How to identify timing chain for tensioner TSB?
04-22-2020, 04:29 PM
#1
Drifting
Thread Starter
How to identify timing chain for tensioner TSB?
I'm in a bit of a conundrum here and need some insight. My 1999 makes a bit of chain tensioner noise when I first start her. It's not always there, but probably 80% of the time it is for the first 30 or so seconds after a cold start. TSB 10/00 1551 indicates that the tensioner part number 996 105 180 54 is the old style and is to be used if you have the older roller style IMS chain. The bad news is that -54 is NLA and my engine was replaced at some point and doesn't have an engine serial number on the block. Therefore I'm not able to use that to determine which style of IMS chain is inside my engine (i.e. the older roller style or the newer toothed style).
So the long of the short is this: Is there an an access point on the engine which would allow me to determine which style of IMS chain I have? I have a wireless borescope so I could potentially use that as well. What I'd like to avoid is having to drop the engine to pull the cam covers to do this.
Fwiw, my IMS bearing was changed about 5 years ago. A double row IMSB came out and a new LN Engineering IMSB was installed. This tells me that even though the engine is a replacement, it is still early enough to have a double row IMSB.
EDIT: changed wording to reflect that this concerns the IMS chain, not the cam chains.
So the long of the short is this: Is there an an access point on the engine which would allow me to determine which style of IMS chain I have? I have a wireless borescope so I could potentially use that as well. What I'd like to avoid is having to drop the engine to pull the cam covers to do this.
Fwiw, my IMS bearing was changed about 5 years ago. A double row IMSB came out and a new LN Engineering IMSB was installed. This tells me that even though the engine is a replacement, it is still early enough to have a double row IMSB.
EDIT: changed wording to reflect that this concerns the IMS chain, not the cam chains.
04-22-2020, 05:34 PM
#2
Isla
I have a 99 C2 with the old style double roller chain and I upgraded my IMS chain tensioner a while ago with the latest type available on design 911 , on there if you enter your car model and year it only lists the parts compatible, hence why I bought the one I did, which had a newer part number, I don't think the newer tensioners or the ones on the later hyvo chain are different dimensions , the newer tensioners are upgrades to reduce leak down and start up rattle, if you really want to look which chain you have you will have to put the engine at TDC and remove the ims chain tensioner , luckily it's underneath the engine in the centre just behind the sump plate , it's the only place you will see which chain you have as the other two large cam chains running from the ims to cams in the heads and the small vario chains also in the heads are still roller chains so there's no point looking in there, but I'm pretty sure it's irrelevant which chain you have on your ims , the tensioners are interchangeable as far as I know , hopefully someone else will chime in for confirmation, I could try searching on design 911 for a tensioner for an early 3.4 then a later 3.6 to see if it comes up with the same part number , the site is pretty good and updates to new part numbers which supersede older discontinued parts when porsche upgrade the part , I'll have a look!
I have a 99 C2 with the old style double roller chain and I upgraded my IMS chain tensioner a while ago with the latest type available on design 911 , on there if you enter your car model and year it only lists the parts compatible, hence why I bought the one I did, which had a newer part number, I don't think the newer tensioners or the ones on the later hyvo chain are different dimensions , the newer tensioners are upgrades to reduce leak down and start up rattle, if you really want to look which chain you have you will have to put the engine at TDC and remove the ims chain tensioner , luckily it's underneath the engine in the centre just behind the sump plate , it's the only place you will see which chain you have as the other two large cam chains running from the ims to cams in the heads and the small vario chains also in the heads are still roller chains so there's no point looking in there, but I'm pretty sure it's irrelevant which chain you have on your ims , the tensioners are interchangeable as far as I know , hopefully someone else will chime in for confirmation, I could try searching on design 911 for a tensioner for an early 3.4 then a later 3.6 to see if it comes up with the same part number , the site is pretty good and updates to new part numbers which supersede older discontinued parts when porsche upgrade the part , I'll have a look!
