Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 Engine Rebuilding Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Rod Bearing Inspection - IMS gear inspection

Chasing a slight knocking sound evident at idle.. new chain tensioner made no difference.
Thought I would go "all in"...



Last edited by mikedsilva; 12-27-2019 at 02:44 AM..
Old 12-22-2019, 03:16 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Sep 2015
Location: Costa Rica and Pennsylvania U.S.
Posts: 1,955
Rod bearings

The horizontal marks on the rod bearings would bother me.You have Loctite 574 orange between the main bearing webs and that is bothersome.Bearings do not look that old.Are there Mahle pistons or aftermarket ones in the motor?Did you check flywheel endplay?# 7 main has some different wear.Was the case bolted together and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred
Old 12-22-2019, 06:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Quote:
Originally Posted by faapgar View Post
The horizontal marks on the rod bearings would bother me.You have Loctite 574 orange between the main bearing webs and that is bothersome.Bearings do not look that old.Are there Mahle pistons or aftermarket ones in the motor?Did you check flywheel endplay?# 7 main has some different wear.Was the case bolted together and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred
hi Fred
Pistons are CP.
Did not check flywheel endplay.
Case was bolted and checked with bore gauge.
Bearings are Generic glyco.

What do you make of the markings on the rod bearings? I've never seen that before.. Engine has only done a few thousand miles.
Old 12-22-2019, 10:43 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Mar 2019
Posts: 400
In the other thread you said that the noise was more pronounced at idle when cold and gets less audible when warm. That's almost always a piston to cylinder wall clearance issue. Not necessarily a defect; it happens with some brands of pistons because of the aluminum alloy used during manufacturing. That is, assuming the piston to wall clearance was within specs.
Old 12-23-2019, 08:21 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Feb 2004
Location: denver
Posts: 526
I had a set of Glyco rod bearings (2.4-2.7) that had horizontal marks fresh out of the box. I returned them and went with AA Cleveites.

john
Old 12-23-2019, 12:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Sep 2015
Location: Costa Rica and Pennsylvania U.S.
Posts: 1,955
Horizontal marks

The marks are there as a high point to accumulate pockets of oil for better lubrication on the Mulsanne Straight at 400 kph.Ciao Fred
Old 12-23-2019, 01:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Registered User
 
Join Date: Apr 2007
Location: wisconsin
Posts: 2,539
Did your crank have ridges or wear?

Could some of those be scratches from mic’ing the bearing in the case?
Old 12-23-2019, 06:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Wondering if this could be the source of the intermediate clicking sound...
Intermediate shaft gear.

https://youtu.be/vQ5jWb4AUHg

Old 12-24-2019, 03:18 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
Join Date: May 2004
Posts: 415
Those markings are typical of the housing bore too small. Too much bearing crush will show up as similar markings. Refit the caps, tighten the fasteners how you previously had and measure the housing bore.
Old 12-24-2019, 05:50 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Quote:
Originally Posted by Neil Harvey View Post
Those markings are typical of the housing bore too small. Too much bearing crush will show up as similar markings. Refit the caps, tighten the fasteners how you previously had and measure the housing bore.
I did that today actually.. I measured my rod bearing clearances as between 0.04mm 0.05mm and one at 0.07mm...
Old 12-24-2019, 06:03 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered User
 
Join Date: May 2004
Posts: 415
Maybe you misunderstood my suggestion. You need to measure the housing bore of the rod (BE) without the bearing shells installed.
Old 12-24-2019, 06:59 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
VFR750's Avatar
 
Join Date: Mar 2004
Location: Windsor, CT
Posts: 1,893
Mike

The loose fit of the gear mesh does sound pretty loud. So that may be why you can hear it.

Also fits the data. As the engine warms up the aluminum gear grows more that the case because it is bathed in the hot oil and closes the clearances. Making the ticking sounds quieter.
Old 12-24-2019, 09:42 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
 
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Quote:
Originally Posted by VFR750 View Post
Mike

The loose fit of the gear mesh does sound pretty loud. So that may be why you can hear it.

Also fits the data. As the engine warms up the aluminum gear grows more that the case because it is bathed in the hot oil and closes the clearances. Making the ticking sounds quieter.
Thanks for the feedback.
I'm hoping this is the issue. What I found was that at initial cold start, it was quiet for a few minutes.. then the 'knock' occurred.. then as it got to operating temp, it would quieten down almost 100%.
I will get the rods checked by my machine shop and have them massaged if required. Have also ordered Clevite bearings for reassembly.

Still trying to figure out the whole 2 different size gears thing.. mine has a '1' stamped on it and from what I can tell, the replacements from Pelican, only come wiht a '0'...
Old 12-24-2019, 12:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Feb 2004
Location: denver
Posts: 526
There is a chart of what size gears can go with what size case (don't have it handy). there are several options that work. In the end you just need a certain amount of clearance between gears.

john
Old 12-24-2019, 12:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Oct 2008
Location: Nash County, NC.
Posts: 7,388
Mike. I have a 1 if you need it.
Bruce
Old 12-24-2019, 12:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
VFR750's Avatar
 
Join Date: Mar 2004
Location: Windsor, CT
Posts: 1,893
Here is the table

Last edited by VFR750; 12-24-2019 at 06:18 PM..
Old 12-24-2019, 06:15 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Jul 2013
Location: Brisbane, Australia.
Posts: 941
Quote:
Originally Posted by VFR750 View Post
Here is the table
OK, that answers another question I had about what the 0 and the 1 reference.. That table is VERY helpful and the first time I have seen it, thank you.
I will duck out to the garage to check my case, but pretty sure it has a '0' stamped on it. But I am not sure what my crank gear is stamped.. I don't think I can see a number on that one?
So reading the table, it seems that the ideal scenario for a 0 stamped case, is to also have a 0 stamped crank gear and 0 stamped IMS gear.
But it is permissable to have a bit of a mismatch so long as the backlash is within the limits shown.
Assuming my engines parts are original, and my case is a 0 and my IMS gear is a 1, then my crank gear should be a 0 too.
Gauging the table, it seems that the 1 ims gear is a 'tighter' fit.. but that I can also fit a 0 ims gear but it will likely not be as tight, but still within spec.
I'm tempted to buy a new 0 IMS gear as that is all I can find.. Is a 1 IMS gear available new?

Bruce, here is a photo of my current gear.. showing tooth wear..how does yours compare?

Last edited by mikedsilva; 12-25-2019 at 02:51 PM..
Old 12-25-2019, 02:28 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
Join Date: Oct 2008
Location: Nash County, NC.
Posts: 7,388
Intermediate shafts

Right now itís late so there is no side pictures available before tomorrow
You can see the stamping on the gears.
Bruce


Old 12-25-2019, 05:32 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
 
Registered User
 
Join Date: Dec 2019
Posts: 2
7 main has some different wear.Was the case bolted tog filezilla uc browser rufus ether and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred

Last edited by kamyle ben; 12-28-2019 at 01:21 PM..
Old 12-26-2019, 11:31 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Registered User
 
Join Date: Mar 2019
Posts: 400
Since you're homing in on the intermediate gear, did you happen to check the backlash? Was it within specs? From your video it looks a bit over spec.

Old 12-26-2019, 07:39 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 08:36 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.