70 S, RHD, Signal Orange, UK->Australia->UK

[Barry]

Perhaps I might be allowed to interject that one odd symptom was that, with the car in the air and any gear selected, there was an odd 'brrrr' noise if you turned the wheels with the clutch dipped. The noise stopped with the clutch pedal back up.

Either way, at no point did there seem to be a connection between box and engine.

[911hillclimber]

I'm intrigued.
With the trans/engine apart what have you found?
I presume the clutch assy is new, flywheel correct and the thrust bearing correct.
Was the assembly right? Is the clutch correct for the car?
What about the box, rebuilt?

[Barry]

Perhaps I might be allowed to interject that one odd symptom was that, with the car in the air and any gear selected, there was an odd 'brrrr' noise if you turned the wheels with the clutch dipped. The noise stopped with the clutch pedal back up.

Either way, at no point did there seem to be a connection between box and engine.

Thinking about it, I might have described that the wrong way round. Regardless, brrr was definitely involved!

[Barry]

I'm intrigued.
With the trans/engine apart what have you found?
I presume the clutch assy is new, flywheel correct and the thrust bearing correct.
Was the assembly right? Is the clutch correct for the car?
What about the box, rebuilt?

I'll let Richard explain where things are I must underline though how superb the engine sounds: incredibly crisp and clean running for a brand new build. It's a quality thing.

[jwhillracer]

Ummm. Please forgive me if this suggestion seems stupid/obvious/already checked.
I have seen a case before where the "pull" clutch assembly was fitted with a 915 centre plate, rather than the smaller bore one for the 901/911 box. That might well give a funny brrrrrrr sound when the clutch id pressed and the centre plate drops on to the gearbox input shaft...………….

JW

[911hillclimber]

Exactly my thoughts, is the clutch correct for the trans.

[inaglasshouse]

Ummm. Please forgive me if this suggestion seems stupid/obvious/already checked.
I have seen a case before where the "pull" clutch assembly was fitted with a 915 centre plate, rather than the smaller bore one for the 901/911 box. That might well give a funny brrrrrrr sound when the clutch id pressed and the centre plate drops on to the gearbox input shaft...………….
JW

Thanks JW, thanks Graham.
Yep, you got it. 915 friction plate with 901 (actually 911) gearbox. Congratulations! No prize I'm afraid, just the satisfaction.

Barry also guessed it before we took the gearbox off. I was sceptical, given that it was not me who assembled the engine to the clutch + box. I'm an idiot and could easily have made that mistake, but this was the work of professionals...

So, as you say, smaller bore 911 gearbox input shaft barely touching the sides of the hole in the 915 friction plate.
Feel free to add your own smutty metaphor here, but I doubt you'll come up with anything as funny as my main social group (school run mums, who have a variety of excellent euphemisms and anecdotes around the havoc wreaked on their insides by motherhood).

Super easy to sort out, and no harm done. Result.
Onward to the oil leak(s).

[Gary71]

smaller bore 911 gearbox input shaft barely touching the sides of the hole in the 915 friction plate.

One positive is that it makes the box really easy to fit Glad it's sorted.

[johnM]

And you will find the 911 friction disc is reassuringly expensive too. Glad it’s an easy fix tho.

[inaglasshouse]

Thanks both.
Yes, there does seem to be a premium for the 911 friction plate. In fairness, I guess it's bit of a low volume product (only a few production years - just 70 and 71?).

[Lightweight_911]

.
- but still cheaper than the 'one year only' '69S clutch disc ...

.

[inaglasshouse]

.
- but still cheaper than the 'one year only' '69S clutch disc ...
.

Something to look forward to, there!

[inaglasshouse]

So the other problem revealed by initial running was a fairly sizeable oil leak. Or leaks.
Not quite a gush, but more of a drip than a weep, if you know what I mean.
Seemed to be coming from the oil cooler area, and since I'd lazily / optimistically just bunged the original back in, cleaned but not pressure tested, the cooler seemed the first likely culprit to check.

Following a modest investment in a Stomski Racing pressure tester (and yes, I do realise there are cheaper ways to achieve the same result, but I can never resist buying another slightly obscure tool...), the result: nope, cooler is fine:

[Dougieboy1]

I realise you may have already discounted this but I had an oil leak on mine on start up - was one of the rocker covers - left hand side as you look at the engine, front end. Something to do with the combination of lack of stiffness of the originals and heat cycling, leaving can be random as a result.

Swapped out the originals for a set of stiffer turbo spec covers, leak cured.

[BILLY BEAN]

Richard,
Your pressure test looks conclusive. However, the cooler for my 2.7 pressure tested fine after a good clean. Unfortunately, on installation and putting the engine on a dyno it did leak slightly. The only explanation to this I could think of is that the pressure test is done cold whilst on the engine the cooler leaked once up to temperature?
Good luck with it.
Kirk