Crankshafts

[GG]

Anyone have a Lambda crankshaft lying around?

Its for an article on how Lancia balanced their V4 crankshafts. Much analysis has been completed, but want to confirm the Lambda portion.

All that is needed are a few simple measurements from different Lambda crankshafts, which will be compared with the drawings. If you have a crankshaft and a ruler handy, I would love to hear from you. Only three simple measurements and the number of the shaft.

Original or reground crankshafts are both useful. Results will be shared once completed.

Thanks!

Geoff

[donw]

 Geaff

I have one in my stores what measurements do you want? It may take me a while to get it.

Don

[GG]

Looking for the length of the center bearing, adjacent web thickness and the overall width of the web….
Should be:
length of center bearing - 32-33mm or 37-38mm
web thickness - 12.5mm or 15mm
overall web width  - 109 or 111mm. (not easy to measure, and less important.
and the crankshaft or engine number…

Thanks!
Geoff

[Mikenoangelo]

Geoff have you includes the Augusta in your work?
Mike

[GG]

Yes, the Augusta (and all the other V4s) are addressed. The work was started some years back, and went on hold for a while (embarrassingly so...). But all the crankshafts were studied in detail. Hopefully something can be released reasonably soon.

It turns out there are (at least) 5 different crankshafts used for the Lambda, and they are not easy to figure out. It would be good to check what is on the drawings vs. what was actually made - thus the request for Lambda measurements.

The Augusta part of the story is pretty clear - but if you have an original connecting rod, it would be good to get its weight - if you don't mind. It turns out that the connecting rod weights, the angles, and some other dimensions are all important. To be answered soon! Please have patience,  its full of detail, but don't want to make mistakes. Thank you.

[Mikenoangelo]

Oh - I've just put the Augusta rods back in! I did weigh the piston and rod together including the bolts (822gms) but did not separate them as the circlip retaining the gudgeon pin is very hard to remove without damage.

Karl mentions a weight of 460 gms for the rod and 430 for the piston in Morris Parry's Augusta Newsletter so mine seems a bit lighter, but whether rod or piston I can't say. No doubt he will comment! My piston is the same make as Karl's and I see John Milham give 436 as the weight of his piston so perhaps my rods are lighter or my kitchen scales need recalibrating!

I look forward to reading your treatise!

Mike

[Kari]

I am sorry for distracting from Lambda matters. As I am looking for a replacement con-rod for my spare (Augusta) engine, I came across several rods. One of them seems to be very close to original. The white metal is cast directly to the big-end as from factory. However the inside diameter is 41,70 mm, therefore it's undersize. The width is 25,0 mm which is correct. The mass is 399 gr. which is very close to my other con-rods. Small end is 106 gr.

The masses reported in Morris Parry's Newsletter were taken many years ago with another scale and as Mike points out, some scales could be not as accurate as desired.

I hope that helps  Karl

[Dikappa]

I have cranckshafts idle here, will try to measure it tomorrow Geoff!
Want one to make a designer lamp?

[Parisien]

Want one to make a designer lamp?

Koen, I will be sending you a bar of soap to wash your mouth out with, heresy!!! 

P

[GG]

miniatures? Lambda and Appia.

[Mikenoangelo]

Just need to find a 3d printer which will print EN40B nitriding steel.

Mike

[Dikappa]

OK! Here are the results from the Belgian jury...I fear this will only add to the confusion...

As the web thickness is not the same for all webs I measured them from nose (front of engine) to tail (flywheel end)
I measured on the plain faces, not on the thrust bearing faces

In order from left to right on the first picture:
Crank 1:
   This crank has completely different webs as the other cranks, think it is very very early. (see second picture)
   center bearing width (not measured acurately) 32mm Web thickness: 13.5/13.5/14.6/14.6/14/13
   web width 113 crank number (center web) 36, engine number (frontal face of first web) 17

Crank 2
   This crank presents extra holes in the webs the others have not...see third picture
   center bearing width (not measured acurately) 32mm Web thickness: 14/13.5/14/14/14/14
   web width 109 crank number (center web) 603, engine number (frontal face of first web) 3891

Crank 3:
 center bearing width (not measured acurately) 37mm Web thickness: 14/14/11.7/11.7/14/14
   web width 111.3 crank number (center web) F653H, engine number (frontal face of first web) none marked there

Crank 4:
 center bearing width (not measured acurately) 37mm Web thickness: 14.2/14/11.4/11.4/14/14
   web width 109 crank number (center web) 226, engine number (frontal face of first web) 6354

Crank 5:
 center bearing width (not measured acurately) 37mm Web thickness: 15/16/12/12/16/15
   web width 108 crank number (center web) 202, engine number (frontal face of first web) 13138

Crank 6:
 center bearing width (not measured acurately) 37mm Web thickness: 14/14.2/11.5/11.9/14/14
   web width 109.4 crank number (center web) F570, engine number (frontal face of first web) 6679


I hope you still can get some sleep now Geoff, if you need more detail, accurate measurements, let me know!

[GG]

Koen -

Thanks a million for this. Superb!
These all make sense - and fall into place quite nicely. There is only one odd one - the unnumbered.
Lets wait for a few more samples, and then results will be shared...

[GG]

Several folks provided information, thanks for all the help, especially to Koen, who gets a gold star.

A summary of findings was promised. So here goes...A few things help sort this out:

- web heights - the very early crankshafts had shorter webs in the center, easy to note. See Koen's no. 1 above. These were soon replaced with full height webs.
- drilled crankpins - used early on, replaced with solid crankpins with 10-6A drawing, late s.5, 1925.
- the center bearing - originally 32mm, lengthened 5mm for s.7 and later; in order to maintain overall length, two adjacent webs were thinned (from 15mm to 12.5mm), easy to spot.

Web "width" in theory follows a logic (a bit wider for later crankshafts, adjusted for balancing), but there is some odd variation in the early shafts, as can be seen on the attached spreadsheet. For the moment, not a big issue.

For simplicity's sake, the attached diagram shows crankshafts separated into groups, offered here for convenience, to try and track the changes. They are:

I   original t.67 -per drawing 10-6, from 1922. Has the short webs, see Koen's first crankshaft. Drilled crankpins.

II    transitional period - still used on t.67, some with short center webs, others with full height webs. Drilled crankpins, but variation in web widths and balance. No drawing found.
 
III   used for late s.5 and s.6, from 1925 on - per drawing 10-6A of 1925, as it was first drawn. With  full height webs, solid crankpins, oil passages now diagonal drillings.  Short center main bearing. Also used as replacement for earlier engines, on diagram as IIIA.  

IV   for early s.7, to match the new forged connecting rods (the early forged rods) - per Drawing 10-6A with double circle revisions, with short center bearing. No examples have been found,  it may not have been made.

V   last version, from s.7 through s.9, also called 11-6 - per drawing 10-6A with single circle revisions - has longer center bearing to match s.7 and later blocks. Also two thinner center webs (12.5mm vs. 15mm). Very consistently made, most common.

If anyone has a crankshaft for groups I, II or IV, that remains of interest, as would any corrections to this. Hope this makes sense!

Geoff

(note: attachments updated 7.23.20)