The solution to chain rattle

[Guitarmageddon]

LOL!

Is chain rattle that grindy noise my car makes for half a second when I turn it on?

What is that annoying whine the car does on really cold starts that doesn't go away until RPMs drop to idle 800?

Yes...that would be chain rattle. But as far as the noise, probably has something to do with the timing/fuel mixture being adjusted on cold starts. Not sure which it is, someone chime in? Because mine will sit at around 900 for about 45 seconds, then you can feel the car run smoother when it changes the timing/mixture, before the RPM's idle.

[ProgMetalHead]

I was told a long time ago that the whine is normal, but in case it's not, I'd like to get it taken care of while I have CPO.
I'm not concerned about the rattle...it's really only for half a second.

[Canton Racing]

We should have pricing for the kit at some point today. We are going to be offering special pricing for anyone that emailed us with interest. If you want to get in on the special pricing email [email protected]

[Canton Racing]

pricing is available. Will most likely only offer the special pricing for the first run of caps so if you want one be sure to email [email protected]

[blackv8-s4]

I have an 05 s4 that developed the rattle in the last year at 82k. It just got worse by the week over the last 12 months. I am really worried about it so I ordered an accusump kit today from Canton. After everything I have read and experienced I am a believer in this solution to at least prevent damage from things flopping around in there on cold starts. But the funny thing is, Mine was really bad for the last month unless I cranked the engine a few times without starting it. And sometimes it was pretty bad even then. Then I changed my oil at 8500 miles instead of waiting until 10,000 which is spec and it all dissapeared. I am now at 600 miles on this oil change with only the faintest chain rattle on start up. I know that it will get worse as the oil gets older, but it does suggest that more frequent oil changing is a partial issue here. I also wonder if better oil, or a different viscosity would improve the length of time before the oil breaks down and the rattle returns. I plan on changing my oil more frequently now anyway, because if it is deteriorating to the point that the chain and tensioner components aren't properly lubricated or sealed, then what is it doing to the rest of my engine? My question is this: which kind of oil will cling to parts when the engine is not running? A 0w 40 was recommended earlier because it would pump up faster, but doesn't that also mean that it would run off parts and out of areas between parts like pumps etc after shut off? So doesn't it stand to reason that a 20w 40 for example, would leave more oil clinging to parts when it is not running. So thicker oil for more "cling" or thinner oil for quicker pump up?

[Canton Racing]

We are still waiting to receive enough orders to start this run. The response to actually placing the orders so far has been very underwhelming. We need sell about 10 of these in order to justify the setup time. If anyone is interested please email [email protected]

[BCsniper]

......Then I changed my oil at 8500 miles instead of waiting until 10,000 which is spec and it all dissapeared. I am now at 600 miles on this oil change with only the faintest chain rattle on start up. I know that it will get worse as the oil gets older, but it does suggest that more frequent oil changing is a partial issue here. I also wonder if better oil, or a different viscosity would improve the length of time before the oil breaks down and the rattle returns..........My question is this: which kind of oil will cling to parts when the engine is not running? A 0w 40 was recommended earlier because it would pump up faster, but doesn't that also mean that it would run off parts and out of areas between parts like pumps etc after shut off? So doesn't it stand to reason that a 20w 40 for example, would leave more oil clinging to parts when it is not running. So thicker oil for more "cling" or thinner oil for quicker pump up?

Do not start using a 20w40. Stick to the Audi recommended oil weights and just go with a smaller oil change interval. Most don't exceed 5,000 miles before changing. However this will not ultimately solve the problem. The rattle might go away for awhile, but not forever. Also just because you can hear the rattle come back does not mean the oil has degraded.

