Tension on tensioners?

[s_wilwerding]

Well, I did the chain tensioner update on Saturday, though I haven't buttoned eveything up yet. My question is, after priming the tensioners, how much tension should they have?

I primed those suckers for about half hour each, and they both took oil, but I could still squeeze them down with my fingers (though it was tough). Should they have more tension after priming them?

I'm thinking of making a setup to pump oil into the tensioners at about 80 psi before putting everything back together, just to make sure that they have a proper amount of tension before starting the car. Anybody every do anything like this?

Thanks.

[ChrisBennet]

Even Hercules could not squeeze a tensioner together with his fingers once it has oil in it. I just installed some tensioners in a motor and the covers aren't on it yet. I'll check tonight.
All I did was squirt some oil in the oil feed hole and pulled the pin.
-Chris

[silverc4s]

The spring provides the tension, the oil acts as a dampener at speed. If you can compress them by hand, and you aren't from Smallville, they are bad tensioners, IMHO...

[s_wilwerding]

Originally posted by silverc4s
The spring provides the tension, the oil acts as a dampener at speed. If you can compress them by hand, and you aren't from Smallville, they are bad tensioners, IMHO...

So, should I assume that they are bad? I bought them from Pelican - how do I go about getting new ones?

[Rot 911]

Originally posted by s_wilwerding
[BSo, should I assume that they are bad? I bought them Pelican - how do I go about getting new ones? [/B]

Just call the parts ordering line and talk to one of the guys there. If they are bad, I can guarantee Pelican will make good on them.

[ChrisBennet]

s_wilwerding,
OK I went home at lunch and checked my newly installed tensioners. I can squeeze them with the tip of a screwdriver just by pressing down with my body weight - not prying. I then used an oil can to pump fluid into the oil feed hole while squeezing and releasing the "piston" about 6 times. It did not firm up.
This could mean one of two things:
1. This is just how they are, and your's is OK.
OR
2. Mine are broken also.
-Chris

[s_wilwerding]

My feeling is that they are bad. I've read a number of people's post that say:

1. That the oil does nothing for the tension - the springs should hold tension by themselves

2. That the first time you pull the pin, regardless of whether you've bled them, you cannot push them down without using a vice.

When I did the job the other day, I was struck that these were not so. I went ahead and installed them, but it bugged me. I've only snugged down the valve covers so far, so it will be easy enough to still replace them with non-defective ones. Obviously, I haven't started the car yet, so no harm done!

[boyt911sc]

Steve,
I recently installed a Carrera tensioner kit (purchased from Pelican) in my '78SC and I have about 500 miles on it. These hydraulic tensioners are so hard to compress manually. I used C-clamp to push the rod down and if you could easily push the rod down, I'll be reluctant to use it.

Have a second opinion and visit a Porsche mechanic or somebody who had installed similar kit near your area. Minimize the risk in your favor. Good luck.....

[ChrisBennet]

Originally posted by s_wilwerding
My feeling is that they are bad. I've read a number of people's post that say:

1. That the oil does nothing for the tension - the springs should hold tension by themselves

2. That the first time you pull the pin, regardless of whether you've bled them, you cannot push them down without using a vice.

When I did the job the other day, I was struck that these we not so. I went ahead and installed them, but it bugged me. I've only snugged down the valve covers so far, so it will be easy enough to still replace them with non-defective ones. Obviously, I haven't started the car yet, so no harm done!

Steve,
I have a slightly different take on this.
Re #1) I believe the spring only extends the piston. I know from experience that it doesn't take much effort to compress a failed used tensioner. The (incompressible) oil filled chamber is what keeps the tensioner hard - like a really stiff shock absorber.
Re #2) I can't remember if I had the same results with new tensioner but I know when I reuse a used tensioner I need a vice to recompress it. This may be because there is still enough oil in it or some mechanism consistent with your #2 behavior.
-Chris

[ChrisBennet]

Steve,
I went out and tried to pump up a tensioner. I rigged a tube to feed oil to the inlet and pumped the tensioner some more. I also tried compressed air.
Were is John Walker when you need 'em?
-Chris

[ChrisBennet]

I shoulda done a search.
Previous failed tensioner post

[s_wilwerding]

Sounds like both yours and mine are defective. I'll be giving Pelican a call this afternoon.

