1.7 camshaft, wear marks, Why is this and is it common...? |
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1.7 camshaft, wear marks, Why is this and is it common...? |
larss |
Sep 24 2011, 10:49 AM
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#1
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Member Group: Members Posts: 429 Joined: 10-September 09 From: Sweden Member No.: 10,787 Region Association: Scandinavia |
Took the cam sout of my spare engine and found this type of groove at top of both of the two middle lobes (not at the outer ones).The engine has some 150.000 km on it. The lifters looks wery fine.
Is this from wear or what ? Should I dump this cam? /Lars S (IMG:http://www.914world.com/bbs2/uploads_offsite/www.lsmteknik.se-10787-1316882959.1.jpg) |
Valy |
Sep 24 2011, 01:26 PM
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#2
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Senior Member Group: Members Posts: 1,677 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
Took the cam sout of my spare engine and found this type of groove at top of both of the two middle lobes (not at the outer ones).The engine has some 150.000 km on it. The lifters looks wery fine. Is this from wear or what ? Should I dump this cam? /Lars S (IMG:http://www.914world.com/bbs2/uploads_offsite/www.lsmteknik.se-10787-1316882959.1.jpg) That is excessive wear. See that recession in the middle of the lobe? The pressures on the lob concentrate in a point just below the lobe surface. That effect causes the lobe surface to collapse without any external signs of wear. Newer cams have a black coating that helps lubrication. I'm sure the lifters are done as well. Take 2 lifters, clean them and put them face to face and look against a light source. Their surface is round so they should touch like this )( and you should be able to see light between them. If they are worn out the surfaces will be || or worst () so you will see full contact between the surfaces. |
larss |
Sep 25 2011, 03:13 AM
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#3
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Member Group: Members Posts: 429 Joined: 10-September 09 From: Sweden Member No.: 10,787 Region Association: Scandinavia |
[Their surface is round so they should touch like this )( and you should be able to see light between them. If they are worn out the surfaces will be || or worst () so you will see full contact between the surfaces. Thanks! The surfaces on the intake lifters are like () so those are bad to. What is the most likely reason for this wear, bad oil, high milage or...? Why did it happen only at the intake lobes/lifters and not at all at the exhaust ones? /Lars S |
larss |
Sep 25 2011, 10:41 AM
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#4
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Member Group: Members Posts: 429 Joined: 10-September 09 From: Sweden Member No.: 10,787 Region Association: Scandinavia |
What is the most likely reason for this wear, bad oil, high milage or...? Why did it happen only at the intake lobes/lifters and not at all at the exhaust ones? and also: Is this a common and typical Type4 issue...? /Lars S |
Dave_Darling |
Sep 25 2011, 11:23 AM
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#5
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914 Idiot Group: Members Posts: 15,048 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Tom Wilson's book tells us that this is the typical wear pattern. Not sure why it would only happen on the intakes.
--DD |
914werke |
Sep 25 2011, 11:24 AM
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#6
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"I got blisters on me fingers" Group: Members Posts: 10,542 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
(IMG:style_emoticons/default/agree.gif) hi-mileage. actually pretty typical wear.
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