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Let me begin by apologizing for a long post.
I had an huge amount of work done to my 2004 Excursion (early model 6.0) earlier this year. ARP studs, new HPOP, ICP, IPR, Ford lifters, Ford push rods, EGR delete, Bulletproof remote oil cooler and filter, EBP sensor and tube, Ford head gaskets, and a bunch of other stuff including eventually a new FICM (not Ford) and a new 140 Amp alternator.
My problem is it sounds to me like some sort of metallic tapping is going on and it doesn't feel as smooth as I would expect -- like a very soft miss. Currently the tech says that there are no "low contributing cylinders". I am wondering if there may be a slightly bent push rod? He is adamant that a bent push rod won't stay where it is supposed to -- I say it depends on how bent it is. I am also worried that a rocker arm may be bent or deformed in some way.
My question is this; Once the valve covers come off -- if nothing looks wildly wrong, where do I begin to confirm that I do not have bent push rods or damaged rocker arms? He says that in order to check the push rods we would have to remove head bolts off of the rocker arms (I think I have that right). But he said we run the risk of compromising the head gaskets if we touch anything like that. If we have to remove head bolts (stud nuts for me?) can you take one rocker arm loose, check that rocker arm and push rod, and put it back together safely? Without having to pull it all the way down and put new head gaskets, etc? That would mean releasing the clamping pressure across both heads at each rocker arm -- is that creating the potential for blown head gaskets?
I know in my youth we would roll push rods on a sheet of glass (12" X 12") because glass is supposed to be flat -- can't bend it or deform it without breaking it first. I assume that still works.
Can anyone help me here?
I now have a Scan Gauge II but it is not set up yet to check all of the readings for the sensors. I also believe I need to check for leaks with simple green and to make sure I don't have any exhaust leaks. But what about the push rod/rocker arm question? Is there another way to verify integrity?
Thank you,
Doug
Last edited by doug42190; 06-07-2016 at 06:50 AM.
Reason: mistake corrected
You don't have to remove the head bolts. You remove the injector and there is a special tool that goes down the injector bore, secures and compresses the valve springs.
It's not cheap but most guys just buy them and then resell for almost the same price.
Five0Jester,
Thank you so very much -- that is perfect! Yes, a little pricey but I can see how valuable a tool like that is. I am certain one is going to be added to my tool collection soon -- new or used.
uhh, yeah. What is the thinking behind the shorter pushrods?
Was the geometry of the valve train found to be wrong after so many millions of collective miles?
How much shorter are they?
uhh, yeah. What is the thinking behind the shorter pushrods?
Was the geometry of the valve train found to be wrong after so many millions of collective miles?
How much shorter are they?
.050 shorter. All I know is when you go into Ford and buy new push rods for a 6.0. They're for the 6.4 That would tell me, yes. A geometry issue.
I cannot add to that other than to say while I was researching all of the mods, tweaks, and repairs I was investing in last February, that was something I ran across. Not sure where now.
Doug
I don't know if we will ever get anything other then speculation on why the shortening of the pushrod. But.......
A too long pushrod would bind the hydraulic lifter in its compressed travel and cause the valve to slightly keep the valve open, burning the valve. We don't see that.
A too long pushrod only makes a change at the hydraulic lifter end, there would not be any change in geometry of the valve train above. Other then the above possibility.
The only real problem we know of is that the original length pushrod can cause valve train bind on initial build, bending the pushrod, so you have a specific clocking of the crank to prevent the occurance. Maybe it's as simple as the shorter pushrod was a design change to eliminate the initial build bind condition, but the literature never caught up to the design change, or International felt just kept the literature in place, in case someone reuses the longer pushrod or aftermarket suppliers don't manufacture the design change.
Since we're on the discussion of pushrods, this is one of the first prototypes of a carbon fiber pushrod ever made in the world. Light as hell and great for a very fast acceleration, high revving engine. And it doesn't bend.
I worked for a seed company of Exxon called Graftek in the late 1970's. Commercially we were known for sporting goods, golf clubs, tennis rackets, fishing rods, first production carbon fiber bicycle, etc. What wasn't known were the automotive parts we were developing in the background. Engine components, driveshafts, springs, both coil and leaf. We were the first company to make those products.
Anyway, enough of a hijack, something I seem to do a lot of lately.
Not a hijack by any means.
Now that's interesting -- the carbon fiber I am familiar with is cloth-like -- what did they do to form it into a cylinder/tube? What was the life expectancy? For racing, that would be a brief application and then replaced, I assume. I guess the 200,000 mile application not so much?
Most people are familiar with woven products, but that's not a very strong product. You need straight fibers and oriented in the direction for the best strength. In the case of the pushrod it's made from unidirectional fiber, all laid in one direction on what is called prepreg. Think of tape, all fibers running lengthwise in a single layer thickness, impregnated with epoxy resin. In this case, several tapes were laid upon one another but the fibers were set at 2 degrees to each other, close to perfectly straight but given some twist as perfect 0 degrees is impossible. The tapes are cut to length and then rolled into a tube shape.
Life expectancy is the problem as hot oil does a number on resins, even epoxy over time. Having a tube that flows oil doesn't help. Later versions had a layer of woven Kevlar to protect the composite as well as restrain the fibers if/when the pushrods would fracture. Great for a few hour race, not so much long term. But they cost so much to make that they were a racing item only. There are most cost effective ways of making a lightweight pushrod.
I've got some very thin lightweight tubes made from unidirectional fiber that are incredibly light weight that you just can't bend. Skinned honeycomb or tubes are the best applications and you can orient the fibers for the strain. Woven fabric is not strong at all, 50% of the fibers are sideways without strength and the ones caring load bend over and below the cross-laid fiber. You want straight fibers. Think wood.
If you really need strength in multiple directions you are better off laying unidirectional fiber at different angles, even up to 45 degrees increments, in layers.
As one of my hobbies I am rebuilding a 28 foot tuna fishing boat. I don't use carbon fiber but I do use yards and yards of biaxial cloth -- both 90 and 45 degree and gallons upon gallons of epoxy (not West System -- too $$$). That was why I was wondering how the tubes were constructed.
Thanks for the information. I can only imagine the cost and how short the life expectancy is.
Doug
06-07-2016, 06:48 AM
How do I diagnose and replace a bent push rod?
