Failed chain tensioner?

[Xiranu]

Hi all
Last year I finally was able to drive my newly acquired 911 after been dreaming of owning one for 20+ years.

The model I a 73 911T targa with an engine from a 1976.
I do not have much about the history of the car, but it is surely fun to drive.

However in August the engine started to make this ticking noise when idling and I put into the garage as I was afraid it might serious.
Here is video: https://youtu.be/_qJSmlKxj2Q

Now I have finally gotten around to pull out the engine and performed a leak down test and rocker arm gaps. All seemed good although some air went through into the casing, but it was identical all on cylinders. No bent or open valves, which was my concern.

I have now pulled off the cover to the chain tensioners and the left seems very spongy and the right one seems very hard.
Here is video: https://youtu.be/dvrCRaNZb7U

I am complete new Porsche owner, so please bare with me.

I am thinking of buying a repair kit for the tensioner and a set of those “safety” collars and then just insert this to the engine.

Is my assumption correct about the tensioner? Is this procedure also something you would go for? Is there something I need to be aware of when doing the work.

The car is not a track car but used when the weather is good. I want it to be ready to April

Br
Randa

[Trackrash]

Yes, you can and should rebuild the tensioners. The older style like you have will loose it's oil over time and need to be rebuilt. It is not a difficult job. Safety collars are a good idea.

Yes, the tensioner you show in the video has failed, because it's oil supply is gone. You are lucky the chain did not jump. In fact at this point, you may want to check the cam timing, since you are in there anyway.

[Xiranu]

Thanks for the quick reply. I shall order two rebuild kits even though the right tensioner seems ok. Then I know when it has been done.

I have made the leak down test, so I am pretty confident the timing has not gone out, but it will be checked after reinstall of tensioners - better safe than sorry

I am planning driving the car during summer and then repair/renovate during winter. Next year is going to be gear box. I do it in baby steps and enjoy the time without rush.
I was very surprised on how easy and fast the engine was to take out.

[Flat6pac]

If you had jumped time, even one tooth, you would have broken rockers.
Bruce

[boyt911sc]

Randa,

Perform a physical inspection/test of your hydraulic tensioners. Compress the tensioner using a long heavy duty screw driver. A good hydraulic tensioner will have a lot of resistance against compression. A bad or failed unit will compress easily.

Tony

[cmcfaul]

A good time to upgrade to the pressure fed Carrera tensioners.

Chris

[gorskined]

toss them both in the trash and upgrade to a set of carrera tensioners ..

[Henry Schmidt]

It's important to member that Carrera tensioners were designed to run wider tensioner arms. This is an important part of the tensioner upgrade. Without this upgrade, tensioner failure is still quite common.
Porsche offers a late style wider arms and we make an up grade as well.
We sell rebuilt late arms as well. We upgrade the bushing to improve reliability.

[Xiranu]

Thanks for all the feedback.

I shall try to repair the tensioners as the upgrade to pressure fed tensioners + arms are quite expensive (>1400$), where the repair + safety collars of both is about 150$.

If the repair fails, then pressure fed tensioners it is.

Parts are ordered and now I just wait for the parts.

/ Randa

[Trackrash]

Just make sure to bleed them and have the upper chamber full of oil. They should be rock hard and impossible to compress with your fingers if done correctly.

Even so they won't go over 100k miles with out another "rebuild". FWIW the only advantage to the Carrera units is they will, in theory, last for ever with no maintenance.

Bottom line is anytime in the future, regardless of the type of tensioner, if you hear the chain noise, especially at startup, don't keep driving it without checking the tensioner.