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Another Rocker Arm Failure

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I replace the whole valvetrain on almost everything that has a rocker arm failure. Or at the very least that particular bank. Most of the ones I get that break work just like keiths picture. pushtubes, bridges, pivots etc are all worn.

 

Better yet is when the lifter blows up.....oh how I love you 6.4! Posted Image

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Better yet is when the lifter blows up.....oh how I love you 6.4! Posted Image

I'm glad I'm not the only one that loves the 6.4L. These engines definitely rank high up on the list of most horrible engines to work on, close to the 6.0L in E-Series.

 

Keith or anyone, is there any way one of you fine gents can upload a youtube video of what a 6.0L or 6.4L sounds like, when the camshaft goes South on one of these? It seems like I've been doing more reading than actually having one end up on my doorstep. The more I read up on the seemingly high failure rate, the more I get scared of seeing one.

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You have better luck than me. I replaced the rocker assy and pushrod and it made 80 miles before the same rocker broke. The vale moved freely but I suspect it had a guide issue? Lucky for me the lease company towed it away...Dont you love this stuff

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Quote:

Funny you mention that. Pretty much all 6.4L engines I've have the valve covers off of, have worn the ball pivot off almost completely where it contacts the valve bridges. Yet on 6.0L engines with equal or higher mileage they all seem intact. The design setup between the two are almost identical. What gives?


The 6.0 doesn't "grow oil" like the 6.4.
If you run the engine on part engine oil and part diesel fuel, bad things are bound to happen.

Has any other company used the term "grow oil"?
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Originally Posted By: rockbronco
Better yet is when the lifter blows up.....oh how I love you 6.4! Posted Image
I'm glad I'm not the only one that loves the 6.4L. These engines definitely rank high up on the list of most horrible engines to work on, close to the 6.0L in E-Series.

 

Keith or anyone, is there any way one of you fine gents can upload a youtube video of what a 6.0L or 6.4L sounds like, when the camshaft goes South on one of these? It seems like I've been doing more reading than actually having one end up on my doorstep. The more I read up on the seemingly high failure rate, the more I get scared of seeing one.

I thought I would never say this but I would probably choose a Eseries ambo to work on over a base engine issue 6.4. Being a mostly fleet shop I see the worse of the worse when it comes to maintance. They just dont get what oil changes mean. When stuff goes bad it goes bad fast! Hey we all saw the base engine problems coming when we went to a common rail fuel system. There is no failsafe so to speak now if its out of oil, not like the 6.4 has that problem though!!

 

I will try and record one next time I get one in the shop. Ive had trucks that run fine but have the tell tale lifter/rocker knock at idle. We start taking bets when we will see that back on the hook!

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  • 3 months later...

The last 2 I have done I have been able to re-use the old line from the pump to the rail with no leaks. I tightened up the line before tightening down the rails fully to make sure I had them in the same place as before loosening them.

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I contacted hotline on this truck so I would have some documentation of what items were recomended to be replaced being this is a customer pay job.Hotline suggested I replace all rocker assy on this one side and inspect push rods.No push rod damage but the cylinder is now low on compression.(200psi).With all valves closed the exhaust side rocker is still tight as if it is under pressure on cylinder #3.What will cause this.Lifter?.

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There are 3 main failures on these:

 

1: the roller grenades and causes alot of play in the rocker and damages the camshaft.

 

2: the lifter siezes in it's bore and keeps the valve open, the piston hits the valve and usually bends the valve and/or breaks the rocker arm.

 

3: the valve seizes in the head and does the same damage as #2

 

What I have been instructed to do in the past is remove the rockers and inspect them along with the pushrods. Check the valves to make sure they are not sticky, if so remove heads for further inspection. Check the lifter movement to see if it is stuck. I just put the pushrod back in and cranked over the engine to see how much it moved.

 

You may be looking at pulling heads on this one regardless.

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The last one I did I also contacted the mother ship Posted Image who recommended inspecting the rest of the rockers. Good advice. More than half were either worn to the point where the tips no longer pivoted smoothly or not at all. That truck got all new rogkers and pushrods. (push tubes for you Canuckians) Posted Image

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Dustin, the 6.4s with pooched cam/lifter that I have heard sound almost like a 7.3 with a bent push tube (something akin to the whopwhopwhop of a helicopter. Pop out the air filter and you can hear it plain as day.

 

Leon, I'd be a tad careful when not replacing any fuel lines... especially if fuel lines are getting charged out on the RO... Personally, I wouldn't get involved with such an adventure... period.

