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YOUR RESEARCHHow to identify timing chain for tensioner TSB?
Leading reported evidence
Replace fwiw, my ims bearing
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Performed · outcome unconfirmed · Original poster
Fwiw, my IMS bearing was changed about 5 years ago.
Leading evidence: 'Replace fwiw, my ims bearing' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace fwiw, my ims bearing' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
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.
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Performed · outcome unconfirmed · Original poster
EDIT: changed wording to reflect that this concerns the IMS chain, not the cam chains.
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Performed · outcome unconfirmed · Original poster
996 105 180 54, is still available and may continue to be used on engines that have the previous style drive chain installed."
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Suggestion
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 wil
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Suggestion
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 wil
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Suggestion
Might be worth checking with the dealership parts dept as these tensioners can get confusing , I believe they have been upgraded a few times to help with start up rattle etc , I might be running the wrong one mistakenly!!
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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.
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 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
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@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.
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.
Isla I went with the one from design 911 which showed to match my year as above ending 59 which is the latest iteration I believe for the early car, the one ending 58 seems to be the one for models 2000 onwards but I'm trusting design911 here, I just went on and bought it TBH, it's in my car and running ? Might be worth checking with the dealership parts dept as these tensioners can get confusing , I believe they have been upgraded a few times to help with start up rattle etc , I might be running the wrong one mistakenly!! Your making me doubt it now! 🙀
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??
Yeah that would definitely be the easiest route as long as there is a number on it. I know I�ve seen plenty of PD parts that have no stampings so I figured I should go into this with all my bases covered.
