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Cam Bearing Failure #4

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broncocliff
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Cam Bearing Failure #4

Post by 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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Re: Cam Bearing Failure #4

Post by 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

Post by jsawduste » January 11th, 2018, 7:19 am

Have the oil passages in the bearings been chamfered ?

broncocliff
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Re: Cam Bearing Failure #4

Post by 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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Re: Cam Bearing Failure #4

Post by 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?

broncocliff
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Re: Cam Bearing Failure #4

Post by broncocliff » May 22nd, 2018, 8:36 am

Russ Pottenger wrote:
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?
Sorry I was not notified of a message. No it wasn't at the 5 o'clock position. I found out that the machine shop had never used the oil control bearings and installed them at the original position of a regular bearing. Do you think this would cause the problem again? If I was to install the bearings at the 5 o'clock position like it suggests do you think this would solve the problem? Have other people used the oil control bearings without problems? I think a few times before could have been from coil bind. Now that I have that fixed, it may have been from the bearings not indexed correctly.
My spring pressures are at 105 on the seat and 480 lift at 265 with 1.80 to coil bind.

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Re: Cam Bearing Failure #4

Post by Russ Pottenger » May 22nd, 2018, 8:25 pm

Moving the oil feed a whole as close to the 5 o'clock position will certainly help.

Edelbrock puts a powdered metal seat in there cylinder head. It's a very hard material. Because of that I would like to see you have more seat pressure. Otherwise what happens is the valve bounces on the seat. It's hardest on the exhaust valve because the valves contact with the exhaust seat is how the valve dissipates its heat.

Ideally you'd like to have another 40 pounds on the seat.
With a progressive spring right around 27 pounds, you'll be around 280ish on the nose.

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Re: Cam Bearing Failure #4

Post by dwg86 » June 18th, 2018, 8:01 am

Make sure your oil pump is sitting flush on the block. Silverxj noticed his oil pump was hitting on a chamfer on the block.

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