OEM or aftermarket? Any recommendations? I am going to go KDD Chrome-Moly push rods, I am also going to replace the lifters while the cab is off and the new KDD O-ringed heads are going on. This 6.0 is stressing me out... but I have had 2 people offer to buy this EX randomly just this week... She aint going nowhere....

 

OEM, so any head studs on the list?

 

The engine is already studded, my mechanic believes the heads that are on it are cracked, so we are going to reuse the ARP studs.

Are MAHLE lifters OEM? Does anyone know?

 

My understanding lifters were originally supplied by Eaton to International, and when they stopped making them International switched to Delphi.

And that would be OE, not OEM. A company can produce a product for the aftermarket that was different in manufacture than produced for the assembly line. My old company did this all the time, and it was still labeled as an "OEM".

When you're redesigning the valve train, you need to think about what part you want to become the "fuse", the weakest link. Right now it's the pushrod. The next from guys that I've observed who go with cam, springs, and pushrods often find the rocker arm is next. So to me, the question becomes what part to you want to sacrifice when things go bad?

 

Im assuming the rockers are in good shape. I will grab OEM Pushrods instead of chrome moly and try and find Delphi lifters. I found a complete set of Mahle lifters for $199 but don't want to buy anything subpar.

 

I didn't try to find Delphi lifters, I just bought the OE in the packs of 4. Once you get into the aftermarket world there is no way other than field experience to know how things hold up, no way to know what the materials are made from, how they are heat-treated, how the quality control is. Not to say I'm not using aftermarket for certain aspects, but that's a leap of faith. The same actually holds true for OE.

Rockers, like any other component, are susceptible to stress fatigue. I'm going with the Colt Stage 2 cam that increases valve lift by approximately 0.035". That stresses the springs more as the rod they are made of twists more. I won't be going high rpm so I'm not worried about the acceleration change from opening to closing, so I'm staying with the stock springs. But the lift brings the valves damn close to the pistons, and I've had to work the problem to get to where hopefully I won't be pulling this motor apart again.

I've done the Hertzian Contact Stress calculations for the cam and roller, and they are high. About 35% higher than the 7.3L valvetrain; my numbers may be off because I have no direct knowledge of the exact materials used, but the 7.3/6.0 is a relational situation anyway. The cam and lifter are highly stressed components in this motor. The lifter roller is barrelled and flattens out on the ramps and nose of the lobes. The lobes also have plastic deformation under the load. It ain't an area you want to stray too far down the rabbit hole.

My first "real" job was in the composites industry, and we were the first company to design automotive parts like leaf springs and driveshafts. But the other things I helped develop were carbon fiber pushrods and coil springs. I have one of those carbon fiber pushrods in a drawer right behind me. Damn light, damn strong, and won't bend. I have respect.

I'll go find it, but as has happened before, here's a guy with KDD heads that went to an aftermarket cam, higher-rate springs, and stronger pushrods. This is the classic tale told over and over with the 6.0 and those changes. Most design engineers at a minimum go for 150% of use. Some, when the bean counters let them, go to 200%. Where do you think the rocker arms are designed to?

This guy is not someone I listen to, FYI. He thinks is just a worn-out part.

 

Never trust a grown man that wears white framed shades...6.0 Bros!
I was looking at lifters today and ran across Dynamic Diesel’s HD lifters that are supposedly the only lifters made in the USA. I called the shop and spoke with Paul and I got a whiff of a snake oil salesman similar to Bill Hewitt. I asked where the lifters were made and he couldn’t disclose the source but claimed they are made in Detroit Michigan. He explained what makes these lifters twice as strong but $60 cheaper than stock ones by shaking a stock lifter and asking if I could hear the “roller slack”. He bad mouthed some other businesses before telling me he needed to get back to work so that was that. I did some more digging and the shop has a terrible reputation so I passed. I think after confiding in Jack I am just going to get stock lifters and guides and possibly a cam if mine looks bad once I get in to inspect it.

