[DeTomaso] Cylinder Heads leaking
Sean Korb
spkorb at gmail.com
Wed Nov 25 22:02:26 EST 2015
I second Larry's "Drive the Hell out of it!" recommendation. Keep putting
oil in there and see where it goes. If it was coming through the
combustion chamber you should see lots of smoke. Mine just blew out the
seals. Yuch! :)
On Wed, Nov 25, 2015 at 5:02 PM, Larry - Ohio Time <Larry at ohiotimecorp.com>
wrote:
> That sounds like good news Sean.
>
> Should you still have a problem after you get it running you need to do a
> complete and proper compression test as was explained earlier. By placing a
> bit of oil in the cylinder (2nd part of the test) it will give you an
> indication on how well the rings are sealing (the oil temporally seals
> them).
>
> In the meantime drive the hell out of it!
>
> Larry (someday) - Cleveland
>
>
>
> -----Original Message-----
> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of sean mundy
> Sent: Wednesday, November 25, 2015 4:36 PM
> To: jderyke at aol.com
> Cc: detomaso at poca.com
> Subject: Re: [DeTomaso] Cylinder Heads leaking
>
> I picked up a leak down tester and removed all the rocker arms so I didn't
> have to worry about getting the valves closed. Good news is all cylinders
> were in the green part of the gauge roughly around 25-30% loss. This is on
> a cold engine and I think you get better readings on a warm engine as
> recommended for this test. I then hooked up the air hose at about 30psi on
> each cylinder to check for air leaks by just listening. I listened in the
> tailpipe, intake, dipstick and watched for bubbles in the coolant. The
> little amount of air hissing could be heard from the dipstick tube. I
> think
> that is normal and based on my leak down results I think the heads and the
> valves are ok.???So back to the drawing board trying to figure out my rapid
> oil consumption. Think now the best plan is to continue to install my new
> Viton valve seals and put everything back together and see how the engine
> runs. If I'm still burning oil at that point then I will go back to the
> possibility that the intake gaskets are leaking and the oil is being sucked
> in that route.
>
> Date: Mon, 23 Nov 2015 14:59:23 -0500
> From: jderyke at aol.com
> To: seanmundy at hotmail.com
> CC: detomaso at poca.com
> Subject: Re: [DeTomaso] Cylinder Heads leaking
>
> You're right- you do in fact need the rockers not only installed but
> adjusted close to the way you'll be running them, in order to ingest
> consistent amounts of air to compress. Further, the plugs should be all
> removed and the throttles blocked wide open during your tests to increase
> the speed of the engine turning over. More speed = more compression= more
> variance between bad cylinders & good ones so its easier to differentiate.
> Then turn the engine over with the starter at least 5 times per cylinder, &
> write down the results. If you change ANY of the above conditions, your
> results will not compare well with others' results, some of which are
> published on line. The test is further described in all of Chilton's
> overhaul manuals & other similar places.
>
>
>
> You have a cylinder with pressurized air in it with
> valves and a gasket sealing one end & a piston & rings sealing
> (more or less) the other end. The famous compression test is a fairly crude
> test from 100 yrs ago, but it should at least point one in the direction of
> the likely cause and narrow down possibilities to one cylinder. Using a
> stethoscope with a pressurized engine (air compressor at 100 psi), I'm able
> to hear air leaking in the carb (bad intake valve), the tailpipes (bad
> exhaust valve) or the breather cap (bad rings or a bad head gasket). If TWO
> ADJACENT cylinders are low or leaking, that indicates a gasket blown
> between
> two cylinders. If you're poor, my stethoscope is an ancient two-ear airline
> sound connector; just be careful to not touch hot metal with the plastic
> tips, which melt. Better ones are at any auto parts store.
