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-   -   '85 TB issue (https://rennlist.com/forums/928-forum/1130955-85-tb-issue.html)

2ndtime928DAD 02-25-2019 02:07 PM

'85 TB issue
 
https://cimg6.ibsrv.net/gimg/rennlis...0368ff72c6.jpg
Tensioner and idler
https://cimg6.ibsrv.net/gimg/rennlis...2d5484918e.jpg
TB tensioner
https://cimg9.ibsrv.net/gimg/rennlis...4583d4c8c4.jpg
Driver side behind balancer
https://cimg1.ibsrv.net/gimg/rennlis...7066adc6b7.jpg
Behind balancer
https://cimg7.ibsrv.net/gimg/rennlis...5675885284.jpg
Balancer
https://cimg8.ibsrv.net/gimg/rennlis...dca784b79b.jpg
Water pump
https://cimg2.ibsrv.net/gimg/rennlis...59f52d9542.jpg
Driver side

https://cimg5.ibsrv.net/gimg/rennlis...9974cc3f1d.jpg
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.

76FJ55 02-25-2019 02:33 PM

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.

docmirror 02-25-2019 02:41 PM

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.

GregBBRD 02-25-2019 02:52 PM


Originally Posted by docmirror (Post 15663399)
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.

Geza 02-25-2019 03:27 PM

You can even see the sprocket teeth marks on the guide from when it was mounted correctly.

docmirror 02-25-2019 03:50 PM


Originally Posted by Geza (Post 15663528)
You can even see the sprocket teeth marks on the guide from when it was mounted correctly.

"witness mark"

Mrmerlin 02-25-2019 06:14 PM

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.

GregBBRD 02-25-2019 11:50 PM


Originally Posted by Mrmerlin (Post 15663960)
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!

2ndtime928DAD 02-26-2019 11:32 AM

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.

Geza 02-26-2019 11:57 AM

O-ring internal to the tensioner.

SeanR 02-26-2019 12:28 PM


Originally Posted by 2ndtime928DAD (Post 15665602)
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.


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