Cam Failure

[dwg86]

Crane offers something called Mikronite. Its expensive!!! $135.00 fro a cam and $200.00 for a set of lifters(16).

That's after you have bought the cam and lifters....right?

Hijack!!!!!
I wonder if that would help a stock cam that was ground for a roller, like SIXPAK did!


More on this story here:
viewtopic.php?f=5&t=105
Fourth page, 2nt post!
Hijack over!!

Flash

Yes, thats after you pay for the cam.

[Flash]

This link might prove interesting. http://www.camshafteng.com.au/fail.htm Read just below the Bullet Major lobe tip wear, major follower wear on isolated lobes only:- Be sure to look at the photo of the lifter bottom.
Check out the home page and you will find it interesting too.

Check out this link to cam lobe tip failure photos. http://www.sacskyranch.com/camshaft.htm

John

Been reading on the First link above and thought this was vary interesting.........

Many of the cam followers supplied these days are made using cost cutting processes where the material structure at the critical centre contact face is only partially chill hardened, and with associated intergranular flake graphite. This is a structure barely adequate for the level of contact forces imposed in engines even at standard specification.
Under repeated high contact forces, cracks form along the graphite flakes and material grain boundaries, such that grains become dislodged, causing pitting of the surface. This further reduces the ability to support the loads, and wear debris which increases the rate of wear to the point of rapid major failure.

I have always wonder why these pits form on the tip of the lobe(Had thought previously, that installers, were just not paying attention to the flaw when thy were installed new )

Flash

[Flash]

I've had several failures in a variety of cam manufactures I swapped to Johnson lifters and haven't had a failure sense. I've been in contact with them to make one with a EDM hole which would even be better no luck yet though.

Were Due you find these Johnson lifters.......and what make them so much better then the others?

Frank, so your machinists thing the problem was created, and can be cured with heavy doses of ZDDP?


Flash

[FrankZ]

No, we're both still stumped. Improper breakin and a lack of ZDDP would cause all of the lobes to exhibt the same wear and isn't the case. So we're back to lack of oil or a faulty cam.

If the cam was the problem then again I would expect wear on all 12 lobes.

The oil pressure has always been good, so the oil supply is adequate as far as the sensor is concerned. Is the oil getting to where it needs to be? Damn good question that I simply do not have an answer for.

[John]

But if the lifters had a less than uniform heat treat, they could flatten a cam with a non uniform failure pattern. (They wouldn't) have uniform wear). If a set of lifters had this condition and the best zddp oil was used it might mask it for a long time. Sacrificial surface for high shear (flat tappet) If such a motor tended to run hotter in the rear we would likely see most failures in the back half of the motor, if the motor saw much idling, warm up's etc, no amount of zddp would prevent this failure. Just thinking out loud, lifters used to come almost chrome looking on the bottom wearing surface, and comp and crane cams had a better finish on the lobes than todays offerings.
Are you still working with McCabes? If so ask them about lifters, Have they looked at the bottom wear surfaces of that set.
John

[John]

Flash, did you ever run any Rhoads lifters? I will swap in a set of the Rhoads superlubes shortly.
John

[FrankZ]

I'm not familiar with the exact process, but it would seem that the cam lobes are not heat treated individually, rather the entire cam is heat treated? Am I way off the mark here?

[John]

Most heat treating is done by the blank manufacture, couple places in Michigan makes most every bodies cast blanks. Yep heat treated as a unit for uniformity. Sold to XYZ cam Grinders and Detroit's auto mfg's.
The company that buys and grinds this casting will go through several steps to grind, surface treat the wear surfaces, the surface hardness quality and grain structure can be damaged during this process.
John

[Flash]

Flash, did you ever run any Rhoads lifters? I will swap in a set of the Rhoads superlubes shortly.
John

No, personally i have not................but my buddy ran then on his chry small block, and I have know of a fue others that have us then. Using them on a 4.0L stroker??????

