928 S4 strange tapping from sump
04-14-2009, 09:52 AM
#31
Intermediate
Thread Starter
Sorry forgot to mention, I only need the carrier as I have already re-built my rollers with new bearings. Should help keep the weight down for transit. Do you also have the two plastic bushes for the tension arm pivot. I'd like to replace these with new ones but they are pretty hard to get hold of !
Cheers
Stuart
04-14-2009, 10:35 AM
#33
928 Collector
Rennlist Member
Rennlist Member
Disaster narrowly avoided.
Hi Guys
Well...... I've finaly had chance to do some further investigations.
I've systematically removed all the ancillaries, one by one, and the tapping is still there. I have removed the front timing covers and temporarily re-attached the top covers & dizzy caps so I could take a closer look & listen to the timing tensioner in motion. The tapping was louder and seemed to be coming from around the flywheel area.
I have dismantled and inspected all of the timing gear parts and have the following observations. There was a small amount of belt "fluff" built up on the timing pionter and in the very bottom of the lower cover; The belt appears to have been wearing on the metal guide plate that is positioned between the belt pully on the crank and the orange front flywheel. Inspection of the timing components themselves reveals the following. The large tensioner wheel is perfect, the smaller tensioner idler has a slight amount of play. The tensioner arm itself is supported on a single shaft with two nylon bushes, both of these exhibit slight wear evident by about 3mm lateral play at the tensioner roller. My 1990 MY S4 has an additional pair of belt guide idle rollers positioned below the crank pulley mounted on a small metal carrier. This carrier is itsef mounted on two projecting pins and is secured by circlips. Both of these rollers are a little bit worn but by biggest concern is the diameter of the carrier mounting pins and the associated holes on the carrier. The left hole is a nice sliding fit on the pin but the right hole is of a much larger diameter allowing the carrier to "ratlte". Does anybody have any knowledge of this arangement? is it normal?
I am planning to replace the two tension arm pivot bushes and have ordered replacement bearings to rebuild the idlers. I have pressed out the bearings from the rollers and am replacing them with SKF twin sealed deep roller bearings 62012RS and 69052RS costing about £20 for the set as opposed to about £100 from any of the UK's independant Porsche specialists and possibly a lot more from Porsche themselves!
It will be a few days before I get all the bits ready for re-assembly.....it is Easter after all. So watch this space to see if a small amount of play in a few bushes & bearings can cause such an alarmingly loud rattle. Whilst I am waiting for the postman if any of you can throw any light on my lower cam belt idler assembly then it would be much appreciated
Happy Easter
Regards
Stuart
Well...... I've finaly had chance to do some further investigations.
I've systematically removed all the ancillaries, one by one, and the tapping is still there. I have removed the front timing covers and temporarily re-attached the top covers & dizzy caps so I could take a closer look & listen to the timing tensioner in motion. The tapping was louder and seemed to be coming from around the flywheel area.
I have dismantled and inspected all of the timing gear parts and have the following observations. There was a small amount of belt "fluff" built up on the timing pionter and in the very bottom of the lower cover; The belt appears to have been wearing on the metal guide plate that is positioned between the belt pully on the crank and the orange front flywheel. Inspection of the timing components themselves reveals the following. The large tensioner wheel is perfect, the smaller tensioner idler has a slight amount of play. The tensioner arm itself is supported on a single shaft with two nylon bushes, both of these exhibit slight wear evident by about 3mm lateral play at the tensioner roller. My 1990 MY S4 has an additional pair of belt guide idle rollers positioned below the crank pulley mounted on a small metal carrier. This carrier is itsef mounted on two projecting pins and is secured by circlips. Both of these rollers are a little bit worn but by biggest concern is the diameter of the carrier mounting pins and the associated holes on the carrier. The left hole is a nice sliding fit on the pin but the right hole is of a much larger diameter allowing the carrier to "ratlte". Does anybody have any knowledge of this arangement? is it normal?
I am planning to replace the two tension arm pivot bushes and have ordered replacement bearings to rebuild the idlers. I have pressed out the bearings from the rollers and am replacing them with SKF twin sealed deep roller bearings 62012RS and 69052RS costing about £20 for the set as opposed to about £100 from any of the UK's independant Porsche specialists and possibly a lot more from Porsche themselves!
It will be a few days before I get all the bits ready for re-assembly.....it is Easter after all. So watch this space to see if a small amount of play in a few bushes & bearings can cause such an alarmingly loud rattle. Whilst I am waiting for the postman if any of you can throw any light on my lower cam belt idler assembly then it would be much appreciated
Happy Easter
Regards
Stuart
04-14-2009, 11:43 AM
#34
Team Owner
I hope that you get the tan colored shaft bushing, I have found that the dark grey bushes are not as tight, and actually replaced my new dark greys with a another set of tan bushes, IIRC Roger sells the tan colored bushes
04-14-2009, 05:03 PM
#35
Intermediate
Thread Starter
Stuart...............given the work you have already done I'd suggest buying a belt tension tool and doing the belt tightening to spec. John Speake has them in your part of the world.
Also, if the lower idlers are the issue pull them off and run the engine............you'll soon determine if thats the concern.
With the new water pump it probably came with a new pin for the roller arm which should be mated to new bearings.