 

There are guys who race that might have some good sources. But I'm looking at the valvetrain as a situation of fatigue....over time.

 

It'll be inspection time for me soon, so I too am looking at OE/Stock lifters. I explored other options but Ford/OE lifters lasted this long with longer pushrods, how much longer could new lifters last with new shorter pushrods that stress the valve train less?

 

They should not stress the cam or valvetrain as the plunger has room, otherwise, we would be seeing burned exhaust valves.

When I talked to Geoff Bardal (Colt Cams owner) about the issue with my cam I also asked him about the need for original or 6.4 length pushrods, and he laughed. He said he and another cam grinder often laugh when the subject comes up as they think the change was nothing more than an inventory reduction. Either is fine.

I had previously looked at cam offerings by Dynamic Diesel and at that time for their Stage 1, you sent in your cam as they reground used cams to that profile. They had/have a video that says with the reground cam you have to use the longer pushrod or the valve train will fail in a few thousand miles. There will be too much valve clearance at the base of the lobe and the lobe as it comes under pressure will fatigue itself to death. They now use a new billet to make the cams, and they now offer a stock cam. Their pricing is less than Colt, and although I didn't talk to Mac about this, I also did not come away warm and fuzzy - went to Colt. I didn't think of it at the time, but I could have asked Geoff if he would grind a new Stage 1 cam rather than a regrind. I really did not want a reground cam.

So you regrind a cam maybe 0.050 to 0.060" and you have too much clearance with the 6.4 pushrods. That doesn't sound like a deep intrusion of a pushrod to me. I think that's what got me all wonky, a non-published video when I heard the thump in my exhaust. You'll hear this again, thank God I freaked and took my motor apart. But as I go back as listen to my motor start in ALL the electrical videos, I can hear mini-thumps with the ground cam CAT put into my motor. And in the cam video, I documented how the lobe baselines got smaller towards the back of the cam, probably close to the issue that DD was talking about. My motor was rebuilt with the 6.4 pushrods in 2010.

When I did the lifter video I documented how much the lifter plungers can go deep into the lifter body, and there's room for both pushrods. Jared at KDD noted years ago that he saw variations in the rocker arms and he thought that is why International went abnormally deep into the lifters, to address that manufacturing issue. That makes sense as the typical pushrod recession in motors is not that excessive, 0.030-0.040". It may be that the problem was a 2003 production issue, so the need drifted away.

I may be on the verge of checking how deep the pushrods go into the lifters in my setup, but that will not answer the question of stock motors as my base circles should be different with the Stage 2 then OE. Not sure I want to revisit that step.

I won't bother you guys sticking my video link here, you guys are pretty well played out with them.

 

Not everyone is played out Jack, especially people like me and SmackDaddy who are about to tear into our engines like you did. Me for the same purpose as you, but him to reseal the bedplate and bearings.

Since my heads were milled down some, wouldn't the shorter 6.4 pushrods make sense or is that still crazy talk?

 

I think your videos are very interesting and full of information any person that owns a 6.0 should know.
I have my stock pushrods and will compare them to the 6.4 pushrods when I pull them. Both Motorcraft parts.

 

If the machinist adjusted the valve stem height properly they would be fine. That takes some math, which if you are a good machinist, should not be an issue.

When you re-surface the seats lets say you taken down 0.002". And you've refaced the valves, another 0.003". Then you've taken 0.005" off the deck. The valves have a greater recession by 0.005" and the head sits lower by 0.005", a total of 0.010". BTW, despite what BPD has shown on the .org, It's incorrect that FelPro gaskets have the same thickness as OE. FelPro is 0.010" thicker, measured by me and they triple-checked their own design and stock to confirm, to compensate for the possibility of machining. Even without machining, I need that extra height for my Colt Stage 2.