>
>
>
> You're looking first for consistent readings and second- significant
> variances in them. +- 15 psi is about normal on used non-race engines and
> should repeat 2-3 times. Variances beyond that either means the fitting is
> not being held in the sparkplug hole tightly ( i use the screw-in ones) or
> there's metal missing somewhere inside. Take the recovery tank off for
> better access to #4 plug. I cut the bracket welds and completely remove the
> whole assembly, then reinstall with a couple of sheet metal screws.
>
>
>
>
>
>
>
>
>
>
> Worst cases are holed pistons, a cracked cylinder with a
> piece of wall gone, a blown gasket or a chunk gone from a valve. But
> they are sort of rare and if the motor was running decently, none
> of these should apply. My best guess is a stuck ring. Several possible
> causes but the fix is replacement (with rings) especially if its a high
> mileage OEM part.
>
> Good luck, Sean- J DeRyke
>
>
>
>
>
>
>
>
>
>
>
>
>
> -----Original Message-----
>
>
> From: sean mundy <seanmundy at hotmail.com>
>
>
> Cc: detomaso <detomaso at poca.com>
>
>
> Sent: Sun, Nov 22, 2015 10:13 pm
>
>
> Subject: Re: [DeTomaso] Cylinder Heads leaking
>
>
>
>
>
> I was thinking the piston needs to suck in some air from the intake valve
> to
> be able to compress it so I thought I needed the rockers
>
>
> installed. I was only getting 30 to 40 psi on 5,6,7 cyl and on 8 I saw
> 200psi. Those numbers dont make sense as the motor was running
>
>
> pretty good power just burning oil
>
>
>
>
>
>
>
>
>
>
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>
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--
Sean Korb spkorb at spkorb.org http://www.spkorb.org
'65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera #1382
"The more you drive, the less intelligent you get" --Miller
"Computers are useless. They can only give you answers." -P. Picasso
-------------- next part --------------
I second Larry's "Drive the Hell out of it!" recommendation.A Keep
putting oil in there and see where it goes.A If it was coming through
the combustion chamber you should see lots of smoke.A Mine just blew
out the seals.A Yuch! A :)
On Wed, Nov 25, 2015 at 5:02 PM, Larry - Ohio Time
<[1]Larry at ohiotimecorp.com> wrote:
That sounds like good news Sean.
Should you still have a problem after you get it running you need to
do a
complete and proper compression test as was explained earlier. By
placing a
bit of oil in the cylinder (2nd part of the test) it will give you
an
indication on how well the rings are sealing (the oil temporally
seals
them).
In the meantime drive the hell out of it!
Larry (someday) - Cleveland
-----Original Message-----
From: DeTomaso [mailto:[2]detomaso-bounces at poca.com] On Behalf Of
sean mundy
Sent: Wednesday, November 25, 2015 4:36 PM
To: [3]jderyke at aol.com
Cc: [4]detomaso at poca.com
Subject: Re: [DeTomaso] Cylinder Heads leaking
I picked up a leak down tester and removed all the rocker arms so I
didn't
have to worry about getting the valves closed.A Good news is all
cylinders
were in the green part of the gauge roughly around 25-30% loss.A
This is on
a cold engine and I think you get better readings on a warm engine
as
recommended for this test.A I then hooked up the air hose at about
30psi on
each cylinder to check for air leaks by just listening.A I listened
in the
tailpipe, intake, dipstick and watched for bubbles in the coolant.A
The
little amount of air hissing could be heard from the dipstick
tube.A I think
that is normal and based on my leak down results I think the heads
and the
valves are ok.???So back to the drawing board trying to figure out
my rapid
oil consumption.A Think now the best plan is to continue to install
my new
Viton valve seals and put everything back together and see how the
engine
runs.A If I'm still burning oil at that point then I will go back
to the
possibility that the intake gaskets are leaking and the oil is being
sucked
in that route.
