Double Nut Method to Tighten Head Studs

(Jochen Glöckner) #21

Your German is wonderful, Robert! Maybe we should switch to “Wellendichtring”, “Kreuzgelenkschmiernippel”, “Abtriebsflansch” and “Drehmomentschlüsseleinstellring”. I bet you know “Donaudampfschiffahrtskapitänspatent” already:-)

Enjoy the weekend


75 XJ6L 4.2 auto (UK spec)

(Paul Wigton) #22

You do… and you’ll clean it up!

(tony) #23

there is a method of measuring, which I quoted

Hammill describes this a being a necessary check to be done

(Frank Andersen) #24

Likely not directly, Lou - the danger is that insufficient seating may cause the acorn nuts to bottom. Which will not give proper torque, and friction, against the head and in the threads (upper and lower) to lock the parts together - preventing unthreading.

Arguably, the thermal cycling during engine operation, and the constant variation in stud tension with the engine running, may play a part. However, while retorquing was a scheduled item on early engines, and still is after a ‘head off’ operation after a couple of thousand miles of running - it is not to counter stud unthreading…

…which is unusual - and signifies a loss of torque. Once loosened; varying loads on nuts and bolts, thermal or mechanical - may cause further unthreading…

It’s important, when using double nut torqueing on ‘free’ studs, that the torque does not twist the studs. They are meant to take tension only - and twisting may cause weakening of the studs.

In short; firmly seating the studs is good enough…

xj6 85 Sov Europe (UK/NZ)

(tony) #25

In the archives somewhere, there is a good description of the correct procedures by a fellow that used to contribute a lot Paul Saltwick, he had a lot of experience and was very well regarded with Jaguar engines

as part of his description he states that the studs only need to be “finger tight”
(which I was always a bit curious how to stop the studs twisting out when a stud nut is undone)

the description included scrupulous cleaning and use of relevant taps

(Robert Wilkinson) #26

Okay, Jochen. I get the message and I will stick to Englisch. :slight_smile:

Came closest with the last word BTW, but I had to look up Dampshiff (very cool!) and I can’t figure out patent–maybe a manifest?

(Frank Andersen) #27

It’s when the studs refuse to twist that real problems arises, Tony…:slight_smile:

There is nothing to be done if the studs unscrews with the nut - and nothing to be done during assembly to prevent it. With age the studs usually immovably corrodes to the head…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

(Jochen Glöckner) #28

Don’t worry Robert, no irony under way!

“Donaudampfschiffahrtskapitänspatent” is just a very popular example of our language’s aptitude to construction: you can simply put words together and the first words will explain or narrow down the meaning of the last one. In this case it is the license (Patent) to be a captain in the course of steam boat traffic on river Danube.

If you’re interested in a “German addict anonymous corner” - let me know: Carl and Pete might be interested as well:-)

Good luck


75 XJ6L 4.2 auto (UK spec)

(Carl Hutchins, Jr. ) #29

Durn, I missed it! But, my understanding of German
remains in it’s infancy at best, more likely retrogressing.

Steam ship, of course!!!

Never exposed to the boats on the Danube. But, the ones on the Rhine fascinated me. Not steamers, I believe…

And are not ships and boats different in German? Size, here.

My son’s restored 60’s era Chriscraft 25’ cabin cruiser is a boat, not a ship. Whereas cargo ships and cruise ships enter our bay regularly.
Not to mention the oil tankers…


(Robert Wilkinson) #30

There are popular cruises now in which the same boat covers both rivers, Carl (with the Main in between). Not sure how it works, but they have finally completed a canal with various locks, etc. that allows a ship or boat to move from the Main to the Danube and vice versa. It’s in Bavaria. I have a few friends who have taken the cruise–they liked it. Of course you can stick to one river or the other if you prefer, for less money.

I think the German and USA definitions of ships and boats are the same. Remember the movie “Das Boot?” I learned then that a submarine is a boat, not a ship.

(Rob Reilly) #31

This quote is also found in the 1955 submarine novel Run Silent Run Deep written by an American submariner.
One I remember from my high school German class was Burgomeistersblindarmentzu"ndung.

(Jochen Glöckner) #32

Indeed, for around 2k EUR you’re in for 11 days of river-cruise from Rhine over Main and Danube, … I think we’re slightly off-topic now though:-)



75 XJ6L 4.2 auto (UK spec)

(Robin O'Connor) #33

I was discussing the thread drift with SWMBO today on the way home from visiting the Lord of the Rings movie set in middle earth (AKA Hobbiton near Matamata) and yes the river cruise is a brilliant way to see the various countries along the way, and you get to unpack your suitcases :slight_smile:

(PeterCrespin) #34

Wenn schon denn schon.

Talking of rivers…

“Ich weis nicht was soll es bedeuten
Das ich zo traurig bin.
Ein Maedchen aus uralten Zeiten
Das komt mir nicht aus dem Sinn…”

(Jochen Glöckner) #35

Hi Pete - I was expecting you to chime in - and indeed you know more of Heine’s lyrics than I do! Maybe I could reply on rivers and rhymes with

“I left a good job in the city
working for the man every night and day.
But I never lost one minute of sleep
thinking of the things that might have been.
Big wheels keep on turning …”

Unfortunately, I don’t know the author of the verses.

Keep the faith


75 XJ6L 4.2 auto (UK spec)

(Paul Wigton) #36

John Fogarty… made an even bigger hit when Ike and Tina Turner covered it.

(PeterCrespin) #37

Don’t be too impressed Jochen - I’ve never heard of Heine and apart from knowing she combs her hair with a golden comb my knowledge of the lyrics ends at ‘Abendsonneschein’ in verse one!. I know the first verse of the Brahms lullaby, but that works fine as the baby you’re holding falls asleep quicker when bored.

You won’t be surprised to learn, however, that like generations of naughty boys, my favourites were Struwelpeter and of course Max und Moritz…

“RUMS! Da geht die Jaguar los, mit Getoesse schrecklich gross.
Dizzytopf und Zundkerzdraht, glucklich kurtz bei ein Ausfahrt.
Schluesseldos und Fackelschein,
Nacht wie schwarz als Huckebein.

(Jochen Glöckner) #38

Thanks, Pete,

for taking us back to Jaguar content:-) - Wonderful combination of original lyrics and sound!

The humour of Wilhelm Busch is gorgeous, even after 150 years (I just had to check it) and tons of so-or-so stand-up comedians. The author of Struwwelpeter actually was a children’s physician and used behaviour patterns that are well documented today for his main characters (e.g. Zappelphilipp ADHS).

See when I find a chance to come to Severna Park - are you still around?



75 XJ6L auto (UK spec)

(PeterCrespin) #39

If you come to Severna Park I will come over. We are about 50 miles west near Damascus.

(Tony Higgins) #40

When faced with similar situation, I chase the threads with a bottom tap running it down until I feel some resistance, go a bit farther, back it out, clean off the crud, blow out the hole and repeat as many times as needed until the hole is empty and clean. For the stud, clamp in a smooth jaw vice and run a die over the threads. As mentioned earlier, the stud can go in finger tight but fully seated, or the acorn nut will seize on the stud before it tightens against the head.
A trick to tighten double nuts or break them loose is to arrange the wrenches in a “V” so you can squeeze them together in one hand.