We are still waiting to receive enough orders to start this run. The response to actually placing the orders so far has been very underwhelming. We need sell about 10 of these in order to justify the setup time. If anyone is interested please email [email protected]

.....underwhelming response? Maybe the issue is that this "solution to chain rattle" is not a solution to the problem, not even a bandaid, more like just ear plugs. This just gets rid of the noise to help some of you guys sleep at night. You really think why your guides fail is due to the wear they receive from less than a second of slack immediately after a cold-start (I know I don't think that is the sole cause)? It's nice that a company jumped in to try to help our platform, but I think it's yet another gimmick item that a company will sell because people ask for it, not because there is an actual benefit from using it. Just because things can be adapted to work on our cars doesn't mean that we have to use them, but hell what do I know.........go for it if it helps you sleep better at night

[0000 V8]

BC,

Canton is only responding to the community with what was asked of them. I can see how it would be frustrating for them because many members have talked about wanting a setup like this and yet no one wants to follow through.

You're right in the sense that this wont solve the problem of the worn guides completely, but it will certainly help some. Canton has been designing and selling there Accusump for many years and are a proven solution for pre-oiling engines and used in many race cars. The usefulness of this setup is not really questionable. Simple put, it's better than nothing.

[BCsniper]

BC,

Canton is only responding to the community with what was asked of them.

hence why I said "It's nice that a company jumped in to try to help our platform"
...to me it seems about on par with one of these shops selling a CAI to a V8 S4 owner. They are doing it because the customer specifically asked for it (and they can make a profit off the install), however they neglected to inform the customer that it gives no performance gains whatsoever and can actually diminish returns

Simple put, it's better than nothing.

see that's where I don't think so. Honestly I don't think this will have any affect to the wear of our timing components. Now to know this for certain it would take several people testing this pretty much from the start of an S4's life and run it for 50-100k miles since that's how long stock components last (actually my old S4 went 130k miles and above).

For full fledged race cars, airplanes, jets, etc I know pre-circulating the oil is helpful if not necessary, however I just don't think this is the case for our cars (however once again, I could be completely wrong.....but then again so could those on the other side of the argument)

[bioluminescent]

.....underwhelming response? Maybe the issue is that this "solution to chain rattle" is not a solution to the problem, not even a bandaid, more like just ear plugs. This just gets rid of the noise to help some of you guys sleep at night. You really think why your guides fail is due to the wear they receive from less than a second of slack immediately after a cold-start (I know I don't think that is the sole cause)? It's nice that a company jumped in to try to help our platform, but I think it's yet another gimmick item that a company will sell because people ask for it, not because there is an actual benefit from using it. Just because things can be adapted to work on our cars doesn't mean that we have to use them, but hell what do I know.........go for it if it helps you sleep better at night

From a fair amount of research, it's my understanding that chain rattle is the culprit in chain guides failing. The impression I was under was that the half second of chain rattle on start up, may a few times a day?, eventually wears down the poorly constructed guides to failure. Therefore, if chain rattle was eliminated, which I think people are claiming this system does and not just hide it, there would be no more wear on the guides. I'm by no means a mechanic though. Am I misunderstanding the cause to chain failure?

Obviously, at this point in our cars' lives testing can not be fully completed, but I really don't see any negatives to trying this set up.

[BCsniper]

From a fair amount of research

by this you mean reading through this very biased thread full of hypochondriacs?

this half a second of rattle, "may a few times a day",
...think again about that statement. The rattle only happens on a cold start (i.e. the car has been sitting all night). So at most you would get this once a day, maybe twice if you have a very short drive to work and the car sits for another 10 hours. The car wont make this noise on a warm start (if it does, you have problems), so really it does not happen all that often, and it only lasts for a second, do you really think this is the sole reason that these guides crack?

....like I said, most of us are not experts so most of the claims we all make can't be supported, but I would put my best guess towards the issue being excessive heat cycling along with just getting too hot then it was intended. Honestly I think pretty much all of the issues that the V8 S4's go through is due to heat. They put an engine that was too big for the engine bay so it gets way to hot with no way to dispel the heat which is why we get warped blocks, scored cylinders, timing components that don't last as long as they should, etc...

[paul61]

I agree with BC, it's a bandaid ,or earplugs if you will.

I did notice a trend on my S4 recently:
About once in every 20 or so start ups, the motor will crank for a few seconds before firing.
When this occurs, there is absolutely ZERO chain rattle.
It's a good guess that the oil pressure rise has had enough time to energize the tensioners??

