Cambelt tensioner pivot bushes and roller bearing
02-22-2017, 05:47 PM
#1
Rennlist Member
Thread Starter
Cambelt tensioner pivot bushes and roller bearing
Anyone got any tips to how to assess the condition of the above items?
I removed the cam belt today with a view to replacing the cam sprockets. That went well but upon inspection of the tensioner I felt I could feel a very small amount of play in the bushes and the main roller.
Perhaps it is prudent to simply replace the bushes and the roller bearing and have done with it.
Rgds
Fred
I removed the cam belt today with a view to replacing the cam sprockets. That went well but upon inspection of the tensioner I felt I could feel a very small amount of play in the bushes and the main roller.
Perhaps it is prudent to simply replace the bushes and the roller bearing and have done with it.
Rgds
Fred
02-22-2017, 05:52 PM
#2
Chronic Tool Dropper
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Where's my aunt Claire's phone number...
The bushings are inexpensive, the bearing rollers somewhat less. Are you planning to change the belt too at this point? Some of the bearing decision hinges on how many more miles they need to last before a major including belt and other wear parts.
Curious why you are going in just for the cam sprockets.
The bushings are inexpensive, the bearing rollers somewhat less. Are you planning to change the belt too at this point? Some of the bearing decision hinges on how many more miles they need to last before a major including belt and other wear parts.
Curious why you are going in just for the cam sprockets.
02-23-2017, 06:33 AM
#4
Rennlist Member
Thread Starter
Dave, Bob,
Ah- the mysteries of life!
Normally I service my 928 every year and then every other year I try to do some major maintenance/project work depending on need, budget inclination etc etc. This year, that i have moved into my own home and have a nice big double garage, I decided I would do a major inspection first of all to see what really needs attending to over and above that which I know needs to be done and do so without time pressure knowing that at the end of the day I can put htings to one side, throw a sheet over the motor and close bonnet.
Now I have just about everything apart and I am inspecting anything and everything I can get my hands on. The jobs I knew I was going to do I have parts for and I also know that I can get small parts sent over from the States in a matter of a few days with DHL and now I need to firm up on my shopping list.
I did my first timing belt/WP job two years ago. I found the crank and oil pump sprockets to be in good condtion but the cam sprockets were marginal. I got Colin to send me a couple of recoated sprockets to give that concept a try but as time was pressing two years ago, I decided to box it back up wth the existing cam sprockets pretty confident they would safely last me another couple of years and that has proved to be the case. The top flat of the driver side sprocket is well polished and the coating has gone but there is no obvious depression in the metal. The crank sprocket and the oil pump sprocket still look fine to me but I have to do a more careful inspection.
The timing belt look fine, no strange marks, the tensioner seems to be dry but I intend to put a new boot and clamp on it, but when i pulled the timing belt covers it seemed to me that the belt had been tracking a bit closer to the front edge of the sprocket than I expected [about 2mm from the front edge]. I then took a look at the tensioner roller and the belt seemed to lie at the edge of the roller but no overhang. I then had a flashback to Seth's recent thread wherein he had issues with his tensioner. So I pulled the tensioner off and the roller seemed to spin nicely but I was a bit unsure as to whether I could feel some lateral shake. I can get an opinion on that one later today all being well. I then mounted the tensioner on the pivot arm to see if I could feel any untoward movement and again felt a little unsure as to what I was feeling. Inspection of the tensioner arm suggests to me that there are some inserted bushes for the pivot point but at the moment I am not sure if they are serviceable items or whether a replacement tensioner arm is required. They look as though they are made of some plastic if that does not sound too stupid. If they are serviceable I will order them. Same for the main roller- it looks as though there is a roller race of some kind in there and maybe that is serviceable as well rather than purchasing a new roller complete.
