Assessing an unknown engine

[Lightweight_911]

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It's a long time since I last did that job but I seem to remember I used a 1/4in drive socket/extension/ratchet ...


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[RobFrost]

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It's a long time since I last did that job but I seem to remember I used a 1/4in drive socket/extension/ratchet ...


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That did it. You have to leave it last and raise the manifold as the nut unscrews.

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[911hillclimber]

I replaced those nuts with K type nuts, flanged at one end, but M6 / 10mm AF. This allows a smaller socket on a 1/4" entention etc to do them up etc. on the LOLA carb manifolds where I have less space than you!

They are copper plated too so resistant to corrosion, even cheap for a special fastener on ebay.
Just a suggestion.
Oh, they are clenched to resist vibration, quite useful.

[RobFrost]

That's great advice, Graham. On the 3.2 they're Allen nuts which are also more easily accessible. But the standard 3.2 manifold also doesn't have the flange directly above.

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[911hillclimber]

If your 1/4" drive has a 'wobble' end to it, the smaller socket and that feature will make life much better and ensure you nip the parts together evenly.

[RobFrost]

Ever have one of those days?



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[911hillclimber]

Oh yes, plenty of those happenings in my hobbies!
I think anyone who do these kinds of things have such irritations come along...

You should have seen me fighting to put the trailer onto the Skoda yesterday.

[Gary71]

Ever have one of those days?



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You found a spanner in your oil cooler, that is bad luck

[RobFrost]

I had to get the orange 911 out to turn it around at the weekend, providing the perfect opportunity to bring the engine in behind the car and get it onto a stand.



A mechanic friend of mine vouched for automatic transmission fluid as having the perfect properties to get those pistons moving after forty years sat still in their cylinders.



Those properties seem to be: thin, penetrating, and smells like vomit.

Apparently it's harmless to seals etc. I put it in both exhaust and inlet valves, and inside the cylinders, let it soak one side for a few days, then turned it over and soaked the other.

I've not removed cams before. I heard the torque is quite high, in which case I'm not entirely confident this massive crow's foot is robust enough for the job. So I'm in two minds whether to try it, and reinforce it if it breaks, or simply to reinforce it before I even try.



It also won't fit on the other side, where the tensioner overlaps the massive nut. So I guess I simply take the tensioner off first?

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[Gary71]

I’ve used a similar massive crows foot in the past with success. Can’t remember about the tensioner, but I guess that’s the way.

Do you have the Dempsey book? Invaluable for this stuff

[RobFrost]

I’ve used a similar massive crows foot in the past with success. Can’t remember about the tensioner, but I guess that’s the way.

Do you have the Dempsey book? Invaluable for this stuff

Yes, I have Dempsey.

My fear was the square drive breaking off the crows foot or cracking... the reality is, the arc is expanding and then popping off so I'm gonna need something to reinforce it, and also to keep everything aligned and on straight.

This is with about a 4ft bar and a LOT of torque (i slid two jack handles over the socket bars). I read these are as tight as 150Nm and sometimes with loctite in addition.

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[Bruce M]

If there is a chance Loctite has been used, heat up the big nut to release it. I’ve broken big sockets in the past when they should have been okay because loctite red made a big torque into a ridiculous torque, so i play it safe & warm the nut/bolt.

[RobFrost]

If there is a chance Loctite has been used, heat up the big nut to release it. I’ve broken big sockets in the past when they should have been okay because loctite red made a big torque into a ridiculous torque, so i play it safe & warm the nut/bolt.

Thanks for the heads up. Makes sense because the torque I applied is crazy.

[RobFrost]

To my mild amusement, I had a dream last night in which I was loosening a massive nut with enormous force and it suddenly yielded and turned easily.

I've been getting quite demoralised these past couple of weeks at work, with some jobs building up and a number of customers getting frustrated with delays getting projects out to them. I interpreted the dream as reminding me that the projects will all be delivered and one day all will suddenly return to harmony.

But it also made me think these cam retaining nuts will suddenly come loose. So I decided to remove the cam tensioner from the other side, and have a go there. I'd learnt a bit from my first attempt and was extra careful to keep everything on straight, and start straight away with the massive breaker bars, which actually comprise a couple of heavy duty trolley jack handles slid over the socket wrenches.

Pretty soon I realised that I was going to break the sockets, so I rooted around for my "big berthas" - a couple of ancient half inch drive ratchet sockets which have had the heads welded solid on an arc welder.

With the tensioners off and chains loose, it became apparent i could gently rock the cams backwards and forwards against the valve springs and all appears to rotate nicely.

Being able to feel that I was only moving the cam a degree or two each way, with no resistance from the engine, I was much more confident applying the enormous torque necessary between the two bars, knowing I wasn't going to damage anything, and the nut suddenly yielded, exactly as per my dream the night before.



Within ten minutes I'd turned the engine around, removed the other chain tensioner and the first was off too.

I'm hoping at some point taking all thise bits off will make the engine lighter, but that doesn't seem to be happening yet. With this in mind I turned my attention to the flywheel studs and immediately found that one had already been sheared when being replaced (overtightened), and was holding on by a minimal amount of steel. It turned out another was already broken. I can see why these are single use only.



Once the big washer was off I had to sand the remnants of the head off to get the flywheel over it. It wouldn't be removed easily so I'll weld something on to it, next time I'm using the mig.

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[911hillclimber]

Good going Rob.
The 3.2 engine design is far far better in these areas, but the older engines are now getting on and you will finds these things more and more.

The engine will only get noticably lighter when the heads are off and the engine on the stand feels almost 'stable'

You can rebuild it properly.