garyb Posted December 18, 2012 Share Posted December 18, 2012 have an 08 with cylinder 1 and 8 missing, found shrtft on both of those cylinders around +16, manual power balance screen shows those cylinders missing,relative compression showed cylinders 7 and 8 down 5%, manual compression shows cylinder 8 at 350psi, 7 at 380 psi, and the other cylinders at 400 psi, going to try do a cylinder leak test on cylinder 8 thinking that the easy way to make sure valves are closed is to remove rocker arms since they are suspect any way,but removing the fuel supply tube would make me to have to replace and can not get the cab off on this f-450 because rack that goes over cab what kind of times are you guys getting for rocker arm replacement if this is it? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted December 18, 2012 Share Posted December 18, 2012 Ummm.... you don't necessarily have to replace the fuel lines. We discussed re-using injector lines before, I think that it was discovered that the lines have been reused up to 4 times without issues. It would be preferable though. I have done this quite a few times now without a single leak and since the fittings in question are very visible you will know if they are good or not. I reinstall the fuel rails, connect the lines and torque as outlined in the manual then give the nuts about 1/2 of a flat extra turn beyond the 1 flat turn specified. Quote Link to comment Share on other sites More sharing options...
garyb Posted December 18, 2012 Author Share Posted December 18, 2012 THANKS KEITH THIS IS MY FIRST ROCKER ARM JOB IF THAT IS THE SOURCE OF LOW COMPRESSION, WANTED TO REMOVE #8 ROCKER ARMS AND PERFORM CYL LEAK TEST TO VERIFY NOT GOING PAST THE RING. AND THANKS FOR THIS FORUM EASIER TO TALK WITH OUT WORRY OF WEB MASTER MONSTER WATCHING WHAT WE SAY. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted December 18, 2012 Share Posted December 18, 2012 manual compression shows cylinder 8 at 350psi I don't want to be a negative nelly, but every 64 I have worked on with 350 psi compression on cylinder 8 or 2 ended up being a bent rod.Usually a cylinder leakage test will not catch one of these rods that is "barely" bent. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted December 18, 2012 Share Posted December 18, 2012 I'm not saying you have further engine damage than rocker arms. The last one I worked on only needed rocker arms (it got a complete set). But don't leave yourself open for other problems. I would make sure that they understand that the rockers may not be the end all to their problems. Always good to leave it open ended on a 64.Worst case scenario that I was talking about, truck ran decent but smoked sometimes. Ended up with 4 bent rods all reading no lower than 350 psi.Green arrow tells the tale that the leak down test wouldn't.Resulting contact with crankshaft counter weight.Management made me repair this engine and put it back into service. Quote Link to comment Share on other sites More sharing options...
garyb Posted December 19, 2012 Author Share Posted December 19, 2012 looked at history on this engine and has multiple repair attempts at cylinder 8 had rocker arms replaced a yr ago, #8 injector was leaking and replaced, egr cooler failure a couple of times, and when i performed cylinder leak test was leaking about 21-22% could hear air from dipstick tube and removed oil fill cap and hear leak,regulated the air to 100 psi and gauge would drop to 90psi, but this is on a cold engine and piston is not necessarily at tdc on compression just removed rockers and did test dont have any further autherazation to tare down, rockers show tips possibly recessed but not broken need new rockers to compare to no real obvious damage. Also seen turbos was replaced over leaking oil at 1 time. history has me concerned , a couple of those other repairs could have missed slight engine damage and sent this guy down the road. Quote Link to comment Share on other sites More sharing options...
garyb Posted December 19, 2012 Author Share Posted December 19, 2012 hotline states that cylinder leak test is not recommended in diag procedure because compression helps seal valves, was unaware of this I thought that i seen this test some where on this post, possibly on 6.0 liter which seams to have a simular valve configuration. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 16, 2013 Share Posted May 16, 2013 Has anybody ever figured out what causes rocker arms to break in a 6.4? I only ask because I replaced all the arms on one bank on 2 days ago, and now the truck is back with a horrendous bottom end knock. There was a substantial amount of metal filings in the oil after the repair, which hotline related to the broken rocker arms, and told me to change the oil and let the filter do its thing to remove filings from the lubrication system. I am wondering if the arm broke because we had a little piston to valve contact due to a failing rod... Ideas? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted May 16, 2013 Share Posted May 16, 2013 I often thought excessive idling might be a contributing factor in rocker arm failure due to poor oiling up top during long idle periods. What is the average MPH when dividing miles into hours? Did any of the other rockers show wear when removed, or just one fluke broken arm? Remember the oil filter only works on a warmed up engine, oil filters bypass up to 90% of the oil during warmup because you can't push cold oil through filter paper. Random thought- if you see flakes in the oil and mgmt decides to run it, would it be a good idea to run the engine 30 minutes on a mix of 75% diesel fuel and 25% engine oil in the crankcase to flush it, and then change the oil and filter again? Running a super thin mix would be filtered much better than regular 15w40, and the thin mix would not be detrimental if the engine were not loaded. (think of what lubes a two stroke MC engine, and if the turbos were not heated up they would be OK with the thin mix) Sorry for your pain, it sucks when shit like this happens. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 16, 2013 Share Posted May 16, 2013 It's no pain. I documented everything properly. Inolved hotline at every step. It is a good customer who is 3 weeks from the end of his warranty, so I'm quite content that he's getting an ESB. He was going to spend $5K on DieselCare, but now he won't have to-seeing that the early shortblock will be gone. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted May 16, 2013 Share Posted May 16, 2013 Every broken rocker I have pulled off of a 6.4L had all of the rocker tips worn down, seized or missing. This causes the rockers to start operating with a tilt on them. If worn badly enough the lifters can hyper-extend. The last one I did even blew the rocker apart. The broken rockers are almost always broken out on one side around the fulcrum ball. I consistently hear that the rocker arm failures were attributed to poor maintenance. Quote Link to comment Share on other sites More sharing options...
