So, a couple of questions:
Is the 15" reading steady, or does the needle flutter
?
When you read your timing, is the vacuum line off the
vacuum advance, and is the vacuum line plugged ?
What RPM are you at when you are reading the 10
degrees BTDC ?
I determined the worn valve guides condition by
referencing pictures that are associated with using the vacuum gauge. There are
about a dozen conditions that the gauge can diagnose.
You said that the RPMs went down when you sprayed. Watch
the vacuum gauge when you spray. Also, spray after the engine is fully warmed
up.
Ron
----- Original Message -----
Sent: Monday, October 26, 2015 3:45
PM
Subject: Re: [Chrysler300] Chrysler 300H
idle speed
Thanks Ron.
I have had the engine rebuilt less than 50,000 miles ago (but many years)
after over 300,000 miles.
Distributor rebuilt by Philbin last year.
Damper rebuilt the year before (timing mark issue)
New plugs last week.
New plug wires (solid core) last year
Carbs “restored” by Ace Fuel in San Jose
I checked vacuum and did respond as soon as I did, I had 15 inches which
was unaffected by idle mixture adjustment.
Timing is at 10 BTDC
Idle at 650 (sometimes).
Fresh fuel
How did you trace your problem to worn valve guides by using a vacuum
gauge? What specifically said “worn valve guides”?
Do you think carb cleaner sprayed on the intake manifold causing engine
speed changes meaningful?
What else would you suggest?
Thanks, Mike
Hi Mike -
With all due respect, what you are doing is taking
'wildazz guesses' at the problem, rather than finding the true issue. With
this approach, you will end up wasting your time and wasting your money.
You need to do a proper diagnosis of the problem in
order to determine the solution.
Please reread my previous responses. If you have
never used a vacuum gauge, there are plenty of write-ups on the internet and
some videos on YouTube. It is the best tool for diagnosing top end problems on
your engine.
Note: I was in the same situation that you are in,
about a year ago. Rough idle in gear (slow idle, fully warmed up engine). Also
thought it was vacuum leaks. I resealed intake manifold, sprayed carb
cleaner, got a new carb base gasket, etc. Still had the same problem. I hooked
up the vacuum gauge. It was reading 13-14" at slow idle, rather than 18-20",
which is normal. The fluttering needle was traced to worn valve guides,
which is likely in an engine with 204,000 miles. So the heads are coming off
soon for a rebuild.
Ron
From:
"Michael Moore" < mmoore8425@xxxxxxx> To:
"Mark Souders" < mrs954@xxxxxxx> Cc: ronbo97@xxxxxxxxxxx, chrysler300@xxxxxxxxxxxxxxxSent:
Monday, October 26, 2015 2:55:38 PM Subject: Re: [Chrysler300]
Chrysler 300H idle speed
Mark,
Check this out: A cracked intake manifold on the bottom side could
explain it.
Thanks, Mike
Intake
Manifold Silencer Insulation Kit (Chrysler,
Dodge, Plymouth)
This
Intake Manifold Insulation was used all through the 1960s, and into the
1970s on big blocks, except hemi. It's not likely to have been
used on 440-6 engines, and it's not likely to have been used on
mid-1970s-and-later high performance blocks. Its purpose was listed
in parts catalogs as "Valve Tappet Noise Reduction Silencer Package."
Some say its real
purpose was to prevent the intake manifold from cracking due to
heat. Some say it was only used on air conditioning
cars. Those who have observed many original engines have seen its
two pieces tucked under the intake manifold. It is POSSIBLE to
install these exactly-reproduced pieces after your manifold is already
in place, but it's much easier to do like |
|
the
factory did. The pieces were placed on the pan, large piece in front,
small piece in rear, then the manifold was bolted in. These pieces
should have engine paint overspray. These silencers are a heavy
aluminum foil filled with a fiberglass insulation pad. The foil is
correct in size and shape. The pads are a pair that don't look like each
other, nor did the originals. The edges of the pads are sealed
correctly. Retainer not included. |
$25.00
a set (+ $11.00 S/H USA)
Mike,
That intake manifold gasket is a one-piece metal pan. Ideally, when you
remove the intake you should replace that metal gasket because the area around
each runner crushes when you torque down the bolts. Could be that it's leaking
and drawing in your carb cleaner and affecting the RPM or burn. On a side
note, there should also be an insulation pad tucked in between the intake and
the gasket pan, to reduce the valve noise. I know, because mine is missing,
too.
Mark
-----Original
Message----- From: Michael Moore mmoore8425@xxxxxxx
[Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> To:
Ron Waters < ronbo97@xxxxxxxxxxx> Cc:
chrysler300 < chrysler300@xxxxxxxxxxxxxxx> Sent:
Mon, Oct 26, 2015 2:12 pm Subject: Re: [Chrysler300] Chrysler 300H idle
speed
Hey
Ron,
I just sprayed some carb cleaner around the intake manifold with
engine idling ca 750-800 (still cold).
I had not connected the vacuum gauge. On the 300H 2x4 intake
manifold, there is an area midway along the sides of the manifold which
usually has the paint burned off and is where there is an opening through the
manifolds to the valley below. When I sprayed that area, on both sides,
the engine “changed” . It seemed to run smoother but at a lower rpm (??). I
thinks its odd that it’s where that opening in the manifold is on both sides
so carb cleaner is going into the valley. I think SOMETHING there is leaking
but don’t know what. That manifold was removed last in 1986 in Ray Dorn’s back
yard in Portland while I was on my way back from a meet in Victoria. I had a
bad case of valve recession and had to have hardened seats put in on the road.
I did not have a torque wrench so I just tightened the dickens out of the
screws . I wonder if the gaskets have just burned.
Thanks,
Mike Moore
300H
ps. I think my failing starter made its last start! (Maybe)
Mike -
How are you testing for vacuum leaks ? My method is to hook up a
vacuum gauge and get a reading. Then with the gauge still connected, spray
carb cleaner at the base of the carb and around the edge of the intake. If the
numbers change significantly, you've found the problem.
Ron
-----
Original Message -----
Sent:
Monday, October 26, 2015 7:02 AM
Subject:
Re: [Chrysler300] Chrysler 300H idle speed
Thanks Keith for your input. I am not at all convinced I have
all the vacuum leaks identified and fixed. I reused my existing base
flanges gaskets with sealant added but ordered a new set of gaskets. I need
a new phenolic spacer but have been unable to find one yet on line. I am
also concerned that it may be the intake manifold to block leaking.
Meanwhile, the starter began to fail so I have to replace it. My plan now is
to ship the dis back to Philbin and ask Mark to check it for stability
because the timing does move around a bit and I should have realized that
would cause the hunting. I need to do that to scratch it off my list if
nothing else. I have also ordered a new set of ignition cables, and I
do not think its those either.
If I have to take the intake manifold off, this is probably the time to
replace the camshaft with the stock camshaft (-although as I write
that I ask myself “What does that disassembly have to do with replacing the
camshaft?”-probably very little as the tasks are pretty much unrelated I
think).
Best, Mike Moore
300H Morgan Hill, Ca
Mike,
I suppose it could always turn out to be a distributor issue, but I'm
putting my money on your finding yet one more vacuum leak you haven't
plugged. Your symptoms sure sound similar to the challenging ones I had on a
Quadrajet GM car until our carb guru Jim McGowan at the Quad Shop found vac
leaks in my carburetor. Are you pretty sure everything is tight now in the
intake area?
Keith Boonstra
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