[v12-engine] Piston liner sealant

My mechanic already has the bottom put back together. Will he be
able to manipulate the piston liner up to put loctite in to seal?
Thank You–
mattdelo
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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Well, he is stupid, I would take my motor and run to another mechanic if I
thought I couldn’t do better.

John Ashcroft.----- Original Message -----
From: “mattdelo” mattdelos@yahoo.com
To: v12-engine@jag-lovers.org
Sent: Wednesday, January 22, 2003 7:15 PM
Subject: [v12-engine] Piston liner sealant

My mechanic already has the bottom put back together. Will he be
able to manipulate the piston liner up to put loctite in to seal?

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My mechanic already has the bottom put back together. Will he be able to manipulate the piston liner up to put loctite in to seal? more !

The one time I’ve seen liners taken out, (out of a 6 liter) some practically
fell out, (& this was without the bottom end in place) others had to be
vigorously tapped out from below with a punch resulting in scoring of the
aluminum the cylinder slips into (no big deal there.) A number of the
liners were carbon & cresol crusted between the aluminum & sleeve. It
looked like DEFINITELY a good idea to run a bead of sealant around the
bottom of each liner.

Unless he has some sort of special tool to PULL the liners up by an inch or
so, I think the answer is no. He’ll have to remove the bottom end to seal
the sleeves. If he does it any other way I think he might risk getting
contaminants (metal particles etc) into the engine.

Knowing the propensity of most people to be adverse to do work over
again…

Good luck!

Paul Kobres
85’ XJS
Columbia SC

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I’ve been screwed over by a mechanic rebuilding my 12 before. If he doesn’t
know to seal up the liners than there may be other things he didn’t know how
to do. Take your engine and run!

-Chris

-----Original Message-----
From: owner-v12-engine@jag-lovers.org
[mailto:owner-v12-engine@jag-lovers.org]On Behalf Of John Ashcroft
Sent: Wednesday, January 22, 2003 4:43 AM
To: v12-engine@jag-lovers.org; mattdelo
Subject: Re: [v12-engine] Piston liner sealant

Well, he is stupid, I would take my motor and run to another mechanic if I
thought I couldn’t do better.

John Ashcroft.

----- Original Message -----
From: “mattdelo” mattdelos@yahoo.com
To: v12-engine@jag-lovers.org
Sent: Wednesday, January 22, 2003 7:15 PM
Subject: [v12-engine] Piston liner sealant

My mechanic already has the bottom put back together. Will he be
able to manipulate the piston liner up to put loctite in to seal?

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 !

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 !

My mechanic already has the bottom put back together. Will he be
able to manipulate the piston liner up to put loctite in to seal?
Thank You

mattdelo

We love science experiments on this List! Why don’t you have your mechanic
try it, and then keep us all apprised of how long the new engine
lasts!!!

Seriously, he screwed up big time, and should not be charging you do fix his
mistake. Also, you might want to take a look into other mistakes he’s
already made, and that he will make as he continues this work. He
obvioulsy is not familiar with these engines and seems to rely on farm
tractor repair techniques to get by.

Also, to answer another question you improperly posed to the XJ-S List
(engine issues belong here only), the sleeves are not sized to the block.
The pistons are sized to the sleeves. The sealant that is specified for the
sleeve/block juncture is not to ‘glue’ the sleeves in place. It is to
provide a sealant for the coolant, and a flexible sealing material is
specified. Sleeves are usually a fairly loose fit in the block; if you
attempt to rotate a V12 with the heads off, you will break sleeves loose and
their will be coolabnt everywhere - and now the motor must come out to fix.
Never rotate the lower end of a V12 without the heads in place unless the
sleeves are clamped down with a fixture that prevents them from lifting as
the piston rings grab them.

Sorry for all the bad news, but at least you have caught this problem before
the engine was back in the car.

John

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John G. Napoli wrote:

the sleeves are not sized to the block.
The pistons are sized to the sleeves.

So John are you saying that if one wants a 7 or 8 liter engine, that the
block is not machined in any way, that a new sleeve/piston set (and rods
and maybe crank) is all that is required??? Seems illogical from what I
have read about this engine, but then again, I don’t have first hand
experience with the Jag V12 engine at this level either.

