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Cam Bearing Failure #4

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broncocliff
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Where's the "any" key?
Posts: 23
Joined: April 24th, 2014, 2:51 pm
Vehicle Year: 1998
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Vehicle Model: Cherokee

Cam Bearing Failure #4

Postby broncocliff » January 9th, 2018, 1:03 pm

:deadhorse: I have used this site for much of my build and it has very helpful information. I read all the way through silverxj's posts about his cam failure. Here is where I'm at and if there are any other suggestions I would really appreciate it. I keep finding small things to change and hope for the best but nothing has worked. I'm so disappointed in this but at this point I have to much money invested into this project to for go it. Least I'm removing and installing my self.
I have a built 4.6 stroker pretty much every year now since 2014.
Some of the specs:
1998 4.0 block bored .030 over
4.0 rods, Icon pistons
scat crank
68-232-4 comp cam with lifters x2 (replaced it once to make sure it wasn't the problem)
Made a cam pin that came out to .005 play in cam as suggested by Silverxj
Edelbrock head with the springs re worked to 1.750 installed height 105# on the seat, at .480 open 260#, .180 from coil bind
Teflon coated cam bearings with oil control bearings
Magnafluxed block
Checked straightness of cam tunnel
I just ran the last install for about 100 miles, oil pressure cold starts at 50 and drops to 10-8 psi when hot. Drained oil and found metallic oil and copper bearing material in oil filter when I cut it open. I have used zddp, different oils everytime when suggested by someone else. This last time was 5w-30 and then 15w-40 after running for 10 minutes.
Used 10w-30 last time which only lasted the break-in of the new cam. After the last time changed springs in the head to the ones listed for this time.
I'm thinking I need a new block just wondering if anyone else has any other suggestions. It has been through with a fine tooth comb and haven't found the culprit.

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SilverXJ
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Stroker Displacement: 4.6L
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Radford, Va
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Re: Cam Bearing Failure #4

Postby SilverXJ » January 11th, 2018, 4:16 am

Make sure you don't have binding any where else in the valve train. I doubt you do with the Edelbrock head, but its worth a check. Also, see if you can check for any other oil leaks.

What is the clearance on all your bearings?

jsawduste
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Re: Cam Bearing Failure #4

Postby jsawduste » January 11th, 2018, 7:19 am

Have the oil passages in the bearings been chamfered ?

broncocliff
Where's the "any" key?
Where's the "any" key?
Posts: 23
Joined: April 24th, 2014, 2:51 pm
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: Cam Bearing Failure #4

Postby broncocliff » January 12th, 2018, 9:57 am

SilverXJ wrote:Make sure you don't have binding any where else in the valve train. I doubt you do with the Edelbrock head, but its worth a check. Also, see if you can check for any other oil leaks.

What is the clearance on all your bearings?

Yeah no other binding was found. I had the block magnafluxed and they didn't find any. Pretty simple oiling system with one oil tube supplying it all. I checked the oil pump on the block all the times. Jb welded the sump to the oil pump. Primed oil every time with oil coming out of every push rod. Clearances were .0015 to .0025 on all bearings across the board. Checked every one.

jsawduste wrote:Have the oil passages in the bearings been chamfered ?
ON what bearings are you referring to? The cam bearings that I used are the oil control bearings N7b with teflon coating added to them. I used sealed power crank and rod bearings.

Russ Pottenger
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Posts: 566
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Vehicle Model: Cherokee

Re: Cam Bearing Failure #4

Postby Russ Pottenger » January 12th, 2018, 10:31 am

Standing in front of the block, did you position the camshaft oil feed hole somewhere around the 5 o'clock position?


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