Chain Tensioners: How hard and Could it save a blow up?

I'm thinking on changing my chain tensioners. There have been several folks posting here about chain guides wearing out. I wondered if constant pressure from a good chain tensioner would help. Has any done this job? Do you think it will extend the life of the engine until I can go in and change all the chains out. Working toward addressing all the concerns about these engines. Doing water pump, thermo, and rear hoses. Figure while I'm there I'll do the tensioners.

I've got a new bank 1 tensioner due from Pelican tomorrow. I'm starting with bank 1 because I understand it is the one most likely to drain down first. I have the "1 sec rattle" on startup but it only happens on the first start of the day, so it takes a full day to drain down and even more noticeable after two or three days taking 2 or 3 seconds to clear. Mine is an early '00 and I understand the tensioners were updated with a stronger spring in '01. I'm also changing the oil from 0w40 to 5w40 so I'll probably run it for a couple days just to see if it is the higher weight that makes a difference and then install the new tensioner next week.

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Just wondering if you ever got the tensioner installed and how it went? I'm pretty sure I have this issue so new tensioners might be in my future as well.

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Thanks for searching The updated tensioner has a big preload spring on it so it's a big improvement, you will lose a little oil during the install so you should have some container to catch it. I lived in Virginia a long time ago!

I have not installed the tensioners. This conversation is in preparation for work to happen this spring. I'm still working in my driveway. Looks like I'll need a set of cam lockdown tools. The next thing I'm going to do is drop the oil pan and see what I find on it. Black or green bits, but hopefully nothing. That will determine my next move. The tensioners replacement was really a question about did anyone think it would be helpful in preventing further damage to the chain guides from slapping. We didn't really get a good response from this inquiry. Maybe your prompt will help. Thx!

Following. One of our Box's is a little rattly on startup and I'm wondering how big a PITA this will be.

Yes it should be addressed accourding to Jake Raby. Flat tensioners and worn pads can cause a timing chain to jump at start up and wreck an engine. I have the start rattle and my timing offsets are on the high side do im pulling the motor and changing pads, a couple chains and tensioners in a few weeks. Ill try to document my repairs in a fresh thread.

On a continuum Jake is on one end and the rest of us are somewhere else. Hope someone can post up a solution that doesn't involve pulling the engine.

U can do the tensioners with the motor in, not easy but can be done. Im not sure what solution u r looking for? If the tensioners arent holding they need to be replaced. By deffinition they r "tensioners" if they r flat, they allow the chain to slack. There r documented chain and engine failures because of this so yes its an issue that should be fixed. If u choose to ignore because cost or conveinence just like bore scoring and the ims its a gamble and u might win or loose. my motor has over 200k miles and i dont have much history so between that and the info from the dme im not gonna gamble.

It sounds like the tensioners are a bit of a challenge to change. No problems and I'm confident I can pull it off. I don't have any chain issues that I aware of, but I'd like to do as much preventative maintenance as I can. These engines seem to be time bombs. If changing out the tensioners will buy some time before I pull the engine I'm willing to do the work. Just like changing out the water pump and IMS is good preventative maintenance. Having tight chains seems like a good idea. Yep, saw that Raby goes on about tensioners. I think he is information is good, but his demeanor is condescending.

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Let us know how it goes and any data you might find that is helpful. The water pump wasn't too big of an issue. Just took some time to get to it.

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I have the tensioner but due to a case of "while I'm in there" with the trans out I keep doing other stuff. I should have everything done by Sunday if the new AOS arrives, but who knows. Regarding the bank-1 tensioner (see pic, new one is on the right) the reach on the new one is about 1mm longer. I pushed down on it on a digital scale and the plunger first moved at 16.x lbs for the new one and 14.x lbs for the old one. Not very scientific but it's all I got. I'll follow up once everything is all back together.

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if u r gonna go through the effort i would pull the cam deviations and make sure u dont need pads or guides. i dont see the motors as ticking time bombs, i see them as a candle that burns bright thus burn out sooner. They just need more love more often.

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I'd like to give mine as much love as I can.

I am also about replace the tensions/guides/chains. After doing a bore scope on the engine, the bores are good, but we found chain guide material in the oil pan. Additionally, we also found bits of green o-ring, like the one on the tensioner pictured above, in the oil pickup tube. The job will be conducted in a few weeks, as I am currently just waiting on parts to show up. At the same time, I will be addressing some other cooling items. LN low temp thermostat, water pump, and a center radiator. I will let you know how it goes.

Initial research to project underway: Can it really be as simple as removing and replacing? Isn't some sort of "hold or lock? required on the cams? Posted pic from pelican (thank you) showing tensioner for cyls 1-3. https://cdn4.pelicanparts.com/techar..._med/Pic16.jpg

Kinda bank 2 is more difficult. here is a thread that has more info, but several more out there https://rennlist.com/forums/996-foru...ensioners.html