Peace of mind not hearing it but, I'm afraid that's all.

[bioluminescent]

by this you mean reading through this very biased thread full of hypochondriacs?

this half a second of rattle, "may a few times a day",
...think again about that statement. The rattle only happens on a cold start (i.e. the car has been sitting all night). So at most you would get this once a day, maybe twice if you have a very short drive to work and the car sits for another 10 hours. The car wont make this noise on a warm start (if it does, you have problems), so really it does not happen all that often, and it only lasts for a second, do you really think this is the sole reason that these guides crack?

....like I said, most of us are not experts so most of the claims we all make can't be supported, but I would put my best guess towards the issue being excessive heat cycling along with just getting too hot then it was intended. Honestly I think pretty much all of the issues that the V8 S4's go through is due to heat. They put an engine that was too big for the engine bay so it gets way to hot with no way to dispel the heat which is why we get warped blocks, scored cylinders, timing components that don't last as long as they should, etc...

Not just this thread, but just about every thread links chain rattle to chain failure. In fact yours is the first opinion I've read about that does not. I'd be interested to know if anyone experienced chain failure with no chain rattle evident prior to. The excessive heat could be a very logical reason, as well, but the rattle seems the more obvious for me at least.

Even it was only 1/2 second a day (on cold days it's more like 2-3 times for me) on an 04 like mine that adds up to almost a half hour of chain slapping against the guides during it's 9+ year life. This clearly can't be beneficial for the car. If this system claims to eliminate chain rattle, I would have peace of mind knowing that the chain was no longer slapping against the guides on cold start ups, and not causing additional deterioration.

[Canton Racing]

hence why I said "It's nice that a company jumped in to try to help our platform"
...to me it seems about on par with one of these shops selling a CAI to a V8 S4 owner. They are doing it because the customer specifically asked for it (and they can make a profit off the install), however they neglected to inform the customer that it gives no performance gains whatsoever and can actually diminish returns

The Accusump has been used for pre-oiling for over 30 years. We were not trying to sell a gimmick. We see this type of reasoning a lot as we don't offer products that are performance gain oriented. Our products are of a preventive nature. We design products to prevent costly failures and issues which makes people very skeptical. From the information we gathered mostly from this thread since we are not VW/Audi engineers we saw this as a pre-oiling issue. We felt that while the Accusump does not fix the root cause that it could help prevent this issue for those that are concerned about it. Since none of our traditional Accusump plumbing methods could be applied we needed to R & D an entirely new piece to make this work. We got a good response to the feelers and I pushed to have this product designed. Like we stated before we are not VW/Audi engineers and do not have experience with the intricacies of the motor but we do feel as if pre-oiling can help this issue.

[Latosa]

Hey guys , I always like to say "not impossible is just an opinion" after so many replies the only thing I can say is that my setup is been RUNNING strong,maintenance free ,and ZERO chain rattle for ONE YEAR NOW IN MY S4 since it was put in service ,also this is not the first time I used a accusump for my cars or customers ,I do frabrication work on drags cars for alot people and I always recomend the accusump for them. Regardless what order people may think that if it works or not ,I respect there opinion but is been working for me ! And me knowing some aeronautics for 18 years now as a full time job I can tell you almost every system in a Aircraft has a accumulator or a pre-oling system to prevent failures .So is up to you to try it out or not .As for canton racing I know there trying to help so is either you buy it or not ,all can say great product.

[KAL]

Just hurd from my indy. Will be adding my name to the list!

[s2carlo]

Hey guys , I always like to say "not impossible is just an opinion" after so many replies the only thing I can say is that my setup is been RUNNING strong,maintenance free ,and ZERO chain rattle for ONE YEAR NOW IN MY S4 since it was put in service ,also this is not the first time I used a accusump for my cars or customers ,I do frabrication work on drags cars for alot people and I always recomend the accusump for them. Regardless what order people may think that if it works or not ,I respect there opinion but is been working for me ! And me knowing some aeronautics for 18 years now as a full time job I can tell you almost every system in a Aircraft has a accumulator or a pre-oling system to prevent failures .So is up to you to try it out or not .As for canton racing I know there trying to help so is either you buy it or not ,all can say great product.