Some will not touch the stems, because the lifter should have enough depth to compensate. In the example I showed about with the old pushrods it should be 0.083", and the 6.4 pushrods 0.130". That's not what you want to do though to be precise, but there is compensation. But I haven't measured the exact depth the stock pushrods dive into the lifters.

A: More common is to take off on the stem whatever you took off the deck, 0.005".

B: But you should at least also take off the change in seat and face, another 0.010".

C: And if you really want to go German Engineering, you should add the average factor in the rocker arm ratios, race teams like Pensky and Roush adjust if the intake and exhaust are different like our trucks are. But you don't have to go this nuts.

Rocker 1.4 ratio x 0.010" = 0.014" off stem. There are enough other factors in the game that normally that should not be necessary. But International (or Ford) does not give a value for proper valve stem height over the spring seat, so it's really a hard task to exact sort through unless you are working on a uber number of 6.0 heads and have the value from multiple head measurements. I have a set of two. ??????

Option B should be fine.

Some quick data from my videos on my motor so far.

An issue with my needle bearings of 75k, with the knowledge there was a lot of debris running thought this motor from the CAT screwup of not fully cleaning the block and mis-assembling the bearings.


The fracturing of the lifter roller needles from debris entering the area, carried by the oil. A big enough fracture can jam the roller or once the friction level of the bearings rises higher than the sliding forces of the roller to lobe, roller flat-spotting will occur. The fracture can also occur with long-duration oil or overheated oil that has deminshed lubrication value. Good oil, not excessive oil temp. Know your Delta.





The compressive force on the needles is high, pounds per square inch. The values may be off as I don't know the exact alloy. At least the bearings are flat.




Lifter plunger force again the upper valve train, you would need more to open the valve but there is a force on the cam, roller and oc course rockers and bridges as there should be.




Compressive loads on the lobes and rollers. The "closed" lifter force is not over the entire base circle, its when the lifter's check valve is first closed and goes to a locked hydraulic state. The change in width is due to the plastic deformation of the roller which is barrel-shaped, and the compression of the lobes flat surface, slightly depressed. The depth of the stress is important in consideration of the depth of the lobe surface hardening. If you have a regound cam that is not re-hardened, or the initial hardening is at that or a lessened depth, stress fracture of the surface will happen sooner. Other things can screw this up, bad machining, lubrication, scuffing of the ramps (2003 cams design), debris in the oil, etc.

But when you compare the Hertzian Contact Stress values between the 7.3L and the 6.0L, and increase of ~35%, you can see why the 6.0 has a higher cam/lifter failure rate than the 7.3.








Progressive stages of cam lobe failure on 6.0 cams. The first two are from my own cam.



















The progressive failure of lifter roller surfaces, which I think may have a lower rate, it's the cam that fails first.





Stalling needle bearings.






Hey, now I don't have to do a video!

 

So I think when you pull heads, it's important to pull the lifters that you can and inspect the lobes with a borescope. Me, I'd pull the HPOP cover and if not enough access, pull the HPOP and check those back 4 lobes too.

 

So, I have ordered the following for my truck.

KDD Oring heads
MAHLE Complete engine gasket set, Including black diamond head gaskets
MAHLE OE Lifters (they are USA Made and delphi from what I can gather)
Ford updated Oil Cooler
Ford Push Rods
Ford Stand pipes
New S&B air intake with dry filter
Ford ICP Sensor and Pigtail
cam position sensor
crank position sensor
Ford Rocker clips

My mechanic has aggreed to pull the engine and remove ALL of the lifters for inspection and replacement. So that is being done as well as the new heads... etc.

QUESTIONS - Should I mess with the cam? The motor is coming out and going on a stand. I dont know what all is involved with a cam on this motor. How much more work would I be asking of my mechanic if I tell him I want to put in a new cam? Also, are cam bearings necessary? My mechanic said he would have to have a machine shop replace the bearings as he does not have the tools to do it right. If a new cam is recommended, will the above parts be compatible with a stage1 replacement?