Cam bearing failure

[Mike B]

Bad news bears folks, I've got cam bearing failures in my 4.7l stroker. The shop that machined the block said they don't normally see these failures if zddp oil is used along with a proper breakin procedure, which I have followed to a T. My failures were at bearings 2 and 3, 1 and 4 look good. Only reason I discovered this is because I had to pull oil pan to address an oil leak.

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[Mike B]

I have to break my posts up so that I dont get logged out, been through this already today in the first go around, having lost an entire post.

So now, I have a howard camshaft from clegg engine, its their stage 2 cam, I can post specs on that later on if its relevant. The block is a 91 block installed in a 95, the shop checked everything, and I paid for a line bore honing as well. The head had work done to it by Clegg also, so heavier springs, larger valves, etc.

Where do I go from here other than replacing bearings and inspecting camshaft???

[Mike B]

Also noteworthy, my oil pressure has been consistently high, like 60-80 psi high, when priming the oil before startup, i had oil to all pushrods immediately. So what the hell!?!??! I didnt hear any knocking up til the point of dropping oil pan either.

[bleedsblue]

Maybe this is a totally NOOB question, but how do you tell if the cam bearings are shot with the cam still in the block?

[Mike B]

Maybe this is a totally NOOB question, but how do you tell if the cam bearings are shot with the cam still in the block?

If you zoom in on the photos right in the center, you can see the cam bearing material "oozing" out of its bore, pictured are the 2nd and 3rd bearings. Guess this is not an uncommon issue.

Another note, started the jeep so I could move it, heard it knocking for the first time, it was brief, but there. I put a stethoscope to the block and it all sounds normal after that startup.

Going to try to find a shop to do the bearings asap, need to find out what bearing brand is best though.

[bleedsblue]

Bad news. Sorry buddy. Do your order all your stuff from Clegg over the internet? Or are you here in Utah?

[Mike B]

I ordered it from their site.

[bnelson]

Possible that the oil holes were not lined up?

[Mike B]

Possible that the oil holes were not lined up?

Funny thing about that, I talked to the shop that installed them, they asked me if they were installed correctly...... you installed them, not me, you tell me whats supposed to be correct, you're the expert!

But in all seriousness after talking to clegg, I have a strong feeling that were not lined up correctly per durabonds spec. Theyre supposed to be installed at the 2 o'clock position, where a shop i talked to thats closer to me said that 12 is the standard. Well, I hope that this new shop ill be working with can help me resolve the issue so that I dont have it again.

I'll report back when I tear the block down, currently in the middle of a regear for the heep. Front is done, going to the rear now, fortunately it's a 29 spline 8.25, so theres less messing around there.

[Cheromaniac]

Possible that the oil holes were not lined up?

This.

Maybe this is a totally NOOB question, but how do you tell if the cam bearings are shot with the cam still in the block?

The bearing material appears to have been squeezed out of the block journals like toothpaste.

[gradon]

I had bad cam bearings for at least the last 40k miles of my 12year/120kmi stroker. Hot idle oil pressure was down to 10psi. I installed new ones a few weeks ago along with the comp cam 235. I’ll be honing and re-ringing tomorrow or Sat.

[Mike B]

Got the block tore down and sent to shop, oil holes were lined up where they were supposed to be, but boy did those bearings look ugly. Dont look like they spun at all, so that was a saving grace. Cam journals look good enough to polish up and send. The shop will install the cam when everything is done and check to ensure it spins freely like it should.

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The center 2 bearings took most of the damage, the one in the back looks untouched, the front is okay, but started to wear down. I wish there was a definitive answer on this issue for as many bearing failures I've seen on this site.

[Randy Bobandi]

So those are Dura-Bond Bearings?

[Mike B]

So those are Dura-Bond Bearings?

Yes, they were. Now they are shit. Im not sure what the engine shop will put back in, but they stated that cam bearing failures are a dumb problem, as they shouldn't happen at all. Im going to ask him to check the runout of the cam just cause. Hes going to polish the surfaces, so no matter what, if that was the problem before, it shouldn't be now.

[KarmaKannon1]

Keep us posted. I have a sneaking suspicion I have a similar issue. What did your oil look like?