I have recently completed all of the body work and the painting of
my S1 OTS and am now beginning the reassembly. I purchased my kit
in a large number of boxes but the stalled PO had the engine and
transmission completely rebuilt before I acquired it. He told me at
the time that it had new Isky cams as part of the rebuild but it
was not at the top of my list of concerns at that time.
Now I would like to understand what I have, and to make any
decisions if it is not what I want before I install the engine into
the car. I really do not want any radical performance issues and
would have preferred stock cams given the choice. It is obviously a
big step to swap these out and retime and shim if I choose to. I do
have the original cams but have not checked them seriously for
straightness and profile condition. I do not have the PO’s
reasoning for replacing the cams.
The markings on the cam is as follows:
X75
Iskenderian
OCUS
5715cc
A quick look at the Isky web site I do not find these particular
numbers so I would appreciate any suggestions for their meaning and
characteristics.
I plan to get a degree wheel mounted and profile the cam for timing
and lift even if I find some specifications for these numbers. So
my question is really twofold; any thoughts on finding more
information on these cams, and having that, what considerations are
important in deciding to keep or replace them.
I value the expertise of so many on the list that I look forward
to help in making this evaluation.
Thanks–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Gary, I have had several sets of Isky cams, XM3’s at present, but do
not recall what if any markings were on them. Call Isky’s hot line and
talk to a technician and I bet they will be able to help you.
Bob
889076
Plymouth, Mi.On Sep 8, 2013, at 3:35 PM, gbrinker wrote:
Background:
I have recently completed all of the body work and the painting of
my S1 OTS and am now beginning the reassembly. I purchased my kit
in a large number of boxes but the stalled PO had the engine and
transmission completely rebuilt before I acquired it. He told me at
the time that it had new Isky cams as part of the rebuild but it
was not at the top of my list of concerns at that time.
Now I would like to understand what I have, and to make any
decisions if it is not what I want before I install the engine into
the car. I really do not want any radical performance issues and
would have preferred stock cams given the choice. It is obviously a
big step to swap these out and retime and shim if I choose to. I do
have the original cams but have not checked them seriously for
straightness and profile condition. I do not have the PO’s
reasoning for replacing the cams.
The markings on the cam is as follows:
X75
Iskenderian
OCUS
5715cc
A quick look at the Isky web site I do not find these particular
numbers so I would appreciate any suggestions for their meaning and
characteristics.
I plan to get a degree wheel mounted and profile the cam for timing
and lift even if I find some specifications for these numbers. So
my question is really twofold; any thoughts on finding more
information on these cams, and having that, what considerations are
important in deciding to keep or replace them.
I value the expertise of so many on the list that I look forward
to help in making this evaluation.
Thanks
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Sun 8 Sep 2013:
Gary,
If the engine is in running order, you might want to see how you
like these cams. You can change cams just as easily with the
engine in place (but it’s easier with the bonnet off).
I bought my car with some kind of moderately hot cams installed,
and I grew to hate it that way. The idle was high and lumpy, and
in slow traffic situations, I was in and out on the clutch all the
time.
The XK engine is NOT a high-speed unit, and for street use, you
will probably want to stay under 5000 rpm. The stock cams have a
decent high end and good tractability all the way down to idle.
Hot cams will be slightly better at the high end, but you lose the
flexibility for which these engines were famous.
I am in the process of replacing my cams with stock late XJ6 cams.
My understanding is that these have similar profiles to stock e-
type cams, but have a ‘‘clearance ramp’’ incorporated which allows
wider and more tolerant clearance settings.
You will of course get varying opinions on all this.–
Bob Frisby, S2 FHC
Boise ID, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Sun 8 Sep 2013:
Isky Cam update:
I called Iskendarian tech line this morning and found out that the
X75 that I thought was probably the grind spec was really a date
code. I had to rotate the engine a bit more and found that I really
had two more numbers that I missed earlier.
XM-2
5901
So this appears to be a higher lift but mild increase in duration
compared to the other listed specs.
Now my question is what can I expect for drivability from this?
Anyone with experience on the XM-2?
Also, where would I find the geometry for the stock cams? I will
dig into the manual as I expect it should be there.