[s_wilwerding]

Well, I called Pelican, and they said that I could return the tensioners and they would send me new ones. Only problem - the tensioners are already in the car. I don't know of a good way to get them out semi-permanently, other than try to reinstall the old tensioners.

Anybody have any ideas?

[Jbabic]

Let me know if you want to buy my used tensioners, they are in great shape. they were in my 2.7 but I bought a 3.0 that had them, so I have an extra pair. I would take $100.

[RoninLB]

well, i gotta do cams one of these days and was wondering if I should do new tensioners after 40k mi.. even asked a big 911 rebuilder for an unofficial opnion..he confirmed my thoughts that I should keep the tens. that I know are working fine.. personally I would feel more secure in slightly used tens. than new ones..not a pro here, only an opnion.........................Ron

[Jason 74 911]

I installed new oil fed tensioners, bought from pelican, about 4-5 months ago. I haven't driven the car much because of oil leaks even after replacing all the gaskets. It turns out most of the rocker shafts were leaking. Installed o-rings which seemed to really help. Once I installed the o-rings, I noticed noise coming from the front left of the engine around #1 or #2. It sounded like it was coming from the cam chain, but out of inexperience, I though no way those are new tensioners. So, I readjusted the valves 2 or 3 times thinking the valves were loosening from installing o-rings on the rocker shafts. I buy virtually all my parts from Pelican and luckily happened upon this tech article. I am convinced that I have a failed or bad tensioner. The noise is loudest when the engine first starts and is cold. It then gets signifaicantly queiter as the engine warms to temperature. Which leads me to the following questions I hope can be answered from the experienced owner/mechanics out there.

1) What are the symptoms of a failed tensioner?
2) I have driven the car probably about 50 miles total with these symptoms. It still runs strong. Have I done any damage?
3) If the chain skips a tooth will it still run?
4) Has anyone else returned tensioners to Pelican?
5) Any suggestions?

Thanks for your assistance.

Jason
1974 911

[Jim Savage]

jbabic,

I might be interested in your tensioners. I'm in Hamilton so I could come over and check them out. Shoot me an email if interested. Jsavage489@aol.com

Jim

[silverc4s]

Jason asks the following questions...:

1) What are the symptoms of a failed tensioner?
A lot of clattering noise from one of the chain cases -the sound of a moving chain hitting stationary cases, etc.. pretty noticeable. If you don't have a stethoscope, you can just use a long screwdriver to transmit the sound (pointed end to the engine, right?
2) I have driven the car probably about 50 miles total with these symptoms. It still runs strong. Have I done any damage?
Most likely not, if it still starts and runs okay. Just don't rev it very high or up and down very quickly..
3) If the chain skips a tooth will it still run?
I do not think so. It depends on your cams, but I think one tooth is about 12 to 14 degrees of timing error - danger of valves hitting is there.
4) Has anyone else returned tensioners to Pelican?
Yes, read previous posts. If they are faulty PP will take return & exchange, I think.
5) Any suggestions?
Verify noise source. If it is the chain case, i would pull the offending tensioner & exchange it. Right away

[Jason 74 911]

Hi Jim,

Thanks for your reply . You gave me the answers I wanted to hear. Changing the tensioner is just an inconvenience, damage would have been very unpleasant. I done a lot of work to her and just got her running right. Now I hope the head studs hold. Oooh!

Cheers,

Jason 74 911

[Jason 74 911]

Sorry Bill,

Thanks for the reply.

Jason 74 911