Author Topic: Cam lobe wear  (Read 31685 times)

Offline Belgium Cuda

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Cam lobe wear
« on: August 08, 2008 - 04:54:51 PM »
How can I tell if my cam have lobewear after breaking in? I have low compression on 1 cylinder and vibrations. Have changed everything
possible externally like plugs, wires, carb, coil etc. Now it's time to open it up. Engine is a standard built -69 440.  :1zhelp:
1970 Challenger Convertible - to become a Hemi tribute
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Offline wally426ci

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Re: Cam lobe wear
« Reply #1 on: August 08, 2008 - 05:29:54 PM »
Bent valve? :dunno:
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Offline Belgium Cuda

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Re: Cam lobe wear
« Reply #2 on: August 08, 2008 - 07:18:28 PM »
Is that posible to see with the head on?
1970 Challenger Convertible - to become a Hemi tribute
1968 Charger R/T 500 cui stroker

Offline MEK-Dangerfield

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Re: Cam lobe wear
« Reply #3 on: August 08, 2008 - 07:24:46 PM »
I know 4Cruisin blew a cam on breakin. Sorry I can't tell you how he figured it out. There was definitely a broken lobe though.   :eek4:


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nivvy

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Re: Cam lobe wear
« Reply #4 on: August 08, 2008 - 07:32:11 PM »
what kind of springs did you run on break in....... on cam break in you should use single springs... if have double springs remove inner springs.....   :working:

Offline Chryco Psycho

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Re: Cam lobe wear
« Reply #5 on: August 09, 2008 - 02:46:50 AM »
measure or even just watch the rocker arm lift , or use a magnet & pull the lifters out through the heads

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Offline Belgium Cuda

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Re: Cam lobe wear
« Reply #6 on: August 09, 2008 - 07:02:12 AM »
Camshaft is out and looks like it has a strange wear for beeing new but if it's enough to create low compression and vibrations in the car/engine I don't know. I do get different meassurements with a digital micrometer when I meassure the exhaust lobes. Maybe better to pull the heads aswell?  :clueless:
1970 Challenger Convertible - to become a Hemi tribute
1968 Charger R/T 500 cui stroker

Offline 500Stroker

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Re: Cam lobe wear
« Reply #7 on: August 09, 2008 - 07:39:52 AM »
try takin the pix with nothing in the background.  The camera is focusing on everything but the cam.

Offline Belgium Cuda

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Re: Cam lobe wear
« Reply #8 on: August 09, 2008 - 10:03:48 AM »
New try!
1970 Challenger Convertible - to become a Hemi tribute
1968 Charger R/T 500 cui stroker

Offline LAA66

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Re: Cam lobe wear
« Reply #9 on: August 09, 2008 - 10:14:52 AM »
 Have you checked the valve springs on the low compression cylinder? :dunno:

Offline Belgium Cuda

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Re: Cam lobe wear
« Reply #10 on: August 09, 2008 - 12:19:18 PM »
Some additional info, the number on the back of the cam is 960697, it's a MP purple cam but I can't find the number back anywere. The previous owner
said it should be a 440 standard cam. Springs looks good but look at the wearpattern of the rockers, is that normal?
1970 Challenger Convertible - to become a Hemi tribute
1968 Charger R/T 500 cui stroker

Offline Chryco Psycho

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Re: Cam lobe wear
« Reply #11 on: August 09, 2008 - 12:56:11 PM »
the back lobe on the cam does look weird , it should have a narrow track on one side of the lobe to rotate the lifter until it goes over the top where the spring load is highest , over the top it should go full contact

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Offline bb71challenger

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Re: Cam lobe wear
« Reply #12 on: August 09, 2008 - 01:00:11 PM »
Hey CP what oils still have the good stuff in them for protection. It sure seems like cams get wiped a lot more frequently in the last 10 years or so.
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Offline 'Cuda Hunter

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Re: Cam lobe wear
« Reply #13 on: August 09, 2008 - 01:35:05 PM »
Supercuda chiming in on Cuda Hunter's nickel again. This doesn't sound like a wiped cam lobe, especially if the measurements of comparable cam lobes (exhaust/exhaust, intake/intake) is within a few thousandths of an inch (.005"). As this is a fresh engine, it would have been a good idea to do a leakdown test before teardown, to determine where the compression loss was. Since it's torn down now, the thing to do is to check the torn-down components. Are the ring gaps lined up? This can cause the problem you are having. as well as a failed head gasket or cylinder head casting. If you used the original head bolts, one of those could be suspect, also. The wear on the rocker arms is normal, and the cam lobe wear does not look like it's out of the normal range either, but measurement of the lobes for both base circle and lobe lift would tell you more. Specifications aren't necessary, just careful comparison of the cam lobes. I hope this is helpful to you.
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Offline Belgium Cuda

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Re: Cam lobe wear
« Reply #14 on: August 09, 2008 - 01:47:47 PM »
Thought about leaktest but nobody in this farmerland can do that so that's why. I will meassure the lobes but still think I should pull the heads since I come so far. I would never forgive myself if I put it together and still have the same problem even with a new cam.
1970 Challenger Convertible - to become a Hemi tribute
1968 Charger R/T 500 cui stroker