Tensioners or...

[gridgway]

In my 69 2.0, I had a big clatter on startup last weekend. I instantly turned off thinking big ends or similar. Then I worked out that you can't go from fine to destroyed bearings overnight. So I tried again and it started with no bad noises at all.

So then I thought about chain tensioners. They are unknown on this engine and not oil fed. Is that a likely, or can anything think of anything else that might be the culprit?

As it's winter, I could take the covers off and check the tensioners, chains and ramps which looks to be possible with the engine in situ.

Any hints and tips? I'm not inclined to go to oil fed ones. Just either fix the ones in there and fit safety collars or go to mechanical ones.

Anyway all help appreciated.

Cheers
Graham

[911hillclimber]

Look at this thread Graham.
3rd picture down and the usual tech comments from Chris at Fenn Lane.

viewtopic.php?f=2&t=63641

[gridgway]

Thanks Graham, I had seen the other thread so I'm planning on using the repair kit (in the absence of other suggestions). Just wondered if a one off clatter was possibly a tensioner.

I listened to the noise of a 993 on YouTube that had a tensioner gone. It had a zhh zhh zhh noise with a few revs on that I've not got. But at idle the clatter sounded similar. But I'm clutching at straws a bit.

Assuming I don't bugger up the timing, it looks like a fairly straightforward job! It'll take me an entire winter of Saturdays though I wager!!

Graham

[fetuhoe]

The only tensioner that is likely to clatter once is a Hydraulic Unit that is slow to pressurise.

If a spring has broken in a mechanical tensioner or a ramp has collapsed it will clatter and continue to be noisy.

Rather than mucking about with the engine sitting on a jack or similar it is probably quicker to drop the engine and have adequate space/light to see what is going on more clearly.

[gridgway]

Ah, in which case it's not the tensioner as they are not hydraulic.

I'm not equipped to drop the engine out at home really. And it's certainly fruitless to do so without better cause as it were.

I'll just do an oil change over the winter and see what the spring brings when I run out again.

Graham

[gridgway]

Rather than mucking about with the engine sitting on a jack or similar it is probably quicker to drop the engine and have adequate space/light to see what is going on more clearly.

Just re-read... does this mean you have to support the engine to get to the chain covers?
Thanks
Graham

[SeanP]

The last time I had the chain covers off of an engine in the car I had to remove the exhaust box and rear tinware and had to work from under the car. Didn’t have to remove the engine bar etc. It is tight and had to do most of the work from the underside of the car. The left side tensioner is easy to remove/ replace as you can keep the tension on the chain with vice grips, the right side is a bit more of a faff

Hope that helps

Sean

[911hillclimber]

I've had a hydraulic tensioner fail (relief valve ball and cage came adrift) and mercifully, the 3mm steel ball bearing was resting in one of the ribs inside the left cover along with the cage!)
Lucky.

Got to it and did the fix (re peened the cage/ball into the steel tensioner body) with the engine in the car, pain in the ass.

The noise was blood curdling and constant after it failed.

60K miles later and all is still well.
Getting a 911 engine out and back in is good for the soul, anything on a race car is a synch by comparison

The best way however to fully work on the 911 engine....

[gridgway]

Hmm, not quite sure how I feel about it now!! Certainly doesn't look that fun a job with the engine in the car and one the basis of one clanky startup, it's not really a strong diagnosis. I certainly don't have the time nor the facilities for an engine in/out. But having had a worry about them and having no maintenance history of the motor at all, it doesn't seem right to not do anything.

Graham

[911hillclimber]

Simply book it in with Chris for some guards?

You need to be careful what you are doing with the tensioners, anything dropped might fall into the engine (there are LOTS of spaces in this area) and then you are going in a different direction...
Working tightly with the engine still in the car only makes it more tricky.

[gridgway]

Getting a pro on the case is the obvious thing to do, but it'll need to be local to Epsom where the car is really.

I still like the idea of popping the covers off over the winter to see what's there.

Graham