MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - Head bolt sequence

has anyone got a photo of the head bold tightening sequence for a 1953 1250cc YB?

Regards
Vaughan
V Rich

Hi Vaughan,

This is from the TC WSM, but it would be the same for all standard XPAG motors. The sequence for Laystall aluminium heads is different. They have the sequence numbers cast into the alloy.

Cheers from South Australia,
Bob Schapel

Bob Schapel

Bob -- slight thread drift warning--
The XPAG headstud sequence has always intrigued me
starting in the middle, going out to the ends then coming back, whereas MGB for example and most other cast heads start in the middle and work outwards-
I think the secret is to not be too greedy and just work up in small steps until full tension spec is reached.
You mentioned the Laystall aluminium head being different--same with the Derrington B series head, it also has a unique tension pattern and a lower tension spec. but these later MSX alloy heads for B's they use the std. sequence but with reduced tension---bit weird when they're sort of a copy of the Derrington unit-

willy
William Revit

Thanks All for the info.
Regards
Vaughan
V Rich

Like Willy I have always wondered why there are different tightening sequences for different heads. I get it that it is important to not stress the head when torquing it up, not that I have ever heard of anyone doing any damage by doing it wrongly (perhaps they are to embarrassed to admit it). I suppose that if you use the book method you can blame the factory rather than yourself if it doesn't work out - good luck with blaming what is now a supermarket though. I can, just about, understand that there are, maybe, different regimes necessary for different materials, say; steel and alloy, but find it difficult to accept that not adhering to a prescribed method is to be flirting with trouble. The older nethod was to torque down in one go and under these circumstances it may be prudent to stick to the recommended method but I find it difficult to accept that starting from the middle and working out is better than working from the outside to in. Surely a mixture of the two must always be better: start at either, miss every second stud and come back via the others perhaps. The best method must surely be to combine this with starting at a lower setting and increasing as you go around your chosen sequence two or three times. Just my thoughts.
Ian
ian thomson

Y Series Manual on page C14, shows illustration No C-13 with the same sequence as depicted by Bob.
cheers
Stuart
Stuart Duncan

This thread was discussed between 28/01/2022 and 29/01/2022

MG MG Y Type index

This thread is from the archives. Join the live MG MG Y Type BBS now