In reply to a message from Norman LUTZ sent Mon 18 Mar 2013:
Using this method, have you had many studs shear off with a need to
then drill the remains out (not a nice job)?
If you aren’t planning on replacing the studs anyway, do you feel
the cost of timeserts and the risk of a stud shearing off whilst
over-torqueing them to destroy the threads in the stud is still
worthwhile? If you are replacing the original studs anyway, is it
worth the extra hassle?
By the way, I can easily pull a head, leaving all studs intact, in
less than 30 mins using a tool with no damage to any studs or block.–
Neville - http://www.XJ13.eu, XJ13 in-progress.
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Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
23
Awesome. I’ve come up with one more line of questioning: For
clarity, you’re yanking JUST the 7/16" studs, right? You’re not
yanking the 3/8" studs, are you? And are you yanking ALL the 7/16"
studs, or are there just particular ones you yank while merely
removing the nuts on others?
– KirbertOn 18 Mar 2013 at 14:46, Norman LUTZ wrote:
If the shank of the stud is not too corroded I reuse them
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In reply to a message from V12 Racer sent Tue 19 Mar 2013:
I’ve never had a stud shear off yet.
All my engines are rebuilt as 6 Litre engines witha 95mm bore.
This increases the stud loading by more than 25%. So the use
of ‘‘Timeserts’’ is mandatory as far as I am concered.
When I first started doing the 6L engines I used to get new 1/2’’
studs made at great cost, that was before I discovered ‘‘Timeserts’’.
The end 4 studs are removed normally but I still ‘‘Timesert’’ them
for obvious reasons.–
The original message included these comments:
Using this method, have you had many studs shear off with a need to
then drill the remains out (not a nice job)?
If you aren’t planning on replacing the studs anyway, do you feel
the cost of timeserts and the risk of a stud shearing off whilst
over-torqueing them to destroy the threads in the stud is still
worthwhile? If you are replacing the original studs anyway, is it
worth the extra hassle?
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In reply to a message from Norman LUTZ sent Tue 19 Mar 2013:
I like your thinking Norm, just have at her and get on with it.
Having looked at the timesert site, various thread solutions
exist: 14, 20, 24 TPI on the 7/16th diameter studs. with
various depths of threading into the block, up to 1.5’’
This must open the door to other manufacturers studs which
may be more cost effective than jaguar studs.
I was just about to order a full set of new jaguar studs,
may be prudent to rethink this
cheers–
The original message included these comments:
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
26
This must open the door to other manufacturers studs which
may be more cost effective than jaguar studs.
Doubtful. You’ve gotta have a full matched set, and they all have to
be the correct length. No other V12 will be any cheaper, two sets of
V8 or V6 or I6 will probably be needed, and you’ll still be fiddling
to make them work.
I was just about to order a full set of new jaguar studs,
may be prudent to rethink this
Why are you replacing them? They’re really expensive and rarely need
replacing.
– Kirbert
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 21 Mar 2013 at 18:32, Repairman wrote:
In reply to a message from Kirbert sent Fri 22 Mar 2013:
Kirbert,
Yes they are expensive, as is everything else on the motor.
I dismantled two V12’s and from the collection putting
together a single V12, albeit slowly.
Anything consumable: bearings, rings, gaskets, o-rings and
so on are being replaced with new, setting a standard.
In the process of removing the heads some stud threads got
chewed, bent, mangled, and some I just personally have a
grudge against. Some of them are in mint condition.
For the amount of money being put into the project,
replacing coolant pickled, stressed, 25 year old mains studs
makes sense.–
The original message included these comments:
Why are you replacing them? They’re really expensive and rarely need
replacing.
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It has been reported than when TWR had their XJS homologated, they went
through a selection of several hundred production con rods and selected
twelve of the lightest ones. Apparently they saved significant rotational
weight. I have a figure in my mind of 80gm.
Later they were able to cast their own using the Jaguar castings, so that
they looked like the originals. There was no restriction in material
specification, only you had to use the factory “part”.
Rod failures they had in racing were traced back to casting defects in the
factory parts.-----Original Message-----
My amazement of building the motor is just how ‘out of spec’
everything is, on both motors.
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Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
29
It has been reported than when TWR had their XJS homologated, they
went through a selection of several hundred production con rods and
selected twelve of the lightest ones.
Rod failures they had in racing were traced back to casting defects in
the factory parts.
No doubt! Sounds like they were selecting the rods for maximum
defects! Never, NEVER select the lightest items from castings from
the same mold! The lightest ones are the ones with the voids.
– Kirbert
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 26 Mar 2013 at 11:51, Mark Eaton wrote:
In reply to a message from Mark Eaton sent Mon 25 Mar 2013:
Jaguar V12’s never used ‘‘cast’’ rods, they were always FORGED.–
The original message included these comments:
Later they were able to cast their own using the Jaguar castings, so that
they looked like the originals. There was no restriction in material
specification, only you had to use the factory ‘‘part’’.
Rod failures they had in racing were traced back to casting defects in the
factory parts.
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Apologies. Forged from the factory dies? Defects were reported to be traced
to inclusions in the metal.-----Original Message-----
Jaguar V12’s never used ‘‘cast’’ rods, they were always FORGED.
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Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
32
Jaguar V12’s never used ‘‘cast’’ rods, they were always FORGED.
Well, yeah, that makes sense. Still, I would be hesitant to choose
the lightest examples in a group.
