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-   -   Tensioner Quandary (http://forums.pelicanparts.com/porsche-911-technical-forum/855908-tensioner-quandary.html)

Hawkeye's-911T 03-13-2015 03:55 PM

Tensioner Quandary
 
The engine & car have not been run for nearly 20 years. The mileage on the the clock is 153,000+ & has not functioned for who knows how long. I would like your opinions or advice as to my options & the steps to take re: the chain tensioners. The car will never be tracked as it was hardly an eye-watering performer to begin with. So with that in mind: http://forums.pelicanparts.com/uploa...1426289226.jpg
L.H.S. cam & tensioner with the tensioner ‘piston’ measuring approx. 1/2” (13mm) exposed.
Tensioner arm has about 7/32” (5mm) clearance from chain box housing.


http://forums.pelicanparts.com/uploa...1426289342.jpg
R.H.S. cam & tensioner with the tensioner ‘piston’ measuring approx. 1/2” (13mm) exposed – same as L.H.S
Chain on idler arm sprocket has approx. 1/4” (6mm) clearance to underside of ramp.

Are these measurements within acceptable safe & normal operating limits?

Do I refurbish the tensioners before I install the safety collars or just leave them as they are?

I will be replacing the chain ramps as recommended by many on the board. I previously purchased a new set of ramps & safety collars from our host.
Any help or advice will be greatly appreciated. Thanks in advance.

Cheers
JB

RSTarga 03-13-2015 04:45 PM

Put a set of the last generation 930 tensioners on with appropriate spacers and ramps etc. Rebuilt is ok.
Use 60wt oil. Why take a chance on destroying your engine.

Flat6pac 03-13-2015 05:06 PM

Get the antique chain rails replaced and put a set of tensioner guards on for safety.
Bruce

Hawkeye's-911T 03-16-2015 08:43 AM

Thanks for your responses guys. The remedial steps discussed will definitely be taken. However, I still have an uneasy feeling about the tensioner plunger/piston extension from the tensioner. I have scoured a large number of threads on the subject but I'm still unable to find or determine a definitive number for the upper limit of the plunger travel - the worn chain scenario coming into play.

Am I being overly concerned with this 'perceived issue', or should I proceed as planned & then enjoy a cold brewski?
Once again, many thanks.

Cheers
JB

Edit: I took a flat blade screw driver to one of the chain guides this morning - it was really "bendy"

tharbert 03-16-2015 09:32 AM

Bruce has way more experience here but... When I opened up my chain towers the first time, one of my tensioners had a collar and the other didn't. Fishing around in the sump. I found all the pieces. The collar was broken, sheared at one of the bolts. It could be the PO trusted the collars even after the tensioner had failed and the resulting pounding was too much. In any event, I'm not a fan of them.

I suggest along with the rebuilding the tensioner that you look into the Jerry West mod, placing a shim inside the tensioner to limit it's collapse rather than using a collar.

2˘...

Trackrash 03-16-2015 09:59 AM

I am still using the same tensioners that you have and have put almost 200K miles on them, BUT I have rebuilt them three times over the years. Those style tensioners only have a small reservoir of oil, which does not last forever.

Collars are a very good idea, they likely saved me once.

The chain on the right side of your motor is nearing it's limit due to wear. The chains will get longer as they wear.

I imagine that you will be looking at a major overhaul of your motor at some point in the future. At that time you may want to upgrade your tensioners as well.

So to answer your question: rebuild your tensioners and add collars now before running the motor.

Jon B 03-16-2015 04:22 PM

Quote:

Originally Posted by RSTarga (Post 8529369)
Put a set of the last generation 930 tensioners on with appropriate spacers and ramps etc.

Best Advice ^^^

The tensioners pictured were aftermarket replacement items, they are not genuine Porsche and not 930 tensioners.
I doubt they can be rebuilt, nor would you want to. Replace them.

The chain ramps pictured were the worst type Porsche ever used, should definitely be replaced before they literally fall apart.

If your chain sprocket supports are not bushed, replace those as well. They were a major cause of tensioner problems.

Hawkeye's-911T 03-16-2015 07:30 PM

This is starting to sound & become more expensive by the minute. I was leaning toward Flat6pac & Trackrash's advice. The situation in which I find myself now, is becoming less & less clear. It looks for all the world, I am heading down a very slippery slope.

Cheers
JB

Jon B 03-16-2015 09:19 PM

Quote:

Originally Posted by Jon B (Post 8533468)
The tensioners pictured were aftermarket replacement items, they are not genuine Porsche and not 930 tensioners.

Genuine Porsche chain tensioners since 1968 had a Porsche trademark ("P" inside inverted triangle) cast into the housing.
930 tensioners had internal improvements from previous versions, and reinforced housings (red arrow).

Your tensioners are inferior 1970's aftermarket replacement items.

http://forums.pelicanparts.com/uploa...1426568741.jpg

Trackrash 05-28-2016 07:00 AM

Update
 
Repair kit found here. Porsche Chain Tensioner Repair Kit: Engine Mechanical &amp Timing and Related Parts
http://forums.pelicanparts.com/uploa...1464447492.jpg
http://forums.pelicanparts.com/uploa...1464447511.jpg

Porsche 911 Chain Tensioner Repair Rebuild Kit
Part No: 91110590101 http://forums.pelicanparts.com/uploa...1464447615.jpg

enzo777 06-01-2016 08:04 AM

hello thanks for picks (Trackrash).- have you de second pic, in full sice??? and other page of this manual.- Instruction of rebulit.
What parts, of this is more comun fail??? What part i will check???

In Argentina i can´t buy this kit (or buy in other country, custom is close), i will try find and buy o´rings, but i don´t know what tuo do with the springs.- Replece with similar new or put used again???
regards
Enzo

Trackrash 06-01-2016 02:59 PM

I think all you will need are the o-rings. If it can't be easily depressed when you fill with oil and bleed it, you should be good to go. Here is the Porsche workshop manual instructions.http://forums.pelicanparts.com/uploa...1464821958.jpg

Trackrash 06-01-2016 03:15 PM

More
 
http://forums.pelicanparts.com/uploa...1464822941.jpg

enzo777 06-06-2016 09:11 AM

Hello
thanks thanks Trackrash
you realy help me.-
best regards

enzo777 06-06-2016 09:14 AM

Hello
i have mechanic tesioner in work order condition (in 2,4 engine from targa 1972), but i don´t know, how old they are or how kilometers.- I buy safe collar; but i think maybe i can rebuilt them before put safe collar.- O better, i can put safe guards inside of them (than pressure - fed tensioners).- Because i read some safe collar can brakes.- You know is posible put inside guars in mechanic tensioners??
regards
Enzo

Discseven 06-06-2016 03:04 PM

JB... here's a look at '79 930 clearance.

http://forums.pelicanparts.com/uploa...1465254184.jpg


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