Some of you may remember my travails with my 4.2 engine
reassembly a few weeks ago. I took the advice of many
helpful responses and did a complete tear down,
examination, and measurement of everything with mostly
satisfactory results. Bores and journals looked great and
fell within specs and found that crank had been cleaned out.
The only problem I found was that about a 3/8 inch of the
contact surface of one of the middle rings had chipped off
next to the gap, so I’m now in search of a replacement.
These are new AE pistons .020 over with pre fit AE rings. I
haven’t called around to the usual suppliers yet, but most
web sites seem to suggest that I can only get full sets in
which case a new piston is probably cheaper if I can even
find that as a single. I’ve read many archives and from the
lack of mention, I assume all manufacturers are
dimensionally the same, correct? So, it comes down to how
important is it that I use an AE replacement and does
anyone have suggestions of where I might source this.
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 Fri 27 Nov 2015:
Performance unlimited do a range of no gap rings which I
used in the past with a plus 20 thou AE piston, gapping is
something you must do, don’t take it for granted, and your
ring would have been chipped on fitting I would guess. I
would personally never replace just one ring regardless of
mileage, replace all head items in sets also, then you get
uniform wear…in theory of course…–
The original message included these comments:
Some of you may remember my travails with my 4.2 engine
reassembly a few weeks ago. I took the advice of many
helpful responses and did a complete tear down,
examination, and measurement of everything with mostly
satisfactory results. Bores and journals looked great and
fell within specs and found that crank had been cleaned out.
The only problem I found was that about a 3/8 inch of the
contact surface of one of the middle rings had chipped off
next to the gap, so I’m now in search of a replacement.
These are new AE pistons .020 over with pre fit AE rings. I
haven’t called around to the usual suppliers yet, but most
–
Keith.P. Series2 Roadster
exmouth, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
Ask John Carey. The late lamented Dick Vandermeyden had
some 5+1 piston sets and you might be able to get an odd
one.
Just because the bore and the deck to pin size is the same
(and the latter may vary a fraction) doesn’t nean the
skirt design or piston mass are compatible, let alone
exact crown spec/CR. Some pistons have a cast-in ferrois
expansion control ring for example.
The engine would run but you might be off on balance or
torsional resonances at cruise? I’m as cheap as they come
but even I would not fit odd pistons…–
The original message included these comments:
lack of mention, I assume all manufacturers are
dimensionally the same, correct? So, it comes down to how
important is it that I use an AE replacement and does
anyone have suggestions of where I might source this.
–
1E75339 66 D, 1R27190 70 FHC, 79 S2 XJ12L
Gaithersburg, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
I’ve read many archives and from the
lack of mention, I assume all manufacturers are
dimensionally the same, correct?
Gary,
That is a very bad assumption. Pistons and rings must be
individually fitted to the bores because they are not the
same. A broken ring is a serious failure and my advice
would be to determine the cause before you repeat the
error. I would be measuring bore clearances, ring gaps,
side gaps, looking for signs of detonation and more
assembly mistakes.
Paul–
The original message included these comments:
Some of you may remember my travails with my 4.2 engine
reassembly a few weeks ago. I took the advice of many
helpful responses and did a complete tear down,
examination, and measurement of everything with mostly
satisfactory results. Bores and journals looked great and
In reply to a message from PeterCrespin sent Sat 28 Nov 2015:
Pete,
thanks for mentioning the Vandermeyden parts stash again -
yes we do indeed have pistons for sale.
6 ea 4.2 Hepolite - Pistons 18393 - .020’’ .508mm
6 ea 4.2 Hepolite - AE Pistons - 8.7:1 21397/STD
there is also a lot of 5ea. C28025 and 1ea. C33090 pistions–
The original message included these comments:
Ask John Carey. The late lamented Dick Vandermeyden had
some 5+1 piston sets and you might be able to get an odd
one.
–
john carey : (888373) Bettie IV - my '63 S1 FHC
Los Gatos/California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from john carey sent Sat 28 Nov 2015:
Bits and pieces.
Busted rings usualy result
from a slip of the compressor
on installation. However, inadequate end gap
is another cause. Or, just a material flaw.
Only with great reluctance would I
reuse rings that had been seated.
Leakage almost certain.
If you have the dimensions and the
characteristic of the piston, you
can shop for a replacement set.
Dimensions means all, not only the
bore size !
A light scuff of the bores seems
necessary, even if the hatch of the
original hone still show.
Old tale:
Ak Miller and crew built the
‘‘Caballo de Hierro’’ to race in
Mexico circa 1950. Auto writer
Brock Yates went with the crewa
well traveled Olds V8 as a chase car.
It busted a piston. Caballo was
Olds powered. A local Olds dealer
provided facilities. Brock and crew
begged for an old piston from the
scrap heap. No, senores, no es possible!!!
Vendemos uno Nuevo…
Fixed, on with the race.
Carl–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
I have a spare 5 set of Deves rings .020 for AE
pistons …if you want a set let me know…–
Pjwilletts 62 ots, 60 Bugeye sprite
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
Did this motor run at a lll? sounds like tight ring gap on
install. Also to much clearance in grove if ring is too
thin will break rings like you can’t believe (running
engine)
I wouldn’t run a different piston from the other 5.
Has the bore been sized to fit those pistons? different
pistons have different piston/wall clearance spec.
I’d get the new rings.
If you can get the actual AE rings on those pistons even if
yu have to get a set. I would go with that.
Check and gap and vertical clearance of ring in piston gap.–
The original message included these comments:
The only problem I found was that about a 3/8 inch of the
contact surface of one of the middle rings had chipped off
web sites seem to suggest that I can only get full sets in
–
S1 XKE 1966. I really got to put this back together…
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Bill B 2 sent Sat 28 Nov 2015:
Thanks all for your thoughts.
