Morris C8 Crankshaft specs.

[Richard Farrant]

Originally Posted by Mike Kelly

Getting back to the crankshaft size. Most crankshaft journals should be a rounded off figure eg 2" or 3" or whatever . Using a simple micrometer , it is a easy job to work out the size of the journals ? Mike

Hi Mike,
I rebuild a lot of vintage engines, and must say that crank journal size at Standard do not commonly appear as "rounded off" measurements. I have the 1945 Morris Commercial C8 workshop manual and no where in it can I see crankshaft dimensions, although it does list the two undersizes available.
I suggest anyone removing bearing shells to carefully check the numbering on the back of the shell to determine what undersize it may be (or even STD).

When measuring crank journals always check for ovality too, when determining if they are worn.

[Mike K]

Originally Posted by Richard Farrant

Hi Mike,
I rebuild a lot of vintage engines, and must say that crank journal size at Standard do not commonly appear as "rounded off" measurements. I have the 1945 Morris Commercial C8 workshop manual and no where in it can I see crankshaft dimensions, although it does list the two undersizes available.
I suggest anyone removing bearing shells to carefully check the numbering on the back of the shell to determine what undersize it may be (or even STD).

When measuring crank journals always check for ovality too, when determining if they are worn.

Yes I should have written 'to the nearest 1/16" or similar' ! The big end journal on my Indian Lister is 3" diam. I think my series 1 Land Rover has 2" big end journals but that's a guess?

[T Creighton]

Mike and Richard.
I have two crankshafts at the engine shop tagged red and yellow
Red measures 2.110" to 2.114" Yellow measures 2.112" to 123"
My book (probably the same as Richard's) says -015" and -030 shells are available.
Jeff the reconditioner thinks the two shafts have been ground but????
He needs to grind the best one down another 0.010"
I have a rusted block here that still had the crankshaft installed. It has a reconditioning brass tag that states Pistons +0.020" Big ends -0.015 Mains -0.015
The tag says B&W was the workshop and the date Feb 1945
We still don't know what the original size should be which was my original query.
Who is good with the math?
Terry

[T Creighton]

The shells on the rusted engine block have the following:
Rear: service C9175-G-25FL
Centre: service C25-G-5EL
Front: service C24-G-5FL
Does this mean anything to anyone? I assume the G indicates the repair size which according to the tag is -0.015.

Ian Cox (Cox and Turner UK) says the last 4 engines they have done the mains were white metaled and line bored to suit the freshly ground shaft due to the scarcity of repair size shells.

Terry

[Mike K]

Standard size would probably be 2.125" which is 2 and 1/8"

[Lynn Eades]

Terry, Jeff should be able to guess closely what the original size was,judging from the type and size of shells removed?
I have some details here in front of me for bi metal steel backed bearings:
Babbit on a steel back is usually 0.004"thick.
Copper/lead is overlaid ) 0.008" to 0.020" thick
Tin/ Aluminium is the same, 0.008 to 0.020" thick.
(I guess a known steel backing thickness is needed)
Tri metal bearings are usually the same as the last two with the addition of 0.001" of babbit
Do you have a source of shells?. I guess you ask them to give you a shell tunnel size (measure them) and if they sound right, have Jeff grind to suit after you have them in hand?

[Richard Farrant]

Thinking outside of the box, the early Nuffield tractors had a Petrol/TVO version of the engine in the C8. Obviously this should be checked out just in case there are any slight differences in crank mains and pins, but have a look at this download and check the Spec on the petrol engine crank on page marked at bottom 'General Data 9'.

http://vieux.tracteurs.free.fr/pdf/nuffield_1.pdf

regards, Richard

[T Creighton]

Thanks for that link Richard. Most helpful.

It is a pity the Morris book did not have all those engine particulars. Then it would be so easy to compare.
Some of those Nuffield numbers look familiar though.
I have looked at "Sparex" Nuffield pistons but they do not seem to be flat tops like the Morris truck.
I will go and do some measuring.

Kind regards, Terry

[Richard Farrant]

Originally Posted by T Creighton

Thanks for that link Richard. Most helpful.

It is a pity the Morris book did not have all those engine particulars. Then it would be so easy to compare.
Some of those Nuffield numbers look familiar though.
I have looked at "Sparex" Nuffield pistons but they do not seem to be flat tops like the Morris truck.
I will go and do some measuring.

Kind regards, Terry

Hi Terry,
If the Sparex pistons are concave on top, then they are low compression ones for the Vapourising oil Nuffield.

With that link I sent, there are more, if you want to see more on the Morris engine, substitute the 1 in the web address, for 2, and 3.

I cannot understand why the crank details are not in that C8 book, all similar army manuals for Austin, Bedford, etc. include this.

regards, Richard