No problem with them.........except, they sound like a mechanical cam that has .010-.020" to much or loose valve adj.
Never heard of a lobe going flat or the Hyd going bad inside of the lifter..........But then again this was 10 years ago, when there was enough ZDDP, so we didn't need to know it was even in there

SUPERLUBESS?????.......Maybe were not talking about the same lifter.........Guess i will have to go do some reading

Frank,
I'm sure you read this link from John earlier..........but if not, here it is again..... good short read
http://www.camshafteng.com.au/fail.htm
Now you know as much as i do

One more thought, if you took a bad or poorly hardened lifter,like that, that is showed under the microscope.......... In the Link above, you could polish it up to look just as good as a properly heat treated lifter(You can polish a turd........but in the end its still a turd ) ...Sorry couldn't resist

EDIT: When and took a look...............a different way, of a cam saver lifter, with Rhoads Variable duration Hyd I like it!


Flash

[FrankZ]

HOW dose the oil pump affect the cam? does the driving of the cam try too force the cam to the back of the block or the front?
If the cam driving the oil pump, in return, cause/tries to push the cam forward against the preloaded spring in the cam button................ that might make sence(Don't know how much this theory hold water either.

WHY is it, that it's # 5 or 6? Has any one had #2 or even a #4 cam lobe failure??

Through the lifter bore and oil draining down from the head.

Water, oil and electricity all have one thing in common, they will all follow the path of leasst resistance. Substitute "Oil" for "Water and consider the path that the oil must travel. Is it easier (RE - less resistance) for the oil to travel to the far end(s) of the lifter oil galley or to the #3 & #4 lifted bores? Make sense?
I'll be pulling galley plugs and inspecting for blockage and or debris before reassembling my junk.

[oletshot]

HOW dose the oil pump affect the cam? does the driving of the cam try too force the cam to the back of the block or the front?
If the cam driving the oil pump, in return, cause/tries to push the cam forward against the preloaded spring in the cam button................ that might make sence(Don't know how much this theory hold water either.

WHY is it, that it's # 5 or 6? Has any one had #2 or even a #4 cam lobe failure??

Through the lifter bore and oil draining down from the head.

Water, oil and electricity all have one thing in common, they will all follow the path of leasst resistance. Substitute "Oil" for "Water and consider the path that the oil must travel. Is it easier (RE - less resistance) for the oil to travel to the far end(s) of the lifter oil galley or to the #3 & #4 lifted bores? Make sense?
I'll be pulling galley plugs and inspecting for blockage and or debris before reassembling my junk.

If this is referring to the HV pump being source of failure, that path hasn't changed between the standard and HV pumps. I would think the HV pump would be better. High volume pump should piss oil out all the same holes a standard pump would, just more of it because of the pressure build up. That may be part of the mystery, how does the cam get oiled at idle. Is it the squirt hole in the con rod? Maybe with HV pump the oil stream shoots farther and actually gets less oil on the cam than the standard pump. Just farting ideas outloud.

[seanyb505]

Its nice to know we have turds for lifters, the HV pump pisses oil all over the place, and oleshot is just farting ideas around the engine. Ahh, potty humor lol...

[oletshot]

Yeah, this thread is in the toliet and it stinks.

[Flash]

Getting back on topic

If the cam is lubed by the rod(and i thing it is)........could the extra stroke mess with the way the oil is being throw around???

Frank,
Also, could the rod, by accident, be put on wrong and was throwing the oil differently.(throwing it out ward instead of inward towards the cam)
......the jeep have a small hole between the two rod half, on one side, that sling the oil like the Chry V8 ..........Right............IF not How does the oil get to the cam on a 4.0L/stroker



Flash

[FrankZ]

Flash,
The Cam bearings are oiled via the oil galley that runs the length of the block. It also provides oil to the lifter bores and the crankshaft journals. Holes in the block casting allow for additional cam shaft oil when the oil drainss from the cylinder head. In pic one the yellow arrow points to the hole in the lifter bore than feeds oil to the lifter itself. There is a hole in the side of the lifter that allows it to fill and pump oilt to throuhj the push rods to the rockers. Pic Two shows the path that the oil tales to the crankshaft journals and the oil galley plug at the front of the motor.

Hope that clears things up.

BTW, as far as I know the connecting rods play no role in oiling the camshaft.