What are the differences between a Mk IV and MK V engine? I
am working on a Mk IV that has a Mk V engine in it that
needs work. The original engine from the car is sitting on
a bench partly taken apart. I am thinking I will re-build
the original engine and swap it into the car, but I was
wondering what parts may or may not be interchangeable. My
dad swapped the engines in the 1960s and for some reason he
can’t seem to recall if he had to make additional changes to
make it work.
Thanks
Doug Faust–
Doug Faust
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
There are quite a few minor differences but the most fundamental is that
MkV crankshaft
has a longer nose and a much fatter crankshaft pulley. I’m not sure that
MkV pulley would
fit with the MkIV radiator and chassis cross member. I suspect that your
father will have used
the MkIV crank and pulley when he built the engine or he will have had
the MkV crank machined
to the size of the MkIV one.
Peter
Doug Faust wrote:> What are the differences between a Mk IV and MK V engine?
In reply to a message from peter scott sent Thu 1 Sep 2011:
Hi,
In which case if he used the MKV water pump the belt will be
tensioned and not straight as this was compensated by an
offset plate between the engine block and water pump body.
My MKV has a MKIV engine and water pump. I have bought a MKV
water pump too so I have both and I have no need to the
refurbished back plate for the MKIV water pump, so in case
you need one, I have one extra.
I had to repair the water pump as the bearings failed, most
likely due to the belt not being straight and pulling the
pump impeller forward all the time.
Cheers,
Pekka T. - 647194–
The original message included these comments:
There are quite a few minor differences but the most fundamental is that
MkV crankshaft
has a longer nose and a much fatter crankshaft pulley. I’m not sure that
MkV pulley would
fit with the MkIV radiator and chassis cross member. I suspect that your
father will have used
the MkIV crank and pulley when he built the engine or he will have had
the MkV crank machined
to the size of the MkIV one.
Peter
In reply to a message from peter scott sent Thu 1 Sep 2011:
it will interchange
I m on a stupid french hotel keyborad whuich seems to have been
dedsigned by cir=troen
sorry I canT GIVE MoRE DETails, this hS Tkzn �� mins–
The original message included these comments:
has a longer nose and a much fatter crankshaft pulley. I’m not sure that
MkV pulley would
fit with the MkIV radiator and chassis cross member. I suspect that your
father will have used
the MkIV crank and pulley when he built the engine or he will have had
In reply to a message from ptelivuo sent Thu 1 Sep 2011:
Thanks for the input guys. Are there any parts suppliers
left in the US for these engines? I have several boxes of
valves, bearings, rings and several gasket sets, but I am
sure there is going to be something I need and don’t have as
I piece this engine back together. Also, does anyone know
if there any shops still in business in the northeast US
that have experience in pushrod jag engines?
In reply to a message from Craig Harper sent Mon 12 Sep 2011:
To insert a Mk V engine you will need to remove the alloy spacer
behind the water pump , and use the MK IV pulley and damper
arrangement.
Also the Mk IV generator mountings. The front and rear engine
plates are different too. Likewise on a RHD car the rocker cover
abd air cleaner are different… but will all interchange.
You will need to use the MK IV twin engine pipes. There are a lot
of parts for push rod engines available but it,s not a ‘send me a
catalogue deal’ as with XKs.
Work out what you need , then ask. The CJA N&TB has had many
articles on rebuilding these engines.
There aren’t just a slightly old fashioned vesion of an XK engine.
They have there own needs and quirks but if done properly are a
very strong and reliable engine
I presume teh original MK IV engine was removed due to aalloy
conrod issues.
If replacing with a MK V one ,. make sure it’s a Zeries with steel
rods.
Peter yes I have finally worked out how to get the ‘’@’’ sign on a
continental keyboard, Why on earth did they make it s obscure???–
Ed Nantes SS
Melbourne, Australia
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –
If I can’t tempt you to come a little further north to where we are
civilised and have @ I have a Smiths 270 sweep temp gauge for you. (Can
offer you free accommodation although not free transport.)
Peter
Ed Nantes wrote:>
Peter yes I have finally worked out how to get the ‘’@’’ sign on a
continental keyboard, Why on earth did they make it s obscure???
In reply to a message from Ed Nantes sent Wed 14 Sep 2011:
I’m not sure what the reason was for the engine swap. Not
sure if there was a particular reason or just a matter of
installing an engine in better shape. There are ~ 50 years
of CJA bulletins in boxes I can sort through and absorb some
more knowledge on the subject. Good winter activity…
Thanks–
The original message included these comments:
I presume teh original MK IV engine was removed due to aalloy
conrod issues.
