Joined: Aug 2017 Posts: 3,215 Threads: 100
Reputation:
26
Location: Darkest Bedfordshire
15-09-2019, 08:02 AM
(This post was last modified: 15-09-2019, 08:07 AM by Chris KC.)
Likewise, the very best of luck Tony.
For me the big question here is do you stick as close as possible to the original? = a proven design that most owners will be happy with, keeps the car as original as possible, as long as spares can be had and price isn't crazy. Let's face it, Phoenix cranks have been dependable and popular for the last 30-odd years.
Or do you 'improve' - bigger journals, metric sizing, counterbalancing, etc. etc. = will make some of the razz boys (no disrespect!) happy but I'm not sure your average A7 owner wants metric pins or a racing engine. Once you start innovating you will please some people and put others off - I wonder if any two of us would want it done the same way? And say an owner has the money for the crank but can't afford rods as well, will he be able to use Austin rods or does he have to shell out for the whole deal? Plus every step into the unknown increases your risk that something will go bad.
Personally if I were taking this on I'd want to keep costs as low as possible while delivering a reliable package as close as possible to the original parts and keeping all the bits interchangeable. Keep it simple...
Good that you are talking about flywheels. I spent the last couple of days sorting out one which wanted to be inside the crankcase instead of out!
p.s. My understanding is the same Ian - a forged crank is the optimum way to go for strength but unless you have the budget for production tooling a billet is a safer bet for small batches. I think simply having new parts is a huge step forward compared with (frequently cracked) 80-year-old originals.
Joined: Aug 2017 Posts: 1,437 Threads: 59
Reputation:
17
15-09-2019, 09:15 AM
(This post was last modified: 15-09-2019, 09:17 AM by Charles P.)
There's an argument to modernise a bit - the early Renault 4 that we nick the bearings from has been out of production for a long time so parts supply could be an issue but they did make millions of them. Any alternative bearing would need to be high volume to assure ongoing supply. Improving the balance is a good move but are flywheels really a problem for most people? Also not everyone puts new rods in with a new crank so the interchangeability is important.
I guess that the key here will be to understand the price/volume relationship and then make decisions about production methods. To understand that you'd need to know where Phoenix (the historically dominant supplier) prices will be when they've got sorted out after the recent difficulties. A well regarded company that falls into their sort of financial problems may well have been underpricing!
Charles
Joined: Aug 2017 Posts: 1,257 Threads: 32
Reputation:
28
Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
At the moment, the Phoenix situation being unclear, it would seem to be a good time to look into making new cranks. But. If I was fitting a new crank into a high performance engine (which I have done more times than I remember) I would want it to be a 1.5inch variety. The smaller, new, cranks are perfectly ok for normal engines, and I’ve done a fair few of these too. The question is why would I pay more to have a crank for my road car, even if it’s technically better, if the old type was perfectly adequate.
Alan Fairless
Joined: May 2018 Posts: 2,798 Threads: 533
Reputation:
20
Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
15-09-2019, 11:45 AM
(This post was last modified: 15-09-2019, 12:44 PM by Tony Griffiths.)
Now, while you can fire up your 60-year old 6.5-inch Colchester and make your own billet crank, just in case you've not seen one being made on a more modern machine here are a couple of videos showing the process. The first is a "simple" 15-year MAZAK that just turns the basic crank: https://www.youtube.com/watch?v=hyRBbGb2UDA Impressive enough, but the next shows how things developed with a complex, multi-function CNC machine able to complete the entire process in one operation - including drilling holes and oilways, tapping, forming and machining a gear: https://www.youtube.com/watch?v=81UjjSH2iFw
In either case, I don't know what the floor-to-floor time is, but twenty years ago the figure for a CNC machined cast aluminium Harley Davidson crankcase was just 50 seconds, compared to over one hour using a series of manual machine tools.
Joined: Aug 2017 Posts: 2,247 Threads: 33
Reputation:
35
Location: Deepest Frogland 30960
Car type: 1933 RP Standard Saloon
Very impressive Tony. You can see now why they're expensive!
Joined: Aug 2017 Posts: 1,453 Threads: 21
Reputation:
15
Location: The village of Evenley
Car type: 1934 Austin Seven RP Deluxe
That WFL millturn machine is incredible, I know I’m a bit out of date when it comes to machining centres, but that video was a real eye opener...so all Tony has to do is order one of those then? 
Joined: Aug 2017 Posts: 1,437 Threads: 59
Reputation:
17
They do sell a 200k plus Harleys a year so the hardware, software and programming is pretty well spread out.
I remember when Colvin Gunn made a crank from billet he said to me "Everyone has one crank in them. Thankfully that's me done"
C
Joined: May 2018 Posts: 2,798 Threads: 533
Reputation:
20
Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
"I remember when Colvin Gunn made a crank from billet he said to me "Everyone has one crank in them. Thankfully that's me done"
...I like it!
Joined: Aug 2017 Posts: 1,808 Threads: 99
Reputation:
21
Thank you for all the replies.
Hard to answer everything.
Ivor, sorry I don't have £750,000.00 that's 3/4 of a million for a new multi-function CNC. Yes that's what they cost. And they hold there prices used.
The point of our favourite supplier, having financial difficulties. Is a valid one. Price risses coming??? On the same theme, if the company invests in more modern machinery. Someone will have to pay for it. Price risses coming???
The price for an inferior crank and rods could easily push up to the price of doing the job properly price.
So don't thank me for my efforts yet.
I have NO money layed out, and can just walk away. That's why ive asked for all your input.
Sadly this offer is on the table now, and won't be there when the forsite of rising prices, quality issues, availability. Have all overtaken us.
It's sounding like it's easier to walk away, and smugly say I told you so in the future.
Tony.
Joined: Aug 2017 Posts: 923 Threads: 52
Reputation:
5
Location: The delightful town of Knaresborough, North Yorkshire
Tony Betts, it is wonderful that you are doing this!
Personally I wouldn't care whether anything was in metric or imperial dimensions.
If I was spending many hundreds of pounds on a crank, I would want to spend more and have new rods. And the idea of a new flywheel as well makes a lot of sense to me.
Shell bearings? Yes please.
If timing gears are likely to wreck this, then should new ones be offered as well?
|
