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MG TD TF 1500 - XPEG block 'W-in-Diamond' logo

By request, Roger Wilson’s comments regarding the ‘W-in-Diamond’ logo on XPEG blocks, from a longer article written by him and published in the MG Car Club T Register magazine ‘TTT’ in 2004, and posted to this forum in 2005 with his consent.

‘Quite simple really. Originally these blocks had M, MG, or W cast on them according to the vehicle into which they were to be fitted. By June 1952, Morris Engines were only making the 1250cc version, and undertook substantial changes to the block and head to improve the cooling. This was when the block to head water passages changed from oval to round, plus other changes to the head. However, also by June 1952, the main use of these engines was in the Wolseley 4/44, so Morris Engines probably decided they didn't want to produce special castings and batches of engines that were unique for MG. Thus they only continued to use the W casting boxes for the blocks, although they obviously changed the internal cores to incorporate the modifications. New casting numbers were introduced, and they are visible on the block and head. Later on, when the bore walls were moved out and other water passages moved to produce the XPEG block and head, Morris Engines probably only modified the cores of one or two casting boxes (of head and block), although they did change the casting numbers. The block became AEF117, but on the head, although the old number was (badly) filled in, it seems they forgot to engrave the new number; thus after casting, and possibly some more cleaning up, someone stamps on AEF118.”
’As the XPEG engine was only used in the MG, you could ask why they didn't do the necessary block changes to some of the old MG casting boxes (for blocks) that they had lying around since June 1952. That I don't know; it is possible that they (Morris) were thinking of putting the 1466cc engine into the Wolseley 4/44 - who knows! It is more likely that they had already "changed" the MG boxes into W boxes.
- XPAG casting numbers;
Oval water hole, head 22952
block 24142, then 24146, then 24445
Round water hole, head 168422
block 168421

- XPEG casting numbers; head AEF118 (stamped on)
block AEF117
Steve Gee

Hi Steve,

The only incorrect information here is in relation to the TF1250,round water hole head TF1250s had 168425,with the first five(5)numbers cast in and with the number 5
stamped in. (Wolseley 4/44 heads had the cast in head numbers 168422.)

Roger and I discussed this point a year or two ago with him agreeing with me re the corrected TF1250 head designate.

Cheers
Rob Grantham
TF3719("Aramis"),TF9177("Athos").
Rob Grantham

Hi there Rob - I agree with your note. Once the TF was introduced then Morris Engines Division would need to finish many more (round hole) cylinder heads with large valve chokes, as well as with the original smaller size. I don't think they actually introduced a new casting as they would have changed the casting number in the casting boxes, and this would then not need a grinding/stamping operation. The different choke sizes would be produced when the chokes were bored to size, and I think that when the machinist bored out the chokes to the larger size, he probably ground off the last 2 of the casting number and then stamped on a 5. It seems a bit labour intensive, but it is obviously what they did. The new number would help identification during later assembly to ensure the correct valves were fitted, as well as when the engines were assembled - and possibly when the assembled heads or engines were kept in a store-room.
I realise this point is a not clear in my original article/booklet, although I do mention it in appendix 2, so I will clarify it.
Roger Wilson
R A WILSON

I'm strictly guessing, but I am still convinced that the ONLY identification of a real XPEG, is thw W in the diamond.

The engines your are discussing were in the 1951 to 1952 period, and a lot can happen in three years.

Gord Clark
Rockburn, Qué.
Gordon A Clark

Check out this old link:
http://www.british-cars.net/mgtd-mgtf1500-bbs/stamping-on-a-xpag-block-2009111715430723616.htm I'm positive the late 53 TD with XPAG 1250 in town has the W in the diamond. For years we assumed it was a Wolseley block, until the info that the MG was dropped, and both the MG and Wolseley units used the same casting. So just because it has a W in the diamond alone doesn't mean an XPEG block. George
George Butz

Hi Roger,

Thankyou for your as per usual professional
knowledge on MG matters.Appreciated.

Cheers
Rob Grsntham
TF3719("Aramis"),TF9177("Athos").
Rob Grantham

(remember.... MOGWOG..... Morris/Wolseley/MG...)
gblawson(gordon- TD27667)

This thread was discussed between 29/08/2011 and 30/08/2011

MG TD TF 1500 index

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