Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

'85 TB issue

 
Old 02-25-2019, 02:07 PM
  #1  
2ndtime928DAD
User
Thread Starter
 
Join Date: Mar 2018
Posts: 11
Default '85 TB issue


Tensioner and idler

TB tensioner

Driver side behind balancer

Behind balancer

Balancer

Water pump

Driver side


Passenger side
Had a great time at breakfast back in February was glad to finally meet everyone. Unfortunately for me someone noticed my timing belt on the passenger side was riding forward almost a quarter of an inch. I finally been home long enough to break it down and try to see what's going on. Posting several pictures in the hopes that someone can give me a clue. The belt rotates clockwise the passenger side belt is forward the driver side belt it's setting perfect. My thinking tells me the issue would be a 4 the passenger side belt, this would be the belt tensioner correct? I also noticed the spacer behind the balancer is no longer angled or sloped instead it's almost perfectly straight. Any insight? Thanks again for everything.
2ndtime928DAD is offline  
Old 02-25-2019, 02:33 PM
  #2  
76FJ55
Addict
Rennlist Member
 
Join Date: Nov 2008
Location: Grapevine, TX
Posts: 1,030
Default

I would suspect the bushings on the tensioner arm or it couild also be the pivot bolt that tensioner arm mounts on.

As for your crank guide washer; it looks like the forward washer was/is installed backwards. the bevel should be towards the belt to help guide the belt without cutting into it. you can also see the wear pattern from the belt on the forward side of the washer from when it was originally installed facing the other way.
76FJ55 is offline  
Old 02-25-2019, 02:41 PM
  #3  
docmirror
Shameful Thread Killer
Rennlist Member
 
docmirror's Avatar
 
Join Date: Aug 2004
Location: Rep of Texas, N NM, Rockies, SoCal
Posts: 19,490
Default

Replace the bearing on the tensioner, and the bolt. Check the pivot bushing in the tensioner and the pivot shaft should be a snug fit. The witness marks on the crank gear guide washers indicate that at least the outer one is on backward. Maybe the inner one too.
docmirror is offline  
Old 02-25-2019, 02:52 PM
  #4  
GregBBRD

Rennlist
Basic Site Sponsor

 
GregBBRD's Avatar
 
Join Date: Feb 2005
Location: Anaheim
Posts: 9,689
Default

Originally Posted by docmirror View Post
Replace the bearing on the tensioner, and the bolt. Check the pivot bushing in the tensioner and the pivot shaft should be a snug fit. The witness marks on the crank gear guide washers indicate that at least the outer one is on backward. Maybe the inner one too.
Definitely. The backwards crank gear guide washer is cutting the belt....mobile lathe.
__________________
greg brown




714 879 9072
[email protected]

If the kids keep breaking a crowbar in the sandbox, sometimes it is easier to just give them a stronger crowbar, instead of trying to figure out what they are doing in the sandbox.
GregBBRD is offline  
Old 02-25-2019, 03:27 PM
  #5  
Geza
User
 
Geza's Avatar
 
Join Date: Nov 2004
Location: NJ
Posts: 242
Default

You can even see the sprocket teeth marks on the guide from when it was mounted correctly.
Geza is offline  
Old 02-25-2019, 03:50 PM
  #6  
docmirror
Shameful Thread Killer
Rennlist Member
 
docmirror's Avatar
 
Join Date: Aug 2004
Location: Rep of Texas, N NM, Rockies, SoCal
Posts: 19,490
Default

Originally Posted by Geza View Post
You can even see the sprocket teeth marks on the guide from when it was mounted correctly.
"witness mark"
docmirror is offline  
Old 02-25-2019, 06:14 PM
  #7  
Mrmerlin
Petie3rd
Rennlist Member

This Post Sponsored by:
Dow Corning« & DeoxIT«
 
Mrmerlin's Avatar
 
Join Date: May 2004
Location: Philly PA
Posts: 22,614
Default

Based on your pictures you need to get,
Two new thrust washers for the belt guide on the crank.
Put them on so they will act as a funnel for the belt to arrive onto the gear.

NOTE it should be obvious with new washers how they should fit.

Replace the cam pulleys.

Put a straight edge on the crank drive gear to see if the teeth are level if not replace the drive gear.

