shop but sit on the shelf for 6 month. After hours of diagnostics, replacing injectors, wire harness, IDM etc. I start checking for mechanical problem and my exhaust valve was not opening on cylinder # 4. I got new push rod and engine runs great, I did nothing else, and so I have no idea what could cause this but stuck valve. My mistake not check the valves I assumed heads were ready, but I guess not.
I also would think that it is a lifter issue. Could be trash in the oil flowing into the lifter and locking it up.
IF that is the issue, you MAY also have had a valve contact the piston. (Hope that I am wrong!)
On my last teardown I have pictures of all 8 pistons with 4 valve imprints per piston and I had NO bent pushrods OR bent valves. My only issue was headgaskets for the 3rd or 4th time. I would go for the lifter issue. Hydraulics can and do pump up and never release. Seen that from my old 400 pontiac days
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Ford Makes It, International Shakes It, Full Force Fuels It, River City Turbo Spools It, ID Tunes It, and Trucks Unlimited keeps her Rockin the Road with 500+ BADASS Ponies
i would try to stick a new push tube in again and turn the engine over by hand and work with it a little bit and see is it would start to go down. also its more common then I care to admit
You know what? I think you are right, this could be lifter issue. After new push rod was installed I did turn engine by hand and on the first turn it was hard to turn over, it will not pass 4th cylinder. I left it sitting like that for a while thinking what to do next, and then I have try to turn engine over again and had no problem. I made few more turns by hand before I was sure it turns over easy. I was not able to pin point exactly what was a problem so I assume it was stuck valves.
ya there was also a know about valve sticking as well but that only really seems to happen when the truck sits few long periods of times i.e a few months. when put heads on be it for head gaskets or new heads I tap each valve with a hammer to check to see if they are stuck
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Bent pushrod?