Wayne Estrada
1989 Vanden Plas 1989 XJ-S Convertible http://www.JaguarLover.com/wayne
||| Get Your Own Custom Brit Car email addresses and Personal Car Web
Site |||
GO TO: http://www.BritishCarLover.com

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Considering the dilema, let me offer up a possible remedy. If the area
around the base of the liners has been cleaned (relatively) it may be
possible to source a silicone sealant that is very fluid. This could then
be injected around the base and would flow into the crevices. The other
solution is to get a low strength threadlocking compound like the Loctite
222 and apply it around the base in the same fashion. I would further
suggest you call Loctite and ask for tech service and pose the problem to
them. Worked there many years ago, so they may have some new stuff.
Contact me off list if you need help in this endeavor, no need to clutter
with irrelevence.
regards, max

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John G. Napoli wrote:

the sleeves are not sized to the block.
The pistons are sized to the sleeves.

So John are you saying that if one wants a 7 or 8 liter engine, that the
block is not machined in any way, that a new sleeve/piston set (and rods
and maybe crank) is all that is required??? Seems illogical from what I
have read about this engine, but then again, I don’t have first hand
experience with the Jag V12 engine at this level either.

It sounds as if you have a couple of different concepts confused here.

First of all, the ‘sizing’ of the pistons and sleeves is in terms of piston
to wall clearance. Each piston must have a certain amount of clearance to
the cylinder. This clearance is usually measured at the piston skirt
directly underneath the wrist (gudgeon) pin. Why there? Well, because of
course pistons are not round. They are eggshaped because they do not expand
equally in all directions when hot. Cam-shaped pistons expand to a circle
at operating temperature.

When they manufacture the pistons, they are measured. Same for the cylinder
sleeves. The components are matched together to provide the proper
clearances.

Now, on to your second implied question. Why would it not make sense that
you would achieve an increased displacement by fitting larger pistons and
sleeves? This, and stroking the crank, is all you really have to work with.
Since these motors use replacable sleeves that are quite thin, you cannot
utilize a larger piston by boring (or, enlarging the diameter) of the
sleeves.

Most engines with conventional blocks will only safely accept a clean-up
bore of .030 or .040 inches; sometimes you can get as large as .060. But of
course this is just to accomodate taper when rebuilding the engine, and is
not a way to achieve a large increase in displacement. Then, you’d bore the
block and install oversize sleeves. We can’t bore the block at all, so we
can just fit the largest sleeve possible.

When I say that the sleeves are not sized to the block, I mean that any
sleeve can be installed in any location in the V12. The pistons are sized
to the sleeves, as I described above. This is the inside of the sleeve.
The outer dimension of the sleeve (at the bottom) is not additionally sized
to the hole in the aluminum block that the sleeves slip into. Some sleves
will naturally fit more tightly than others as a result of manufacturing
tolerances: the smallest exterior diameter of sleeve in the largest hole in
the block gives the loosest fit, and vice versa. The sleeves are sealed to
the blaok at the bottom by the specified sealant, and that keeps the coolant
out of the oil. The sleeves are prevented from wiggling all over the place
by the clamping action of the head.

The same principles apply for ANY piston/sleeve bore combinations available
for this engine.

Best,

John

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OK, I think I got what you were saying, but still have some nagging
questions/comments…

John G. Napoli wrote:

sleeves? This, and stroking the crank, is all you really have to work with. Since these motors use replaceable sleeves that are quite thin, you cannot utilize a larger piston by boring (or, enlarging the diameter) of the sleeves.(to make larger displacement?) ....you'd bore the block and install oversize sleeves. We can't bore the block at all, so we can just fit the largest sleeve possible.

Really? That is not what I have read previously, but I may be wrong. I
have heard about a) longer stroke (e.g. the 5.2. to 6.0 conversion) and
block spacers to raise the head higher, effectively making more cc
displacement by lengthening the bore (new con rods needed [and crank?])
As massive as this engine block is, the bores can not be enlarged? Is
this because of internal cooling passages around the existing bores?

When I say that the sleeves are not sized to the block, I mean that any
sleeve can be installed in any location in the V12. The pistons are sized
to the sleeves, as I described above. This is the inside of the sleeve.
The outer dimension of the sleeve (at the bottom) is not additionally sized
to the hole in the aluminum block that the sleeves slip into.