– Kirbert
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 26 Mar 2013 at 14:40, Norman LUTZ wrote:
In reply to a message from Kirbert sent Tue 26 Mar 2013:
Jaguar usually ‘‘over designed’’ their components. A V12 rod is
nearly 50% heavier than the equivalent Chevy 6’’ rod and has a lot
lower loading due to the lighter piston and shorter stroke.
I used to spend a lot of time lightening the V12 rod but in the end
gave up and know use the ‘‘Chev’’ 6’’ rod as this weighs around 680gm
compared to the 960gm of the Jag rod.–
The original message included these comments:
Well, yeah, that makes sense. Still, I would be hesitant to choose
the lightest examples in a group.
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In reply to a message from Norman LUTZ sent Sat 16 Mar 2013:
So I’'m at the garage thats doing the engine work that I
cant do and ask casually 'anybody heard of ‘timeserts’
Not a favorable response
Their view is: If the rod is seizing in a given location, it
will continue to seize with the insert, such that upon
removal the insert pops out with the rod. This in turn means
you have a rod with a seized piece of metal on the end, and
you need a new timesert to put in the hole.
According to these guys the timesert plugs come in different
formats. Different attempts to anchor the timesert. Some
have teeth that bite in. Upon removal of these, the hole in
the block can get damaged making the situation even worse.
They prefer Helicoils that only require a hole to be drilled
and an insert put in that will come out cleanly
I have no experience with either so I’m sitting on the fence
on this one, just relaying an opinion–
The original message included these comments:
I now use ‘‘timeserts’’ on all V12 engine rebuilds because I find it
quicker to remove the heads if you over torque the studs and strip
the threads from the block.
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In reply to a message from Repairman sent Wed 27 Mar 2013:
‘‘Timeserts’’ were oringinally developed for PORSCHE to use in the
Magnesium crankcase used in their race engines. Properly installed
they will not come out with the stud.
‘‘Helicoils’’ will not accept high torque applications such as head
studs, ask me how I know?. OK for low torque manfold studs or the
like.
The ‘‘timesert’’ is steel and the likehood of the steel stud seizing
is a lot less than with the stud in alluminum.–
The original message included these comments:
So I’'m at the garage thats doing the engine work that I
cant do and ask casually 'anybody heard of ‘timeserts’
Not a favorable response
Their view is: If the rod is seizing in a given location, it
will continue to seize with the insert, such that upon
removal the insert pops out with the rod. This in turn means
you have a rod with a seized piece of metal on the end, and
you need a new timesert to put in the hole.
They prefer Helicoils that only require a hole to be drilled
and an insert put in that will come out cleanly
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
36
So I’'m at the garage thats doing the engine work that I
cant do and ask casually 'anybody heard of ‘timeserts’
Their view is: If the rod is seizing in a given location, it
will continue to seize with the insert, such that upon
removal the insert pops out with the rod. This in turn means
you have a rod with a seized piece of metal on the end, and
you need a new timesert to put in the hole.
This sounds like the kind of response you get from a shop that A) has
never actually used a timesert, or B) doesn’t want to bother with
timeserts. Possibly both.
– Kirbert
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On 27 Mar 2013 at 19:31, Repairman wrote:
In reply to a message from Kirbert sent Wed 27 Mar 2013:
maybe this will help on using Timeserts, Mercedes Benz, has
a bulletin about repair of aluminum threads, they have,in
Germany, a product that,to me looks exactly like a
Timesert(different name).
MB says it is the only Aluminum,or Magnesium thread repair
they would WARRENTY, using that product!
and just maybe it was developed by Porsche, they donno
anything about engines,or do they,hehe.–
The original message included these comments:
So I’'m at the garage thats doing the engine work that I
cant do and ask casually 'anybody heard of ‘timeserts’
This sounds like the kind of response you get from a shop that A) has
never actually used a timesert, or B) doesn’t want to bother with
timeserts. Possibly both.
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from Ronbros sent Thu 28 Mar 2013:
The problem and the joy of the information age is no what
the question is you will get many conflicting answers. These
answers are generated by qualified and unqualified people.
Some days its just all so confusing.
Cheers–
The original message included these comments:
MB says it is the only Aluminum,or Magnesium thread repair
they would WARRENTY, using that product!
and just maybe it was developed by Porsche, they donno
anything about engines,or do they,hehe.
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I double checked Allan Scott’s book last night and note that TWR upgraded
the standard Jaguar factory studs from EN16 steel to EN24W steel (which
seems to be a high spec version of the ANSI 4340 CrMo steel).
I don’t think there was mention of thread engagement issues in the block.
But he does note that they had trouble with the head NUTS due to poor thread
forming (due to high sulphur content in the steel?). They changed the spec
and had the Jaguar prototyping shop make them special nuts from EN16T steel
(the standard ones were EN16). I “think” the EN16T is a low sulphur heat
treated version that allows tighter machining tolerances.
Perhaps there was a similar issue with the thread tolerances in the block
which was solved by the switch to 4340 studs with better machining
tolerances?
Earlier he mentions they had a lot of problems with head gasket issues until
they “fixed” the inherent design problems. It seems both the Jaguar
engineers and the Gp 44 engineers struggled with this problem. So it is of
interest to know what the final “solution” was.
Rgds
Mark
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In reply to a message from Norman LUTZ sent Wed 27 Mar 2013:
It would appear Jaguar is no longer supplying engine studs
and we are now in the aftermarket arena–
The original message included these comments:
I used to spend a lot of time lightening the V12 rod but in the end
gave up and know use the ‘‘Chev’’ 6’’ rod as this weighs around 680gm
compared to the 960gm of the Jag rod.
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