I should have provided more details. This engine has never
run and the chipped ring clearance etc. is good. I assume
it was an installation slip that caused the chip and they
just went ahead anyway, very easy to believe with the other
problems I found. I am not going to replace the piston,
just looking for a replacement ring. My question about
dimensions was not for pistons but for replacement rings as
vendors seem to just quote ring sets without even
mentioning brand. This makes me think that at least most
replacement rings are made to original dimensional specs.
I would certainly check end gap and side clearance of any
replacement ring.–
The original message included these comments:
Did this motor run at a lll? sounds like tight ring gap on
install. Also to much clearance in grove if ring is too
–
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 Sat 28 Nov 2015:
I purchased cast iron rings from Total Seal for
my engine. If I recall correctly, they’ll sell
individual rings.
If the engine has miles on it, be sure to check
ring land clearance as well as end gap.
Dave–
1969 BRG OTS
Skaneateles, NY, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
Gary when you replace a piston ring it is essential that you
also check the back clearance of the ring. If you get a piston
with rings already installed like from AE you probably don’t
have to do this but if you change rings you need to check it.
Rings come in various widths. During the manufacturing process
pistons are cam ground. That means that when at room temp they
are a slight oval, the shorter dimension being across the
bosses for the pin. The idea is that when the piston heats up
and expands the greatest expansion is through these bosses as
that’s where all the aluminum is. The ring groove is however
machined as a circle when cold so when the piston heats up the
groove is now the oval. You may have enough clearance in the
front and back of the piston and not enough over the bosses.
That causes the piston to force the ring into the cyl wall -
ugly - stuff starts to melt. I know this from hard experience
sadly.
Terry Sturgeon–
68 E Type OTS, 67 E Type coupe, 07 XKR
Victoria, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from inlinesix sent Sat 28 Nov 2015:
Just out of interest, and maybe can be confirmed by older
Australian posters, but I have heard many times, that Jaguar
engines were often rebuilt using rings from GM Holden 253ci
V8 motors, (they had a bore size 92.08mm), but were less
than half the cost at that time…I am not suggesting trying
this–
The original message included these comments:
Gary when you replace a piston ring it is essential that you
also check the back clearance of the ring. If you get a piston
In reply to a message from awg sent Sun 29 Nov 2015:
Coincidence. Just spent a couple of hours fettling/fitting
new rings to standard pistons for a re-lined E-type
engine. Even AE rings on AE Hepolite pistons in a ‘new’
standard block need adjusting. I wonder how long it would
take fettling rings off something else?–
1E75339 66 D, 1R27190 70 FHC, 79 S2 XJ12L
Gaithersburg, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from PeterCrespin sent Sun 29 Nov 2015:
Fettling is fun, I once spent a whole afternoon modifying a
Singer exhaust valve, pin retained, to take a pair of
collets to fit one cylinder of my Mk 5 Douglas, all done
with a bench grinder !!! The right hand exhaust had been
glowing cherry red, and as the clamp was loose, burned the
heel of my right boot a lot hoofing it back in on the
move…my dad told me of times when rings were handcut from
cast pipe, seems there was a standard sized pipe of the day
which worked well with the ten horse Y type Fords…but, if
you ever fit Cords, which I understand are still around from
a long time ago, be prepared to tow start your car, fitted
them to a MK2 3.4 many years ago, would not crank with the
friction generated until it had run for a while…–
The original message included these comments:
In reply to a message from awg sent Sun 29 Nov 2015:
Coincidence. Just spent a couple of hours fettling/fitting
new rings to standard pistons for a re-lined E-type
engine. Even AE rings on AE Hepolite pistons in a ‘new’
standard block need adjusting. I wonder how long it would
take fettling rings off something else?
1E75339 66 D, 1R27190 70 FHC, 79 S2 XJ12L
Gaithersburg, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–
Keith.P. Series2 Roadster
exmouth, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from sozfingers sent Mon 30 Nov 2015:
Interesting:
Cords or Fords. The former very
sophisticated, the latter ones
in that time period, much simpler.
In early days, indeed, engines
were set up very tightly.
Too much for early starters
to spin enough to fire. Tow starts
common. then, left to run at a quite
fast idle with a hose to add cool water.
Tightening the rods on my T was regular
maintenance. A bit misguided. Much later,
I learned that they did much better
if left a bit looser!!! My starters and
batteries were rarely functional.
Hand cranked.
Too tight after a bearing ‘‘adjustment’’.
The street in front and back of our
house was nicely down slope. Just push
and run along side. then, jump in, and
jam it in gear. It would always fire
right up. Back home, add the hose and
let it run about fifteen minutes. Back
to normal til the next time…
Carl–
The original message included these comments:
you ever fit Cords, which I understand are still around from
a long time ago, be prepared to tow start your car, fitted
them to a MK2 3.4 many years ago, would not crank with the
friction generated until it had run for a while…
–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from gbrinker sent Fri 27 Nov 2015:
As a follow up to my search for a replacement AE piston ring
I was unable to find a source for a single or one piston
ring set. I did however find a reasonably priced full set
of .030 over 4.2 AE Hepolite rings on Ebay. For anyone in a
similar situation that might search this thread in the
future, I now have 17 new rings which I will make available
free to anyone that might need a single or even a one piston
set.–
The original message included these comments:
important is it that I use an AE replacement and does
anyone have suggestions of where I might source this.
–
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 Fri 4 Dec 2015:
Compatibility of piston rings is certainly not my area of
expertise, but wouldn’t you be a little safer using 3 new
Hepolite rings on the needy piston rather than mixing up
rings from a different manufacturer?–
Mark 1E14988 67 OTS, 2002 VDP
Burke, VA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–