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MG TD TF 1500 - XPAG Whitworth vs Metric nuts

I am about to start the rebuilding of my second engine which has been apart for over 40 years. I have some of the original bolts, studs and nuts, which not sure whether to use them. I already have Tom's high spec parts, plus Len's cam and rollers.

My question is should I use metric or whitworth bolts and nuts. Wetric can be purchased locally, but need to get Whitworth from either FTFU or Mad Metric

Stuart
Stuart Duncan

Use French Standard Metric with Whitworth heads (From FTFU or Mad Metric for new studs and reuse as many as you can of the bolts (& nuts) that are OK Get a 6 X 1mm, 8 X 1 mm tap & die to clean up threads.
Then a set of Whitworth/ BSF Wrenches does all!
Don Harmer

The use of metric nuts and bolts to me shows a turkey rebuilder, since all the correct hardware is readily available. Don't spoil the ship for a ha'pworth of tar.

To identify what you have, look in the archives for the VERY useful list of engine fasteners, their sizes, threads, etc (Dave DuBois, I believe).

My opinion.

Tom Lange
MGT Repair
t lange

Stuart - E-mail me at SUfuelpumps@donobi.net and I'll send you a complete listing of the fasteners used on the XPAG engines (obsolete French standard metric with Whitworth heads and a listing of the fasteners used in the body (British Standard Fine, which also use Whitworth heads). Cheers - Dave
DW DuBois

Dave,

Along with your list(s) can you offer a few good suppliers? Other than our West Coast usual.

Thanks, Dan
Daniel Nordstrom

Hi all

I have downloaded Gordon Clark's list of engine fasteners from Bud's website and converted it into a spreadsheet.

When I was considering this topic, I thought your replies would be along the lines you have stated - USE WHITWORTH headed bolts and nuts.

Don, I already have the required 6mm, 8mm and 10mm taps and dies plus all the Whitworth taps & dies - all the way up to 1" (the larger taps & dies were my Grand fathers - he was given them (as a set in a wooden box) after his WWI service to start his occupation of Fitter and Turner)

Stuart
Stuart Duncan

Dan - For the Mad Metric fasteners, you will probably go to From The Frame Up at: http://www.fromtheframeup.com/ or to Roger Furneaux at: http://www.mg-cars.org.uk/imgytr/pdf/madmetrics.pdf in England. For the British Standard Fine fasteners you can go to British Tools and Fasteners at: http://www.britishfasteners.com/ Cheers - Dave
DW DuBois

Thanks Dave
Daniel Nordstrom

Stuart - Be very careful with the taps and dies that you have. The metric fasteners in the engine are NOT the standard ISO metric that are found at your local hardware store (or in new cars of today). The metric fasteners in the XPAG/XPEG engines are an obsolete French standard metric, which is referred to today as a fine metric and is not readily available in stores today. Additionally, the ones used in the XPAG/XPEG engines have a Whitworth head and are often referred to as Nuffield's Mad Metric.

"plus all the Whitworth taps & dies"
Do not use those on the fasteners (or holes) in the T series cars. Whitworth fasteners are a course thread, whereas all the fasteners used on the T series cars use British Standard Fine fasteners (they do have Whitworth heads on them, but one size smaller than Whitworth fasteners - i.e. a 1/4 BSF fastener has a 3/16 Whitworth spanner, etc.). This is all rather confusing to someone new to MGs, but it does fall into place as they work with the system. Cheers - Dave

DW DuBois

Pardon me for jumping in here Dave but I'm a bit confused.

Are you saying that the fasteners all have Whitworth heads but some have fine (French) metric threads and others are BSF?

Thanks, John
J Penny

You've got it! Note that the metric threaded bolts are exclusively in the engine and the BSF are in the rest of the car.

Lots of fun when someone has disassembled a car for you and thrown all the bolts in one bucket!
David Littlefield

Further footnotes: Many of the replacement fine metric engine bolts use regular metric wrenches, not whitworth. Lastly the late TDs and TF's used Unified (?) threads in the rear end and wheel studs. George
George Butz

George - Good point, I forgot about little detail. That change was made somewhere in the 1952 TDs and there was not fussing around with keeping the head and nut size to the Whitworth spanners -just another item added to the confusion factor of fasteners used in the T series cars.

John - If I remember correctly, the Mad Metric fasteners are also used in the gearbox. Cheers - Dave
DW DuBois

Dave -

You are correct about the gearbox using Mad Metric nuts and bolts. EXCEPT for the bolts on the outside-right that hold the hanger for the exhaust pipe ... 1/4 BSF, I believe. Kinda makes your head spin.

