| Author |
Message |
Steve Richardson
Guest
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 Posted:
Sun Mar 06, 2005 3:07 am Post subject:
Need help with vacuum gauge readings |
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My 1950 Dodge Wayfarer has low compression in all cylinders (90-105 psi when
it should be 120-150 psi at cranking speed. Judging by the carbon
everywhere, its previous owners had been running it rich for a long time,
and in fact that's the only way I can keep it running myself despite two new
automatic chokes that I finally replaced with a manual conversion. I drive
it, but it has very little power and can't handle hills at all. Timing is
OK and the vacuum advance seems to be working. Plugging in a vacuum gauge
gave only 6 inches Hg, though, where I'd expect maybe 15 or higher. The
needle was steady on idle, no jumping around at all. Depressing and
releasing the gas pedal caused the needle to drop down to 2 but only pop
back to 6, where I'd expect maybe 20 or more. Running the engine fast put
the needle at 9, again very steady with no bobbling around. I'm a little
rusty with this kind of test. Low steady needle could mean what? My
ancient Chilton's for 1940-53 cars says that if it's bad rings the needle
probably should read more than 6 to begin with, and should drop to 0 and
bounce back higher than baseline when the throttle is opened and closed
quickly, which doesn't happen. The behavior seems to match what they show
for valve timing problems, or maybe an actual leak from the head or
carburetor gaskets. Any thoughts or suggestions? Money is tight and I want
to fix only what really needs fixing, not do a complete engine rebuild
unless that's absolutely necessary. It's pretty flat around here anyway --
to heck with the hills!
- Steve Richardson
50 Dodge Wayfarer
76 Triumph TR7 (original owner)
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Guest
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| Posted:
Sun Mar 06, 2005 7:50 am Post subject:
Re: Need help with vacuum gauge readings |
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A steady needle indicates consistant vacuum. A low reading can mean
fouled valves, low compression, poor vacuum source, plugged exhaust,
too much carbon in the combustion chamber - valve area. The vacuum
gage should have the clues to look for on the dial.
I would:
Change the oil to a straight grade 20w or in warm weather or use a 30w
or 15/40 (15/40 is normally used in diesels and has more cleaning
solvents). Consider using that RESTORE product in the oil.
Dump two cans of injector cleaner in the fuel (It does a nice job of
cleaning the carbon out of the valves and combustion chamber).
Find a new vacuum gage attaching point. There should be a plug on the
intake that you can try to remove and screw in a fitting. With
engine at idle, spray some carb cleaner aound the outside base of the
carb and manifold to see if rpm changes - vacuum leak.
Check the points and point gap - you may have lost dwell which realy
makes for a lazy engine.
When you get tired of trying to find 6v electrics at an exhorbant
cost, you might consider moving up to 12v and installing electronic
ignition from a slant 6 and 318 like I did (you need both
distributers to make one for the flathead)
Pete
50 plymouth deluxe
39 plymouth deluxe.
On Sat, 05 Mar 2005 22:07:10 GMT, "Steve Richardson"
<stever_sl@sbcglobal.net> wrote:
| Quote: | My 1950 Dodge Wayfarer has low compression in all cylinders (90-105 psi when
it should be 120-150 psi at cranking speed. Judging by the carbon
everywhere, its previous owners had been running it rich for a long time,
and in fact that's the only way I can keep it running myself despite two new
automatic chokes that I finally replaced with a manual conversion. I drive
it, but it has very little power and can't handle hills at all. Timing is
OK and the vacuum advance seems to be working. Plugging in a vacuum gauge
gave only 6 inches Hg, though, where I'd expect maybe 15 or higher. The
needle was steady on idle, no jumping around at all. Depressing and
releasing the gas pedal caused the needle to drop down to 2 but only pop
back to 6, where I'd expect maybe 20 or more. Running the engine fast put
the needle at 9, again very steady with no bobbling around. I'm a little
rusty with this kind of test. Low steady needle could mean what? My
ancient Chilton's for 1940-53 cars says that if it's bad rings the needle
probably should read more than 6 to begin with, and should drop to 0 and
bounce back higher than baseline when the throttle is opened and closed
quickly, which doesn't happen. The behavior seems to match what they show
for valve timing problems, or maybe an actual leak from the head or
carburetor gaskets. Any thoughts or suggestions? Money is tight and I want
to fix only what really needs fixing, not do a complete engine rebuild
unless that's absolutely necessary. It's pretty flat around here anyway --
to heck with the hills!
