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Strange sound from rebuilt engine...

 
Old 03-09-2013, 03:08 PM
  #391  
Vorsicht
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Here are some pics of the engine opened up:
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Old 03-09-2013, 03:19 PM
  #392  
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On initial inspection it appears the crankshaft is toast. Admittingly, I am using a crude measurement technique (digital calipers) but the journals appear out of round. The specification is 54.971mm to 54.990mm.

One sample measurement:

Journal Diameter Axis 1: 54.9x (within spec)
Journal diameter axis 2 (90 degrees from axis one): 54.2x (way out of spec)
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Old 03-09-2013, 05:01 PM
  #393  
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How does the oil pump feel?
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Old 03-09-2013, 05:12 PM
  #394  
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Originally Posted by Cupcar View Post
How does the oil pump feel?
Like cold, oily metal. Just Kidding. Didn't take it out just yet. How should it feel?
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Old 03-09-2013, 05:19 PM
  #395  
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Originally Posted by Vorsicht View Post
Like cold, oily metal. Just Kidding. Didn't take it out just yet. How should it feel?
It should turn very smoothly. The concern is if some small metal chips managed to get through the pick up screen and into the scavenge pump. The gears should look smooth when view through the ports as the shaft is turned.
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Old 03-09-2013, 05:29 PM
  #396  
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Peter.

Yessir,......you will need another good, used std/std crank and a set of used rods.

I see some case fretting that should be closely inspected, too.

The oil pump should get disassembled and the case inspected for any scoring since these are Mg.
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Old 03-09-2013, 06:04 PM
  #397  
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Originally Posted by Steve Weiner-Rennsport Systems View Post
Peter.

Yessir,......you will need another good, used std/std crank and a set of used rods.
I may have this stuff here.
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Old 03-09-2013, 06:10 PM
  #398  
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I have the following parts if you need them:

Oil Pump
Rods
P&C's
STD Cams
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Old 03-09-2013, 07:29 PM
  #399  
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"I see some case fretting that should be closely inspected, too."

Educate me Steve.....what is "case fretting"?

Gordo
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Old 03-09-2013, 07:51 PM
  #400  
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Originally Posted by 993/907 View Post
"I see some case fretting that should be closely inspected, too."

Educate me Steve.....what is "case fretting"?

Gordo

I was wandering the same thing. I have been studying the photos,but haven't figured it out yet.


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Old 03-09-2013, 08:01 PM
  #401  
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Well I Googled it,and I think he is concerned with the unusual wear pattern above the second crank bearing from the right. Could be a sign of hair line cracks or fracture. That's my guess anyway. Just trying to learn something new.


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Old 03-09-2013, 08:17 PM
  #402  
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Originally Posted by e3photo View Post
Well I Googled it,and I think he is concerned with the unusual wear pattern above the second crank bearing from the right. Could be a sign of hair line cracks or fracture. That's my guess anyway. Just trying to learn something new.

Emerald
Yessir,...that's right,...

The case halves shuffled against themselves pretty hard in that area as well as some light fretting on others.

Race engines get shuffle-pinned in two places on each main bearing web to help prevent this, but that's overkill for street motors.

In this situation, it deserves a closer look and examination.
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Old 03-09-2013, 08:43 PM
  #403  
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I had to google it too. Photo supplied via the interwebs.

Fretting is a special wear process that occurs at the contact area between two materials under load and subject to minute relative motion by vibration or some other force.
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Old 03-09-2013, 08:47 PM
  #404  
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Originally Posted by e3photo View Post
Well I Googled it,and I think he is concerned with the unusual wear pattern above the second crank bearing from the right. Could be a sign of hair line cracks or fracture. That's my guess anyway. Just trying to learn something new.


Emerald
I see something similar on the last "monument" mounted bearing on other end of the case....got it!
Gordo
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Old 03-09-2013, 11:40 PM
  #405  
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Peter, the IMS bearing looks beat (not related to anything you did) so a minor consolation in splitting the case is you avoided another tear down. Glad that suggestion paid off. Just one of those "been there done that" scenarios.
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