In my short experience I have had better results and caused less damage by using a shop-made thread chaser to clean up threads on cases, nuts, and bolts instead a tap and die. My tap or die sometimes creates a second set of threads if I'm not careful about running it precisely 90-deg to the object.

To make the chasers, I used a thin cutoff wheel on my angle grinder to cut a gash perpendular to the threads on a 3-inch 8X1 hardened metric bolt from the hardware store. A small triangular file made the gash in a nut.

Lonnie
TF7211
LM Cook

Lonnie - "You are correct about the gearbox using Mad Metric nuts and bolts. EXCEPT for the bolts on the outside-right that hold the hanger for the exhaust pipe ... 1/4 BSF, I believe. Kinda makes your head spin"

You are right, both on the thread type and the spinning head. I had forgotten another set of 1/4 BSF threads in the engine/transmission pair. The sump has two bosses (one on either side) with 2 holes in each boss holes tapped for 1/4 BSF. They are for the anchor for the clutch cable on the early TDs and they just stayed there for the remainder of production.

You are also right about using homemade thread chasers instead of a tap to clean out the threads. I have used taps that I had abrasive blasted to dull the threads on them for some of the threads. It is particularly important not to use a new tap to chase the threads in any of the aluminum pieces (i.e. timing chain cover and sump). Cheers - Dave
DW DuBois

A correction as to when the rear axle and wheel lugs were changed from BSF to UNF (SAE) was 10 Dec. 1951 - earlier than I thought. Cheers - Dave
DW DuBois

Great articles on threads, dies/taps (and which ones to use and when!) and how and when to clean them... and why.
Printed off the six pages and keeping them in my toolbox. Bloody pricey though buying them, because being heavy, the postage is extremely high to Canada.
Cheers...Barry
0:0:1^96:0:3^111:0:6^81:0:3^76:0:3^62:0:5^13:0:1

Stuart,
Give Industrial Fasteners of Mortdale a call for they may be able to help you, in part. Possibly Whitworth and BSF but doubt French Metric. Also have a talk to Peter Fogarty he may be able to direct you.
John...Sydney
John Walton

Reactivated to clarify bolt head sizes

George & Dave, am I right in thinking from your comments, that from about 1952, Morris used metric heads in lieu of Whitworth heads on the XPAG French metric threaded bolts. Was this on some or all bolts.

1952 is when I believe Morris Motors Ltd became part of British Motors Corporation (BMC).

A check of Roger Furneaux's "Made Metrics" bolt list shows that Roger supplies some bolts as metric headed (13mm which a 5/16 BSF socket will fit) as they are cheaper due to being mass produced, whilst FTFU only has Whitworth headed bolts.

FTFU's latest Engine Hardware Catalog is dated 27 Aug 2015.

As I am in Sydney for a few week, I will be checking local suppliers as per John's post.

cheers Stuart

ps. John expect a phone call.
Stuart Duncan

Not to confuse the issue, but my understanding is that the obsolete French metric threads are in fact different from modern metric threads, with different thread angles or pitches.
If this is true, when buying any modern replacement bolt or nut that claims to be correct (Whitworth) are we in fact buying a modern metric thread with a Whitworth head? In which case, what's the point? Why not just buy modern metric, if the thread's going to be the same in either case?
If the threads are all modern, buying a Whitworth head is purely for "looks" at this point.
I can see an advantage to using the original French metric hreads if you can get them, for better fit.

Geoffrey M Baker

The heads were always all Whitworth, just the threads metric- I think. George
George Butz

Can anyone point us to an actual definition for the obsolete French Metric? I can't seem to find one. I've been told it differs from modern fine metric in some ways, I'm curious as to exactly what the difference is.
Geoffrey M Baker

Geoffrey - I am sending you a chart, Standard Threads. This chart was originally compiled by Don Harmer, who very recently passed away. The original French Standard Metric, is now considered fine metric and as far as I know, is the same thread count and form. Cheers - Dave

DW DuBois

Geoffrey - Looking at the chart, I see that there is a difference in the thread count between the French Standard Metric and today's fine metric, except for the thread count on the 8mm bolts (don't know about the thread form). It looks like if you want the original bolts for the engine, you will have to go through Mad Metrics http://www.mg-cars.org.uk/imgytr/pdf/madmetrics.pdf Cheers - Dave
DW DuBois

If you buy engine bolts off Moss or B&G you will also get the correct metric fine thread for XPAG engines. Often the heads on these bolts are not EXACTLY the correct BSW size but a close metric size that works with BSW spanners. For most people thats close enough.
Dave H
Dave Hill

This thread was discussed between 07/08/2015 and 02/09/2015

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