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Does this sound like chain tensioners?
I get a nasty rattle that lasts for about 2 seconds with a cold start. I think it's probably cam chain tensioners but I thought I'd post it to get a second opinion.
This video doesn't totally capture the sound at its worst and I'm aware there is some residual valve lash clatter even after the first couple of seconds. Concentrate on the initial sound on the start up. http://i19.photobucket.com/albums/b1...rcoldstart.jpg |
Like a gear sliding on chain links sound then it smooths right out? Don't want to be Debbie Downer but that's exactly what my 98 did for about eight months before breaking; I was always of the thought it was the tensioner that went bad. If you check the pelican projects, you will see it references a redesign in tensioners for the 986, which really is a head scratcher how many years does Porsche need to make tensioners before they get it right?
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Sounds like classic tensioners to me.. Pull them out and clean them with some Marvel Mystery oil heated to around 160F... Partially submerge them and pump on the pistons until clean oil appears and then reinstall.. You should be good to go.
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This doesn't all that unusual for Boxsters in my opinion. Mine tends to be quieter with thicker oil
It is tricky to get the right mic to convey what you are hearing; it may not be responding to the first two seconds of noise as much as you would like. Engine experts? |
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Sounds like I have to post a sound clip here as well when winter is over. I had thought chain tensioner removal was a major undertaking requiring one to drop the engine?? Well it's major in my garage anyway.
How long can one get away with dirty tensioners? |
the initial clatter on startup for about a second sounds pretty normal to me and all the Boxsters I have drove (and 996's)
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Pelican's DIY guide to cam tensioner replacement: Pelican Technical Article: Boxster Camshaft Upgrade / Chain Tensioner Replacement - 986 / 987
Instructions say that it can be done with the engine still in the car but doesn't look like a trivial job. |
I was embarking on that same quest but when my leg wouldn't hold me I sold the car to Jake, perhaps in the near future you guys will see a tensioner job or whatever did go wrong. A lot of the tensioner job is dis assembly, however, once all the way to the heads, it does look like a challenge, a job that is not insurmountable but will likely test your patience and every bit of skill you have. Even one of the local crackerjack indy's waived off on that job and he wrenches daily.
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If anybody knows a DIY writeup w/pics on this subject (I've seen the Pelican one) please post a link. |
I must say that my 2001 S (@ 50,000 miles) sounds a lot like Dales car's initial 1 to 2 second "chain being dragged over a log" noise - but mines only on cold startup (though Dales car ticks more than mine after the initial noise has died down).
I'm running Shell Helix Ultra 5W40, changed every 3000 miles, but that hasn't changed the noise since I bought the car from the OPC over 3 years ago. I believe there are 3 hydraulic tensioners involved, which can leak down or get lazy over time, allowing the cam chain tension to become slack and noisy on startup. If I remember correctly, there is a newer version out that has a small keeper spring which helps pre-tension the chains. The engine has tobe locked down to replace /inspect these tensioners. Perhaps someone can verify ...... Perhaps changing to 15W40 oil will help prevent bleeding down? I think a lot of us have the same questions - what are the long term affects of having the hydraulic tensioners slow in pumping up as per Jakes comment above - a skipped chain is the last thing anyone needs, but surely the hydraulic tensioners don't bleed down that far !!! I'm assuming Marvel Mystery Oil is genuine & probably something we can't get here in Australia. |
From what I read in preparation, it needs to be locked down, there are some metal plugs that need to be replaced after the procedure that cover the cam ends. The tool, which looks rather simplistic would be needed. If you had one to copy you probably could but by the time you go to the trouble...After you lock everything you can start. Part of the procedure includes removing a sprocket, with the chain loaded, that part looks like it would be easy to screw up.
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::Marvel Mystery Oil:: |
if i'm understanding right, jake's talking about the chain tensioner (green arrow)
http://www.pelicanparts.com/techarti...mall/Pic23.jpg and not the vario-cam tensioner http://www.pelicanparts.com/techarti...mall/Pic19.jpg also, this little blurb from pelican parts: Quote:
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http://986forum.com/forums/uploads01/0071323888252.jpg
Maybe we will all see a tensioner job when this gets to Ga. I would like to take a minute to tell you guys that Jake Raby and his partner James are principled, excellent people to do business with. Sure, like the rest of you sometimes his prices make me gulp hard. BUT I learned well at Kodak you can drive a price premium when you give excellence, I believe that's what is going on in that shop. Good luck with the car Jake, even if it's a loose screw I'd still write the same about you and hope you feel the same way about dealing with me.. |
Looks like you have cleared things up. My appologies for mis-directing the thread. I didn't know that these were affected by oil crud etc. I though they were just spring loaded and oil damped. Looks like they are accessible in situ.
Does this mean low oil pressure will yield improper chain tension? Yikes! I would guess that it is best to lock up everything before fiddling with these |
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