[Pics] BBC Comp Cam Issue
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BBC Comp Cam Issue

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    Member nelsont509's Avatar
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    Question BBC Comp Cam Issue

    Good day my fellow BOAT enthusiasts..... I recently started hearing a different sound coming from the left side exhaust while cruising. As my valve cover gaskets where leaking a little, I thought, no better time than to adjust the valves, right, glad I did!! With engine at idle, I began my rocker arm adjustment, starting with number one cylinder. That's when I noticed the number 7 intake rocker arm was barely moving....What follows is a series of pictures that I believe accurately shows the issue I found. The cam lobe in question is the second one from the distributor gear. I have yet to find out why...

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    Or Seth, either one Budweiser's Avatar
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    Ya lost a lobe. More often than not, the prime suspect for the cause is improper break in procedure for a new cam. However, there can be other causes too.

    How many hours on that one? Fairly new? Been in the engine and working fine for a decade?

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    Member nelsont509's Avatar
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    Quote Originally Posted by Budweiser View Post
    Ya lost a lobe. More often than not, the prime suspect for the cause is improper break in procedure for a new cam. However, there can be other causes too.

    How many hours on that one? Fairly new? Been in the engine and working fine for a decade?
    Hehehehe..... I've owned the boat for the last decade, 139.2 on the hobbs. Bought the boat with 89 hrs. The last 30 hrs or so, within the last 4 months (moved to Florida). Pry the same cam since a mid-nineties rebuild (original owner). I'm the third owner. Just seems awfully specific for a cam break in issue

    I've got the new Comp Cam coming...any suggestions for break-in, or just follow manufactures recommendations?!
    Last edited by nelsont509; 06-05-2017 at 11:39 AM.


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    Next question, and the big one, what oil were you running?

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    Also, just spotted rust on the 2nd lifter, that's not such a good sign.

    You should be pulling the entire engine down after that much metal ran though it. Likely the cylinder walls have damage with metal debris caught in the piston skirts.

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    Quote Originally Posted by obnoxious001 View Post
    Next question, and the big one, what oil were you running?
    Aeroshell 100w (sae 50) Before me, not a clue.


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    Quote Originally Posted by obnoxious001 View Post
    Also, just spotted rust on the 2nd lifter, that's not such a good sign.

    You should be pulling the entire engine down after that much metal ran though it. Likely the cylinder walls have damage with metal debris caught in the piston skirts.
    Oh yes!! I'm borrowing a bore scope, and a filter cutter from work this evening to look at the cylinder walls and oil filter. I ran a magnet down through the oil pan with little to no shavings...hopefully Wix saved my bacon!!!

    Once I moved to FL, she sat for about two and half years without running, so a little rust, I'm sure, is to be expected...


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  10. #8
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    Quote Originally Posted by nelsont509 View Post
    Oh yes!! I'm borrowing a bore scope, and a filter cutter from work this evening to look at the cylinder walls and oil filter. I ran a magnet down through the oil pan with little to no shavings...hopefully Wix saved my bacon!!!

    Once I moved to FL, she sat for about two and half years without running, so a little rust, I'm sure, is to be expected...
    Based on personal experience taking apart a couple of engines that had lost cams, you are very likely to have some cylinder damage, and one that I worked on for a guy took a whole bunch of time to get the steel out of the piston skirts so he could have it running that weekend. It wasn't one of my engines, and I forget the exact details on why he lost that one. I had one other engine I put together where the customer didn't take heed when I told him no synthetic oil for the cam break in, that one was ugly.

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    Quote Originally Posted by obnoxious001 View Post
    Based on personal experience taking apart a couple of engines that had lost cams, you are very likely to have some cylinder damage, and one that I worked on for a guy took a whole bunch of time to get the steel out of the piston skirts so he could have it running that weekend. It wasn't one of my engines, and I forget the exact details on why he lost that one. I had one other engine I put together where the customer didn't take heed when I told him no synthetic oil for the cam break in, that one was ugly.
    I agree, just takes one lifter to destroy all the pistons skirts and get metal everywhere. From personal experience I would take it apart and clean it, could just get worse.

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  12. #10
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    Quote Originally Posted by nelsont509 View Post
    .hopefully Wix saved my bacon!!!

    Once I moved to FL, she sat for about two and half years without running, so a little rust, I'm sure, is to be expected...
    The filter will take metal out of the oil once it's pumped through it, but when the cam and lifter comes apart, that stuff does not just fall to the bottom of the pan immediately.

    I am suggesting that rust may have been a contributing factor to your cam issue.

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    Or Seth, either one Budweiser's Avatar
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    Quote Originally Posted by obnoxious001 View Post
    The filter will take metal out of the oil once it's pumped through it, but when the cam and lifter comes apart, that stuff does not just fall to the bottom of the pan immediately.

    I am suggesting that rust may have been a contributing factor to your cam issue.
    I agree.

    I didn't look too closely at the pics, other than noting the offending lobe. On second look, after reading mention of rust, all the lobes appear to be compromised by rust. The surface looks pitted.

    In addition to the oiling comments, the pistons aren't typically part of the pressure oiling system. They get oiled by the oil that escapes the main and rod bearings and oil run off from the cam and lifters right above the crankshaft. It's all thoroughly spread about by the spinning crank and the cam and lifter debris will end up in the cylinders.

    Also, 50wt and cold starts may open the filter bypass if it has one.

    It's really worth a tare down, cleaning, and inspection at this point, IMO.
    Last edited by Budweiser; 06-05-2017 at 05:35 PM.

  14. #12
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    Quote Originally Posted by obnoxious001 View Post

    Based on personal experience taking apart a couple of engines that had lost cams, you are very likely to have some cylinder damage, and one that I worked on for a guy took a whole bunch of time to get the steel out of the piston skirts so he could have it running that weekend. It wasn't one of my engines, and I forget the exact details on why he lost that one. I had one other engine I put together where the customer didn't take heed when I told him no synthetic oil for the cam break in, that one was ugly.
    What...I bet it was ugly!!
    I'm taking your personnel experience to be light years ahead of my own, just based on even your latest project you've posted here, very very nice, by the way!!

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    Quote Originally Posted by Tahoe540 View Post

    I agree, just takes one lifter to destroy all the pistons skirts and get metal everywhere. From personal experience I would take it apart and clean it, could just get worse.

    [iurl="http://www.performanceboats.com/attachment.php?attachmentid=972185&d=1496699691"][/iurl]
    Again, thank you for sharing your personnel experience and again, I'm sure yours is light years ahead.
    I have almost no V-8 engine experience, don't get me wrong, I've dabeled a little, but definitely not to the caliber ya'll are. If it were aircraft engines...I've got the "personal experience " !! Lol

  16. #14
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    Quote Originally Posted by obnoxious001 View Post

    The filter will take metal out of the oil once it's pumped through it, but when the cam and lifter comes apart, that stuff does not just fall to the bottom of the pan immediately.

    I am suggesting that rust may have been a contributing factor to your cam issue.
    Agreed. I'm still hoping!! I'm sure the rust didn't help, but, it still seems oddly specific.

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