 1.7 camshaft, wear marks, Why is this and is it common...? |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
| larss |
 Sep 24 2011, 10:49 AM
Post
#1
|
|
Member  Group: Members Posts: 428 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) |
   |
 
|
  |
Replies
| Valy |
Sep 24 2011, 01:26 PM
Post
#2
|
|
Senior Member Group: Members Posts: 1,677 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
QUOTE(larss @ Sep 24 2011, 09:49 AM)  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
Post
#3
|
|
Member Group: Members Posts: 428 Joined: 10-September 09 From: Sweden Member No.: 10,787 Region Association: Scandinavia |
QUOTE(Valy @ Sep 24 2011, 09:26 PM) [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 |
|
|
|
Posts in this topic
larss 1.7 camshaft, wear marks Sep 24 2011, 10:49 AM
larss What is the most likely reason for this wear, bad ... Sep 25 2011, 10:41 AM Dave_Darling Tom Wilson's book tells us that this is the ty... Sep 25 2011, 11:23 AM
rdauenhauer :agree: hi-mileage. actually pretty typical wear. Sep 25 2011, 11:24 AM |
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 16th June 2024 - 05:46 PM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.