Hi Listers:

I have an '89 S2 with 108,000 miles. Just bought it a month ago, and after reading about all the ugly outcomes of a failed cam chain tensioner, I brought it into a Porsche shop to have it inspected.

The mechanic said the tensioner looked fine and that the plastic wear pad had been replaced and looked ok. PO seemed to take very good care of the car. BUT (and as I'm learning, there is always a BUT with Porsches!) he said that the cam chain looked "stretched" to him.

Replacing the chain will be another grand. Haven't heard of this particular way to blow the head. Anyone care to weigh in? Seems to entail taking off all belts, pulling both camshafts, finding the inevitable worn valve lifters, etc. Probably not the right 'DIY starter' project for this first time owner.

Your 2 cents is appreciated!

Noah

 

$1K to replace the chain is too much. I had the job done last year. Click on the following URL and then scroll down a little to "Job #2":

<a href="http://www.weissach.net/WP0AB294XMN410197-History.html#Service_2002-07-01" target="_blank">http://www.weissach.net/WP0AB294XMN410197-History.html#Service_2002-07-01</a>

Karl.

 

Thanks, Karl. I'm assuming the $1k is worst case cost, and would essentially include a belt job at the same time. The biggest hit is the part cost of the chain tensioner itself, which, while the mechanic says looks ok to him, he'd want to replace if he put in the new chain.

The real question I'm getting at is does the chain itself fail? I'd rather wait until the next belt job is needed (10-15k miles) and then do it all at once. I can't find much in the way of online stories of the cam chain itself failing, just the tensioner.

Noah

 

I didn't replace the chain-tensioner. They cost ~$250 (last time I checked). I only replaced the pad and in someways, I regret not doing the tensioner at the the same time.

If you're going to open up the top, and go to all that labor expense, I'd replace the chain as well. They're only $32.

Like you wish, I did it "all at once" and my bill came to ~$2,600 for everything. I replaced and resealed everything at the front and top of the engine. I didn't do the rear seal as that will be taken care of at the next clutch job. I'll be adding a LSD to my tranny at the same time.

So you have a decision. Do everything now and in the process replace the belts early or wait until 120K miles to do the job and run the risk of the top end breaking. What's the risk level? I don't know. Like you, I've heard the stories and seen photos of some horrible breakages but as to estimating a probability of failure in the next 10-15K miles... your guess is as good as mine.

Karl.

PS - I presume you're belt interval is based on 30K miles and not the older 45K mile interval. If its 30K miles, since the belts were changed, I'd replace them now.

PPS - Is your car a daily driver or a weekend car? Mine is strictly a weekend/fun/DE car. I personally wouldn't use a 10 year old Porsche for commuting as maintenance costs are expensive.

 

Interesting perspective(s). The mechanic, whom I'm using for the first time, says in order to replace the chain he'd have to pull of all the belts, break the seals, pull both cam shafts, discover the "inevitable" lifter problems (as he put it) and then replace the chain.

He said it'd be &gt;5 hours labor @$90, and that if he was going to change the chain he'd also change the tensioner, which he priced out at ~$325, I believe. Then throw in the chain, the cost of new lifters, and the inevitable "everything else" he'd find, and I figured we were talking about a thousand bucks easily. (no comment on the obvious part markup pricing).

I did some extensive Rennlist searching and found no descriptions of the chain itself failing. When I asked the mechanic about this, he claimed that the streteched chain changed the angle of incidence with the tensioner and it didn't look quite right.

I'm in Boston, and from what I've heard, this shop is very good, very expensive, and very, very conservative. So I was faced with a decision of pouring more money into a car I've only driven for one tank of gas or adding to my risk profile.

Interestingly, he said that if I didn't want to change the chain, he'd leave the plastic ramp and tensioner in as is, that they looked fine to him and appeared to have been replaced.

So, go figure... Am I making a stupid move? Time will tell. The tensioner has been serviced, and there seems to be some discussion about ways to replace the chain without ripping apart both camshafts. Will look into that further and see if I can pull it off on my own, perhaps. If I do that job, putting in the tensioner for $250 seems straightforward.

Noah

to answer your other questions: yes, belt interval is 30k miles. Why push it?

also, it is mostly a weekend car, though midweek fun is sometimes needed. I telecommute, so I don't have to sit in traffic with the car. In fact I work for a company in Santa Clara, right down the road from you...