In reply to a message from peter scott sent Thu 15 Sep 2011:
Peter
Thank you a very kind offer.
I have just got the I pad to work, I can do J lovers and
receive emails but not send them. So my reply to you is
stuck in my outbox.
We,re only back in u for 4 days, so the home of Rebus
will be a bit far to go.
I saw some interesting cars in UK in august.
I’ll email you when I get home … Or when the iPad
Strega to work properly–
The original message included these comments:
If I can’t tempt you to come a little further north to where we are
civilised and have @ I have a Smiths 270 sweep temp gauge for you. (Can
offer you free accommodation although not free transport.)
Peter
In reply to a message from Doug Faust sent Wed 31 Aug 2011:
What are the differences between a Mk IV and MK V engine?
I am putting a rebuilt Mark V engine into a Mark IV. The
original engine was missing when I purchased the car. I
have just learned that the water pump should be pushed back
an inch and I am trying to operate on the lower pulley/crank
to match.
I pulled off a notched/pressed on portion of the crank shaft
and I am considering how to modify it to accommodate the new
pulley position. Does anyone have experience with making
this modification?–
The original message included these comments:
What are the differences between a Mk IV and MK V engine? I
You need to reduce the length of the Woodruff keyed section from 2.375"
to 2.050" and reduce the
combined length of the keyed section and the threaded section from 3.90"
to 3.55"
Regards,
Peter
Dennis Trull wrote:> Does anyone have experience with making
this modification?
The original message included these comments:
What are the differences between a Mk IV and MK V engine? I
In reply to a message from Dennis Trull sent Sun 25 Sep 2011:
Dennis,
You need the MkIV crank pulley which will fit on a Mk V
crank
It effectively swaps the positions of the pulley and
harmonic balancer.
Short of that you couldtuurn up a plain pulley as on the
SS 3 1/2litres. The prewar cars didn’t have a balancer
and seem to run very well without one. I think Jaguar
only used other after Rolls Royce bought an SS salon,
thrashed it around brook lands, and then poo pooed the
engine has having some issues wit harmonics at certain
revs.
No SS 100has a balancer.
THe water pump is moved back simply by deleting the
alloy spacer.
The front and rear mounting plates are different and
will not interchange without correction.–
The original message included these comments:
I am putting a rebuilt Mark V engine into a Mark IV. The
original engine was missing when I purchased the car. I
have just learned that the water pump should be pushed back
an inch and I am trying to operate on the lower pulley/crank
to match.
I pulled off a notched/pressed on portion of the crank shaft
and I am considering how to modify it to accommodate the new
pulley position. Does anyone have experience with making
this modification?
In reply to a message from peter scott sent Sun 25 Sep 2011:
I notice that the last 3/4 inch or so of the threads on the
end of the crankshaft appear to be cut down a bit compared
to the inner threads. My crankshaft is the same way. I was
thinking mine may have been damaged, but now it looks like
the thread difference is intentional? My pulley nut appears
to thread on OK so maybe there is nothing wrong it.
Thanks
Doug Faust–
The original message included these comments:
In reply to a message from Doug Faust sent Mon 26 Sep 2011:
Yes, the threads on the end of the Mark V engine crankshafts I
have seen are cut down a bit. I don’t know the reason.–
Roger McWilliams
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –
On engines without a damper the starting handle is a socket and fits over
the cut down threads on the end to reach the pronged nut. The handles I have
seen have two prongs.
On engines with a damper like my 3.5 Mark V the damper nut is a deep one
with three prongs that extends beyond the end of the threads, and the handle
has a nub that fits into this deep nut.
I believe the damper was the reason for the extension on the water pump.
Rob Reilly - 627933>I wonder if it has anything to do with insertion into the starting handle?
Yes, the threads on the end of the Mark V engine crankshafts I have seen
are cut down a bit. I don’t know the reason.
In reply to a message from peter scott sent Tue 20 Sep 2011:
In regards to placing a Mark V engine in a Mark IV,
Great news,
I was able to remove the pulley and supporting end piece
correct position. I did this by reducing the diameter of
the back of the end piece to about 1 5/8. Then I increased
the diameter of the pulley and balance wheel to the same.
If the parts are then reversed and inserted from the engine
side the pulley moves about 3/4 of an inch. Bolts need to
be 1/4 of an inch longer and enter from the engine side.
The same threads can be used.
My local machine shop charged $50 to machine these 3 parts.from my Mark V engine and modify it so the pulley is in the