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158Sierra (03-14-2022)
04-22-2020, 05:36 PM
#3
Rennlist Member
I'm in a bit of a conundrum here and need some insight. My 1999 makes a bit of chain tensioner noise when I first start her. It's not always there, but probably 80% of the time it is for the first 30 or so seconds after a cold start. TSB 10/00 1551 indicates that the tensioner part number 996 105 180 54 is the old style and is to be used if you have the older roller style IMS chain. The bad news is that -54 is NLA and my engine was replaced at some point and doesn't have an engine serial number on the block. Therefore I'm not able to use that to determine which style of IMS chain is inside my engine (i.e. the older roller style or the newer toothed style).
So the long of the short is this: Is there an an access point on the engine which would allow me to determine which style of IMS chain I have? I have a wireless borescope so I could potentially use that as well. What I'd like to avoid is having to drop the engine to pull the cam covers to do this.
Fwiw, my IMS bearing was changed about 5 years ago. A double row IMSB came out and a new LN Engineering IMSB was installed. This tells me that even though the engine is a replacement, it is still early enough to have a double row IMSB.
EDIT: changed wording to reflect that this concerns the IMS chain, not the cam chains.
So the long of the short is this: Is there an an access point on the engine which would allow me to determine which style of IMS chain I have? I have a wireless borescope so I could potentially use that as well. What I'd like to avoid is having to drop the engine to pull the cam covers to do this.
Fwiw, my IMS bearing was changed about 5 years ago. A double row IMSB came out and a new LN Engineering IMSB was installed. This tells me that even though the engine is a replacement, it is still early enough to have a double row IMSB.
EDIT: changed wording to reflect that this concerns the IMS chain, not the cam chains.
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islaTurbine (04-22-2020)
04-22-2020, 05:50 PM
#4
I stand corrected, there are two different part numbers, I did 3.4 which has the double chain and 3.6 which had the later chain upgrade so you may have to do as I said and remove theIMS tensioner and stick the camera in to see the ims chain
04-22-2020, 06:26 PM
#5
Drifting
Thread Starter
@Porschetech3 Perfect idea. I wasn't sure if I'd have room to see around the tensioner paddle so I'm glad to know that this is a viable option.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
04-22-2020, 06:43 PM
#6
Rennlist Member
@Porschetech3 Perfect idea. I wasn't sure if I'd have room to see around the tensioner paddle so I'm glad to know that this is a viable option.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
04-22-2020, 08:56 PM
#7
Drifting
Thread Starter
Update: It appears that -54 supersedes to -59 which is still available. -55 for the toothed chain has superseded to -58 and is obviously still available as well. So now my job will be to figure out which chain I have so I can order the correct version of tensioner.
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04-25-2020, 05:25 AM
#8
Originally Posted by islaTurbine
@Porschetech3 Perfect idea. I wasn't sure if I'd have room to see around the tensioner paddle so I'm glad to know that this is a viable option.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
@Noz1974 Are you saying that you used the superseded tensioner with the old style IMS roller chain? The TSB says, "A mixed configuration is not permissible, as the parts are matched with each other. The previous chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
Unfortunately -54 is now NLA as this TSB was written in November of 2000. 996 105 180 55 is the part number for the new style IMS tensioner.
04-25-2020, 05:26 AM
#9
Originally Posted by islaTurbine
Update: It appears that -54 supersedes to -59 which is still available. -55 for the toothed chain has superseded to -58 and is obviously still available as well. So now my job will be to figure out which chain I have so I can order the correct version of tensioner.
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islaTurbine (04-25-2020)
04-25-2020, 05:30 AM
#10
Hey Isla I was just thinking , what about removing the ims tensioner and checking the part number on it, that should tell you which set up you have as the two different chains seem to run different tensioners, even if it's an older part number you should be able to find it and see what it's been superseded with??
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islaTurbine (04-25-2020)
04-25-2020, 09:44 AM
#11
Drifting
Thread Starter
Hey Isla I was just thinking , what about removing the ims tensioner and checking the part number on it, that should tell you which set up you have as the two different chains seem to run different tensioners, even if it's an older part number you should be able to find it and see what it's been superseded with??
