Welcome to the Austin Seven Friends web site and forum

As announced earlier, this forum with it's respective web address will go offline within the next days!
Please follow the link to our new forum

http://www.austinsevenfriends.co.uk/forum

and make sure, you readjust your link button to the new address!

Welcome Austin seven Friends
This Forum is Locked
Author
Comment
Phoenix Crank (size)

Dear all,

I'm still the french guy who try to adapt a Phoenix Crank with Renault rod and piston in a Rosengart engine.

Maybe someone can help me.

Just before send my order to an A7 shop,I'm searching 3 information about these crank. I sent a message to Phoenix (I'm waiting a response) but maybe someone have an answer.



1 - Race of the con-rod.(A on my schema)
1.a. The original distance of the race (letter A on my photo) is 76 mm. Is that right ?
1.b. I need to machine the crank to have a race size of 74 mm. Is it possible to machine the crank to this size (or totally broken the hard metal surface).

2 - Pin size (B on my schema).
2.a The original pin is 1" 1/2 (38 mm). Is it possible to machine the crank pin for 38mm with a tolerence of between -0.025 and -0.041 ?

3. Bearing (C on my schema)
3.a The Rosengart block bore has a diameter of 72 mm with lengh of 28mm and back 19mm.
Can you give me the size of your front bearing and rear bearing by default for Austin Seven.

For information, my rod and piston

Location: Bretenoux (Lot 46) France

Re: Phoenix Crank (size)

A three inches.
B one and a half inches or one and five sixteenth inches.
C one and a quarter unches

Location: Wessex

Re: Phoenix Crank (size)

Dear Ian,

Thanks for your response, but do you have an idea for the question 1.b ?
And for my B question, I need to know the tolerance of the machining.

Location: Bretenoux (Lot 46) France

Re: Phoenix Crank (size)

It will go through the nitriding surely.

Why dont you just fit a spacer under the block. Or find some pistons with a smaller dim between gudgeon pin and crown. And effectivley stroke the engine to suit the crank.

Location: not north wales any more

Re: Phoenix Crank (size)

I always thought that since "1.5" Phoenix cranks are ground to suit Renault 4 shells then Renault rods should fit out of the box

Re: Phoenix Crank (size)

They do, unless of course, the crank is machined to fit Ulster original rods. It's far easier to fit a shim between block and crankcase rather than adjust the stroke to get deck height correct, in fact our cherished suppliers will sell you one ready made.

Re: Phoenix Crank (size)

Charles P
I always thought that since "1.5" Phoenix cranks are ground to suit Renault 4 shells then Renault rods should fit out of the box


Just reread the original. Doh!

No, you'll be through the nitiriding.
Custom crank, shorter rods or a plate.

C

Re: Phoenix Crank (size)

If you talk to Phoenix directly I am sure they will custom machine a crank to suit your needs, it may cost a little more but I have always found them very helpful.

Location: NZ

Re: Phoenix Crank (size)

What is the crown height to centre of the gudgeon pin? What diameter is the R4 gudgeon pin diameter?
Is the top of the piston thick enough to take 2mm off?

Re: Phoenix Crank (size)

Bonjour Alexandre,
Of all the solutions discussed here I would certainly not choose machining a special crankshaft. Of all other propositions here there is most certainly one cheaper and furthermore keeping a commercially standard and available crankshaft.
De toutes les solutions proposées je ne choisirais sûrement pas d'usiner un vilebrequin spécial. Entre toutes les suggestions faites ici il y en a bien une moins coûteuse et aussi qui conserve un vilebrequin disponible industriellement.
Renaud

Location: So so Sunny Brittany

Re: Phoenix Crank (size)

@Hedd Jones,@Charles P, @Alan, Iann Williams
Thanks a lot, good idea, I had it, but not sure of that. With this solution (fit a space under the block) I win performance because I have a better compression than a crankshaft with a lower race.

@Austin in the shed
I had this idea (cut 2mm on the top of the piston. I can win 1, but 2 is too big.



I have still one questioning, my question 2.
The Phoenix crankshaft pin size is 1"1/2 (38,1mm). The Renault con-rod have a diameter in 38mm with tolerance of between -0.025 and -0.041, so the real size must be little bit under than 1"1/2. Do you know if I can re-machined the crank for this size ? (or ask Phoenix to have a crank with this size).

Location: Bretenoux (Lot 46) France

Re: Phoenix Crank (size)

The question of regrinding nitride cranks arises now and then. The following may interest some.

Nitriding forms a compressed surface layer and this has a hugely beneficial effect on fatigue resistance. For the same stresses life is extended enormously. It is presumably why the Phoenix cranks are longer lived than the quality originals. The nitride layer is thin and all but the very lightest of regrinds will usually remove. The crank is then probably no more fatigue resistant than the original. Based on experience with nitrided post production Jowett Laystall cranks, many reconditioners were/are unfamiliar with them, overheat the work, and generate cracks when they attempt to regrind. Reground cranks can be (expensively) re nitrided.