Again, I think I know what you are saying here. I would assume that
all outer diameters of any sleeve would be exactly the same since “the
block can’t be bored” but if the sleeve is thin too begin with then
there is no wiggle room on a larger diameter bore in an “upgraded”
sleeve (inner diameter) size, right?

Not an affront to your knowledge, as I again have no first hand
experience with this engine, but has anyone bored one of these things
out? Or are all these displacement increases due to higher top deck
head spacers and longer cranks. I’ve heard about these 8 and 9 liter
V12s and wondering how they got there. The reason I ask is I am looking
to have, someday, the highest naturally aspirated Jag V12 you can have,
BUT with smooth power and running characteristics. I am guessing
again that when Jaguar designed this engine, the 5.3. config met their
smoothness criteria. But my car guy logic says a 326 cubic inch engine
(5.3 L) is too small for a 4,100 lb car. A 400+ c.i… engine (7.x
liters) would be better. I just don’t want to create a rumbling, rough
running, big block English drag car Camero with this engine. That’s
why I am asking all this.

Wayne Estrada

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OK, I think I got what you were saying, but still have some nagging
questions/comments…

John G. Napoli wrote:

sleeves? This, and stroking the crank, is all you really have to work

with.

Since these motors use replaceable sleeves that are quite thin, you
cannot

utilize a larger piston by boring (or, enlarging the diameter) of the
sleeves.(to make larger displacement?) …you’d bore the
block and install oversize sleeves. We can’t bore the block at all, so
we

can just fit the largest sleeve possible.

Really? That is not what I have read previously, but I may be wrong. I

You are.

have heard about a) longer stroke (e.g. the 5.2. to 6.0 conversion) and
block spacers to raise the head higher, effectively making more cc
displacement by lengthening the bore (new con rods needed [and crank?])
As massive as this engine block is, the bores can not be enlarged? Is
this because of internal cooling passages around the existing bores?

OF COURSE the bore can be enlarged! It’s done all the time and only
requires deep pockets to purchase the larger diameter sleeves and pistons.

When I say that the sleeves are not sized to the block, I mean that any
sleeve can be installed in any location in the V12. The pistons are
sized

to the sleeves, as I described above. This is the inside of the sleeve.
The outer dimension of the sleeve (at the bottom) is not additionally
sized

to the hole in the aluminum block that the sleeves slip into.

Again, I think I know what you are saying here. I would assume that
all outer diameters of any sleeve would be exactly the same

Within normal manufacturing tolerances.

since "the

block can’t be bored"

Right. Because there is nothing to bore!! The pistons ride in the
removable sleeves.

but if the sleeve is thin too begin with then

there is no wiggle room on a larger diameter bore in an “upgraded”
sleeve (inner diameter) size, right?

Wrong. Just but a larger diameter sleeve/piston. The limit is when
adjoining sleeves get large enough to touch each other. But there is plenty
of room for enlargement.

Not an affront to your knowledge, as I again have no first hand
experience with this engine, but has anyone bored one of these things
out?

No, because there is NOTING TO BORE!

But many people have enlarged the bore by fitting larger sleeves and
pistons. Got it yet?

A picture is worth a thousand words in cases like this, and I might not be
describing it in a way that illustrates things. There are plenty of ‘v12
buildups in progress’ sites on the web. Check out some of the online pix
and it will become crystal clear.

Or are all these displacement increases due to higher top deck

head spacers and longer cranks. I’ve heard about these 8 and 9 liter
V12s and wondering how they got there.

Bore and stroke.

The reason I ask is I am looking

to have, someday, the highest naturally aspirated Jag V12 you can have,
BUT with smooth power and running characteristics. I am guessing
again that when Jaguar designed this engine, the 5.3. config met their
smoothness criteria. But my car guy logic says a 326 cubic inch engine
(5.3 L) is too small for a 4,100 lb car. A 400+ c.i… engine (7.x
liters) would be better. I just don’t want to create a rumbling, rough
running, big block English drag car Camero with this engine. That’s
why I am asking all this.

Bywater et al have discussed this numerous times, including quantitative
information on the displacements that are possible. Check the archives.

Best,

John

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