Engine/Transmission (1998.5 - 2002) Camshaft Catastrophe

[WI Huck]

Camshaft Catastrophe



We have come across a problem that nobody we have spoken to can tell us why it happened. Here is the deal; we have a 2001 truck that we put a new camshaft in, new heads with upgraded springs, and twin turbos. The truck left and came back in 50 miles with a miss due to a rocker coming completely off the spring and push rod. We thought it was the head studs stretching, but we retorqued them and they were fine. We readjusted the valve settings and drove it. It ran fine, but before we gave it back we double checked the valve adjustments. Loose again. Then we checked the oil thinking a lobe or two were going bad on the cam. We saw signs of metal and verified it when we cut open the oil filter. The motor was pulled and taken apart for closer inspection. The cam lobes were all good except for the end journal in the back. It wore straight down thru the bearing and into the block at least 1/8 to ¼ of an inch. We checked the valve spring pressures, and although they were much higher than stock they were the same as the company that we bought them from specified.



What is going on here? I don’t get it! The main bearings were all fine and did not block the cam oil feed holes. The camshaft was marred, but did not get hot from lack of oil or installation lube. The front of the cam is supported by the gears turning it, so all the pressure is on the rear bearing or support since there are none in the middle. The only thing that makes sense is that there was too much force pushing down on it. Please let me know if you have seen this before and what can we do to not have it happen again!



Thanks!!!!



Mark

 

[Fishin Guide]

So, only the rear journal was bad? Or did this affect all the journals?



I have actually gotten a camshaft that was bent before. Not likely for what you describe, but anything is possible I guess.



The only other thing that I could think of is a burr or piece of hardened meatl working to sore the journal. But, the cam should not be able to drop an 1/8" and not damage the other journals. I don't see how it's possible.



Just out of curiousity, was this a billet camshaft?



Dave

 

[WI Huck]

The back one was the worst, and the rest were all affected, getting less as you get closer to the gear. We thought of it being bent also, but that would make it tough to install and the wear would go all the way around the bearing, not just straight down.



Thanks for the input! Keep them coming!

 

[RCenters]

Was it a regrind cam ?? if not heat treated correctly they can fail

 

[WI Huck]

We had the cam hardness tested and it is slightly harder than the stock one.



I was hoping that someone here would have run into this before and be able to tell me what went wrong. The block is junk now unless someone can fix it, but it would be tricky. Anyone have a good engine for sale?

 

[rubberneck]

perhaps the journal isn't ground concentric with the others? put it between 2 v blocks on the front and rear journals and put a dial indicator on it. Although if this were the case, you would expect wear around the entire bearing and not just the bottom. Perhaps just a bad spot or out of round which made it act like a grinder as it turned in the bearing

 

[KLockliear]

What were the spring pressures?

 

[ctd8999]

Camshaft

Huck, there is only one cambearing and its in the front. Thanks Steve B.

 

[Msilbernagel]

For whatever reason, the pressure overcame the ability of the oil to maintain a barrier and you had metal to metal.



How is the oil pressure?

What oil was used?

Can you confirm good oil flow to that back cam journal?



The way you are describing the wear, assuming oiling is Ok, either there is too much pressure OR the bore the cam sits in is not true - any chance something is warped?



Mark

 

[AKAMAC]

Which rocker arm came loose? Are any of the lifters scored?

I belive the lifter oil follows the cam lube. If a lifter floated it may have dropped flow/pressure to following bearing surfaces and lifters. Just thinking out loud. Mike

 

[Will24]

How radical was the cam? Cam to crank clearance is pretty slim in a B...



Was it an HO truck? What style cooling nozzles does it have?

What brand of oil filter was used?



Was the motor originally taken apart just for performance upgrades?



How much force was required to push the cam through the front bushing and into the block?



Was lubriplate (or equiv. ) used on all bearing journals and lobes?



Were they stock tappets?



Was the came made from a stock blank, or is it a billet cam? (that was asked before)



Sounds more than likely it was probably an incorrectly manufactured cam, but who knows

 

[Gary - K7GLD]

"The truck left and came back in 50 miles with a miss due to a rocker coming completely off the spring and push rod. We thought it was the head studs stretching, but we retorqued them and they were fine. We readjusted the valve settings and drove it. It ran fine, but before we gave it back we double checked the valve adjustments. Loose again. "



That particular issue sounds like too stiff valve springs pulling the rocker shaft studs outta the head...

 

[Joseph Donnelly]

I always use moly cam lube on the journals. If the cam grinder polished the journals in the wrong direction, the "nap" in the cast iron "rug" or surface will tend to grind into the block. This goes for cast crankshafts too. They are always polished so the nap is layed down in the direction of rotation.

 

[wcjp]

Highly uneducated guess- 12V cam inserted into a 24V

 

[WI Huck]

KLocklier

Here are the spring pressures;

Normal installed height = 55 lbs stock / 190 lbs theirs

Open pressure = 132 lbs stock / 340 lbs theirs



Ctd8999

There is a bushing in the rear that the cam rides on. That is what I am referring to when I say it wore thru that and into the block. The center journals did not have any bushing / bearing, only the casting.



Msilbernagel

I agree with you that it had to be too much pressure pushing the cam metal to metal. We use Rotella T oil and we checked the oil feed passages and there were no restrictions, no spun bearings that would block an oil passage. The factory cam did not have a problem, so I don’t think it was the block.



AKAMAC

#6 and #5 rockers were way bad, and the rest loose. This was because the cam wore into the back of the block and the front was supported by the gears.



Will24

The truck was a stock 2001 that only got taken apart for the upgrades. The install went smooth. The cam was new, but I am not sure if it was billet. I don’t think so because it is not advertised as such.



Gary – K7GLD

If the rocker shafts studs came out it would reduce the pressure pushing down on the cam. I could see where it would mess up the valve adjustments, but not force the cam into the block like this one did.



Joseph Donnelly

There was plenty of assembly lube used on the install and there was no signs of heat on the cam or bushing so I don’t think it was a lack of lubrication. The polish is an interesting thought, but I can’t tell now due to the marring on it.



Wcjp

I am not sure if we got the wrong one shipped, but it sure ran sweet when it was running.





Thank you for all the input. I was looking for someone who ran into this before and could tell me what worked for them. Someone has to make the mistake for new knowledge to be learned, it might as well be us. I just can’t imagine that it takes more than twice, almost three times the force of the stock springs to hold the valves shut on a twin turbo application. Especially on a 24 valve engine where you have two springs on each lobe.



Keep the thoughts and ideas coming. Thanks!

 

[ctd8999]

Cam bushing/bearings

Huck, The 01 may be different than my 99 but I know there is only one bushing/bearing and its at the #1 journal 2-7 are just the block. If there is a bushing/bearing at #7 your block was out of spec before. Do you have a service manual, it give you the tolerances for these bores. Thanks Steve B.

 

[KLockliear]

Those spring pressures should not cause what you are seeing.

 

[WI Huck]

Those spring pressures should not cause what you are seeing.

Thank you for your opinion. Any guess on what would do such a thing? You guys have most likely pushed the envelope on a few engines and I was hoping someone like you would chime in with a BEN THERE DONE THAT!

 

[KLockliear]

Can you post pics of the damage to the cam/block/valve gear? Also, what oil are you running? How much PSI? How long did you break the cam in for?

 

[Jetpilot]

Wi Huck,



Who's cam and springs are these? I have several customers that are concerned about doing a cam swap and having the same issues you have.....



Doug