Chain ramp replacement...gaining access?
 

Greetings all, 3 years ago I bought my '98 boxster with 56000 miles. At that time, I discovered that I had the notorious chain rattle at start up which is often diagnosed as faulty external tensioners. I replaced the tensioners, but, it did not correct or improve the problem.
I have lived with the rattle and have since put 30,000 miles on the car. this year I have decided to pull the engine and address a few maintananaince issues of which includes replacing the chain ramps.
While not a mechanic, I do have mechanical abilities, and thanks to the wealth of information provided through this forum and others, I am ready to tackle this project....hopefully with your help.

My search for information regarding chain ramps has proven to provide an abundance of information concerning the ramps for the cam to cam chains. The process is well documented and appears to be very straight forward. What I am really hoping for is some guidance in what is involved in replace the remaining chain ramps. The only information that I have found is that it does not require splitting the case. Any help in how to approach gaining access to these ramps would sure be helpful.

When you replaced the tensioners did you install the updated IMS tensioner with the large preload spring? It is critical to optimize the issue. If you remove it you can inspect the IMS tensioner paddle wear button for wear. If it is worn down flat, you have excessive clearance requiring removal of the crankshaft housing to replace the paddle.

BY - can you explain the "paddle wear button" ?
Do you see this when you are just renewing the 3 x external tensioners which I believe you can replace (relatively) easily by locking the engine @ TDC.

Would anyone have the part numbers of the 3 x new tensioners (with preload spring) or are they the ones listed on the Pelican website?

The IMS to crank chain tensioner "paddle" has a black wear pad on it's small end. It's about the diameter of your smallest fingernail. This is what the IMS hydraulic tensioner contacts to press the paddle against the chain. If you remove it & look into the hole it is centered in the hole, when new it has a curved surface, but flattens as it wears.


http://986forum.com/forums/uploads01...1428539162.jpg

Pelican has all the tensioners listed, the updated IMS version with the preload spring was phased in during 2001, so it is listed as 2001-2004. It can & should be retrofitted to earlier engines also. With the engine locked @ TDC the 2 lower tensioners are easy to R&R. The 4-6 cyl tensioner is not since you have to remove the A/C compressor & P/S reservoir.

Back to the op question. I replaced the pads on the cam tensioners, fairly easy with the engine out. I did not replace the others as it seemed that I would have to dig a lot deeper to get at it/them.
I did not have the special tool ( essentially a bolt with a left hand thread) to compress the variocam tensioner/actuator thingie although I actually bought a die to make it myself, like all the other tools I used. I posted some pix on those home-made varieties.

Do you have a picture of this tensioner? The one I installled (latest rec.) did not have a large external pre-load spring

Jay... I sent you the updated part numbers last year... did you source them from someone that had old stock???

According to Oak they gave me the latest tensioners available at the time looks like I have been hosed. I had assumed that the external spring had been superceeded....I believe the numbers all matched with what you had but it was long ago. I should still have the boxes...I even checked with them twice!!

So it looks like I have to pull that one out..

If you have the current corrects numbers hit me again!!

That weird; Well the new one PFAFF looked up for me is definitely the one with the bigger spring around it... as the old one I pulled (in the picture) looks almost like the other two... either way I wouldn't pull it and replace it again if I were you... the main thing is you replaced it with one that's not worn out :)

But you know me ...:D

The spring rate and end are completely different; there must be a reason for that

The one that went in had the the double circle symbol and the new type alloy .....but no spring and broad tip. The rest of it looked like the old one

Just looked....remember you sent the numbers via text and I didn't get them as my phone changed!!!

:D LMAO at least you picked the easy one to replace 😄

Anyone have the most current tensioner numbers....especially for the Springer! Chain tensioners ghosts were haunting me in my sleep!

Actually, when I replaced my tensioners, I wasn't aware of the updated one that you are referring to. Once I realized that my chain rattle didn't improve with the tensioners that I replaced, of course, I then learned of the updated tensioner with the exterior spring for the intermediate to crank chain. I have contemplated going ahead and buying the updated tensioner, because I would really like to eliminate the chain rattle. But, I read somewhere that the new tensioner was designed to be used with later engines where porsche had gone to a tooth style chain rather than the roller style that I believe is in my car, being a 1998. I didn't think the new style would be compatible. Is it?

When you refer to the removal of the crankshaft housing, is that synonymous with splitting the crankcase?

here's a link to the technical bulletin re the chain change, when it happened, and what parts changed:

http://www.pelicanparts.com/techarticles/Boxster_Tech/16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf

the tensioner changed with the chain change, but the paddle didn't. is the updated tensioner ok to use with an old chain? no idea. the tsb says "a mixed configuration is not permissible, as the parts are matched with each other."

a review of part #'s shows:

TSB part number of original roller chain tensioner (ie, as of August 2000): 996 105 180 54

current PET part number for roller chain tensioner: 996 105 180 57

superseded by PET part number for updated roller chain tensioner (presume after the chain change or would have been noted in tsb): 996 105 180 59

PET part number updated toothed chain tensioner: 996 105 180 56

why would they update the roller chain tensioner after the fact if the toothed chain tensioner was up to the task?

Yes. There is no way to access the plastic chain ramps for the IMS drive chain without splitting the case.

You could replace all three tensioners, the outer ramps for the vario cam to cam chains, and with some awkwardness the long ramps for the chains that run from the IMS to the heads.

That center chain and ramps are in there for the long haul

Yes it's been in my 2000 engine for 30,000 miles & no chain rattle.

Is the tensioner that you used, one that has the large preload spring that you refered to in your earlier post? It seems those are all updated tensioners that are designed for the updated tooth style chain. From the checking that I have done in catalogues, it appears that those changes took affect in 2001. Although there have been a couple tensioner updates for earlier models, none of those updated tensioners have the external spring. Since you mention that you have a 2000, is it correct that you used a tensioner that is intended for the 2001-2004 boxsters? Do you have the part number for the tensioner that you used?

Early or Later Timing chain tensioner, crank to IMS
 

These might be answers.

For Porsche 911 type 996 / 997 2001-2008, Boxster / Cayman 986 / 987 2001-2008:
PN 996-105-180-58, with big external spring, https://lufteknic.myshopify.com/products/timing-chain-tensioner-crankshaft-to-ims-porsche-911-996-997-boxster-cayman-99610518058

For Porsche 911 type 996 1999-2000, Boxster type 986 1997-2000;
PN 996-105-180-59, without the spring.
https://lufteknic.myshopify.com/products/timing-chain-tensioner-crankshaft-ims-porsche-911-996-boxster-986-99610518057

CK