Installing the Porkensioner eliminates all the idlers rollers (3), the bearings and the main roller arm..........quite a savings in money and maintenance.
Also, if the lower idlers are the issue pull them off and run the engine............you'll soon determine if thats the concern.
With the new water pump it probably came with a new pin for the roller arm which should be mated to new bearings.
Installing the Porkensioner eliminates all the idlers rollers (3), the bearings and the main roller arm..........quite a savings in money and maintenance.
I appreciate your candidness. I have just emailed John Speake at JDSPorsche with a view to acquiring the J.Kempf 928 cambelt tension tool :-) I have also ordered new bushes for the tensioer arm and am in the process of rebuilding all the idle rollers with new bearings. My only outsanding problem is replacing the lower idler carrier and if oz928s4 comes up trumps then we should be up and running in next to no time.
Thanks for your help so far
Regards
Stuart
04-14-2009, 05:17 PM
#36
Intermediate
Thread Starter
Oops.......I've allready ordered the bushes from my local OPC the Porsche Centre in Solihull - nobody mentioned that there was two types!
04-14-2009, 05:26 PM
#37
Intermediate
Thread Starter
Hi John
Sorry for being a pratt, I just emailed you via your JDSPorsche website on Malcolm's recommendation - I did not twig thay you were already watching this thread. I agree the bushes are readily availible, it is the lower idler assembly is proving more troublesome
Sorry for being a pratt, I just emailed you via your JDSPorsche website on Malcolm's recommendation - I did not twig thay you were already watching this thread. I agree the bushes are readily availible, it is the lower idler assembly is proving more troublesome
04-14-2009, 05:56 PM
#38
Burning Brakes
I may have missed this but it stands to be mentioned. Also replace the tensioner arm shaft bolt. Mine was bending and caused the belt to move forward causing it to wear on the tensioner arm.
Also how is the wear on your cam gears? Since you are going in again to re-do the belt might as well get it all done at once.
You might want to get John Kelly's "Timing belt manual" It is very well written and helps those of us who do timing belts only when needed.
Also how is the wear on your cam gears? Since you are going in again to re-do the belt might as well get it all done at once.
You might want to get John Kelly's "Timing belt manual" It is very well written and helps those of us who do timing belts only when needed.
04-14-2009, 07:26 PM
#41
Intermediate
Thread Starter
I may have missed this but it stands to be mentioned. Also replace the tensioner arm shaft bolt. Mine was bending and caused the belt to move forward causing it to wear on the tensioner arm.
Also how is the wear on your cam gears? Since you are going in again to re-do the belt might as well get it all done at once.
You might want to get John Kelly's "Timing belt manual" It is very well written and helps those of us who do timing belts only when needed.
Also how is the wear on your cam gears? Since you are going in again to re-do the belt might as well get it all done at once.
You might want to get John Kelly's "Timing belt manual" It is very well written and helps those of us who do timing belts only when needed.
Thanks for your contribution however on 87 and later the pivot shaft is integrated into the water pump and it is tied at it's "free" end by an additional bracing plate to prevent the bending you and presumably others experienced with the earlier cantilever bolt arrangement. The cam pulleys look OK so I'm not planning to replace them just yet.
Regards
Stuart
04-14-2009, 07:33 PM
#42
Intermediate
Thread Starter
Small world isn't it? You must have the same VAT quarter as me because guess what I was doing this afternoon.................and FUN does not adequately describe calculating the non-EU input contribution to the tax paid at the point of entry for goods imported from the US !!
04-14-2009, 08:33 PM
#43
Rennlist Member
Stuart............you shouldn't need it but I'm also replacing my water pump with a new Laso which has the pivot shaft and brace.
As I run the modern Porkensioner that doesn't run any idlers the shaft and brace are surplus to requirements...............yours/anyones for the stamp
As I run the modern Porkensioner that doesn't run any idlers the shaft and brace are surplus to requirements...............yours/anyones for the stamp
04-15-2009, 08:00 AM
#44
Racer
Join Date: Oct 2008
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Hi oz928s4
Nobody in the UK seems to have one of these and my search for a machine shop to refurbish mine seems to have drawn a blank so far :-(
My Address here in UK is :-
Southside
Livesey Avenue
Ludlow
Shropshire
England
SY8 1HN
I really appreciate your offer, you are an absolute star
Regards
Stuart
Nobody in the UK seems to have one of these and my search for a machine shop to refurbish mine seems to have drawn a blank so far :-(
My Address here in UK is :-
Southside
Livesey Avenue
Ludlow
Shropshire
England
SY8 1HN
I really appreciate your offer, you are an absolute star
Regards
Stuart
I will attend the post office tomorrow with the part...I assume you dont need the bushes now.
So will take just the lower bearing guide housing.
Get back to you tomorrow.
Sorry I cannot respond earlier but [I havent been getting home until after 7.oo pm
04-15-2009, 10:55 AM
#45
Intermediate
Thread Starter
Thanks, I can't tell you just how happy you have made me :-)
Following MrMerlin's comments about there being two types of bushes if your's are the tan coloured ones I would really appreciate those too just in case Porsche supply me with the inferior dark grey ones.
Please let me know how much I owe you and how you would like to be re-embursed
Thanks again
Regards Stuart