Slight starting issue

Thanks Tim and Bob! This explanation makes sense. I'll prop the engine
compartment door open when I expect to be needing the car within 30
minutes or so, and see how that affects this hot carb effect. Since I
have taken everything back to stock (except the SDVA dizzie) I know that
I don't have anything attractive in there for covetous kids looking for
swell performance engine parts. Just a boring old baywindow.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westphalia: "Mellow Yellow (The Electrical Banana)"
KG6RCR

-=-=-
.... "We didn't send you to Washington to make intelligent decisions. We sent
you to represent us."
-- Kent York, Baptist minister to US Rep. Bill Sarpalius.

Bob Hoover wrote:
> "Tim Rogers" > wrote in message
>
>>Another thing
>>that could be working against you is the common problem of engine heat
>>causing the gas to boil out of the carb's float chamber and causing flooding
>>as well. I don't know of an easy fix for that one.
>
> -----------------------------------------------------------
>
> Me neither. The problem is that the manifold is HOT... if the engine
> has been properly assembled (ie, cross-over pipe is not clogged).
> During warm weather the siamesed portion of the intake manifold -- the
> part having the aluminum jacket -- contains a significant quanta of
> heat that gets dissipated into the engine compartment when you shut
> down the engine. A lot of that heat gets absorbed by the carburetor
> even WITH a gasket that provides good thermal isolation between the
> carb and the manifold... the carb has a lot of surface area and the
> air around it is HOT and things roll downhill from there.
>
> I've used two techniques that help the situation. The first is to
> ALWAYS idle the engine for at least a minute before shutting down.
> I've got a clock right in front of me (where I usta have a sun visor)
> and you wouldn't belive how long a minute can be, just sitting there
> watching the gauges. How much does it help? Frankly, not a bunch...
> depends on the weather. Seriously hot day, it helps. Cold day, you
> won't see any change. Middling-warm, like we usually have here in
> sudden California... sorta iffy. But I've made it a habit, don't
> really notice it any more.
>
> The second technique was hi-tek kewl. 12vdc computer fan that comes
> ON when the ignition goes OFF via a thermostatically controlled relay.
> When the temp at the sensor drops below 140, the thing shuts itself
> off. So you get to where you're going, climb out, walk away, the fan
> keeps humming away back there, eventually shuts itself off (you hope).
> Nothing very tricky about the set-up; ripped the parts out of a Ford
> 'Tempo' (? - I lose track) Radiator fan temp sensor. All I did was
> add a couple of relays to include a fail-safe.
>
> So howz that work with the hard-starting? ONE fan, blowing on the
> carb, I didn't see any change. TWO fans, both blowing air OUT of the
> engine compartment, I saw a definte improvement.
>
> But a couple of additional points need to be mentioned. The first is
> that damn PICT-34. It appears to be a LOT more sensitive to engine
> compartment heat than the older round-bowl carbs. Since I stopped
> using 34's I haven't had any problem with hot starts. Keep in mind, I
> drove a '65 whereas Rocky flies a 'loaf. My engine compartment is
> vented directly out the sides of the van whereas he's got that l-o-n-g
> upward column to those high-placed vents up behind his rear windows.
> I suspect his engine compartment stays hotter, longer, than mine does
> and is a contributing factor.
>
> Bottom line: You really gotta love fuel injection :-)
>
> -Bob Hoover

In article >,
Mike Rocket J. Squirrel Elliott et> wrote:
>Thanks Tim and Bob! This explanation makes sense. I'll prop the engine
>compartment door open when I expect to be needing the car within 30
>minutes or so, and see how that affects this hot carb effect. Since I
>have taken everything back to stock (except the SDVA dizzie) I know that
>I don't have anything attractive in there for covetous kids looking for
>swell performance engine parts. Just a boring old baywindow.
>

Another thing. Always crank with the gas pedal to the floor when
the engine is warm... It will clear the flodding really quick.


--
Eduardo K. |
| "World domination, now"
http://e.nn.cl | Linus Torvalds

FOLLOW-UP:

The use of turbo tape or other insulation, in conjunction with a
thermal barrier gasket, was the originally recommended fix for this
problem but VW stopped recommending it when they found it promoted
rusting of the manifold. The rust would progress under the cast
aluminum of the siamesed section and cause the aluminum to crack.
This sounds pretty extreme and I suspect the problem was linked to the
use of salt on the roads but since the dealer did the install they
were also responsible for the required repair.

