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+--- Thread: The chance of new crankshafts and rod etc (/showthread.php?tid=3309)
The chance of new crankshafts and rod etc - Tony Betts - 14-09-2019
Hi all,
As many of you already now, I've been handed the chance to develope a new crank with one of the country's leading manufacturers.
The outcome is a billet crank, that may have further development to improve the balancing design.
The sad news is the first production price estimates are in? And yes they are not cheap.
Rather than just say NO to the price, I don't give up on anything easily. And in talks with the company we covered the possibility of new rods to go with the crank.
I've always had a problem,same as any other crank manufacturer of getting FULL WIDTH shell bearings for new 1 5/16 rods.
Pics below of the shells that are supplied for for new 1 5/16 rods, against an austin rod. They cover around 75 percent to what they should do.
TBC.
[attachment=7744]
RE: The chance of new crankshafts and rod etc - JonE - 14-09-2019
Tony - what happens with 3 bearing crank rods - are there still shells made for those... or are those rods much narrower in section?
That always seemed to be a good theoretical reason for a well put-together three bearing engine; not having to do white metalling.
RE: The chance of new crankshafts and rod etc - Tony Betts - 14-09-2019
This is were the company has a lot of developement work being done.
They can manufacture to austin spec, from the designs of a modern rod.
And most important of all, they will have full width SHELL BEARINGS. And the shells have a rating for race use. That wouldn't even look at vetting hot before 10 thousand revs.
Also this way the rods can be perfectly balanced with the crank from the start.
The next phase that was talked about, is NEW flywheels could be made to complete the set.
Again imagine being able to by a brand new crank, rods, and flywheel. All balanced ready to fit.
For the crank and rods, we could be looking at a price of £2,500.00
This is again what's currently on the market as £750 to £860 for the crank, £750 to £860 for the rods. You may have to pay for the shells on top. Or £300 for white metal if you want the surfaces to be full width. A total cost from £1,500 to £1,920 plus there may be more price rises coming.
On top of this, as many are struggling to get good quality bearings. We are starting from scratch. So we can change the bearing journals to a metric size bearing. Which I would have thought would be much cheaper, and would be available long into the future.
My big questions to you, are am I mad. Or would there be interest in high quality cranks, and even higher quality shelled rods. Sold as sets.
Its your chance to tell me exactly what you think, are they just to expensive for seven owners.
Tony.
Hi jonE,
The shells pictured are for 3 bearing rods, yes 3 bearing rods are narrower.
At the moment these are the only opsion anyone has found to put into new rods. For 1 5/16 cranks.
They can work, and many are useing them. But I have seen several NEW cranks with a warn out groove the same width of the shells.
Tony.
RE: The chance of new crankshafts and rod etc - Bob Culver - 14-09-2019
It is not made clear if the proposed crank is of specifically nitriding steel and to be nitrided.
Fatigue life of the crank is the vital factor, especially as, quite apart from the competition fraternity, very many cars run raised c.r. and most are run at consistently higher revs than in their day.
About the highest attainable fatigue resitance is obtained by a forging of suitable steel correctly heat treated and nitrided.
Anything else, unless perhaps with rolled fillets, is likely to be little different from the original Austin or older aftermarket products. I gather the former were of steel superior to that used in many other cars.
With attention to clanliness and no disintegrated timing gears, white metal gives long wear life on an unhardened crank without a filter. (my car .002 max at 100,000) Harder modern bearings are intended for hard cranks and usually a filter (although VW Beetle ran without). Nitrided cranks are very hard and should survive almost anything.
RE: The chance of new crankshafts and rod etc - Tony Betts - 14-09-2019
hi bob,
trying to remember to put everything in one thread is not my strong point.
but YES, they would be made from EN40b billet. and nitrided.
they would be supplied with a full spec sheet, that includes all checks done in manufacture.
the only other crank that supplies a spec sheet to back up quality is HADLEY.
as i sed the company is one of the best, and highly respected.
im not looking to have these made in large numbers, more like 10 at a time.
if there is genuine interest, they can be supplied by christmas.
which is somewhat a much shorter time, than the 18 months ive been whaiting for the last company i ordered with.
tony
RE: The chance of new crankshafts and rod etc - Zetomagneto - 14-09-2019
Tony, why not just do 38 mm cranks for everyone, that way only one crank needed for the racers, and ordinary folks.That way you continue with the very nice Hadley rods.
Watching with interest, Gene
RE: The chance of new crankshafts and rod etc - Ian Williams - 14-09-2019
I am interested to know more Tony, are these counterbalanced Billet cranks or basically to normal A7 design? As I understand it one of the advantages of the hip forged cranks we have been enjoying since the advent of the Allen cranks is how the grain of the steel forging flows with the shape of the crank. I am no expert in these matters but are these advantages lost if going back to a billet crank or am I missing important considerations? If of course they are counterbalanced the bending cycles will be greatly reduced. I am also interested in why you are going for 1 5/16" shells, again I may be missing important considerations but the current 1 1/2" cranks have a greater beam strength going to 1 5/16" seems a backward step unless again something like counterbalancing is in the mix?
PS I am not trying to pick holes in what you are proposing, I am excited by the prospect of a step forward, I am just trying to understand the advantages from a lay mans point of view.
RE: The chance of new crankshafts and rod etc - Chris KC - 14-09-2019
I think the current supply of 3-brg shells is old Reliant stock, slowly dwindling I guess. Of course a new 'wide' shell could always be cut down to service an Austin 3-brg rod if the bore in the rod was the same size (but you can't make narrow shells wider...)
RE: The chance of new crankshafts and rod etc - Tony Betts - 14-09-2019
hi gene,
fair point.
the negative is, notice i dont have the lovely 45 degree rods in stock.
the profit in them is so small, its pointless in producing them as a business.
i only have them made when i need then for myself. or counterballanced cranks.
although in saying that, i did let my last set go to help someone out. and now need some for myself. so will look at having some more made.
hi ian,
the difference is apparently very small as pointed out to me, and it depends on how you want to gain strength.
ill leave all names out of this thread, as i dont want it to open out as a slanging match. but some things have to be explained to answer questions.
strength in forgings is good, but cracks can be forced in the process. i have returned cranks in the past with cracks. and thats why i produced the kiddy cranks a few years back.
when forgings are produced, the manufactureing company probably scrap 10 percent before they are sent for machining. companies will then machine 1 1/2 first. if there are inclusions. those billets will be machined to 1 5/16. then 1 1/8. there may still be some that are scrapped at the end of machining.
if there is any loss in strength of a billet, the gain is its unlikely there will be inclusions in high quality billets.
as for how they will be finished, counterballanced. is hard to answer. others can point out ballancing austin cranks better than me. but the bassics are austin cranks can only be ballanced outside of the engine. when the cranks are running inside the engine. the force is all on one side, and they are no longer ballanced. this may be able to be altered with counterballances.
and ian dont worry about picking holes. the hole point of this thread is i working out if its work producing better and higher quality products for austin 7s???
thanks tony
RE: The chance of new crankshafts and rod etc - Colin Reed - 14-09-2019
HI Tony,
Sounds like a great project and good Luck,
Just a couple of things.
your explanation re Forging or billet is spot on
cost wise the billet is the only way for small runs
Both types use Nitriding which will penetrate .010 to .015 th so if needing a regrind just re nitride
some form of counter weights I feel would be beneficial
Re Fly Wheel a much lighter mass on the OD would help if thinking of manufacturing
Coiln
NZ