Hi guys, I have a similar issue: '01 C2 with Tiptronic, 90K miles - had the sump dropped in October to install the LN 0.5 qt deep sump, along with spin on filter and magnetic drain plug. Switched to DT40 oil and Napa gold filter. There was no metal in the sump, but there were brown plastic bits that I understand are the timing chain adjuster pads. Unfortunately did not get a bore scope done while the sump was off so don't know if bore scoring is an issue or not. Car has been stored since early Nov with the usual precautions (Stabil in 91 Octane, ethanol-free gas, etc.) I am planning to do the LN IMS solution in the Spring and got a Durametric to check the cam deviations. Last weekend when I tried to start her up (first time in approx 2 months) to drive to get the engine up to temp, it took a couple tries and the chains rattled like crazy until it settled down enough to get it on the road. After a 20 minute loop, keeping revs around 3,000, came home at temp and she idled fine at 700 rpm with a/c off. No codes on the Durametric but cam deviation was -7.14 degrees for cam 1 and -2.83 for cam 2. So I am now planning to get the chain adjuster pads replaced first , then with the engine out, do the UAOS, RMS and IMS Solution at the same time, along with the trans mount. My questions are: 1) is it ok to drive it occasionally until March or is it too risky for a chain to jump a cog and damage the engine? 2) Is it better to start it weekly or leave it for another couple months and drive it to my Indy (approx 20 mins drive)? 3) Or is it so bad that I should get a flatbed to take it to the shop? Thanks Bill

I would say u r fine to drive. I have put about 2500mi on mine with the rattle and similar cam deviations. Actually just did 360mi trip, longest since ownership. Its just an issue that needs attention and fixed, although a skipped chain can happen its not super common.

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According to a LN Engineering, Porsche states that the cam deviation should be at most 6 degrees difference between the two bank. Raby suggests 4 degrees. Seems like you have quite a bit between the two at nearly 10. I wouldn't drive it until it was addressed. We obviously have a difference of opinion already. Good conversation. Thx.

Is it the difference? (ie -7.14 - -2.83 = 4.31) or the absolute value of each cam deviation # that is used to determine when out of spec?

That's 4.31 degrees by my math. Outside of Jake's spec, but within Porsche's. Also remember reading somewhere that cam deviations on either bank getting up to around 8 degrees will trigger codes related to enrichment being out of range.

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Dude! This is exactly what I am interested in doing this spring. I would be grateful for any updates or insights you have. Be encouraged!

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For my part in this, I am just replacing the bank-1 tensioner, not any pads since my filter has been clean. I have the crank locked at tdc along with the cams on that bank. My rattle is 1 sec after a day but a little longer after several days. Although I think I hear the rattle coming from the left side I'm not sure of it so I'm just changing the tensioners one by one - bank-1, then bank-2, then IMS. Since bank-1 has the drain hole on the bottom it seems to drain oil soonest and also it does have a superseded part that came out in 2001 that is clearly different than the original. I would be interested to know if those with a Mk2 have tensioners that look the same as the one on the right in the picture, which is the newest one (part #996.105.186.02). Also, if all the wear (and plastic chips) occur only during start up (the rattle) I wonder if it would be smart to use a kill switch and crank for 15 sec to build oil pressure if you haven't driven in awhile. I know mine has been pan off, IMSB exposed, tensioner and plugs out for 2+ weeks now and I will be cranking for 30 sec (plugs out) before I start it up to get the oil around. We've been told "it's normal" to hear the short rattle but it's still not good and these cars didn't rattle when they were new, that I know of.

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True, it�s within Porsche spec, but don�t forget, there is also the absolute value of the cams relative to the crank, and so one bank is still -7 from the crank, which is not ideal. But I agree, tensioner pads will be required at some point sooner or later.

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pretty sure from zero degrees not between both banks.

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I will let you know what we find. The project all started because I was burning oil on deceleration. One thing lead to another, as is typically the case. The AOS was failing, so I will also be adding a UAOS. Since we did a bore scope, I also added a .5 quart deep sump from LN, along with other various parts. I hope that by addressing some typically weak points of the M96, it will be good to me in the long run.

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There are two different measurement values for two different things. There�s cam deviation between the two banks, and relative to each other. So -7 on one bank and -3 on the other bank produces 4 degrees between the two. Obviously, we would prefer both banks to have the same timing (-7, -7) between them, which is zero difference. Separately, there�s timing between the crank/IMS and the cams. We would want that timing to also be zero difference between the cams, but with (-7, -7), we are 7 degrees off even if we are zero between the cams. Therefore, ideal timing would be (0, 0) cam deviation, which is rare, even from the factory, even when new. Anytime the deviation is off, it�s because of wear, which could include tensioner pad wear, the tensioners themselves, chain stretch or wear, sprocket changes, etc. I had (-4, -2) before my four cam tensioners were replaced. It was close to (0, 0) afterwards. While this is still within Porsche spec, I clearly still had wear that was visible, and the mechanic was already in there replacing the solenoid that failed.

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Ok, I have the results from changing to the updated bank-1 tensioner ( 996-105-186-02-M100) . P-car sat for four days, I would assume enough time for it to significantly drain down. Had zero startup rattle at all whereby normally I would have 2-3 seconds before it dissipates. I'm pretty happy about this since I would expect that the rattle is from the chain beating against the pads, scraping and eventually chipping off pieces. I had zero plastic pieces in my last oil change so maybe with this update I'm good to go for another 50k miles. Another factor is that I filled with 5w40 Liqui Molly and I think the prior owner had 0w40 M1 in it, so the heavier weight might help a little. I think the bank-1 is most prone for this issue since: 1. it is furthest from the oil pump so oil has further to travel (bank-2 tensioner fills almost immediately). 2. it is in an upright position, with the fill hole on the bottom, more likely to drain whereas the other two tensioners are sideways or inverted, and 3. the new tensioner has a stronger spring, perhaps 10% stronger and it is approx 1mm longer than the original part, so Porsche saw fit to address this. I know there was a new tensioner available with MY01 (mine is MY00), but I believe there were other part numbers available over the years, so it could be a solution for later years also. I don't know if there are updated bank-2 or IMS tensioners, but at this time I don't see the need to address them. Great that the bank-1 is the easiest to access also.