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+--- Thread: head bolt torque and block (/showthread.php?tid=7900)
RE: head bolt torque and block - Ruairidh Dunford - 11-08-2022
Oooh matron!
RE: head bolt torque and block - Charles P - 11-08-2022
Whilst at VSCC Prescott last weekend the scrutineer, who I do know, pointed to a castellated half shaft nut, luxuriating in its nakedness without a split pin and said "They should be pinned".
I pointed out that in the 25 years I've been driving the car they've never had split pins but are just very, very, very tight (murder tight perhaps). They do not get loose but I do periodically check and after a few months they never tighten any further.
Charles
RE: head bolt torque and block - Alan - 12-08-2022
This goes back to Ruairidh’s point. There is no advantage to a split pinned joint in that application. If the nut isn’t tight the pin won’t stop the joint failing, but if it is tight it won’t come undone. I had a run in with a scrutineer many years ago who insisted that A7s had to have penny washers under the wheel nuts. The fact that my car had West London wheel centres with conical seats made no difference. When I produced my FIMechE card and said I would protest his decision he backed down. None of this changes the fact that if your head gasket won’t seal at 18ftlbs there is something wrong.
RE: head bolt torque and block - Denis Sweeney - 12-08-2022
Do not put myself in the orgasm brigade Rhauiridh.
Knowledge gained through experience is a wonderful thing to have, sadly having come to A7’s late in life it is something I do not possess so can only gain that through my own successes and mistakes or by the written word.
My Ruby head was torqued to that given in the Companion in the absence of anything better.
RE: head bolt torque and block - Ruairidh Dunford - 12-08-2022
You are a lucky man Denis, others will not be.
RE: head bolt torque and block - Denis Sweeney - 12-08-2022
Well that fairly scares the pants off me, but it also raises more questions, like the validity of the article in the Companion.
Was this an authentic Austin directive to dealers printed in the Austin Service Journal January 1939 as the article portrays, or a figment of someone’s imagination.
Does anyone have copy of such original directives??
If it is an original directive it then raises the question as to why the torque stated was correct/worked back then in 1939 and not now?? Quality of materials??
This is not being argumentative just curious
RE: head bolt torque and block - Charles P - 12-08-2022
Useful sense check here
https://www.classicfasteners.com.au/content/BS_Torque_Settings.pdf
Most important fasteners will be R grade, the old "55 ton" steel.
Maybe the Austin Service Journal was an early pilot of the internet, which also has an ability to cause havoc by spreading some duff information?
Charles
RE: head bolt torque and block - Ruairidh Dunford - 12-08-2022
I have a handbook from the 1939 V12 Lagonda my great grandfather drove.
Inside the cover is an erratum page, it reads:
“Firing order should read…”
The Companion is a collection of interesting articles, some of which have errors in them, just like any publication. When researching anything, I try to read from a number of sources and then ask questions, before deciding what to do for the best.
I stand by the point that simply because something is in print, does not make it correct - this includes my post, of course.
RE: head bolt torque and block - Denis Sweeney - 12-08-2022
Point taken but would like to know if the said “directive” was genuine, does anyone have access to these?
RE: head bolt torque and block - Ruairidh Dunford - 12-08-2022
You used to be able to buy full reprints from the Seven Workshop, but if the error was made at source, it will still be in there.
Charles’ grid above is a good sense check, as he suggests.