VAPOR LOCK

[jerry hoxsey]

Emery,

It has been my experience over my years of fixin everything from satellite
computer systems to lawnmowers, that the last thing touched before the
problem is usually the cause. You have driven in hotter weather than we are
having now with no problems. My educated guess is you need to cool down
that engine compartment. Air scoop under the radiator, blower under the
drivers seat, whatever. I will bet a Jim Anstett margarita that if you
removed the newly installed insulation you would not have this problem. I
too insulated the engine compartment but so far no problems.
Let me know if I can help. 15 days til DURANGO!!!!
Jerry

 

[darren paget]

This is the exact same problem I had with my SOB. The one thing which
finally cured it for me was adding two 16" electric fans pushing air
through the radiator, not pulling, and removing the Clutch fan. It was a
radical solution but I had tried absolutely everything else up to that
time. I knew the vapor lock was caused by the heat the engine produced
and the proximity of the fuel lines to that heat. It was not possible to
reroute the fuel lines so I started with the cheapest fix and moved on
from there. I even moved the exhaust pipe to get it farther from the
fuel lines. Don't know if any of this helps but.....
BTW FWIW the most expensive attempt I made was a new high volume
radiator at $550.00 parts only. The twin fans cost me $635.00 and did
solve the problem. Whether or not it was that alone or the combination
of things, I don't know, but I finally managed to get it to run at 190
deg. even in 95 deg temp at 4000 ft. uphill through the mountains.
Darren

- --
Darren Paget
76 Experimental
Another Fab Day
http://www.TZEplus.com

 

[terry & diane skinner]

Just a small question on this problem of the engine compartment getting so
hot. Has anyone tried running without the plastic wheel well liner
installed????
We are up to a whooping 70 degrees and it hasn't rained sense the 4th.
.............Terry

Terry & Diane Skinner
Webfooted in Washington

 

[emerystora]

>This is the exact same problem I had with my SOB. The one thing which
>finally cured it for me was adding two 16" electric fans pushing air
>through the radiator, not pulling, and removing the Clutch fan. It was a
>radical solution but I had tried absolutely everything else up to that
>time. I knew the vapor lock was caused by the heat the engine produced
>and the proximity of the fuel lines to that heat. It was not possible to
>reroute the fuel lines so I started with the cheapest fix and moved on
>from there. I even moved the exhaust pipe to get it farther from the
>fuel lines. Don't know if any of this helps but.....
>BTW FWIW the most expensive attempt I made was a new high volume
>radiator at $550.00 parts only. The twin fans cost me $635.00 and did
>solve the problem. Whether or not it was that alone or the combination
>of things, I don't know, but I finally managed to get it to run at 190
>deg. even in 95 deg temp at 4000 ft. uphill through the mountains.
>Darren
>
>--
> Darren Paget
> 76 Experimental
> Another Fab Day
> http://www.TZEplus.com

Hi Darren - my problem is not engine overheating because my coolant
gauge (digipanel) shows below 180 even in this heat. I believe the
heat is coming from my exhaust manifold and pipes and from the
manifold crossover so I don't need to push any more air through the
radiator -- I have to force more air up toward the rear of the motor
box. Your other suggestion of insulating the fuel lines with your
insulation product is a very good one and I'll contact you about
that. I had read years ago that about 1/3 of the waste heat from an
engine goes out through the radiator, 1/3 through the exhaust and 1/3
radiated from the block and other components.

Emery Stora
77 Kingsley
Santa Fe, NM
77 Kingsley
Santa Fe, NM

 

[gene]

Emery

Interesting point here, Jim Kanamata thinks that when the tanks are low on
fuel, the pumps start to pump some air and cause problems. That is also why
he uses a reservoir. =20

How much fuel did you have at the time ??

gene

>Emery, I experienced a problem with my Holley TBI fuel
>pump related to its ability to pull gas out of the
>tank when the fuel is low. I checked the vacuum on
>the inlet side of it compared to a new pump and there
>was significant difference. It could be that your
>fuel pump is getting weak and running hot.
>
>I'll send you a note from Holley regarding a heavier
>duty pump they make. Mine has never vapor locked in
>the 100+ deg texas heat (lower altitude of course).=20
>Years ago my old carburated Blazer+trailer had a vapor
>lock in Eisenhower tunnel (I-70) on a Labor day
>weekend .. talk about embarrased. Put in an elec pump
>in it after that but the pump got hot when I ran it.
>
>Bill '74 GL/Tx
>
>__________________________________________________
>Do You Yahoo!?
>Get Yahoo! Mail =96 Free email you can access from anywhere!
>http://mail.yahoo.com/
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

 

[emerystora]

>Emery
>
>Interesting point here, Jim Kanamata thinks that when the tanks are low on
>fuel, the pumps start to pump some air and cause problems. That is also why
>he uses a reservoir.
>
>How much fuel did you have at the time ??
>
>gene

Gene - the tanks were totally full.

Emery

 

[paul bartz1]

Jim:

Are you aware that you can obtain new wheel well liners from Cinnabar??

Paul Bartz

From: owner-gmcmotorhome
[mailtowner-gmcmotorhome]On Behalf Of GMC73CL
Sent: Saturday, July 08, 2000 10:39 AM

Terry,

I plan to put mine back in as soon as I can repair them satisfactorily. I took
them out
before the trip because I was afraid they would FALL OUT. They are not in
good shape around the bolt holes. I can't offer any advice on leaving them
out, but it did work for me for that 18 day trip.

 

[les watson]

Terry....

That is high on the list of things to try.
Thanks for you suggestion.

Les & Sharon Watson
Orem Utah (104 today)
77 Palm Beach (Likes it Cool)

>Just a suggestion from an old alley mechanic. Wrap the fuel line (steel)
>with an a bare aluminum wire. The solid wire will help dissipate the heat
>into the air. It worked on those old flat head
>Fords.........................Terry
>Terry & Diane Skinner
>Webfooted in Washington