Appreciate any input, thanks.–
The original message included these comments:
The markings on the cam is as follows:
X75
Iskenderian
OCUS
5715cc
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Mon 9 Sep 2013:
Gary,
XM-2 is 258 duration and 0.404’’ lift with 0.008/0.010’’
clearances. Factory cams in 1966 were 252 duration and
0.375’’ lift with 0.004/0.006’’ clearances. My experience with
these cams is there is little or no performance increase
below 4000 rpm and they are very noisy at idle. Perhaps a
performance decrease below 3000 rpm. The problem with
reground early (2 bolt) cams is what little quieting ramps
there were are ground away. When considering your options,
the first thing to do is inspect the shims and valve stem
heights. Many of these heads have been around the block a
few times and every time the seats are cut, the valves sink
closer to the cams, which can put you out of the factory
shim range. Only a limited amount can be removed from the
stems because the shims must sit proud of the retainer. One
solution is to fit a reground cam which has around a 0.040’’
base circle reduction. If your head has reground cams and
thin shims, you may not be able to fit stock cams. In my
opinion, the best cams for a road car are the post 69
parabolic cams fitted at the wider clearances.
Paul–
The original message included these comments:
Isky Cam update:
I called Iskendarian tech line this morning and found out that the
X75 that I thought was probably the grind spec was really a date
code. I had to rotate the engine a bit more and found that I really
had two more numbers that I missed earlier.
XM-2
5901
So this appears to be a higher lift but mild increase in duration
compared to the other listed specs.
Now my question is what can I expect for drivability from this?
Anyone with experience on the XM-2?
Gary,
I ran XM2 Isky cams for a couple of years and with Super Trapps and
no mufflers and K&N filters the engine would not rev past 3 grand with
the stock needles. If you like give me a call at 734-355-5039 some
evening, not today, and we’ll go over the in’s and out’s of Isky cams.
Bob
889076
Plymouth, Mi.On Sep 9, 2013, at 1:32 PM, gbrinker wrote:
In reply to a message from gbrinker sent Sun 8 Sep 2013:
Isky Cam update:
I called Iskendarian tech line this morning and found out that the
X75 that I thought was probably the grind spec was really a date
code. I had to rotate the engine a bit more and found that I really
had two more numbers that I missed earlier.
XM-2
5901
So this appears to be a higher lift but mild increase in duration
compared to the other listed specs.
Now my question is what can I expect for drivability from this?
Anyone with experience on the XM-2?
Also, where would I find the geometry for the stock cams? I will
dig into the manual as I expect it should be there.
Appreciate any input, thanks.
The original message included these comments:
The markings on the cam is as follows:
X75
Iskenderian
OCUS
5715cc
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from PS sent Mon 9 Sep 2013:
Thanks Paul for the very detailed comments. It appears that all of
the effects are negative in my mind. Now I need to decide on
waiting to experience them after installation or taking some
preemptive action. All I know about the rebuild is that all new
parts were used: springs, valves, tappets, pistons, etc. as I have
the old parts. I do not know the existing shim thicknesses. I just
measured the base circle on the installed cams at .970 which is
probably the expected value for a regrind. Perhaps a next step is
to pull a cam and map the shims to get a better picture of the
total geometry and the seat depths. I think I will study the
geometry to make sure I understand your comments about the use of a
stock cam.
Appreciate your expertise!!–
The original message included these comments:
these cams is there is little or no performance increase
below 4000 rpm and they are very noisy at idle. Perhaps a
performance decrease below 3000 rpm. The problem with
reground early (2 bolt) cams is what little quieting ramps
there were are ground away. When considering your options,
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Stevenson Robert sent Mon 9 Sep 2013:
Bob, thanks a lot for the offer to speak with you about this issue.
I think I will take you up on it after I have collected a bit more
background information. Do you attend the JAGM meetings? If so, I
might take a drive north and do so face to face.–
The original message included these comments:
the stock needles. If you like give me a call at 734-355-5039 some
evening, not today, and we’ll go over the in’s and out’s of Isky cams.
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Gary We’ll be at the meeting this week. If it’s not raining i’ll
probably drive the 64 and you’ll probably be surprised at how little
difference there is in valve clatter between 4 & 6 and 8 & 10
clearances.
Bob
889076
Plymouth, Mi.On Sep 9, 2013, at 3:50 PM, gbrinker wrote:
In reply to a message from Stevenson Robert sent Mon 9 Sep 2013:
Bob, thanks a lot for the offer to speak with you about this issue.
I think I will take you up on it after I have collected a bit more
background information. Do you attend the JAGM meetings? If so, I
might take a drive north and do so face to face.