Totally agree with Latosa. Same for my system & opinion!
Even if it did not help for anything else I am happy I got rid of the horrable sound!

[TarlCabot]

I don't want to jinks myself, but this B7 has over 101k miles and NO chain rattle or other issues, all original parts and I just hit the track this last evening for some time slips and vids... check em out :/ (me thinks i need to re-think my shifts... 7.5k vs. 6.5-6.8k ???) maybe better 60/330ft and/or 1/8 ET/MPH !

[B6JoeS4]

I cannot believe this thread is still living. Looks like someone is just trying to make a bunch of money selling kits that do nothing but make a noise go away so guys can sleep better at night.

[KAL]

If the rattling stops doesnt that mean the chain has stopped rattling around and banging up against the chain components which is what causes wear overtime???

[speedshopmike]

wow that was a truly painful read.
guys, i'm newish and nobody here, but i owned/ran a (traditional, domestically oriented) speedshop for two decades, have been in the automotive performance aftermarket for many more years, and built more engines than i can recall.
so ima chime in w/ my 2 cents.
in no particular order:
first, i sold lots and lots of Canton product.
they make top grade parts.
the accusump is absolutely not a gimmick; it's very, very legit and some version of it is used basically universally in nearly all racing.
second, the chain guides are engineered to have the chains slide/roll around them, not slap upon them, creating stress risers (the place the first break will begin).
think about the amount of energy it takes to make that much noise so clearly audible through the cam covers, thru the hood, insulation, etc.
(slap your wife half that hard and see if she minds.)
the obvious take away here is that having oil psi built up prior to start, through anecdotal evidence supplied by several posters here, tells you that the a'sump eliminates the chain rattle by pretensioning the chains, thus removing impact damage, thus greatly reducing the chance of premature catastrophic guide failure.
does that mean the guides won't wear out in the long term?
no it does not; eventually, sooner or later, i reckon they will.
as well, by not having the tensioner itself flopping about until charged with oil it too should last notably longer, or forever if it doesn't clog - it's designed to apply a steady force, not bang around.
third - guys....for crissakes, help yourselves out - these internet forums aren't the source of all wisdom - it's clear just from this thread there's a whole lot of clueless and misinfo going around.
if you have product questions, go to the manufacturers' sites (or, god forbid, call them on the phone) and learn for yourself what a product does and how it works; you'll be able to make much more informed decisions.
fourth - as for canton, be grateful a big player took an interest in a relatively microscopic sales opportunity, not to mention a thread on a relatively obscure forum.
fifth - disclaimer - i have zero experience with these engines myself - i've been looking for the right S4 for about a year, my brother found and grabbed me what will hopefully be a great one, an 04 w/ 78k that isn't in my hands just yet and i haven't laid eyes on as it's well out of state.
anyway, a part doesn't know what name is on the valve covers, a motor's a motor when it comes to stuff like this - it's my belief that killing the rattle will enable the guides and likely the tensioners to live to and beyond their DIL.
fwiw, especially since i happen to have an accusump still laying around (i'm essentially retired) it'll be one of my first modifications to the car.
HTH someone, no offense intended.

[t28sentra]

I have to agree with Speedshopmike. I've been emailing Canton about this product and I appreciate their interest in our platform. This is something I'll be purchasing.

[KAL]

+1. I have added my info to the buyers list. I think the math is simple; here no sound equals a significant decrease or elimination of damage to the components from the chain.

[B6JoeS4]

BUT.

You still have to worry about the adjusters failing, which accounts for about half of the timing failures.
Heat cycles still make the nylon guides dry and brittle.

[IslandHydro]

BUT.

You still have to worry about the adjusters failing, which accounts for about half of the timing failures.
Heat cycles still make the nylon guides dry and brittle.