For top quality work cranks are ground, nitrided, lightly ground again, although many seem to get by with just a post nitride linish.

The original unhardened Austin crank in my car developed less than .002 wear in 100,000 miles. Nitride layer is very hard and certainly with w.m bearings, wear should be negligible, filter or not.

Location: Auckland, NZ

Re: Phoenix Crank (size)

Alexandre,

Derek Sheldron has had at least two special order Phoenix cranks machined to his requirements (Rosengart engines) in the least couple of years.

He is currently driving back though Germany on the Eurotour but will be very familiar with the special order side of Phoenix - I am sure he will reply in due course.

Re: Phoenix Crank (size)

Alex,
Have emailed Mark at Phoenix with your question. Machining for them should not be a problem as the majority is done before hardening. Will let you know his response.

Location: Oakley , hants

Re: Phoenix Crank (size)

Alexandre BILLAUD
@Hedd Jones,@Charles P, @Alan, Iann Williams
Thanks a lot, good idea, I had it, but not sure of that. With this solution (fit a space under the block) I win performance because I have a better compression than a crankshaft with a lower race.

@Austin in the shed
I had this idea (cut 2mm on the top of the piston. I can win 1, but 2 is too big.



I have still one questioning, my question 2.
The Phoenix crankshaft pin size is 1"1/2 (38,1mm). The Renault con-rod have a diameter in 38mm with tolerance of between -0.025 and -0.041, so the real size must be little bit under than 1"1/2. Do you know if I can re-machined the crank for this size ? (or ask Phoenix to have a crank with this size).

The phoenix crank big end journals are machined to 38mm (1.496") to accept R4 shells.
Another way to get round the rear main bearing problem is to machine the bore slightly bigger 73mm and sleeve the bore to fit the Austin rear bearing at 71.424mm.
Does anyone know Paul Smith who used to sprint a Rosengart,Was his engine Rosengart or Austin ?

Re: Phoenix Crank (size)

Dear all,

I received an email from Phoenix. He can machined the crank with my dimension.
(Tolerence of between 1"1/2 (or 38mm) -0.025 and -0.041). It's important because I can't assembled R4 conrod with 1"1/2 strict. (or re-machined the white metal).

Just a last question for you. Let me know the size (diametre) of the bore diameter of your engine block for the rolling bearing (front and rear) ?
I have a a doubt, I want to be sure that Austin bore bearing are the same than Rosengart.

Location: Bretenoux (Lot 46) France

Re: Phoenix Crank (size)

Alex'
You will need to specify the bearing size that fits your crankcase, Phoenix have the specification for the LR2, but double check on your çrank before ordering, definitely different to the Austin as Rosengart only used metric bearings.
My email to Phoenix seems to have worked.

Location: Oakley , hants

Re: Phoenix Crank (size)

Rear bearing is 79.37mm
Front bearing is 71.42mm
Not as I quoted before on previous thread.

Re: Phoenix Crank (size)

Ive never measured but are they really meteicated?

Those numbers look suspiciously like 3 1/8 and 2 13/16

Location: not north wales any more

Re: Phoenix Crank (size)

Just converted the fractional imperial sizes to metric

Re: Phoenix Crank (size)

I'm coming back after few days. I exchanged emails with Phoenix and they can machined crank with my dimensions for a nice price.

For information for my Rosengart :
A : 3" (16,2mm)
B : Diam : 38mm with negative tolerence [ -0,025 ; -0.041 ]
C : Front and Rear bearing 1"25 ( 31.75 mm)


Just an information, I'm really surprised because Rosengart block are boring for rear and front bearing with a diameter 72mm. I think for Austin is 3.125inch (79,375 mm).

Location: Bretenoux (Lot 46) France

Re: Phoenix Crank (size)

Anyone ever thought of stroking a seven engine with Renault rods, Phoenix specially ground with a longer throw to suit and std height or even Honda pistons? There may not be enough clearance on the crankcase to accommodate the greater throw, has anyone ever investigated to find out?

Location: NZ

Re: Phoenix Crank (size)

I'd rather have a block you could bore to 60-61 mm.
I think to stroke the crank you would have to reduce the big end journal dia..

Re: Phoenix Crank (size)

I don't know but I find most 1.5in set ups only just fit in the crankcase as it is. I'm not sure that stroking is the way to go, it I'd be happy to be proved wrong. Like Shed I'd like a block that could be bored to more than 58mm. There are pistons that would do it, I looked, years ago, and could get to 1100cc but the blocks wouldn't stand it.

Re: Phoenix Crank (size)

Hi Dave, can't get your email to work. Could you get in touch pls. All the best, W