Date: Mon, 23 Nov 2015 14:59:23 -0500
From: [5]jderyke at aol.com
To: [6]seanmundy at hotmail.com
CC: [7]detomaso at poca.com
Subject: Re: [DeTomaso] Cylinder Heads leaking
A You're right- you do in fact need the rockers not only installed but
adjusted close to the way you'll be running them, in order to ingest
consistent amounts of air to compress. Further, the plugs should be all
removed and the throttles blocked wide open during your tests to
increase
the speed of the engine turning over. More speed = more compression=
more
variance between bad cylinders & good ones so its easier to
differentiate.
Then turn the engine over with the starter at least 5 times per
cylinder, &
write down the results. If you change ANY of the above conditions, your
results will not compare well with others'A results, some of which are
published on line. The test is further described in all of Chilton's
overhaul manuals & other similar places.
You have a cylinder with pressurized air in it with
valves and a gasket sealing one end & a piston & rings sealing
(more or less) the other end. The famous compression test is a fairly
crude
test from 100 yrs ago, but it should at least point one in the
direction of
the likely cause and narrow down possibilities to one cylinder. Using a
stethoscope with a pressurized engine (air compressor at 100 psi), I'm
able
to hear air leaking in the carb (bad intake valve), the tailpipes (bad
exhaust valve) or the breather cap (bad rings or a bad head gasket). If
TWO
ADJACENT cylinders are low or leaking, that indicates a gasket blown
between
two cylinders. If you're poor, my stethoscope is an ancient two-ear
airline
sound connector; just be careful to not touch hot metal with the
plastic
tips, which melt. Better ones are at any auto parts store.
You're looking first for consistent readings and second- significant
variances in them. +- 15 psi is about normal on used non-race engines
and
should repeat 2-3 times. Variances beyond that either means the fitting
is
not being held in the sparkplug hole tightly ( i use the screw-in ones)
or
there's metal missing somewhere inside. Take the recovery tank off for
better access to #4 plug. I cut the bracket welds and completely remove
the
whole assembly, then reinstall with a couple of sheet metal screws.
A Worst cases are holed pistons, a cracked cylinder with a
A piece of wall gone, a blown gasket or a chunk gone from a valve. But
they are sort of rare and if the motor was running decently, none
of these should apply. My best guess is a stuck ring. Several possible
causes but the fix is replacement (with rings) especially if its a high
mileage OEM part.
Good luck, Sean- J DeRyke
-----Original Message-----
From: sean mundy <[8]seanmundy at hotmail.com>
Cc: detomaso <[9]detomaso at poca.com>
Sent: Sun, Nov 22, 2015 10:13 pm
Subject: Re: [DeTomaso] Cylinder Heads leaking
I was thinking the piston needs to suck in some air from the intake
valve to
be able to compress it so I thought I needed the rockers
A A installed.A I was only getting 30 to 40 psi on 5,6,7 cyl and onA
8 I saw
200psi.A Those numbers dont make sense as the motor was running
A A pretty good power just burning oil
_______________________________________________
Detomaso Forum Managed by POCA
Posted emails must not exceed 1.5 Megabytes
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To manage your subscription (change email address, unsubscribe, etc.)
use the links above.
--
Sean Korb [12]spkorb at spkorb.org [13]http://www.spkorb.org
'65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera
#1382
"The more you drive, the less intelligent you get" --Miller
"Computers are useless.A They can only give you answers." -P. Picasso
References
1. mailto:Larry at ohiotimecorp.com
2. mailto:detomaso-bounces at poca.com
3. mailto:jderyke at aol.com
4. mailto:detomaso at poca.com
5. mailto:jderyke at aol.com
6. mailto:seanmundy at hotmail.com
7. mailto:detomaso at poca.com
8. mailto:seanmundy at hotmail.com
9. mailto:detomaso at poca.com
10. mailto:DeTomaso at poca.com
11. http://poca.com/mailman/listinfo/detomaso_poca.com
12. mailto:spkorb at spkorb.org
13. http://www.spkorb.org/
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