So, if I have this right the chain rattle is primarily due to the adjusters not being in proper position until oil pressure moves them there. Lets imagine that for some reason they (the adjusters) get stuck in the disengaged position, and the chain just continues it's loose rattling around with the engine running. Don't you think that would lead to rapid deterioration of all the parts the chain is smacking against, including the guides and non-engaged adjusters? If so, why do you think it's not a problem during the short time that the oil pressure hasn't come up to speed and the adjusters are out of position (start up rattle)? Why do you continue to say this can't be a fix, or at least an aid in reducing the issue?

[bioluminescent]

BUT.

You still have to worry about the adjusters failing, which accounts for about half of the timing failures.
Heat cycles still make the nylon guides dry and brittle.

By your own admission, you're ripping on something that can reduce the risk by 50% (33% if you include your heat theory).

[t28sentra]

The plastic becomes brittle, the chain slap exposes the issue of the brittle components (leading to failure). In any event, the cost to replace tensioners is in the thousands. This product is said to be around $500. If the $500 cost extends the life of timing components I'm all for it. Hell, most of us spend more than that on tires...

[Tugboatguy]

I love this thread, it has all the best points to make it a good read.
1) You have a good product or idea that works.
2) You have forum members argueing back and forth about Pro/Cons
3) You have someone with an engineering degree that makes him think he knows everything and that you should all listen to him, even though his degree is only partaly relevant. ( Anyone remember a little thread about carbon build up on RS4's ? And the twit with an electrical ENG degree who insisted that since his company built portable Gensets he was an expert and therefore Carbon build up was Not a problem, lol).
4) You have a lot of people missing the fact that the product has implications beyond the narrow focus of the thread.

So what what do we have? We have a proven product that Prelubes your engine, is this a good thing? Yes. Not only are you getting oil to the tensioners/guides/chains faster, you getting oil to the main and rod bearings faster and that is always a good thing ( If it wasn't we wouldn't spend thousands of dollars on Prelube pump systems on our vessels engines.)
The big problem with our engines is that when they decided to go with the chains and plastic guides instead of a all gear drive they didn't put more thought into lubricating it and to top it of they went with tensioners that only work properly when oil is applied? Really?
When our engine starts the pump starts to push oil though the oil galleries to verious components and eventually to the tensioners. Ok so now we're ok right?
Well not so much, are our chains and guides being properly lubricated at this point? Nope not even close. The chains and guides are lubed by spill oil not direct feed like the bearings and tensioners etc, this means that oil returning to the sump from the heads and from the bearings at the back of the gears and probably some leak-by from the tensioers gets onto the chains and that lubes the guides. Basically luberication is provided by the oil getting on the chains and getting flung around in the case, now there may be some sprayers from the oil gallery but from pictures I've seen I don't think so (an Audi Tech what to chime in here?) When we run our Prelube pumps (they are usually a much higher Volume pump than the pressure pump on the engine) on our big engines we run them for about 10 min to get oil everywhere!)
Ideally our engines S4/RS4 Should have a Prelube pump (and sprayers at the leading edge of each guide but that would require the engine being pulled so Not practical) I'm thinking of installing a Turbowerx pump but this will require tapping into the sump and a small inline spin on filter, wireing, relay, back- flow valve, pressure switch, on/off switch..
The Acusump unit is a very good and fairly simple solution, it will charge the adjusters and get oil to the chains etc a lot faster. This is a good thing.

[speedshopmike]

BUT.

You still have to worry about the adjusters failing, which accounts for about half of the timing failures.
Heat cycles still make the nylon guides dry and brittle.

if the adjusters aren't banging around they're far less likely to break, as i mentioned.
we can't help heat cycling; it goes with being an engine...but we can keep the chains from beating the crap out of the guides.
it's quite logical, Spock.

[KAL]

So then guys then who is in? I would like to get this into my car asap so lets get the minimum number of orders up!

[jeffrey146]

I'm sure mine will wear out eventually. However, I'm at 102k. No chain rattle at all. Also on original clutch so I guess mine is made of steel. haha

[BCsniper]

You still have to worry about the adjusters failing, which accounts for about half of the timing failures.
Heat cycles still make the nylon guides dry and brittle.

