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Fergy Crank in a TR4


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Hi Folks,

there is a thread running on this forum asking for a crank and I mentioned, tongue in cheek, about the Fergy TRactor crank.

 

A couple of years ago a similar question was asked and 'Dick' on this forum came in and said about the Fergy crank.

 

From that I went off and bought a second hand tractor crank (it was completely knackered. I think TRactors have a hard life).

 

Firstly - are they available - yes. New, Apprx £375 incl Main and Big-end shells plus the thrust washers (excellent value)

 

Secondly - are they any good. Most definitely, to a point. The material spec and casting is identical to that which ST used.

 

Thirdly - will it work - yes. But it is like saying will a dinner fork do the same as a whisk - almost.

 

So what is going on. The TRactor crank spins at a max of apprx 2000rpm and because of this certain limitation can be used to make it cheaper.

Big-end journal - these have the TDC oil hole. No cross drilling as per the later TR's.

 

This is not a problem unless you are racing at 5000rpm for hours. Thus there are no 5/16" plugs in the crank webs.

The rear oil seal has no scroll; it is plain. It utilises a very big lip seal that sits directly into the block and held in place with a piece of old tin. Something like the Rover seal used now but without undersizing the journal.

Does it work -probably no worse than the scroll.

 

Coming from India, some of the dimensions are a touch out. No more than a 0.001", nearer 0.0005" - good enough for touring.

The worst area was the area at the front crank bearing and the sticky out bit - a few thou adrift in length.

 

Would it work as a touring crank - yes.

Would I use it - No. The reason being that a blank casting is available for not a lot and it needs machining.

Machining is where the cost rises dramatically. (I would use it if needs must or for a good larf)

 

The SDF (inspiration and funds) have teamed up with Moss (contacts) to get this project sorted.

Through a club member we have had the crank optically scanned and from that computer drawings created that will talk to the

machine shop.

The drawings will be signed off today or tomorrow and sent to India to make sure firstly that the machines are happy with the software and then produce a very small batch of oversize cranks for measuring.

If this stage is good then the cranks will be detail machined in the UK - this is the most costly part of the process.

 

As for price, this is still being worked on but it will be in the region of 1/3 or 1/4 of a Phoenix steel billet AND it will be a precise replica

of the ST crank.

 

Timing - probably later this year.

 

Roger

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As for price, this is still being worked on but it will be in the region of 1/3 or 1/4 of a Phoenix steel billet AND it will be a precise replica

of the ST crank.

 

 

Thanks for the update Roger - for those not in-the-know, how much are Phoenix steel billet cranks ?

 

...... Andy

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Lots, the revised NSF crank being developed here will be an excellent low cost alternative.

 

Mick Richards

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Can you explain "NSF", Mick ?

 

@ Roger, thanks for the good news !

Edited by Chris59
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Hi Pete,

very good question.

There are still a fair few out there but slowly dwindling.

Speaking to one Northern supplier he is happy to sell them but with no guarantee. How old and how many miles have they done.

 

£100/200 for a basic crank requiring machining.

£200 or so for the machining.

 

I went to buy two cranks about three years ago and both were cracked at the #4 BE/web radius.

 

Roger

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Hi James,

if all goes well then they will be marketed by Moss - hopefully by the end of the year.

 

One of the two prototypes has so far done about 10K in the last year with no issues.

 

For all intents and purposes they are an exact replica of the original crank.

 

Roger

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" For all intents and purposes they are an exact replica of the original crank."

 

Oh goody I like originality, will they break in the same place as the original ones at 4200 rpm??

 

Had such an incident some 30 years ago and bought a used one from Bob Soden in Wallingford for £25 (I think). Brought it home as cabin bagage in a holdall.

Nobody batted an eyelid. - those were the days!!

 

James

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Hi James,

will it break - almost certainly if you turn the engine on :o

 

The standard crank actually did very well. Not that many breakages. It would be nice to know how those cranks that did break how did they break.

I know some of the racing boys broke a few. I have one from a raced engine but not by me. also know of one that broke without the racing.

 

On the positive side a new crank must last longer than a seriously reground old crank.

 

A crank as hand baggage :o you silly twisted little boy :P

 

Roger

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Not by me :ph34r:

 

In the late 70's my boss was running a TR4, he had a crank break.

I had predicted this (possibly more luck than anything else) because in top gear foot down hard his gear lever used to rattle loudly.

At the time there was a theory that this indicated a worn rear main bearing, causing the crank to flex - particularly at it's resonant frequency, which was regarded as being approx. 4000 revs.

 

How much truth there was in that I don't know.

 

Bob.

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Err...as somebody who raced a standard TR4 crank ground down to -60 thou on the big ends (deliberately) and won the TR Register Championship with it twice and used Massey Ferguson tractor bearings I think that there is too much angst with regard to cranks that are ground over the standard journal sizes !

If continued access to bearings are the worry then I daresay the continued availability of more heavily ground bearing sets will be more available rather than standard dimension varieties, and if you think that a roadgoing or even modified car will require a new forged crank that can achieve better power figures and stand more abuse than my prepared crankshafts...well good luck with that ! Get them ground and used.

 

However as a recommendation Roger as willing guinea pig and the SDF are developing an extremely affordable well thought out replacement crank which will probably exceed the oil tightness currently enjoyed by TR owners, (in the absence of standard crank oil spattering you'll have to develop an underbody anti rust system to replace it !). So I'm very happy that the SDF is farsighted and TR supporting cranks are being sourced for the benefit and preservation of all 4 cylinder owners.

 

Mick Richards

Edited by Motorsport Mickey
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When I eventually managed to strip down my current project 4A engine after 30+ years in dry hibernation ( albeit seized), I was amazed to find a standard sized crank in good enough order to simply be polished - I wish the same could be said for some other parts of the same engine!

 

By all accounts, that would seem to be pretty amazing, but fingers crossed I'm not tempting fate for the future.

 

Cheers

 

Rich

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Hi Mick,

The design will 100% mimic the ST crank - scroll oil seal and warts.

The Christian Marx rear seal can be fitted as can the Rover lip seal with machined journal but that will be up to the customer.

Otherwise there will be to many combination to machine and stock as standard.

 

Roger

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Hi Rich,

when you had the journals polished did the workshop NDT the crank for cracking.

If they did then you should be happy .

 

Roger

Roger - yes and all the reciprocating parts were balanced together with the flywheel and clutch so hopefully it will be a good 'un!

 

Cheers

Rich

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