 

John... use a dial indicator to verify lifter movement. Intake lobe lift should be 0.229" - exhaust 0.2326 -allowable loss is 0.002". FWIW, we used to have one tech that couldn't install pushtubes to save his life.

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(push tubes for you Canuckians) Posted Image

 

Funny, I have been in Canada for 35 years and never heard the term "push tubes". Even going through my apprenticeship they were push rods.

 

Also, has anyone noticed that the new rocker arms have a small hole drilled into the end for the push rod. New rockers for the 6L are the same way. And the 6.7L has them factory installed.

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I did some 6.4 rocker arms and had the same low compression in one cylinder after the repair. I found the metal clip on top of the lifter came out causing the lifters push rod cup to roll. I got the cup back in place minus the clip but it didn't matter the engine blew up 500 miles later due to a front cover failure. Truck was a 08 F550 paramedic/rescue unit and I wasn't going to short block this one. I put a stick on the accelerator pedal out back of the shop until the engine locked up, got a new complete drop in for this one.

6.4 engines SUCK ASS. Posted Image

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Funny, I have been in Canada for 35 years and never heard the term "push tubes". Even going through my apprenticeship they were push rods.

 

That was a Grampy Jim reference. Posted Image

 

FMT - I think we can all agree that the 6.4L is a bit of a strange engine with the ways that they can fail. Perhaps the new calibration will help reduce the number of catastrophic failures we see over the years.

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Welllllll, push tube ain't so Canajun nor is it so Grampy Jim-ish....

 

A reference to a Cummins service tool "Specifications: 3375522 Cummins Service Tool: Injection Timing Tool. (3375522) The tools is required to determine the relationship of injector push tube travel to piston travel so that fuel injection occurs at proper time."

 

From an advertising brochure extolling the virtues of the DDEC engine "The overhead cam allows for direct actuation

of the fuel injectors without push

rods or push tubes. The result is high fuel

injection pressure and better fuel economy."

 

From the manual for installing the TECbrake on a 3406 "4. Insert the rocker adjusting screws into the push tube

ends."

 

And from the manual for installing a PACbrake on a Cummins "Check that the bottom end of each push tube is seated in the cup of the cam follower.'

 

What's in a name? Back in ancient times, a "push rod" was a push rod - solid with no hole up the middle. Then manufacturers discovered they could make a sronger piece without adding weight by making them tubular... Called "push tubes" by some and "push rod tubes" by others, some die hard old timers could not give up the name "push rod". Still later, manufacturers discovered they could make these hollow push rod tubes part of the oil delivery system and used them to transport oil to the - hmmmm, I'm not sure if we should call it a "valve cover", a "rocker arm cover" or a "rocker box"... Posted Image

 

Younger people hear these misnomers and mispronunciations and keep the old flames (if not burning, then at least) smouldering. (Nothing new here... it's Wenzday here in Alberda and in May I should be going back to Emmonon - prolly have a sammich for lunch.... but I'm sure you get the picture).

 

Somehow I got used to using the term "push tube" for those pieces that are part of the oil delivery system and "push rod" for those that aren't.

 

Posted ImagePosted ImagePosted Image

 

It's been about 50 years since the last automotive automatic transmission was manufactured that had a rear fluid pump in it. Most of the techs I know have never even seen a transmission with a rear pump in it... yet everyone (even me when I get caught up in the giddyness) feels the need to call the transmission fluid pump a "front pump".

 

Bill.... the 6.0 certainly did have problems with "growing oil". T'would be early aught three and leaking injectors were all too common. At one point we were making bets on how much "oil" we would drain out of a motor.

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Welllllll, push tube ain't so Canajun nor is it so Grampy Jim-ish....

Well you are the ONLY person I have come across using that "name"... come to think of it, you use a lot of terms I havent heard anywhere else! Posted Image

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Originally Posted By: Jim Warman
Welllllll, push tube ain't so Canajun nor is it so Grampy Jim-ish....

Well you are the ONLY person I have come across using that "name"... come to think of it, you use a lot of terms I havent heard anywhere else! Posted Image

"Old speak" maybe?

 

There'll always be one that you haven't heard yet... I could use 'gudgeon pin' just for the sake of using 'gudgeon pin'. Crankshafts used rope packing instead of seals.... we'd call it a propeller shaft.. release bearings could be throw-out bearings...

 

Some of these terms may be obscure to some folks (depends on if you've lived a sheltered life or not, I guess Posted Image )yet common place to others? I guess one mans creamed chipped beef on toast is another mans shit on a shingle....

 

Besides... I might actually keep some of you on your toes....

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