- Steve Richardson
50 Dodge Wayfarer
76 Triumph TR7 (original owner)
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Steve Richardson
Guest
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| Posted:
Sun Mar 06, 2005 6:29 pm Post subject:
Re: Need help with vacuum gauge readings |
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OK, great! It's going to be a nice warm day and this gives me something to
do outside other than cutting down dead trees, cleaning up the flower beds,
fixing the flat tire on the lawn tractor, and other Spring chores ad
nauseum. It's also a good day to install that old Allstate turn signal
kit -- drivers around here don't seem to understand what hand signals mean.
Thanks Pete!
- S Richardson
<cselby@mts.net> wrote in message news:422a747d.31569531@news.mts.net...
| Quote: | A steady needle indicates consistant vacuum. A low reading can mean
fouled valves, low compression, poor vacuum source, plugged exhaust,
too much carbon in the combustion chamber - valve area. The vacuum
gage should have the clues to look for on the dial.
I would:
Change the oil to a straight grade 20w or in warm weather or use a 30w
or 15/40 (15/40 is normally used in diesels and has more cleaning
solvents). Consider using that RESTORE product in the oil.
Dump two cans of injector cleaner in the fuel (It does a nice job of
cleaning the carbon out of the valves and combustion chamber).
Find a new vacuum gage attaching point. There should be a plug on the
intake that you can try to remove and screw in a fitting. With
engine at idle, spray some carb cleaner aound the outside base of the
carb and manifold to see if rpm changes - vacuum leak.
Check the points and point gap - you may have lost dwell which realy
makes for a lazy engine.
When you get tired of trying to find 6v electrics at an exhorbant
cost, you might consider moving up to 12v and installing electronic
ignition from a slant 6 and 318 like I did (you need both
distributers to make one for the flathead)
Pete
50 plymouth deluxe
39 plymouth deluxe.
On Sat, 05 Mar 2005 22:07:10 GMT, "Steve Richardson"
stever_sl@sbcglobal.net> wrote:
My 1950 Dodge Wayfarer has low compression in all cylinders (90-105 psi
when
it should be 120-150 psi at cranking speed. Judging by the carbon
everywhere, its previous owners had been running it rich for a long time,
and in fact that's the only way I can keep it running myself despite two
new
automatic chokes that I finally replaced with a manual conversion. I
drive
it, but it has very little power and can't handle hills at all. Timing is
OK and the vacuum advance seems to be working. Plugging in a vacuum gauge
gave only 6 inches Hg, though, where I'd expect maybe 15 or higher. The
needle was steady on idle, no jumping around at all. Depressing and
releasing the gas pedal caused the needle to drop down to 2 but only pop
back to 6, where I'd expect maybe 20 or more. Running the engine fast put
the needle at 9, again very steady with no bobbling around. I'm a little
rusty with this kind of test. Low steady needle could mean what? My
ancient Chilton's for 1940-53 cars says that if it's bad rings the needle
probably should read more than 6 to begin with, and should drop to 0 and
bounce back higher than baseline when the throttle is opened and closed
quickly, which doesn't happen. The behavior seems to match what they show
for valve timing problems, or maybe an actual leak from the head or
carburetor gaskets. Any thoughts or suggestions? Money is tight and I
want
to fix only what really needs fixing, not do a complete engine rebuild
unless that's absolutely necessary. It's pretty flat around here
anyway --
to heck with the hills!
- Steve Richardson
50 Dodge Wayfarer
76 Triumph TR7 (original owner)
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Guest
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| Posted:
Mon Mar 07, 2005 2:06 am Post subject:
Re: Need help with vacuum gauge readings |
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When I read the post I was formulating
an answer in my head, then I read Petes
answer and it could'nt have been better said. He even got the carb
cleaner spray
on the intake manifold trick.
Nice reply.
Dan
Milw |
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Guest
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| Posted:
Mon Mar 07, 2005 6:12 am Post subject:
Re: Need help with vacuum gauge readings |
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My mother thanks you
On Sun, 6 Mar 2005 15:06:14 -0600, LAIKA1@webtv.net wrote:
| Quote: | When I read the post I was formulating
an answer in my head, then I read Petes
answer and it could'nt have been better said. He even got the carb
cleaner spray
on the intake manifold trick.
Nice reply.
Dan
Milw
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