–
The original message included these comments:
the stock needles. If you like give me a call at 734-355-5039 some
evening, not today, and we’ll go over the in’s and out’s of Isky
cams.
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Mon 9 Sep 2013:
I have XM2 Cams installed in my 4,2 litre 3-SU E-type.
They are very smooth, idle well and are even in throttle
response.
The correct valve adjustment is .012 intake and .014’’
exhaust cold.
They are not noisy in spite of that wildy big clearance.
I have UB needles installed as per Joe Curto recommendation
I used to have even richer needles a few years ago and it
was a screamer.
This is not a high performance cam. It provides a little
more power and torque without being lumpy or nasty.
this was the standard cam supplied by GT Jaguar for their
first performance upgrade.–
The original message included these comments:
I called Iskendarian tech line this morning and found out that the
X75 that I thought was probably the grind spec was really a date
code. I had to rotate the engine a bit more and found that I really
had two more numbers that I missed earlier.
XM-2
5901
So this appears to be a higher lift but mild increase in duration
compared to the other listed specs.
Now my question is what can I expect for drivability from this?
Anyone with experience on the XM-2?
Also, where would I find the geometry for the stock cams? I will
–
'68 OTS : ‘03XJR I canna’ change the Law of Physics–Sco
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Hi Richard,
Isky has recommended at least two different valve lash settings, 8 &
10 & 12 & 14, on their Jag cams over the past, that I know of, 15 or
so years. I questioned Isky’s hot line technician about this and was
told that 8 & 10 would be fine and that’s the way the XM3’s been set
for at least 7 years and the XM2’s for several years before that. Your
description of the XM2 cams is exactly the same as my experience!
Bob
889076
Plymouth, Mi.On Sep 9, 2013, at 9:42 PM, Richard Kuschel wrote:
In reply to a message from gbrinker sent Mon 9 Sep 2013:
I have XM2 Cams installed in my 4,2 litre 3-SU E-type.
They are very smooth, idle well and are even in throttle
response.
The correct valve adjustment is .012 intake and .014’’
exhaust cold.
They are not noisy in spite of that wildy big clearance.
I have UB needles installed as per Joe Curto recommendation
I used to have even richer needles a few years ago and it
was a screamer.
This is not a high performance cam. It provides a little
more power and torque without being lumpy or nasty.
this was the standard cam supplied by GT Jaguar for their
first performance upgrade.
The original message included these comments:
I called Iskendarian tech line this morning and found out that the
X75 that I thought was probably the grind spec was really a date
code. I had to rotate the engine a bit more and found that I really
had two more numbers that I missed earlier.
XM-2
5901
So this appears to be a higher lift but mild increase in duration
compared to the other listed specs.
Now my question is what can I expect for drivability from this?
Anyone with experience on the XM-2?
Also, where would I find the geometry for the stock cams? I will
–
'68 OTS : ‘03XJR I canna’ change the Law of Physics–Sco
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from PS sent Mon 9 Sep 2013:
Correct clearances for XM-2 cams is .012 and .014.
I have these on my car and they are not what I would
consider noisy.
I recently had them re-shimmed as part of a valve job.
I’ve had them on my car since 1980.
You can go a lot richer if you are looking for power increases.
Currently using UB needles. I had some others that were even
richer and the car really came alive in the old days, but
the current gasoline doesn’t put out as much power and
mileage was horrible. It wasn’t that big of deal when
gasoline was $1/gallon and I didn’t have all the
responsibilities that come with age.–
The original message included these comments:
XM-2 is 258 duration and 0.404’’ lift with 0.008/0.010’’
clearances. Factory cams in 1966 were 252 duration and
0.375’’ lift with 0.004/0.006’’ clearances. My experience with
these cams is there is little or no performance increase
below 4000 rpm and they are very noisy at idle. Perhaps a
performance decrease below 3000 rpm. The problem with
reground early (2 bolt) cams is what little quieting ramps
there were are ground away. When considering your options,
–
'68 OTS : ‘03XJR I canna’ change the Law of Physics–Sco
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Richard Kuschel sent Tue 10 Sep 2013:
Correct clearances for XM-2 cams is .012 and .014.
Richard,
Not according to the ISKY spec sheet that came with XM-2’s in
2000, it lists 0.008/0.010’’. They are two bolt cams, but I’ve
seem them also ground on four bolt cores. I have degreed XM-
2, XM-3 and X-5 and GTJ-25 cams in a head on the bench and
none of them have ramps like the factory post 69 cams.
