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I've never investigated the cost of having a steel crank made, but Racestorations do one for about £2,250 + VAT and these people make one offs http://allencrankshaft.co.uk/crankshafts.html

 

Phoenix http://www.phoenix-crankshafts.co.uk/steel-crankshafts.html do cranks for a number of vintage engines too, so I don't think getting one made or even a batch is a problem though I suspect the price will put off some owners.

 

Ash

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There is a foundry down here that have made a number of one off or small batches of cranks. Last time I was there they were doing a batch of Bugatti cranks.

Stuart.

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So now you lot are making me nervous. I have a freshly machined (.010 under) crank in the basement. It has been crack tested. Is there something that I should be looking for that would be indicators for premature failure before I rebuilt the TR3 engine ?

 

Stan

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Hi Stan,

certainly on #4 big-end journal at the radius to the web look for cracking and or significant machining marks (tool marks) - this also applies to ALL other journals.

Ash's crank went at #1 BE which is odd but never the less actual.

 

If you can, get it checked using Fluorescent Magnetic Partical. If you have a small airfield near you somebody will be doing NDT.

 

At British Airways one of my 'nearly' collegues came up with a device that would inspect steels for stress and would indicate when failure was likely.

It was a bit like the 'Tin pellets' in the fuel tank but it did seem to work.

 

Roger

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I shouldn't worry too much Stan, TR cranks break but not that frequently. They are getting on in years, many of them have been round the clock a time or two, one fine day a crank just decides it's time for meltdown - so it goes bang, and in due course will get melted down. That's life.

 

If it's been machined by a sensible man, crack tested, and it's going to be balanced on assembly, you've a good chance of a long and happy life. You're as likely to get t-boned on a roundabout as break the crank, if your number's up then so be it. Next day you might win the lottery . . . .

 

Cheers,

 

Alec

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I agree Alec.

 

Interestingly mine had been cracked for a very long time apparently, before it finally let go, so it's definitely worth have cranks crack tested when the engine is in bits as a precaution IMO.

 

I am having the replacement I've bought tested and balanced before putting it in.

 

Ash

Edited by Ashley James
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Phoenix http://www.phoenix-c...rankshafts.html do cranks for a number of vintage engines too, so I don't think getting one made or even a batch is a problem though I suspect the price will put off some owners.

 

Some years ago, (not sure when but C&B/Moss were in Manor Rd, North Sheen at the time) C&B were offering for sale brand new 4 pot cranks, my original crank had just had to be ground to 30tho' due to an oil pump drive failure, so, with an eye to the future, I managed to buy one of these cranks during a VAT discount period ( around £280!!). They came in a nice wooden box and were supplied by Pheonix!

So my guess is Pheonix could be commissioned to produce some more if enough people stuck their hands up.

 

Have recently been building the new crank into an 89mm engine,... had it balanced while the rear scroll was being converted to a lip seal, comment was "crackin' crank, very little needed to be taken off, well balanced out of the box" .

Engine and gearbox go back in the car this weekend.

Cheers rob

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I have emailed Pheonix about their crankshafts and they do supply them for the 4 pot TR as well as con rods, I am waiting for a little more information and permission to post their response

 

Cheers

 

Alan

Edited by Kiwifrog
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Ok From Pheonix

 

"Prices as follows;

 

1 or 2 £1750 each

3 or more £1500 each

Con-rods £200 each

All our cranks are made from EN40B T billets.

Delivery circa 12-14 weeks from receipt of a 1/3 deposit plus 20% VAT if you do not have a VAT number"

 

The response above is from an individual ie me asking about their cranks. All their cranks are made from a steel billet they make a lot of cranks for MG's and Austin 7's as well.

 

I think there could be a possibility for the SDF to contact this and other suppliers to see if they can arrange some sort of club discount. I am unable to make malvern this year but if there is another SDF member who is going to the SDF meeting could they bring this up as it would appear to be a matter that if not pressing now will soon become so.

 

The price of a reground crank is around the £450 mark plus £200 core charge from AN other supplier

 

Cheers

 

Alan

Edited by Kiwifrog
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Just discussed this with our top TR engine builder who's seen more broken cranks than most. Even a crank that was crack tested and the journals ground undersize with the correct corner radius. He puts it down to casting techniques of the day, original minor flaws creating stress points, and general fatigue over 50 plus years, with no single cause evident. Just the luck of the draw.

 

Doesn't seem to matter whether the fan is on or off, the fan extension is on or off, or even if fitted with a high tech harmonic balancer.

 

At race revs, he described how the blocks and cranks flex quite markedly, as evidenced by scuffing on the edges of the main caps. Regular crack testing becomes a vital part of race engine maintenance.

 

In road cars, engines that run on badly are particularly at risk. He's just replaced a crank in such a car with cracks on both sides of the centre main journal.

 

Here's the scary part - there's a pattern of failure in cars being quietly reversed out of the driveway !!!.

 

Breakages remain relatively rare, but I'll be a bit edgy when next backing out of the garage.

 

Viv.

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If you Google Charles Church you'll find he crashed his Spitfire and was killed. The reason was that the crank broke because the crankshaft journals had been ground with insufficient radius to prevent cracking, which is what mostly likely have happened to mine.

 

 

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It's important to understand that the day they actually break is the culmination of gradual deterioration. The crank was already cracked and had been gradually worsening for some time. The metallurgist explained how this had happened with mine,,which he said had been cracked for a ling time before it gave up.

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Mine's been balanced and will now have a Moss torsional vibration damper that may protect it for the future. The sad part is that I don't get the crank back till tomorrow, it's Prescott on Sunday and then I have a week of afternoons to rebuild the car. Luckily work is quiet at the moment, but I still may not get it to Malvern.

 

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Hi Ash,

hoping not to start a 'yes it does, no it doesn't' argument but the crank failure is due to Tensile(bending) loads not torsion(rotation).

The crack face pattern gives the clues.

 

Roger

 

 

No chance of an argument with me Roger, you may well be right. The only thing I can be sure of is that it was cracked for a long time before it bust. As I said I've had the crank, flywheel and clutch balanced, which ought to help and I'm fitting the Moss damper that looks like torsional types as you might fit to a six, but is less compliant. perhaps it's purpose is to damp bending vibrations.

 

Ash

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