So, if I have this right the chain rattle is primarily due to the adjusters not being in proper position until oil pressure moves them there.

NO, Cam Adjusters and Chain Tensioners are two separate things. The rattle has nothing to do with the cam adjusters. And as he said the cam adjusters are usually the cause for the catastrophic engine failures we see. You'd be surprised how many people are running around with cracked guides everyday and don't know it and their cars run fine.

if the adjusters aren't banging around they're far less likely to break, as i mentioned.
we can't help heat cycling; it goes with being an engine...but we can keep the chains from beating the crap out of the guides.
it's quite logical, Spock.

...once again cam adjusters do not equal tensioners which is what causes the noise.
(and everyone talks about guides "banging around". 1 second of rattle is not them banging around constantly everyday.)


To recap, the Accusump product is great and does exactly what it has been designed to do. For many this is great and fixes the issue that people endlessly complain about (1-2 seconds of rattle upon a cold-startup).

Does this really fix the underlying problem and will prolong the life of your timing components? ..........well that has yet to be determined. We are not at all denying the benefits of pre-oiling or that it is necessary in tons of automotive, motorsport, and aeronautic aspects, but whether it is really needed, or whether it will actually benefit our cars over their lifetime has yet to be seen. By all means, buy the kit, just don't expect to become immune from having any kind of timing component break because you have a bit more tension on your guides for 1-2 second per day.

[jeffrey146]

Anyone know anything about the moroso unit sold by summit? That's what my dad put in his home brew airplane. It's cheaper and 3q rather than 2q. This idea makes sense to me. Even if it didn't help the chain issues throwing some oil in the motor/pressure before it starts could never be a bad thing. Seems like it would be good for cars in the winter that are not garaged. My dad put on in his airplane so he could bring it inside and keep it warm. I don't know too many people who would do this but the oil inside the car would be kept warmer.

[speedshopmike]

NO, Cam Adjusters and Chain Tensioners are two separate things. The rattle has nothing to do with the cam adjusters. And as he said the cam adjusters are usually the cause for the catastrophic engine failures we see. You'd be surprised how many people are running around with cracked guides everyday and don't know it and their cars run fine.


...once again cam adjusters do not equal tensioners which is what causes the noise.
(and everyone talks about guides "banging around". 1 second of rattle is not them banging around constantly everyday.)


To recap, the Accusump product is great and does exactly what it has been designed to do. For many this is great and fixes the issue that people endlessly complain about (1-2 seconds of rattle upon a cold-startup).

Does this really fix the underlying problem and will prolong the life of your timing components? ..........well that has yet to be determined. We are not at all denying the benefits of pre-oiling or that it is necessary in tons of automotive, motorsport, and aeronautic aspects, but whether it is really needed, or whether it will actually benefit our cars over their lifetime has yet to be seen. By all means, buy the kit, just don't expect to become immune from having any kind of timing component break because you have a bit more tension on your guides for 1-2 second per day.

i was quite clear in stating tensioners and guides are not the same thing; i didn't mention the adjusters at all ( i asssume you are referring to the the electric cam phasers? - again, i have zero audi-specific knowledge) .
nor did i say or imply the tensioners are banging around every day constantly; this thread is only about startup rattle.
here's a thread with photographic results of a guide that broke & separated.
http://www.audizine.com/classifieds/...k-miles&cat=24
ps - going back i see that i used the word adjuster when i meant chain tensioner; my oops.

[BCsniper]

i was quite clear in stating tensioners and guides are not the same thing; .........
ps - going back i see that i used the word adjuster when i meant chain tensioner; my oops.

see, and it wasn't just you. I quoted IslandHydro who wrote "So, if I have this right......" I was just correcting him (and you) that cam adjusters and tensioners are not the same thing since as you said "i have zero audi-specific knowledge". I wasn't trying to be condescending, it's just that this is not all common knowledge, even for all of the Audi community since the B6/7 4.2 motors are a slightly different beast

B6Joe took one of the photos from the back of the engine and labelled the parts to better explain what everything is, I'll try to find it.

