[E-Type] Compression Test - Carb Piston Hold Open

E-Type
1

What’s the best way to hold the pistons up? Don’t want to
risk damaging the piston and don’t want to restrict air
flow. Paint stick maybe?

Thanks.

By the way, can I change my user name and still stay linked
to previous posts?–
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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2

In reply to a message from golfnut324 sent Sun 8 Jul 2012:

Disregard this question. I found that a carpenter’s shim on
its side fit perfectly and I think I’m justified in being
pleased that, after 45 years and NO other engine work except
the top half was worked in 1994, the compression came out
172-179-171-173-172-175!–
The original message included these comments:

What’s the best way to hold the pistons up? Don’t want to

–
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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3

Wow!! If your gage isn’t bad that is great compression.
LLoyd

My driveway is long enough that you can appreciate the conflict between the desire for privacy and the terror of being completely lost .----- Original Message -----
From: “golfnut324” caggilbert@gmail.com
To: e-type@jag-lovers.org
Sent: Sunday, July 8, 2012 2:33:51 PM
Subject: Re: [E-Type] Compression Test - Carb Piston Hold Open

In reply to a message from golfnut324 sent Sun 8 Jul 2012:

Disregard this question. …

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4

In reply to a message from LLoyd sent Sun 8 Jul 2012:

Father bought car new and babied it until he died in '92.
Been mine since. May be advantage to having been in the
family? But now it’s time for a clutch!–
The original message included these comments:

Wow!! If your gage isn’t bad that is great compression.

–
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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5

In reply to a message from golfnut324 sent Sun 8 Jul 2012:

Craig,

If you have time, try taking the reading again without holding the
pistons up. I’ll bet you get approximately the same numbers.

Jerry–
Jerry Mouton '64 FHC 889791 ‘MIK Jaguar’
Palo Alto, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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6

…but I think you have to crank the engine longer…
LLoyd

My driveway is long enough that you can appreciate the conflict between the desire for privacy and the terror of being completely lost .----- Original Message -----
From: “mouton” jerry@moutons.org
To: e-type@jag-lovers.org
Sent: Monday, July 9, 2012 9:42:03 AM
Subject: Re: [E-Type] Compression Test - Carb Piston Hold Open

In reply to a message from golfnut324 sent Sun 8 Jul 2012:

Craig,

If you have time, try taking the reading again without holding the
pistons up. I’ll bet you get approximately the same numbers.

Jerry

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7

In reply to a message from mouton sent Mon 9 Jul 2012:

Jerry,

I’ll try that. FWIW, a few times I noticed that the ‘‘shim’’
dropped off it’s edge on one of the carbs during the
cranking. In those cases I did not notice a difference in
reading after repeating with the pistons propped again.

I did run the test at least twice on each cylinder and
consistently got the same reading. I was pleased with the
closeness of the readings as much as the absolute value.

Fluids are now drained, interior half stripped, tunnel work
is done and starting on the engine bay disconnects. I know
it sounds familiar to y’all and my son and I are having a blast.

Thanks for all of your help and participation at this and
other forums!

p.s. Can I change my nickname? I noticed most of you use a
form of your real name as a nickname.–
The original message included these comments:

If you have time, try taking the reading again without holding the
pistons up. I’ll bet you get approximately the same numbers.
Jerry

–
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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8

In reply to a message from golfnut324 sent Mon 9 Jul 2012:

Craig,

I don’t know about the nickname, but golfnut324 is probably as good
as any! Your email address always shows and it says your name, too.

Jerry–
Jerry Mouton '64 FHC 889791 ‘MIK Jaguar’
Palo Alto, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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9

In reply to a message from mouton sent Tue 10 Jul 2012:

So be it! I’ll be known as golfnut324 because I am, a
golfnut that is.–
The original message included these comments:

I don’t know about the nickname, but golfnut324 is probably as good
as any! Your email address always shows and it says your name, too.

–
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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10

In reply to a message from golfnut324 sent Sun 8 Jul 2012:

Hi,

ok, that looks good, BTW after the cyl head rebuild I seem
to have a constant 176-175-173-174-174-175. (a 1966 4.2L)

But a friend who’s car I was helping to sort out developed a
sudden oil leak into the air intake and from the inlet cam
cover, not much oil, but high pressure and very messy.

Very high oil pressure, especially when revving a bit, it
would jump off the scale and inject oil into the air intake
through the breather.

We suspected the oil filter housing and valves, and next the
breather but nope, in the end we measured compression and it
turned out to be: 187-186-0-173-183-180!

So otherwise nice, but cyl. nr #3 !?!??! The needle would
not move at all, absolute zero compression. A stuck valve?
That’s what we thought, but with a primitive compressed air
leak-down test showed all the air was going straight into
the crankcase, as if the piston had a hole in it.

The piston looks fine from what we can see though the plug
hole, but surely piston rings can not evaporate without any
rattles and other noises, can they? And even if they were
shot, with a warm engine and lots of oil you’d expect the
needle to move at least a bit, right? No?

Anyone (Ken?) with experience in taking the pistons out
through the bottom? Can you get any of them out without
removing the crank? When I replaced the big end bearings and
con rod bolts and nuts I thought I could have taken the
pistons out too, if required. I did not as there was no
need, but now I am not sure what to tell this friend of mine
about his options, or some alternative to a complete
professional rebuild, huh?

Cheers,
Pekka T. 1E76372BW MOD–
The original message included these comments:

Disregard this question. I found that a carpenter’s shim on
its side fit perfectly and I think I’m justified in being
pleased that, after 45 years and NO other engine work except
the top half was worked in 1994, the compression came out
172-179-171-173-172-175!
Craig Gilbert - '68 E-Type FHC
Birmingham, AL, United States

–
MKV 3.5L DHC, E-type 2+2 Ser.1 MOD, XJ6C MOD, XJ8 Executive
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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11

In reply to a message from ptelivuo sent Fri 13 Jul 2012:

Pekka,

Yes, rings can sometimes disappear quickly and quietly. I’ve
seen it a few times. No, you can’t remove the pistons out the
bottom. I would try to find a borescope - something very had
has happened to that one cylinder, and one way or another, you
will end up, at a minimum, pulling the head off. But, from
the sound of it, the bottom end is broken.–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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12

In reply to a message from Ray Livingston sent Fri 13 Jul 2012:

Hi Ray,

Thanks! That’s what I was afraid of! I think I can borrow a
scope of some sort, we’ll see if there’s a hole in the
piston or something.

The blowby test was like blowing air into the crankcase as
if there was no piston. Still I could feel with a long pin
there was a piston in there and it was moving up and
down…beats me!

I’ll report back but it seems that none of the three pro
workshops in Finland are willing to take off the head of an
E-type before the end of September!

I won’t do it, if was my own care, then maybe, but in this
case it’s not worth the effort and the risks of breaking
something doing it.

Cheers,
Pekka T. 1E76372BW MOD–
The original message included these comments:

Pekka,
Yes, rings can sometimes disappear quickly and quietly. I’ve
seen it a few times. No, you can’t remove the pistons out the
bottom. I would try to find a borescope - something very had
has happened to that one cylinder, and one way or another, you
will end up, at a minimum, pulling the head off. But, from
the sound of it, the bottom end is broken.

Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States

–
MKV 3.5L DHC, E-type 2+2 Ser.1 MOD, XJ6C MOD, XJ8 Executive
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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