Metric Dimensions in a TR

[Ian Vincent]

I have just been doing some measuring to determine the precise spacing of the cylinders in a 4 pot TR engine and was surprised to find that as near as makes no difference, they are at exactly 10cm spacing.  Would anyone out there know why a metric dimension would have been used back in the days when everything else would have been Imperial?

Rgds Ian

[iain]

Hi Ian

isn't  10cm = 4"as near as damn it ( 3.93701)?

Just a thought

Iain

[j-eichert]

Isn't the bore (83mm … 86mm … 87mm) metric as well?

 

Regards, Johannes

[MikeF]

I think I read somewhere that the engine is based on a 1930's French design...……..

 

Mike

[Z320]

Did the french invent the fast running combustion enigne  ??

But indeed there have been traditional some imperial dimensions on cars wourldwide, for example for hydraulik cylinders / seals and pipes / threads on pipes,

and also traditional some continental dimensions on cars wouldwide, for example threads on spark plugs (who invented this?), engine cylinder bore an stroke.

Ciao / Cheers, Marco

[Dic Doretti]

I have read somewhere the Ted Grinham, the Technical Director at Triumph copied the engine of the Citroen Traction Avant when designing a engine for the Vanguard, he ran a Citroen at the time. The Citroen engine has wet liners and the main components; camshaft, carbs, exhaust and distributor are in the same position as the TR engine. The MG T series engine has metric nuts and bolts because Morris bought tooling from Hotchkiss, a French company, very confusing but I only rounded off one big end bolt before realising.

                Cheers Richard 

[Ian Vincent]

Iain, Nope it's not 4", I was measuring to less than half a mm and 4" would be 10.16cm.  I wasn't nearly 2mm out.

I suspect that Mike / Richard probably have the right answer or somewhere near it.

Rgds Ian

[Motorsport Mickey]

"Too many people think the Vanguard engine was a copy of a Continental design, which is nonsense. The confusion is caused because the Fergueson tractor WAS built with Continental engines while the new Standard unit was still under development, but there is absolutely no other link between the two. Harry Webster recalls vividly that the engine which influenced it most of all was the famous Citroen wet liner traction avant design of the  1930s, and points out acidly that the only connection with Continental was that both units were eventually asked to tackle the same job on the tractor".

Taken from Triumph Cars...The complete 75-year history by Richard Langworth and Graham Robson (tips hat).

The motor taxation system run by the British government revolved around engine size, a 1 1/2 litre engine or 2.0 litre engine etc was taxed differently and of course in competition the cars were rated accordingly to the engine capacity measured in cc. So it makes sense for internal dimensions where it alters cc to be quoted in metric units, ie bore and stroke, the metric system making the conversion between a volume and linear dimension corelated and easier to juggle.

The rest of the engine can be in Black Russian (sorry that's a cod piece) or any other unit of measurement. As a time served engineer from the 1970s and having taken the sage advice of Fishermens Friend sucking, pipe smoking older engineers " make sure you buy all your micrometres, verniers and other toolmaking tools in metric young Mick" (they were the days) and then having a drawing office still turn out all the blueprints in Imperial it gave you a crash course in conversion tables, mental gymnastics as you convert them and pre calculated crib sheets which still stands me in good stead today. However when measurements get tight and you start splitting tenths of one thousandth of an inch (or 25.4 etc mm) the metric system gets a little unwieldy with too many units and in my opinion the Imperial system wins out. 

Mick Richards

Edited February 28, 2019 by Motorsport Mickey

[Ian Vincent]

Mick,

You should have tried doing estimates based upon schedules of materials where the quantities were in feet and inches and your currency was in pounds shillings and pence!

Rgds Ian

[stuart]

1 hour ago, Ian Vincent said:

Mick,

You should have tried doing estimates based upon schedules of materials where the quantities were in feet and inches and your currency was in pounds shillings and pence!

Rgds Ian

Yep used to have to do that in my first job!

Stuart.

[Ian Vincent]

34 minutes ago, stuart said:

Yep used to have to do that in my first job!

Stuart.

And that would have been before the calculator was invented.

Ian

[Motorsport Mickey]

Ready Reckoner is good enough for anybody.

Mick Richards

[stuart]

1 hour ago, Ian Vincent said:

And that would have been before the calculator was invented.

Ian

Yep but I could never get on with a slide rule much to my Dads exasperation.

Stuart.

[ianc]

In the 1940s/1950s, my father, a Master Butcher, had scales which measured solely in pounds and ounces - not the later type which computed the cost for one. My father would weigh the meat and then compute the cost in his head whilst tying the bundle and conversing with the customer, often advising on how to cook the meat.

Always impressed me for, as Ian Vincent has mentioned, the currency was pounds, shillings and pence - a challenging computation when weighing in pounds and ounces.

Use of a slide rule (still have mine) made one think hard about placing of the decimal point, especially when calculating square roots!  Also have my Log Tables (includes trigonometry tables), with the right edge of each page cut and marked so as to speed look-up.

In the shop, the cash register didn't tell one the amount of change required, one counted change upwards into the customer's hand.  If given a ten bob note for meat costing 8/4 (eight shillings and fourpence), one would hand over a couple of pennies, saying 8/6, a tanner (9 bob), and a shilling (ten bob).

Ian Cornish

Edited March 1, 2019 by ianc

[Ian Vincent]

You wouldn't buy much meat with 50p nowadays!

Rgds Ian

[ianc]

True, Ian!  Occasionally, I used to assist Janet, the cashier in my father's shop, and I recall the first time a customer tendered a five pound note.  This was a white sheet, folded more than once because it was so large, and looked splendid when laid flat.  Very few of those appeared back then.

Ian Cornish

[Ian Vincent]

My Father in Law was a butcher, he specialised in the catering trade.  He had his own yard and a stall at Smithfield along with a shop in Camberwell.  When my wife and I were first married we never had to buy meat, we just had to make a once a month trip to his shop to stock up.  Then we went to Australia to live and by the time we cam back he had sold the business and retired.

Because they only ever had the best at home, my wife won't touch meat that has too much fat on it - totally spoilt.

Rgds Ian