lmorris Posted May 17, 2013 Share Posted May 17, 2013 I had one that broke the tip of the valve stem above the keepers, what a mess. 2 new valves, a bridge and rocker fixed it right up. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 18, 2013 Share Posted May 18, 2013 I've had a bit more time to look at mine... The noise it's making isn't the bottom end, it's just popping back through the intake. Something is wrong with the lifter-which must have been what caused the initial failure. I pulled the VC off, and the exhaust valve bridge has fallen out. The push-rod is engaged to the rocker arm and the lifter, but I can slip the bridge in and out with no problem. Quote Link to comment Share on other sites More sharing options...
2006 Posted May 18, 2013 Share Posted May 18, 2013 I've seen that recently. Truck came in with a missfire and no engine noise. Replaced 1 broken rocker arm. Started engine, the missfire was gone but it made a popping noise. Ran the engine without the valve cover and I could almost remove the bridge by hand. Ended up being a roller lifter. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted May 19, 2013 Share Posted May 19, 2013 I got one right now that's getting long blocked because of a roller lifter. There's no way I'm interested in marrying one of these. Quote Link to comment Share on other sites More sharing options...
Aaron Posted May 19, 2013 Share Posted May 19, 2013 Says the 6.0 owner. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 21, 2013 Share Posted May 21, 2013 I was pricing out DieselCare for a few customers of ours... DieselCare for a 6.4 is around $2000 more than it is for a 6.7. That just helps to confirm my arguement that the 6.4 is the biggest piece of junk diesel engine we've seen in a long time. Sorry, Aaron. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 21, 2013 Share Posted May 21, 2013 Update... I've pulled the head to check the lifter, but I can't get the lifter out of the bore. It is sitting about half an inch lower than the others, so I would assume the roller has failed and mangled the bottom of the lifter. Quote Link to comment Share on other sites More sharing options...
Mikill Posted May 22, 2013 Share Posted May 22, 2013 ^^^^When the lifter is mushroomed at the bottom and can not be removed the cam lobe is usually trashed as well. The were saying to replace the short block when that happens because of damage to the lifter bore but not sure about lately. Haven't had one in awhile. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted May 22, 2013 Share Posted May 22, 2013 Well, if he can somehow force the lifter out then I am sure the bore would be damaged. Maybe the lifter can he held up as far as it will go and the camshaft slid out allowing the lifter to drop out of the bore and be retrieved? Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 22, 2013 Share Posted May 22, 2013 Or, I'm just putting in an ESB and not worrying about getting the lifter out. Quote Link to comment Share on other sites More sharing options...
joshbuys Posted May 23, 2013 Share Posted May 23, 2013 Short Block that one, don't even mess with it, I've personally only seen a handful with this type of failure where the lifter bore didn't have some damage. If the lifter is mushroomed out enough to keep it from coming out of the bore then it has made contact with the bottom of the bore and damaged it. At least that has been the case in all the ones I've done. If you pull the head off the opposite bank you can look down between the lifter bores and see the mushroomed lifter/damage to the bottom of the lifter bore. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted May 29, 2013 Share Posted May 29, 2013 Update: The one I long-blocked ended up making it no more than 50 KMS. (about 30 miles) on the post-repair road test (my home and back into work), before needing towed back in with cylinder #1 intake rocker broken. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted May 30, 2013 Share Posted May 30, 2013 Update: The one I long-blocked ended up making it no more than 50 KMS. (about 30 miles) on the post-repair road test (my home and back into work), before needing towed back in with cylinder #1 intake rocker broken.Okay, after getting it back together and having it run on all eight cylinders again for a good couple of hours without issue, it now refuses to start ............ Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted May 30, 2013 Share Posted May 30, 2013 I've never done a 6.4 long block... Only complete drop ins or ESBs... What does the long block come with? Quote Link to comment Share on other sites More sharing options...
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