Alright, this time I really give up on eliminating start up rattle.

[san rensho]

Well, I replaced the two lower chain tensioners with the new updated parts (which incidentally, did not have external springs) trying to eliminate the whince inducing start up rattle. The result, no change whatsoever. I thought I had nailed it because when removing the old IMS tensioner, it was completely slack. So I'm glad I replaced the tensioners, but it did not solve the problem.

Incidentally, the video below is exactly the type of noise that my car makes, occasionally, on a hot start up, after the car has not been up for about an hour. The start up noise from a dead cold start is similar, but not quite as loud.


enginenoisemovie - YouTube

[md10835]

are you talking about the chain ramps or the variocam? did you replace it with porsche's part or LN's?

my car has always "rattled" on start up - similar to the video you posted. but after warmed up it doesn't do it on subsequent starts. always attributed it to the nearly 100k miles on the original plastic ramp guides. the noise does subside somewhat right after an oil change but comes back eventually.

**nevermind the questions. i was mistaken about the part you replaced. reading a little more i realized what you meant**

[clearyje]

Unbelievable, My 99 has the exact same rattle on cold start. I thought it was coming from the muffler.

[Meir]

looks like you will have to get to the pads.
the parts are not that expensive, but it is not a simple process.
if you already have the cam locking/timing tool you can give it a go.
my engine doesn't rattle at all at the moment (76k) , but camshaft deviation readings shows i will probably have to do it in the feature.

[san rensho]

Originally Posted by Meir

looks like you will have to get to the pads.
the parts are not that expensive, but it is not a simple process.
if you already have the cam locking/timing tool you can give it a go.
my engine doesn't rattle at all at the moment (76k) , but camshaft deviation readings shows i will probably have to do it in the feature.

Interesting. So you are saying the noise is from wear on the vario-cam pads, or do you mean the chain ramp pads? In any event, if its either of those, I'm not going there, because at that point, since I'd already be in there, I would of course have to replace all the lifters, just to rule them out as the cause of the noise.

Another question, cam deviation shows pad wear? I'm at around -5.6 on the 1-3 bank and -4.3 on the 4-6 bank.

Thanks.

[md10835]

Originally Posted by san rensho

Interesting. So you are saying the noise is from wear on the vario-cam pads, or do you mean the chain ramp pads? In any event, if its either of those, I'm not going there, because at that point, since I'd already be in there, I would of course have to replace all the lifters, just to rule them out as the cause of the noise.

Another question, cam deviation shows pad wear? I'm at around -5.6 on the 1-3 bank and -4.3 on the 4-6 bank.

Thanks.

both have plastic covering that the chain slides along. this is what i thought you meant you replaced. after a while, as you can imagine, the plastic wears and lets a little slop into the chain - though i would imagine the ramp guides would be more responsible for the noise than the variocam pads since the variocam actuates at a higher RPM.

i think the "normal" deviation is up to +/- 4 degrees, so anything outside of that is "not normal". i think after enough the chain will start skipping teeth and then ... :ah:

as an aside, i've been at -8.8 (1) and -5.6 (2) for ~20k miles...

if you cut open your filter / remove the oil pan and look for little bits of plastic - either black (ramps) or creamy tan (variocam) color.

[gomarlins3]

My 1998 does makes that same noise and it only has 29,000 miles on it.

[recycledsixtie]

My 2001 2.7 Boxster has the same rattle on it at cold starting. I have about 40K miles on it. I could easily spend $5-10k on fixing noises and putting in new clutch and ims replacement and rms. But I am not spending that kind of $$$ yet. :dance:

[Meir]

In the 5 chains engines, we have total of 8 pads.
2 pads for each chain that goes from the IMS to the camshafts (parts # 33 X2 and #30 X2)
And another 2 (part # 9 X4), that are seating on the variocam system that holds each set of camshafts.
There is another pad that seats on the chain that connects the crankshaft to the IMS (part 19).
i never read anywhere about replacing this part, but I assume it is the same as the other pads.
The tensioners you replaced (pars # 24,34,35) are basically pressing against the pads, and keeping the chains in the correct tension.
So if the peds are worn out, you will still have “play” with new tensioners. Same goes for the pads on the variocam, held by the timing chain between the 2 camshafts, and part # 7.


There is a great write up at the pelican site

Pelican Technical Article: Boxster Camshaft Upgrade / Chain Tensioner Replacement - 986 / 987

and also a very nice clip on UTube that show how the all system works.
i will try to post it later, together with a link to another interesting thread in that subject.

[Meir]

forgot to attach the drawing :

[Meir]

OK.
this is the tread i was talking about:
Boxster Project 16 : Camshaft Upgrade / Chain Tensioner Replacement - Pelican Parts Technical BBS

and this is the UTube clip:

Porsche Boxster S engine rebuild 08 - YouTube

[pothole]

Do you know what I think that noise is?

I think it's the starter motor sticking momentarily. Here's why.

My car makes exactly the same noise. When the ignition barrel went funny, causing the starter motor to stay engaged until you twisted the barrel back a bit, the noise carried on much longer - basically until you twisted the barrel back to disengage the starter.

I made a recording of it before I had worked out what was going on:

http://www.youtube.com/watch?v=QTy8jvx0VrY

[Meir]

Originally Posted by pothole

Do you know what I think that noise is?

I think it's the starter motor sticking momentarily. Here's why.

My car makes exactly the same noise. When the ignition barrel went funny, causing the starter motor to stay engaged until you twisted the barrel back a bit, the noise carried on much longer - basically until you twisted the barrel back to disengage the starter.

I made a recording of it before I had worked out what was going on:

986 Boxster horrid start up noise.wmv - YouTube

pothole might have something there.
your cam deviation values are better then mine, and i don't have a rattle at all