Paul–
The original message included these comments:
Correct clearances for XM-2 cams is .012 and .014.
I have these on my car and they are not what I would
consider noisy.
Paul,
I have Isky cam spec sheets and I believe the older that came with
XM2’s listed 8-10 and a few years later the specs changed to 12 -14
when I got the XM3’s and this was when I talked to Isky and they said
8-10 would be fine. I just checked my records and I installed the
XM2’s in 2001 and the XM3’s in 2006 and I’d bet Isky changed their
specs somehow in between those to dates. When you degreed the XM3 cams
did you happen to check the lift?
Bob
889076
Plymouth, MiOn Sep 10, 2013, at 1:52 PM, PS wrote:
In reply to a message from Richard Kuschel sent Tue 10 Sep 2013:
Correct clearances for XM-2 cams is .012 and .014.
Richard,
Not according to the ISKY spec sheet that came with XM-2’s in
2000, it lists 0.008/0.010’’. They are two bolt cams, but I’ve
seem them also ground on four bolt cores. I have degreed XM-
2, XM-3 and X-5 and GTJ-25 cams in a head on the bench and
none of them have ramps like the factory post 69 cams.
Paul
The original message included these comments:
Correct clearances for XM-2 cams is .012 and .014.
I have these on my car and they are not what I would
consider noisy.
In reply to a message from Richard Kuschel sent Mon 9 Sep 2013:
I too run them, but in the 140 which is currently running
an early E head. I personally love them in the 3.4, esp
linked with the CR gearbox, she flat gets and revs to the
sun. No low end issues here either, however, I do agree
top end noise is a bit higher, but not terrible IME.
Jeff–
The original message included these comments:
I have XM2 Cams installed in my 4,2 litre 3-SU E-type.
They are very smooth, idle well and are even in throttle
response.
In reply to a message from Stevenson Robert sent Mon 9 Sep 2013:
Hi Bob,
I suppose that Isky could have changed the settings.
I got the .012/.014 settings from Lou Fidenza who built my
engine at Gran Turismo Jaguar back in 1980. He did confirm
that it was an Isky cam. They were building some highly
modified engines at the time that would really wail.
Now, it is possible that he may have used a different
setting than Isky may have recommended at that time (perhaps
to avoid damage from high revs and temps, but this is my
speculation) but their current specs are .012/.014.–
The original message included these comments:
Hi Richard,
Isky has recommended at least two different valve lash settings, 8 &
10 & 12 & 14, on their Jag cams over the past, that I know of, 15 or
so years. I questioned Isky’s hot line technician about this and was
told that 8 & 10 would be fine and that’s the way the XM3’s been set
for at least 7 years and the XM2’s for several years before that. Your
description of the XM2 cams is exactly the same as my experience!
Bob
889076
–
'68 OTS : ‘03XJR I canna’ change the Law of Physics–Sco
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Hi Richard,
Yes Sir, Lou built some great engines! In fact the he/they made the
headers and stub stacks that are on my engine. I’m a little surprised
that Lou owned up to using Isky cams but I always figured that Lou and
Bills cams were either an Isky design or ground by them. Isky’s XM2
and other Jag cams have been around at least from the late 50’s and I
think that it was SCG that ran an article about then called “hot
sticks” that listed, among others, these cams.
Bob
889076
Plymouth, Mi.On Sep 10, 2013, at 4:21 PM, Richard Kuschel wrote:
In reply to a message from Stevenson Robert sent Mon 9 Sep 2013:
Hi Bob,
I suppose that Isky could have changed the settings.
I got the .012/.014 settings from Lou Fidenza who built my
engine at Gran Turismo Jaguar back in 1980. He did confirm
that it was an Isky cam. They were building some highly
modified engines at the time that would really wail.
Now, it is possible that he may have used a different
setting than Isky may have recommended at that time (perhaps
to avoid damage from high revs and temps, but this is my
speculation) but their current specs are .012/.014.
The original message included these comments:
Hi Richard,
Isky has recommended at least two different valve lash settings, 8 &
10 & 12 & 14, on their Jag cams over the past, that I know of, 15 or
so years. I questioned Isky’s hot line technician about this and was
told that 8 & 10 would be fine and that’s the way the XM3’s been set
for at least 7 years and the XM2’s for several years before that.
Your
description of the XM2 cams is exactly the same as my experience!
