SC Chain tensioners, revisited

phaques · 06-30-2006, 03:12 AM

I'm looking for a little technical guidance....I'm going to buy an 82SC with 120K mi and stock chain tensioners that have never been touched. I'm a little worried about making the long trip home before I can get it to my garage. Is it reasonable to try and install the collars - or do something - out on the road as a quick fix to avoid the possibility of a total collapse of the tensioners?

Rick V · 06-30-2006, 04:00 AM

Howdy neighbor,
You can do the collars but you need to drop the muffler to remove the chain covers. Just drive it home then upgrade to the Carrera tentioners. Are you going to DIY or do you have a shop in C-Ville already?

anthony · 06-30-2006, 08:01 AM

The car made it how many thousands on miles on the original chain tensioners?

I'd just drive it home unless they are making some kind of odd noise and sound like they may fail.

I assume you are having a mechanic do a PPI. If the car checks out you could have the mechanic install collars while he's doing the other work.

Superman · 06-30-2006, 08:18 AM

Frankly, there are those who would not worry much at all about your tensioners. The '82 SC had the upgraded chain wheel carriers, which provided better geometry. Some say the older chain wheel carriers were much of the reason for tensioner failure. Collars alone would be a reasonable final fix for your car, actually. And then, if there is a future failure (unlikely, many would say), your valves will not get bent.

yelcab1 · 06-30-2006, 08:27 AM

I would just drive it.

Plecostomus · 06-30-2006, 10:22 AM

Just make sure not to challenge it on the ride home!

phaques · 06-30-2006, 10:53 AM

Thanks for all the feedback! This is what is so great about the 911 DIY world (which I have been out of for a while since selling my last 911) - you post a question, and one day later you've got 5 solid replies. I owned a 325is for a while, and I'd post on related boards there and wait for a reply...and wait, and wait, and wait.

Anyway, thanks. I'm going to do my own PPI, and I'll probably do my own work on the tensioners, if I do anything. I'm not sure I would recognize the early signs of tensioner failure - any way to describe the early warning signs?

Won · 06-30-2006, 10:58 AM

Some people here will scare the crap out of you that your tensioners are gonna fail as soon as you step on the gas... At least that's how I felt when I got my 83 with 114K last June. It didn't have Carrera tensioners and it's unclear if the collars have been installed. I keep meaning to open up the cover one day and possibly rebuild the tensioners with Porsche kit, but it hasn't happened so far. Over 6K miles driven last year with plenty of autocross and "backroad" runs, and still no problem. I may be pushing my luck here, but to me the chance of the tensioners failing is comparable to the chance of me getting into an accident. If that worries you so much, why don't you flatbed it?

DARISC · 06-30-2006, 11:16 AM

FWIW,
I bought my 82 SC w/178k on it from a mech. engineer who'd owned it for 12 years, did his own valve adjustments, etc. and said he'd researched the topic & decided not to spend the money to upgrade the tensioners, based on what he'd read regarding his 82 and later SC factory changes that had been made relating to previous year's problems.

I had the car gone through thoroughly after I bought it and had the Carrera tensioners installed to play it safe, even though no bad noises were coming from the engine.

Rick V · 06-30-2006, 11:22 AM

Quote:

Originally posted by phaques
I'm not sure I would recognize the early signs of tensioner failure - any way to describe the early warning signs?

I was getting a pulsation around 2800rpm. I just figured it was because the PO limp-wristed the car around, and that the tumeup and some healthy foot would solve the problem. My problem(with the car) went away as soon as I replaced the tentioners. I had one on the verge of failing. I won't be buying any lottery tickets for a while since I used up all my luck on that one!
If you get in a jam with the car just stop by Airport Rd. auto and look me up, I wrench there, and if I can give you a hand I would be happy to.(not the company type but from me)

2.7RACER · 06-30-2006, 11:44 AM

For peace of mind, I would find out from the PO if these are the original timing chains. Likely they are. 24 years is a long time. I would replace the chains and while I'm in there .........

