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Anyone know what was used to make TR 4 cylinder cranks? was it EN 16 or 24 or what

I ask because my original crank that I have had for 30 years all wrapped up in oily paper appears to be bent?

With the main bearings in both ends and the center main bearingless (ie bearings taken out) the center main on the crank has a 5thou run out on a DTI

I want to get it bent straight but that depends on the material it s made of

Any one help on the metal of the crank or know abody to straighten it

It only has to move 2.5 thou

Thanks in advance for any help

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Hi Roger

Yes fitted all the bearings and the crank turns after an initial stutter

Back story is that I now get the block line honed (as for my race engines)

With a steel crank (just reground) a line honed block the crank will turn in the bearings on simply gripping the nose of the crank and twisting gently

The new old crank was stiff in the block and would only turn with much greater force hence take out the middle bearings and DTI the bearing surface

Of course without middle bearings the crank turns on gentle nose twist as it should

More back story: I have had disasters with my race engines and now found that my Stewart Warner (American) rev counter under reads: A snap on box with Tachometer facility run in parallel to the SW rev counter show that at 5K revs on the SW rev counter the engine is doing 5700. So As I have been running my engines to 7K they have actually been nearly 8K and not lasted long!!!! Had the rev counter since I built the car 20+ years ago. Expensive experience!!!

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You should contact http://www.johnmacnab.co.uk/ 

from memory they say they can straighten to within .0005 Thou, so you can reckon it may well be  a couple of 1/10s below that even.  

Michael I've had a couple of EN16 standard TR cranks bend when hardened, the worst was a 10 thou bend from centre bearing to the nose. I returned it to the suppliers and it came back with 0... that is zero runout on the bearing surface (still at the agreed dia undersize), I had to check my DTI (clock) I thought it was broken ! (no idea of the engineers used for this). 

Mick Richards

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Hi Mick

Thanks for the contact details It sounds like the place to take the crank

I have to say that I have become less enthusiastic about tuftride and nitride as there is this risk of bending as a result

I get to feel that the better way to go is lower revs (less risk) and learning to drive better


PS I previously looked at the crank for EN something and couldn't find it - there are various other numbers on it - I bought it about 35+ years ago with a fiberglass bonnet doors boot lid and a set of wings with wildly stretched arches, which I used on the car when I raced (occasionally) with the TR Reg series in the eighties I think.

Those were the days when Mick won everything!


Edited by MichaelH
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You do wonder if the staightening process may induce stresses that will shorten the life of the crank?

Probably not as much as overrreving by a thousand! However I don't see you becoming a 300rpm rev limit pootler Mike.

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Hi All

Spoke to the people as Mick Richards suggest  (John MacNab) and looked at their web site. they seem happy to bend a bit of EN16 steel without damaging it

when asked the details of our weighty 15 KG crank the response was "Oh small then!""

So I will get the crank to them apparently £60-70 + vat treatment

Look forward to getting back to building an engine up out of the bits I've got in the garage



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