 

i started an informal survey here a few monts back. bottom line is change the pad at about 60-70, change the tensioner every other pad, or about 120. assuming your mileage is legit, i dont think you are walking on thin ice by waiting till 120 to sort things out.

also, will you post a description of your car good bad etc, and price paid for my informal price check of S2s

 

Thanks Tom. I started a "stretched chain" thread on the email discussion list for S2s and the consensus seemed to be the same as your advice.

My car is an '89 944S2, metallic black, LSD. As far as I can tell it is stock -- no Konis, no chip, no stiffeners, etc. Condition is good - paint is fine, sunroof clearcoat has some pits, one 2" scrape on the passenger door. Leather seats have small rips and I will replace.

A daily driver, not a show car. Perfect weekend car with the kids.

Car has 108k miles, a new clutch, wiper motor, radiator, head, belt job, rear tires, plug wires, distributor cap, stub axle seal, etc. within the last 2k miles. I did one motor mount.

I paid $7400 including the full set of shop manuals and the Haynes manual. I'm the fourth owner. I have complete paperwork back to the window sticker.

Everything works with the exception of the digital clock (the LCD has partially failed). It has an alarm system and nice Sony CD player.

Hope my data helps, would love to see your pricing data if you can post or email it.

 

you got a good deal. about 9500 for a car with your miles and some work seems the average. check the archives under the 924/944 board for postings by a bunch of us.

by the way, are your kids midgets? "perfect weekend car with the kids." yeah, right, but for how long.

 

The chain doesn't really stretch, it wears so the rollers have more clearance and then they wear the cam teeth. I think the key to longevity is replacing the complete tensioner assembly at regular intervals, not just the pad. I replaced mine at 50K and will probably do it again at 120K (currently at 91K). When I did mine the pad was very dark brown and somewhat brittle. I have the cam cover off now for painting and everything looks nearly like new, including the pad, which is just slightly less white than when it was new. FWIW, I use Red Line 10W40 oil.

 

My kids are 4 and 5. "Midgets" is the appropriate descriptive phrase at this point. They fit perfectly in the back seats of my S2, and are very excited that their feet touch the floor!

Working on additional ways to perhaps develop a 4 point harness for them. Ever tried something like that in the back?

Noah

p.s. thanks for the price info!

 

Noah,

I can relate to "pouring cash into a car you've only had for a tankful of gas." I bought mine with 118K miles and the original tensioner as far as the maintenance records showed. I went ahead and replaced the whole assembly at 124K.

The S2 is an extremely tough car, but it's important to check its critical maintenance items, such as timing/balance belts and the tensioner. AFAIK, the belt change interval is higher on the S2 than on the early NAs. About 45K is OK.

Replacing the tensioner itself is no big deal. I don't consider myself to be overly mechanically inclined and yet I'm comfortable with doing this.

The main caveat is to torque the bolts properly, because overtightening will cause them to break. You'll need a torque wrench that can be set to 10 Nm (7.5 ft/lbs)

If you open the valve cover, it's a good idea to replace the gasket and O-rings, because they will probably leak otherwise.

As far as replacing the chain itself, I agree with Tom Pultz in that the problems with the cam teeth probably result from changing just the pad and not the whole assembly, since the tensioner loses spring with wear. There was an excellent article on this subject in a past issue (1999 I think) of 911 & Porsche World.

IIRC, replacing the chain necessitates removal of both cams. Check out the excellent write-up on the procedure at the Clark's Garage website.

 

For what it's worth, here is a picture of the chain in question. Anything look out of the ordinary?

<img src="http://noah.eckhouse.com/chain.jpg" alt=" - " />

Thanks!

Noah

 

For those interested, I scanned the article on the cam chain tensioner replacement from an old issue of "911 and Porsche World." A fellow lister has them posted on a website:

<a href="http://wingnutt.dyndns.org/944S2tensioner1.html" target="_blank">http://wingnutt.dyndns.org/944S2tensioner1.html</a>

For those of you with broadband, I'd be happy to email the 2MB zipped file with the pages in .jpg format. "Fair use" of copyright.

 

Thanks Stephen!

 

Fantastic article... do you have the rest of the series?

Noah