Bob
889076
–
'68 OTS : ‘03XJR I canna’ change the Law of Physics–Sco
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Stevenson Robert sent Tue 10 Sep 2013:
Bob,
The XM-2 measured 0.399’’, GTJ-25 0.402’’ and the XM-3 0.420’’.
The big surprise was the stock post 69 parabolic cams, the
duration at 0 lift is more than 40 degrees over the
regrinds. The quieting ramps are vastly different, which
explains why the XJ-6 idles like crap when the clearances
close up in the normal wear cycle. Isky’s initial clearance
suggestion is the same as the Jaguar competition handbook.
I bet they changed them when the 4 bolt cores started coming
in and their suggested clearances were tighter than stock.
I have confirmed on a EFI engine using a wide band O2 sensor
that the big valve S3 head with stock cams out flow the XM-
2/GTJ-25 on an earlier 7E head.
Paul–
The original message included these comments:
specs somehow in between those to dates. When you degreed the XM3 cams
did you happen to check the lift?
Bob
Hi Paul,
Sounds like you have a flow bench at your disposal, lucky man! The
measured lift on my MX3’s was .442 and as that is closer to coil bind
then I liked I used their valve springs and as a point of interest
Chevy LS1 and Vortec 1999 up 4800-5300 engine valve spring shims are a
perfect size for 6 cylinder Jag engines. I’m running the S3 valves and
seats in the 3.8 head which presents problems in itself as I’m sure
that you know. As this the head sits I can never run stock cams on the
inlet side. Oh well, fun and games!
Bob
889076
Plymouth, Mi.> In reply to a message from Stevenson Robert sent Tue 10 Sep 2013:
Bob,
The XM-2 measured 0.399’’, GTJ-25 0.402’’ and the XM-3 0.420’’.
The big surprise was the stock post 69 parabolic cams, the
duration at 0 lift is more than 40 degrees over the
regrinds. The quieting ramps are vastly different, which
explains why the XJ-6 idles like crap when the clearances
close up in the normal wear cycle. Isky’s initial clearance
suggestion is the same as the Jaguar competition handbook.
I bet they changed them when the 4 bolt cores started coming
in and their suggested clearances were tighter than stock.
I have confirmed on a EFI engine using a wide band O2 sensor
that the big valve S3 head with stock cams out flow the XM-
2/GTJ-25 on an earlier 7E head.
Paul
The original message included these comments:
specs somehow in between those to dates. When you degreed the XM3
cams
did you happen to check the lift?
Bob
In reply to a message from Stevenson Robert sent Mon 9 Sep 2013:
Oh what a frustrating day!!!
I planned to attend this evening’s Jaguar Club of Michigan meeting
and get the chance to spend a few minutes with Bob absorbing his
experiences with Isky cams. A few miles short of Ann Arbor my
Acura’s speedometer and tach both went to zero and a few minutes
later the engine died. I’m guessing that my charging system gave up
the ghost though I had no indication of this and the battery
discharged beyond the ability to operate the ignition. Being about
40 miles from home and without tools and in a driving rainstorm I
decided to call a flatbed to bring the wounded home, a first time
in over 50 years of driving. A promised 20 to 30 minute wait turned
into a 3 hour saga as an accident interrupted the first truck, and
then a failed transmission waylaid the second; at least this is
what the dispatcher claimed. Is there a more helpless feeling than
being at the mercy of someone at the other end of a phone line.
Anyway it was almost 11 PM when I made it home.
Now for some more cam info. I did take the time today to measure
the valve lash on the rebuilt and never run engine that was claimed
to be set up by the best in the Ozarks. All of the exhaust gaps
were right at .012 in and the intakes read 7, 8, 6, 8, 6, 3. A call
to Isky reinforced the spec 12 and 14 as someone reported here.
Now that I understand that this cam is a relatively mild increase
to the stock duration and lift, I’m thinking of at least giving it
a try. The question remains though as to what gaps should I plan
on. The intakes clearly need some attention so I plan to pull that
cam and at least record the shim thicknesses to get some idea of
the seat conditions.
Does it make sense to leave the exhaust at 12 and shoot for 8 or
maybe 10 on the intakes? Going to spec would likely require a
complete new set of shims.
What do the experts recommend?–
The original message included these comments:
Gary We’ll be at the meeting this week. If it’s not raining i’ll
probably drive the 64 and you’ll probably be surprised at how little
difference there is in valve clatter between 4 & 6 and 8 & 10
–
Gary Brinker - 1E11523 66 OTS Mid Restoration - Maumee, Ohio
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–