| [GMCnet] Frame Rail Temperature [message #95388] |
Wed, 11 August 2010 19:46  |
Ken Coit
Messages: 151
Registered: November 2005
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Has anyone shot a temperature gun at the frame rail to see how it compares
with the ambient and road temps while underway or standing? Maybe we have a
built-in heat sink for the fuel line just waiting for us?
--
Ken Coit, ND7N
Raleigh, NC
Parfait Royale
1978 Royale Rear Bath, 403, 3.07
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| Re: [GMCnet] Frame Rail Temperature [message #95456 is a reply to message #95388] |
Thu, 12 August 2010 07:39  |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
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| Ken Coit wrote on Wed, 11 August 2010 19:46 |
Has anyone shot a temperature gun at the frame rail to see how it compares
with the ambient and road temps while underway or standing? Maybe we have a
built-in heat sink for the fuel line just waiting for us?
--
Ken Coit, ND7N
Raleigh, NC
Parfait Royale
1978 Royale Rear Bath, 403, 3.07
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i had asked if anyone shot a reading off the tank and no one has. i think these are real starting points to find where the problem is.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] Frame Rail Temperature [message #95460 is a reply to message #95388] |
Thu, 12 August 2010 08:18 |
Rusty
Messages: 197
Registered: October 2005
Location: Philadelphia Pa
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I thought it had already been determined to be the close proximity to the road surface of a thin tank design with alot of surface area
Rusty
75 Glenbrook
Philadelphia Pa
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| Re: [GMCnet] Frame Rail Temperature [message #95486 is a reply to message #95460] |
Thu, 12 August 2010 10:05 |
Ken Coit
Messages: 151
Registered: November 2005
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Rusty,
I used to think so too, but the more I think, the more I wonder. There is
anecdotal evidence of fuel tank heating and I am sure the tanks warm up on
hot days, but I find the sudden onset of starvation on a cold road surface,
my case, to be unrelated to the mass of fuel heating just because I stopped
at a toll booth in February in the mountains of WV. I think the low mass and
slow moving fuel around and over the engine has a lot more to do with the
sudden onset of fuel starvation.
The temperature of the fuel in the tanks might be contributing to the
potential disaster, but there is no way a 15 second stop at a toll booth is
the only factor. There has to be a bubble somewhere else, not in the bottom
of a slightly pressurized tank where the fuel is exiting at a rate of about
1.6 milligallons a second, or 0.2 ounces, 1/5 of a shot glass, per second at
speed and a lot less at idle. How big is the float bowl? How long is the
fuel line? I believe the fuel is getting an extra thermal boost in the
engine compartment, either as it is transported or as it sits in the fuel
bowl and that is what causes the failure, not the ambient temperature of the
fuel in the tank. If the fuel were boiling in the float bowl, the mechanical
pump would still pump. My float bowl was empty, twice.
If I had an operating coach I would be instrumenting the carb intake for
temperature and pressure to see what I could learn. I've already shot enough
money at this problem for it to have gone away and to remove the side affect
of no power assist for the brakes, but I want to know more.
If the heat of the fuel in the tanks is the trigger or catalyst for the
stumbling and failure, then I have the heat sinks to build a cooler before
recirculating fuel to the tanks, but I think that to be a waste of time and
resources, as the machine runs fine except in specific circumstances related
to heavy load followed by stopping and once it stops, not restarting for
maybe 30 minutes at most, not the length of time it takes to cool down a
tank of fuel.
I certainly am grasping at straws and have never designed a fuel system or
known the chemistry of fuels, but the anecdotal evidence is becoming clearer
in my mind if in no others. I think Emery is on the right track to re-route
the fuel lines and get more ventilation into the engine compartment,
especially at a standstill when there can be no ground effect suction to
help evacuate the space.
I hope I sound friendly, because I am. If I don't sound that way, let me
know. The World needs more friends.
On Thu, Aug 12, 2010 at 9:18 AM, Rusty <gmc@bauerlein.com> wrote:
>
>
> I thought it had already been determined to be the close proximity to the
> road surface of a thin tank design with alot of surface area
> --
> Rusty
> 75 Glenbrook
> Philadelphia Pa
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Ken Coit, ND7N
Raleigh, NC
Parfait Royale
1978 Royale Rear Bath, 403, 3.07
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| Re: [GMCnet] Frame Rail Temperature [message #95492 is a reply to message #95388] |
Thu, 12 August 2010 10:38 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
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I remember awhile back someone had temp sensors in the tanks but I don't remember who. His electrical was spotless and he even had a G meter, and lots of other gauges.
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