Cam bearing failure (pics)

[amcinstaller]

yea, those slots are really wierd looking, like someone cut tem by hand with a cutting wheel. have you checked the depths on them to see how cosistant the depth is? i see the picture showing the width, but not depth.

[SilverXJ]

They do look like they were cut by hand. Which isn't a problem. I just don't like how big they are. For what its worth Comp Cam's lifter bore grooving tool only cuts something around .020" x .010" groove. If those grooves are as deep as they are wide, doing the math for all the lifters would be equivalent to a leak the size of a 1/4" hole. (sqrt((12X.065x.065)/pi)x2. That is a lot especially when you take into consideration that the pump only has a 1/2" hole to pass oil through to the block .

As for why they are there, the one thing I can think of is to increase oil to the cam because it is still a cast cam which is splash lubed. Which is a fine idea in itself.

[6TIME]

Agreed! Splash lubed cam's have survived just fine for a long time! Before this ZDDP deficiency thing has come to light in newer oils, lobes have been going flat in just about every type of flat tappet engine. I think that this has spurred a flurry of new methods to direct more oil to the cam...More is not always better. As I understand, oiling systems are designed to balance adequate oil flow to every critical part of the engine. There are many orifices in the lifter galley and valve train that help keep pressure down at the cam bearings and other critical areas. When lifters are grooved, and the amount of oil pressure/flow to the cam bearings isn't somehow measured after the modification, it could put the system severely out of balance. A HV oil pump could provide enough flow to protect the cam bearings? But who's to know until the motor is torn down or a failure is evident. Like Silver said! All of those grooves add up to a significant leak that robs oil destined for the cam journals.

[scalper]

like i have mentioned before i am running 2 roller strokers with no problems but i am using a hv pump.the groove in my lifters look just like those. i have been using 20w50 valvoline vr1 oil this summer.pulled the pan on my daily driver with 15000 mile on the cam and everything looked fine. i wouldent trip over weather the grooves look inconsistent are were cut with a wizwheel.

[basscat]

Scalper, I think you're right and am going to put it back together with the 505 setup. I have the money to get a flat tappet cam and lifters so the cost doesn't weigh into the decision.

Question for you, did you notch your rod bearings so oil could get to the squirter holes in the rods? The replacement bearings from Clevite didn't have the holes and I'm wondering how oil gets to the distributor gear otherwise.

[SilverXJ]

The notch in the rod bearings supposedly help lube the piston walls and cam. I put the notch in the Clevite bearings myself using a dremel. Only one side needs the notch. The King bearings had the notch in them. I don't know if they are necessary though. The cam gear should get oil from a hole in the head dripping on it.

i wouldent trip over weather the grooves look inconsistent are were cut with a wizwheel.

Its not how it was done, its the size that is the issue.

If it were me I would send those lifters back and ask them to send you some un modified lifters and either groove the lifter bore or groove the lifters much smaller.

[scalper]

basscat,i did not notch the rod bearings on my motors.good luck.

[scalper]

basscatt,were your rod bearings notched? i dont have a set of rods laying around so im not sure of the size of the hole in in the rod . i dont think the groove in the lifters is much bigger than the hole in the rods. imo blocking off the holes like most rod bearings do and even aftermarket rods should offset any oil pressure loss that the grooved lifters may cause.in fact your getting direct oiling to the lifter and cam lobe instead of slinging oil around like the hole in the rod would cause. im not saying that was a bad design it supplied oil to many 4.0 cams with good results. am i making any sence of this?

[SilverXJ]

The groove in the lifters is much bigger than the groove in the rods. Also, the hole in the rods is at the end of the line for the oil.

[basscat]

The replacement bearings I used (when the cam bearings failed) did not have a hole in them so it seems the blocking off of the squirter holes does not provide an offsetting benefit to the pressure loss due to the lifter grooves. My thought was that the hole in the rod bearing lined up with the hole in the crank precisely when the rod was moving up and the squirter hole was pointing at the cam. When the holes aligned, there was a quick shot of oil delivered which may create a pressure drop pulse but is so quick in duration that it is insignificant. I was asking the question because I was concerned about oiling to the crank position gear only. One thing I am sure of, the lifter roller tips got plenty of oil.

[scalper]

yea that makes sense now.

[SilverXJ]

My thought was that the hole in the rod bearing lined up with the hole in the crank precisely when the rod was moving up and the squirter hole was pointing at the cam. When the holes aligned, there was a quick shot of oil delivered which may create a pressure drop pulse but is so quick in duration that it is insignificant.

Never though of it that much, but that makes perfect sense. Now the real question is if they provide any benefit or not.

One thing I am sure of, the lifter roller tips got plenty of oil.

LOL. I think so as well!

[basscat]

FINALLY got all the replacement parts from 505. Will try to get it together next week.

[basscat]

Update. 505 recommended I check the runout on the cam before putting everything together. Sure enough, it was at .007 which is out of spec. I sent it back to 505 and they straightened it (for free - I think). Anyway, just got the cam back yesterday and headed to the machine shop...

[SilverXJ]

Check the run out again. It could have been damaged during shippping.