This technique (ie, insulating the manifold) might be worth a try here
in sunny sudden California using some of the more modern insulations
such as Fiber-Frax. (Home boys used ironing board pads with pretty
good results :-)

-Bob Hoover

More likely a fuel, vapor lock,heat soak thing.The gas in the line get hot
sitting in the line between the pump and the carb.4 or 5 seconds for the
pump the pump up new gas.No biggy.The choke shouldn't even be activating
after only 30 minutes.If it is,roll it back some more(less pressure-CCW).
"Mike Rocket J. Squirrel Elliott"
et> wrote in message
news
> We're talking the Wonderbus here.
>
> New Mexi 1600 longblock w/ SVDA dizzie, new 34 PICT/3 carb w/ choke
> connected. Stock oil bath air cleaner with air pre-heat hose connected,
> clean manifold with preheat tubes clean and connected.
>
> Cold starts -- very easy.
> Hot starts (dash into 7-Eleven for curry Squishie) -- also very easy.
> Warm starts (sittin' for 30 minutes) gotta run the starter motor for 4-5
> seconds before engine catches.
>
> Maybe the choke does not quite track the engine's condition in between hot
> and cold?
>
> --
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westphalia: "Mellow Yellow (The Electrical Banana)"
> KG6RCR

Wrapping the fuel line 'tween the pump and carb with tin foil helps if it's
a problem.As a side benefit,it keeps aliens from jamming your motor.
"Tim Rogers" > wrote in message
...
> "Mike Rocket J. Squirrel Elliott"
> et> wrote in message
> news
>>
>> Maybe the choke does not quite track the engine's condition in between
>> hot and cold?
>>
>>
>
> ...............That's right. It doesn't work effectively when the ignition
> has been off for more than a few minutes. You get too much choke with a
> hot
> engine and flood the engine. I used to adjust it back almost all the way
> 'lean' when driving in hot weather to lessen this problem. Another thing
> that could be working against you is the common problem of engine heat
> causing the gas to boil out of the carb's float chamber and causing
> flooding
> as well. I don't know of an easy fix for that one. Do you have one of
> those
> fiber whatever isolators between the carb and the manifold?
>
>

"ilambert" > wrote in message
...
>
> Wrapping the fuel line 'tween the pump and carb with tin foil helps if
it's
> a problem.As a side benefit,it keeps aliens from jamming your motor.
>
>

.............That would help if there was vapor lock in the line caused by a
hot engine compartment. It wouldn't do anything for the more common problem
of gas boiling out of the carb's float chamber.

"ilambert" > wrote in message
...
>
> More likely a fuel, vapor lock,heat soak thing.The gas in the line get hot
> sitting in the line between the pump and the carb.4 or 5 seconds for the
> pump the pump up new gas.No biggy.The choke shouldn't even be activating
> after only 30 minutes.If it is,roll it back some more(less pressure-CCW).
>
>

..............The gas in the line doesn't boil as easily as in the carb's
float chamber. The float chamber is vented so that pressure can't build up
like it does in the line where there's a float activated valve leading into
the float chamber. When pressure rises, the boiling point rises. Vapor lock
is a relatively uncommon problem compared to the typical flooded out
situation involving the carb's float chamber vent spewing gas down the
throat of the carb.

True,true.But the amount of gas in the line is much greater and I don.'t
know of a cure for chamber heat.
"Tim Rogers" > wrote in message
...
> "ilambert" > wrote in message
> ...
>>
>> Wrapping the fuel line 'tween the pump and carb with tin foil helps if
> it's
>> a problem.As a side benefit,it keeps aliens from jamming your motor.
>>
>>
>
> ............That would help if there was vapor lock in the line caused by
> a
> hot engine compartment. It wouldn't do anything for the more common
> problem
> of gas boiling out of the carb's float chamber.
>
>

On Fri, 29 Oct 2004 22:25:59 -0400, "ilambert" >
wrote:

>Wrapping the fuel line 'tween the pump and carb with tin foil helps if it's
>a problem.As a side benefit,it keeps aliens from jamming your motor.
>"Tim Rogers" > wrote in message
...
>> "Mike Rocket J. Squirrel Elliott"
>> et> wrote in message
>> news
>>>
>>> Maybe the choke does not quite track the engine's condition in between
>>> hot and cold?
>>>
>>>
>>
>> ...............That's right. It doesn't work effectively when the ignition
>> has been off for more than a few minutes. You get too much choke with a
>> hot
>> engine and flood the engine. I used to adjust it back almost all the way
>> 'lean' when driving in hot weather to lessen this problem. Another thing
>> that could be working against you is the common problem of engine heat
>> causing the gas to boil out of the carb's float chamber and causing
>> flooding
>> as well. I don't know of an easy fix for that one. Do you have one of
>> those
>> fiber whatever isolators between the carb and the manifold?
>>
>>
>
I've had that problem as well time ago. Sure enough it was the metal
fuel line that comes from under the car that goes to the gas tank, it
was touching the manifold causing vapor lock. One easy way to find
out: Next time it locks up, pour some cold water on the fuel pump to
cool it down. If it starts right back up... You know what your problem
is.





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