The power steering hoses came out easy enough. Dr Bob calls himself "a compulsive tool dropper". I seem to be a "compulsive sprayer". Every time I rain something I seem to end up with some of it sprayed everywhere. To mitigate I place a nice large plastic sheet on the deck. So far managed to spill some coolant despite a large bucket under the radiator hose [I have no useable drain valve on my custom radiator], I managed to spill some ATF at both the pump and rack ends, dropped two spanners int the bowl of ATF and yesterday whilst under the car at the front, managed to get a coolant shower from some spilt coolant sitting on the top of the front valence that I did not spot. That and I have not yet drained the coolant jackets and they are a guaranteed shower both sides!
The power steering hoses definitely need attention so a good intervention. Hope to get those refurbed over here.
With the power steering pump and a/c comrpessor out of the way I think I can get access to the upper control arm holding nuts. Next task is to clean/degrease the lower half of the engine bay.
So far so good!
Rgds
Fred
Ah- the mysteries of life!
Normally I service my 928 every year and then every other year I try to do some major maintenance/project work depending on need, budget inclination etc etc. This year, that i have moved into my own home and have a nice big double garage, I decided I would do a major inspection first of all to see what really needs attending to over and above that which I know needs to be done and do so without time pressure knowing that at the end of the day I can put htings to one side, throw a sheet over the motor and close bonnet.
Now I have just about everything apart and I am inspecting anything and everything I can get my hands on. The jobs I knew I was going to do I have parts for and I also know that I can get small parts sent over from the States in a matter of a few days with DHL and now I need to firm up on my shopping list.
I did my first timing belt/WP job two years ago. I found the crank and oil pump sprockets to be in good condtion but the cam sprockets were marginal. I got Colin to send me a couple of recoated sprockets to give that concept a try but as time was pressing two years ago, I decided to box it back up wth the existing cam sprockets pretty confident they would safely last me another couple of years and that has proved to be the case. The top flat of the driver side sprocket is well polished and the coating has gone but there is no obvious depression in the metal. The crank sprocket and the oil pump sprocket still look fine to me but I have to do a more careful inspection.
The timing belt look fine, no strange marks, the tensioner seems to be dry but I intend to put a new boot and clamp on it, but when i pulled the timing belt covers it seemed to me that the belt had been tracking a bit closer to the front edge of the sprocket than I expected [about 2mm from the front edge]. I then took a look at the tensioner roller and the belt seemed to lie at the edge of the roller but no overhang. I then had a flashback to Seth's recent thread wherein he had issues with his tensioner. So I pulled the tensioner off and the roller seemed to spin nicely but I was a bit unsure as to whether I could feel some lateral shake. I can get an opinion on that one later today all being well. I then mounted the tensioner on the pivot arm to see if I could feel any untoward movement and again felt a little unsure as to what I was feeling. Inspection of the tensioner arm suggests to me that there are some inserted bushes for the pivot point but at the moment I am not sure if they are serviceable items or whether a replacement tensioner arm is required. They look as though they are made of some plastic if that does not sound too stupid. If they are serviceable I will order them. Same for the main roller- it looks as though there is a roller race of some kind in there and maybe that is serviceable as well rather than purchasing a new roller complete.
The power steering hoses came out easy enough. Dr Bob calls himself "a compulsive tool dropper". I seem to be a "compulsive sprayer". Every time I rain something I seem to end up with some of it sprayed everywhere. To mitigate I place a nice large plastic sheet on the deck. So far managed to spill some coolant despite a large bucket under the radiator hose [I have no useable drain valve on my custom radiator], I managed to spill some ATF at both the pump and rack ends, dropped two spanners int the bowl of ATF and yesterday whilst under the car at the front, managed to get a coolant shower from some spilt coolant sitting on the top of the front valence that I did not spot. That and I have not yet drained the coolant jackets and they are a guaranteed shower both sides!
The power steering hoses definitely need attention so a good intervention. Hope to get those refurbed over here.
With the power steering pump and a/c comrpessor out of the way I think I can get access to the upper control arm holding nuts. Next task is to clean/degrease the lower half of the engine bay.
So far so good!
Rgds
Fred