911/996 Timing chain replacement

G'day all, I'm new to this forum & i'm looking for any info on replacing the timing chains on a 02' 911/996 carrera.It is the three chain motor & the cam chain for cyl 1-3 has streched.I have already removed the cylinder heads & there is no damage there thank god!!I was looking for anyone that has done this job before &/or may know of any tricks or things to be carefull of & anything i should also do/replace while i have her apart.Any info would be great. Thanks Evan

You do know that replacement chains don't have master links, right?? Do you plan on full engine disassembly?

G'day mate Yeah i know great isn't it.I have the motor out & heads off already.I know i have to split the block to replace the chains but i have never played with these before.Is there anything to becarefull of before i open her up?Is there anything i should do while i'm there.I'm thinking of doing the IMS bearing although it feels like a new bearing.I plan on replacing all chains & servicing the heads while there off.i've worked out i need a special tool for the gudgeon pins.Anything else anyone can think of apart from the obvious gaskets,guides,tensioners?I was also thinking of replacing the sprockets but they also look fine.It is a 02 911/996 with 65,000kms on it which is about 40,000mls.Also does anyone know if this is a comon problem. Cheers Ev

Welcom to Rennlist. Sorry, I can't help with any answers to your questions. Good luck on the chain swap. Please keep us posted on the progress. Oh yeah, one more thing...... pics would be nice, too!

this is a series of vids.... check it out.

anything you should know....... YEA its a complicated process, the vids above are helpful (although for a Boxser 5 chain motor)

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Just curious, but why do you think the chain has stretched ?

agreed how was this diagnosed, what symtons did you have that caused you to look there

and at only 40000 miles !! Not another thing to worry about!!!!! Pete

I have replacement chains with master links being made.. We already have the units for the older engines than yours. Chains are going bad and there is no way to change the factory ones without a complete tear down. With a master linked chain the old chain can be cut in half, the new chain wired to it and then the old chain used to feed the new one through the engine. Chain issues are nothing new with the M96. They are one of the 21 modes of failure that I have plastered on my wall and trophy shelf of destroyed parts.

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G'day Guys, I couldn't believe it my self but yeah the chain has definitely stretched all the guides are perfect & a new tensioner(the old one had snapped the pin that holds it together i'm assuming because of the slack chain).When i wrap the chain around the sprocket u can see that the chain does not mesh properly and it starts to climb up on the teeth.Where as the other side cylinder 4-6 is perfect.It all started off with a terrible noise/rattle coming out of the cyl 1-3 side.After some research on this site and some others i was convinced it was the IMS bearing & pulled the trans out & checked the bearing but it was perfect.After pulling the engine out & checking everything i could i noticed that when i wound the engine over by hand that the exhaust cam was trying to jump a tooth.The chain had slack in it but the tensioner was all the out.I couldn't believe it was the chain so pulled the heads off to look further inside but all is good.I only noticed after i was pulling my hair out & wrapped the chain around the sprocket & noticed that i did not mesh correctly, i checked the other side & it was fine.Finally i found something.But now i need to replace them.Yeah definitely need to spit the block, is there any tricks that i need to know about as i have never played with these before.I have worked out that i need a special tool to put the gudgeon pins back in.I know i will need a gasket set,new chains,guides,tensioners & i'm thinking of doing sprockets as well.I was also thinking of doing the IMS bearing even though it does feel like band new.Anything else i should do while she is apart??Any help or info would be fantastic as there is pretty much nothing over here for them that i can find anyway.Thanks again Ev P.s Thanks to Redridge for the vids, Your a champ!

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My teaching has been then if the chain worn (it doesn't stretch) enough to be slack beyond the ability of the tensioner to compensate then the sprockets are almost certainly worn as well and they should be replaced. Sincerely, Macster.

Big Ev, When you said "terrible noise rattle" was that all the time, or just at start up? Our 1999 makes a rattle that can only be the chains, but only at start up. Other than some lifter noise for a minute or two, the car is otherwise "silent". The chain noise has been present from about 65,000 km and the car now has about 160,000 km and doesn't really seem any worse. Just wondering how concerned I should be.

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Not very if it has been going on for 95000km. I don't worry about a bit of chain noise or lifter noise upon startup (though there's still not much) with my 02 Boxster and it has nearly 234K miles or nearly 376,500km on its original engine, chains, sprockets, tensioners, clutch, etc. Sincerely, Macster.

Jeffplastow, Yeah it was all the time that was the concern.It was making noise on start up for a while but when it became constant we decided to investigate what was going on.It went back to porsche here in sydney for a week but they couldn't find what it was with out striping it & pretty much recomended a new motor.

here is one for you - if I was doing this job (cams out) I would (lets see if Jake agrees) use a diamond hone and hone every lifter. the reason..... the center section of the lifters mushroom over and the diameter becomes too large to slip back into the larger section causing them to first sick occationally, then permanently. the way... push the bottom (spring) to expose the center and with a very fine hone work around the upper most "lip" untill it is smooth. - here are some pics of what the lip would look like and just to help add to the crazy hysterea and panic I would think this is going to be one of those things we start to see more and more of.... Jake, agree? BTW replacement parts are ~$100/ea so with 12 variocam lifters the math is easy....no shop in thier right mind would repair them, they will surely replace, but if you "are in there" or doing this at home... there is a pre-stick fix - I have no idea how long it takes for the lifters to do this, what reasons or factors that cause/prevent/acellerate, or if you hone them how long they would last/be prevented... this is pretty rough preliminary stuff here....

Yes, lifter issues are becoming more common place.. But the very first M96 engine I worked with was sourced as a core due to lifter issues.. that was the first mode of failure we ever saw, so they are nothing new.

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Did these replacement chains ever come to fruition?

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They came and went .....not very reliable as some had the retaining clips fly off .....The clips would rub the plastic guide if the groove got deeper... The continuous chain is the most reliable,...yea I know its a shame a reliable master link not available...( maybe a "spot-weld" process would be reliable, but would not be a DIY service part)

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Those would have been the chains that used the IWIS provided "E- Clips" as imported by SSF Auto Parts first around 2013 with Motorsports quality chain materials. These were later upgraded to use a single Mercedes style lock, and today they are a crimp together Mercedes style which uses the factory Mercedes tools for the task.