Rick V · 06-30-2006, 11:57 AM

Quote:

Originally posted by 2.7RACER
I would replace the chains and while I'm in there .........

Unlesss you are going to use the "master link" chain that requires splitting the case. An inspection should determine if they are stretched. JMO My 82 has the origional chains.

2.7RACER · 12:24 PM

Rick,
I think you are missing a semi colon which completely changed the intent of your statement.

"Unlesss you are going to use the "master link" chain that requires splitting the case."

Semi colon between chain and that, says what you mean.

Unlesss you are going to use the "master link" chain; that requires splitting the case.

Hey I'm not a English whiz.
But, I have changed my timing chains. I did use the "master link" type.

Chains stretch, even Porsche chains. Stretched chains wear sprockets and retard cam timing. At least inspect for excessive stretch.

Been working with chains for 40 years.

Master links are not a problem, if you orient the clip with the open end away from the direction of chain travel.

Never re-use clips.

Didn't mean to nit pick.
Have fun,

Kraftwerk · 06-30-2006, 12:25 PM

I am still running the original tensioner, got about 111,000 miles on the car. I am thinking of replacing them, instead of an upgrading... should be good for another 100,000 miles, right? Have driven the car at 115 miles an hour for 5-6 hours per day lots of high revving as well. Has anyone ever snapped the chain or is it more a concern with chain stretch?

Just drive it home you should be fine.

DDD · 06-30-2006, 12:29 PM

One additional data point -- I am the 2nd owner of my '83 SC. Original owner said he had the tensioners replaced because they failed upon startup one day. I bought the car in 1994, so that was sometime in the first 10 years of its life. No damage to the engine (he said).

I drove the car from CO to MN with no worries, given what I had read about the improved geometry, and given that the tensioners were relatively new. I have also read that despite the improved geometry, the '82 and later SC tensioners WILL fail eventually. It is just a matter of time. The design is better than earlier 911s but it is still a flawed design.

About 7 years ago I installed the collars just to be safe. So far, no problems (though for all I know the collars have fallen off!). I guess if a tensioner did fail, I wouldn't know about it, because the collar would be holding it up. Kind of begs the question about the purpose of the tensioners to begin with, as I know you can buy a "solid" tensioner that doesn't move, and keeps the chain taught.

Given the work it took to get the muffler off and surrounding tin and shroud to get to the tensioners, I probably should have just upgraded to the oil-fed at the time, but it didn't seem worth the $ to me given the function of the collars.

My $.02 -- drive it home, and then do SOMETHING fairly soon about your tensioners. --DDD

yelcab1 · 06-30-2006, 12:30 PM

I got 180k miles on my original tensioners. Then changed them to hydraulics ones and I wished I had used the money on something else like a macro Nikon lens.

Rick V · 06-30-2006, 12:33 PM

Quote:

Originally posted by 2.7RACER
Rick,
I think you are missing a semi colon

No I just checked and My colon is right where it belongs!

My typing sux and spelling isn't much better.
I personally don't like master link chains, thats just my opinion, I aslo don't like pears, doesn't matter much. I think we are all in agreement get the car home and pull the timing covers and inspect! Get it home is the first priority, all else is secondary. I'm just glad to see another SC in my neighborhood!

phaques · 06-30-2006, 04:13 PM

Rick, since you are in the area here, I want to direct you to another thread I have started about a do it yourself garage idea:
Do-it-Yourself Garage

Everybody else please also go check it out, it's just kind of a local concept.

Rick V · 06-30-2006, 04:26 PM

Ok the shop thing is an idea for later, When are you picking up your car? Inquiring minds want to know.

phaques · 06-30-2006, 04:35 PM

Okay, okay. I'm supposed to meet the guy up north on July 16, and we are on our way further north so I won't be back in C-ville until the early part of August. If the car checks out I'll have my check in hand and drive it up with us. Lots of driving before I get it back here...