Also, your link to an engine with a broken guide, yeah what was that supposed to show? Like I said, I'm sure there are tons of people driving around with cracked guides right now and just don't know it. These things break, it's just the way it is. My point is that I don't want people thinking their parts wont break just because they no longer have a rattle.


Here's the photo:



as you see there's a bunch of junk back there, and the plastic guides are only one of the problems. There are a couple more back there that can lead to a failure. It would be great if this product significantly prolongs the life of the guides and tensioners, but my point is that there is more to worry about than just that, so don't make it think you become invincible to any kind of failures.

[speedshopmike]

see, and it wasn't just you. I quoted IslandHydro who wrote "So, if I have this right......" I was just correcting him (and you) that cam adjusters and tensioners are not the same thing since as you said "i have zero audi-specific knowledge". I wasn't trying to be condescending, it's just that this is not all common knowledge, even for all of the Audi community since the B6/7 4.2 motors are a slightly different beast

B6Joe took one of the photos from the back of the engine and labelled the parts to better explain what everything is, I'll try to find it.

Also, your link to an engine with a broken guide, yeah what was that supposed to show? Like I said, I'm sure there are tons of people driving around with cracked guides right now and just don't know it. These things break, it's just the way it is. My point is that I don't want people thinking their parts wont break just because they no longer have a rattle.


Here's the photo:



as you see there's a bunch of junk back there, and the plastic guides are only one of the problems. There are a couple more back there that can lead to a failure. It would be great if this product significantly prolongs the life of the guides and tensioners, but my point is that there is more to worry about than just that, so don't make it think you become invincible to any kind of failures.

i didn't see anyplace that someone's claiming all the internal components will become invincible after an Accusump.
i certainly didn't.
the broken guide photo was merely illustrative - note it is *broken*, not just *cracked*.
there may well be plenty of guys running around w/ cracked guides, but once a big chunk of guide falls out of place, the motor's "done".
i wear a helmet when i ride motorcycles but that doesn't mean my legs won't get broken (again) when a buick hits me (again).
(of course other shit can go wrong, this is Earth, welcome to it).

[daneo]

I think this thread is appropriately titled. I'd put down some money just to never hear that rattle again. Oh, check this out: http://www.audiklub.org/data/files/V85VD2.pdf Scroll to page 22 and there's a nice diagram and description of how the chain tensioners work with oil pressure. It's for the A6/A8 40valve v8, but our system should be pretty close.

[speedshopmike]

I think this thread is appropriately titled. I'd put down some money just to never hear that rattle again. Oh, check this out: http://www.audiklub.org/data/files/V85VD2.pdf Scroll to page 22 and there's a nice diagram and description of how the chain tensioners work with oil pressure. It's for the A6/A8 40valve v8, but our system should be pretty close.

that's beauty info, great score!
i quote from your pdf link:
"In the case of the new V8 engines, an
interlock function and an oil reservoir were
added to the proven system during the
course of further development.
These new features prevent vibrations in the
chain drive which has a positive effect on
acoustic behaviour during the start phase.
Owing to the Ferraria effect in the chain drive
when the engine is started, vibrations which
generate noise occur until sufficient oil
pressure has built up."
<coughbullshitcough>
nice valvetrain design though, and some solid engine technical specs i've been curious about.
thanks again, daneo.

[snail_power]

I am considering purchasing this, I hope others are too, sounds promising. If we get the full amount needed for canton to set it up I could see this benefitting a lot more people in the future once the custom portion is made.

[Greg Z Manson]

Hello Newbie's first Post - 05 S4 with chain rattle at startup.

The oil accumulator is a great idea and should have been done from the manufacture. Not sure if this was noted in the threads but the early BMW's (E39 M5's) had a similiar issue with the cold start up rattles and the manufacture came out with with oil accumulator that eliminated the rattle - http://www.m5board.com/vbulletin/e39...-do-about.html

Greg Z.