If you have an aluminum oil pump gear get the updated steel gear and remove the 1 mm spacer washer behind the aluminum gear, the steel goes on without this spacer.
.
Replace the idler bearings on the roller/s under the crank drive gear, if they dont turn smoothly.
they can be tapped out of the metal collars.

Replace the idler tensioner roller bearing this goes behind the pivot am bolt
Replace the tensioner roller bearing, this tensiones the belt.
Replace the water pump with a new Laso unit.
Replace the tensioner boot and clamp.

Take the tensioner apart and lay out the parts and post a picture or two so we can see what parts might be missing before you order more parts.
its likely the washer is missing as well as the inner C clip for the boot.

Replace the tensioner pivot bolt and bushings.
Replace the timing belt.
Replace the oil pump O ring and 3 bolt O rings as well as the radial seal.
Replace the front main seal.
Mrmerlin is online now  
Old 02-25-2019, 11:50 PM
  #8  
GregBBRD

Rennlist
Basic Site Sponsor

 
GregBBRD's Avatar
 
Join Date: Feb 2005
Location: Anaheim
Posts: 9,689
Default

Originally Posted by Mrmerlin View Post
Based on your pictures you need to get,
Two new thrust washers for the belt guide on the crank.
Put them on so they will act as a funnel for the belt to arrive onto the gear.

NOTE it should be obvious with new washers how they should fit.

Replace the cam pulleys.

Put a straight edge on the crank drive gear to see if the teeth are level if not replace the drive gear.

If you have an aluminum oil pump gear get the updated steel gear and remove the 1 mm spacer washer behind the aluminum gear, the steel goes on without this spacer.
.
Replace the idler bearings on the roller/s under the crank drive gear, if they dont turn smoothly.
they can be tapped out of the metal collars.

Replace the idler tensioner roller bearing this goes behind the pivot am bolt
Replace the tensioner roller bearing, this tensiones the belt.
Replace the water pump with a new Laso unit.
Replace the tensioner boot and clamp.

Take the tensioner apart and lay out the parts and post a picture or two so we can see what parts might be missing before you order more parts.
its likely the washer is missing as well as the inner C clip for the boot.

Replace the tensioner pivot bolt and bushings.
Replace the timing belt.
Replace the oil pump O ring and 3 bolt O rings as well as the radial seal.
Replace the front main seal.
You should make a copy of this in Microsoft Word....and just cut and paste it every time a belt inquiry comes up!
__________________
greg brown




714 879 9072
[email protected]

If the kids keep breaking a crowbar in the sandbox, sometimes it is easier to just give them a stronger crowbar, instead of trying to figure out what they are doing in the sandbox.
GregBBRD is offline  
Old 02-26-2019, 11:32 AM
  #9  
2ndtime928DAD
User
Thread Starter
 
Join Date: Mar 2018
Posts: 11
Default

Thanks for all the great information. When I first replaced the TB, the bolt to the idler wheel broke. At the time I couldn't find the exact replacement bolt, so I made one (home lathe). I think this and the crank washer is going to be where I'll start. I'll let you know how it comes out. Time to order some parts.
2ndtime928DAD is offline  
Old 02-26-2019, 11:57 AM
  #10  
Geza
User
 
Geza's Avatar
 
Join Date: Nov 2004
Location: NJ
Posts: 242
Default

O-ring internal to the tensioner.
Geza is offline  
Old 02-26-2019, 12:28 PM
  #11  
SeanR
Running up the Odo'
Rennlist Member
 
SeanR's Avatar
 
Join Date: Apr 2006
Location: DFW Texas
Posts: 34,490
Default

Originally Posted by 2ndtime928DAD View Post
Thanks for all the great information. When I first replaced the TB, the bolt to the idler wheel broke. At the time I couldn't find the exact replacement bolt, so I made one (home lathe). I think this and the crank washer is going to be where I'll start. I'll let you know how it comes out. Time to order some parts.

From the looks of everything in your pictures, you really should follow Stans advice to the T. Don't skimp out in it. As I told you at the breakfast you were real close to having a $10k paperweight with that engine.
SeanR is offline  
 


Thread Tools
Search this Thread

Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: