Identify Porsche 356 crank

356 Porsche-related discussions and questions.
Message
Author
Mike Murray
356 Fan
Posts: 87
Joined: Sat Sep 27, 2014 3:09 pm

Identify Porsche 356 crank

#1 Post by Mike Murray »

I just bought a 356 Porsche crank. There is no casting number. Only the stamped numbers 524523 and C520561 or 7
Here are some pictures is a little stamping on the crank that looks like the top of a three leg puller. The letters in it are alp???
Hope you recognize it in the picture.

Many thanks,
Mike

Any idea what it is. There
Attachments
DSC07285.JPG
DSC07287.JPG
DSC07290.JPG
DSC07281.JPG

User avatar
Jacques Lefriant
356 Fan
Posts: 4602
Joined: Mon Dec 06, 2010 1:50 pm
Location: Washoe county NV

Re: Identify Porsche 356 crank

#2 Post by Jacques Lefriant »

hi it is an Alfin stock 356 crank prior to C
 

User avatar
Vic Skirmants
Registry Hall of Fame
Posts: 9279
Joined: Tue Oct 27, 2009 5:02 pm
Location: SE Michigan
Contact:

Re: Identify Porsche 356 crank

#3 Post by Vic Skirmants »

And you shouldn't find a casting number in a forged crank.

Jon Bunin
356 Fan
Posts: 1800
Joined: Thu Oct 15, 2009 11:06 pm
Location: Vista, CA

Re: Identify Porsche 356 crank

#4 Post by Jon Bunin »

Mike Murray wrote:...a little stamping on the crank that looks like the top of a three leg puller. The letters in it are alp???
ALFING Kessler GmbH
http://www.alfing-crankshafts.com/en/home.html
Jon Bunin

Mike Murray
356 Fan
Posts: 87
Joined: Sat Sep 27, 2014 3:09 pm

Re: Identify Porsche 356 crank

#5 Post by Mike Murray »

Thanks, guys.

Was this an OEM Porsche supplier at the time? Is it something special or just a regular Porsche crank?

thanks,
Mike

User avatar
Vic Skirmants
Registry Hall of Fame
Posts: 9279
Joined: Tue Oct 27, 2009 5:02 pm
Location: SE Michigan
Contact:

Re: Identify Porsche 356 crank

#6 Post by Vic Skirmants »

They were the OEM supplier; it is a standard crank. Made around 1961-62, based on the oil holes in the rod journals.

Mike Murray
356 Fan
Posts: 87
Joined: Sat Sep 27, 2014 3:09 pm

Re: Identify Porsche 356 crank

#7 Post by Mike Murray »

Vic,
Many thanks. Was it PORSCHE oem?

User avatar
James Davies
356Talk Moderator
Posts: 2951
Joined: Thu Aug 15, 2013 9:15 am
Location: Heidelberg, DE

Re: Identify Porsche 356 crank

#8 Post by James Davies »

Yes, Alfing supplied 74mm cranks to Porsche from at least spring 1952. I believe these cranks were used in the 1500 Le Mans cars that year, and eventually made it into the type 546 motor (1500 normal) starting in Sept 1952. Alfing cranks were used throughout 356 production, all the way through the SC model. Alfing was *the* OEM supplier for Porsche.

Before Alfing in 1952, they used Hirth roller bearing cranks on the 1500 motors, and before Hirth, they used VW 64mm crankshafts on the 1100 and 1300 motors. I don't know who made the VW crank. Perhaps that was Alfing too?

Mike Murray
356 Fan
Posts: 87
Joined: Sat Sep 27, 2014 3:09 pm

Re: Identify Porsche 356 crank

#9 Post by Mike Murray »

Many thanks guys.
You are the best!
Mike

Dick Weiss
356 Fan
Posts: 4183
Joined: Sun Apr 20, 2008 12:54 am

Re: Identify Porsche 356 crank

#10 Post by Dick Weiss »

It's a later 50mm main journal crank having thru holes in the rod journals.
Connecting drillings have plugs.

Dick

User avatar
Tom Markussen
356 Fan
Posts: 88
Joined: Mon May 12, 2008 11:43 am
Location: Denmark, Europe

Re: Identify Porsche 356 crank

#11 Post by Tom Markussen »

Can anyone help indentify the crank? I am opening an old motor not used for many decades, original to my 356A Coupe T2 from 1958 that now runs a 912 engine. Engine number "P 70743".

Crank: Alfing "910272", other side "34493 P".

I suppose the 910272 is the internal number of the supplier Alfing. But what is the "34493 P"?
Attachments
IMG_7964.jpeg
IMG_7946.jpeg
IMG_7932.jpeg
Tom Markussen
1958 Porsche 356A Speedster T2 #83967
1958 Porsche 356A Coupe T2 #104598
1960 Austin Healey Sprite MK1 Frogeye #AN5/43259
1955 Alfa Romeo Giulietta Sprint #349

User avatar
Al Zim
356 Fan
Posts: 4309
Joined: Thu Mar 27, 2008 12:37 pm
Location: FT.WORTH/DALLAS TEXAS
Contact:

Re: Identify Porsche 356 crank

#12 Post by Al Zim »

Sometime late in 1961 the Super engines received a crank that was CROSS DRILLED in the rod bearings. These engines numbers were preceded with an engine number that started with ZERO (0) I would assume that there were a great deal of cranks laying around the shop and these were used on the Normal engines. S-90 cranks had a 55MM #1 Main Bearing they were probably hardened which precluded and additional modifications. Zim
www.allzim.com 
356 Parts and Services
www.facebook.com/ZimsAuto/
www.instagram.com/zims_autotechnik/

User avatar
Tom Markussen
356 Fan
Posts: 88
Joined: Mon May 12, 2008 11:43 am
Location: Denmark, Europe

Re: Identify Porsche 356 crank

#13 Post by Tom Markussen »

Hello Zim. Thanks for the reply. I now managed to fully disassemble the crank and measure it. To my surprise it seems to be completely at production tolerances. Amazing! Pls see image.

I have indicated the cross drillings with green. Did all 356 cranks not have these cross drillings? Any idea from what year the crank is from?

I suppose the "910272" is the internal Alfing ID number. But what is the "34493 P"?

Anyone?
Attachments
IMG_7990.jpeg
Tom Markussen
1958 Porsche 356A Speedster T2 #83967
1958 Porsche 356A Coupe T2 #104598
1960 Austin Healey Sprite MK1 Frogeye #AN5/43259
1955 Alfa Romeo Giulietta Sprint #349

User avatar
Harlan Halsey
356 Fan
Posts: 2339
Joined: Fri Mar 02, 2012 2:05 pm
Location: No Cal SF Peninsula

Re: Identify Porsche 356 crank

#14 Post by Harlan Halsey »

Tom Markussen wrote: Thu Sep 22, 2022 2:42 am Hello Zim. Thanks for the reply. I now managed to fully disassemble the crank and measure it. To my surprise it seems to be completely at production tolerances. Amazing! Pls see image.
Not at all "amazing." Properly maintained 356s in normal use rarely show crankshaft journal wear at teardown. That is the reason that the current hype pushing adding full flow oil filtering to the 356 engine is silly.

User avatar
Tom Markussen
356 Fan
Posts: 88
Joined: Mon May 12, 2008 11:43 am
Location: Denmark, Europe

Re: Identify Porsche 356 crank

#15 Post by Tom Markussen »

Harlan: Thought I was lucky. But "built to last" I guess. :)
Tom Markussen
1958 Porsche 356A Speedster T2 #83967
1958 Porsche 356A Coupe T2 #104598
1960 Austin Healey Sprite MK1 Frogeye #AN5/43259
1955 Alfa Romeo Giulietta Sprint #349

Post Reply