| well chit [message #278789] |
Sun, 31 May 2015 15:40  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I had problems with the coach vapor locking at inopportune moments. Like in downtown Atlanta on I - 75 - 85 at 5 in the afternoon. So, when we got home I started in on (obviously) needed repairs/upgrades.
The hoses to the charcoal cannisters were toast, now replaced.
All the wires and hoses on the engine checked and ty-rapped out of harm's way.
Built up a piece of flat steel with two Mr Gasket fuel pumps and a relay, and cut and fitted it from the frame rail to the crossmember the front tank straps bolt to.
Now, the tank valve power pulls in the relay, whose SPDT contacts switch ignition 12V from the main to the aux pump, using the dash switch. Since these pumps draw ``2 amps running, and since I added a relay and a separate fused supply to the ViAir compressor, I used the ignition hot feed to the compressor. It now supplies one relay and one Mr Gasket pump at a time. I will be reducing its fuse to about 10 amps. I teed the output of the two pumps into the fuel feed line going frontwards to the mechanical pump and carb. The pumps have internal check valves,so the running pump will supply the carb. I'll be testing and road trying this setup tomorrow. Next step is to bypass the mechanical pump on the engine. I left a loop in the 12v pump line for a turnover switch. I propose to acquire the safety switch from an 05 - 09 Ranger, which resides on the passenger side firewall just above the toeboard in the pickups. It responds to a sharp blow as well as being 90 degrees or more off level. Way simpler than an oil pressure switch.
In the middle of all this, I am acquiring a Holley TBI system. When I install it, I'll simply remove the Mr Gasket low pressure pumps and duplicate the pump which comes with the system. Thus I'll still have two switched pumps and no valve. They will fit in place of the Mr Gasket ones, so no further plumbing will be required in the back of the coach. The Holley return if there is one) can be teed into the filler vent line.
I hope this cures the vapor lock problem.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: well chit [message #278816 is a reply to message #278789] |
Mon, 01 June 2015 08:05  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Thanks for the offer but a: I've got one pump coming with the system which I will duplicate; and B: At this point I'm not going to do in-tank pumps for a variety of reasons.
For those interested however, Larry's offer wpuld get you the pumps for $25 and about ten bux for a flat rate box. $35 vs Amazon's $50 for two shipped.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: well chit [message #279144 is a reply to message #278789] |
Fri, 05 June 2015 14:01 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I found one more problem - there's no shield between the exhaust pipe and the tanks. Which touch the pipe in a couple of places. So, next up is a day under moving the tanks to the driver's side a bit and installing some heat shielding between the tanks and the pipe. Given all of this, it ought to meet my criteria - Over Monteagle without overheating.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] well chit [message #279152 is a reply to message #279144] |
Fri, 05 June 2015 15:31 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Johnny,
Exhaust heat shields are a good addition to lower the heat input to the fuel tanks. The tanks should be more to the drivers side with enough room to work with the fuel lines and tank electricals.
http://www.appliedgmc.com/prod.itml/icOid/760
These are a good value for the price and you could also make your own if you had the necessary tool to bend the metal.
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCGL Tech Editor
GMCMHI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan
> On Jun 5, 2015, at 3:01 PM, Johnny Bridges wrote:
>
> I found one more problem - there's no shield between the exhaust pipe and the tanks. Which touch the pipe in a couple of places. So, next up is a
> day under moving the tanks to the driver's side a bit and installing some heat shielding between the tanks and the pipe. Given all of this, it ought
> to meet my criteria - Over Monteagle without overheating.
>
> --johnny
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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_______________________________________________
GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: well chit [message #279172 is a reply to message #278789] |
Fri, 05 June 2015 21:15 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I see the logic of the return line for a carbureted engine but I got to wonder - for an injected engine won't the bypass port bleed off the pressure in the line? It's been a looooong time, but if I remember right, the Holley setup I put on the 340 car ran substantially higher pressure than a mechanical diaphragm pump. One was supplied with the system which seriesed into the fuel line from the tank. I'd expect the elevated pressure to help quite a bit with vapor lock as well.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] well chit [message #279174 is a reply to message #279172] |
Fri, 05 June 2015 22:09 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Johnny,
You're right, both the Holley TB and the GMC TB have internal regulators
and bypass return lines.
Ken H.
On Fri, Jun 5, 2015 at 10:15 PM, Johnny Bridges wrote:
> I see the logic of the return line for a carbureted engine but I got to
> wonder - for an injected engine won't the bypass port bleed off the pressure
> in the line? It's been a looooong time, but if I remember right, the
> Holley setup I put on the 340 car ran substantially higher pressure than a
> mechanical diaphragm pump. One was supplied with the system which
> seriesed into the fuel line from the tank. I'd expect the elevated
> pressure to
> help quite a bit with vapor lock as well.
>
> --johnny
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: well chit [message #279190 is a reply to message #279157] |
Sat, 06 June 2015 06:06 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Here are some photos of the OEM GM ones that were installed on California coaches. There should be enough information on them to bend your own if you wish to do so. The ones Jim K. has will also fit the bill and are power coated white.
They get attached to the exhaust pipe with a pair of muffler clamps.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: well chit [message #279191 is a reply to message #279190] |
Sat, 06 June 2015 06:07 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Ken Burton wrote on Sat, 06 June 2015 06:06Here are some photos of the OEM GM ones that were installed on California coaches. There should be enough information on them to bend your own if you wish to do so. The ones Jim K. has will also fit the bill and are power coated white.
They get attached to the exhaust pipe with a pair of muffler clamps.
I forgot to attach the link:
http://www.gmcmhphotos.com/photos/exhaust-heat-shields/p22973-exhaust-heat-shield.html
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: well chit [message #279203 is a reply to message #278789] |
Sat, 06 June 2015 09:26 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Well, I don't have a bending brake... but as long as Kerry isn't looking, I can bend the edge of a piece of galvanized sheet into a right angle using a hammer and a 4x4. These will probably be bolted to the floor, the coach has a 3 inch pipe and not a lot of room to mess around with. I was considering a scoop arrangement to direct air across the pipe but passed on it. It would grab air in line with the front wheels, which means it would also grab rain and crud tossed up by the wheel and throw it directly on the hot pipe. Hopefully, simple shielding will be sufficient,.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: well chit [message #279205 is a reply to message #279203] |
Sat, 06 June 2015 10:05 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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I do not see why you could not go to the big box store and get a length of aluminum rain gutter and cut it to fit. Then, just add the brackets and clamp them to the exhaust system with screw clamps. Or, screw them into the wooden floor.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: well chit [message #279214 is a reply to message #278789] |
Sat, 06 June 2015 14:40 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Thank you! Hadn't though of that - headed for Lowes now!
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: well chit [message #279217 is a reply to message #279144] |
Sat, 06 June 2015 15:42 |
biggreen
Messages: 347
Registered: June 2011
Location: Northeast Florida
Karma: 1
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Senior Member |
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Johnny Bridges wrote on Fri, 05 June 2015 14:01I found one more problem - there's no shield between the exhaust pipe and the tanks. Which touch the pipe in a couple of places. So, next up is a day under moving the tanks to the driver's side a bit and installing some heat shielding between the tanks and the pipe. Given all of this, it ought to meet my criteria - Over Monteagle without overheating.
--johnny
Try this. http://www.gmcmhphotos.com/photos/member-galleries/p45296-heat-sheild-front-of-tanks.html
R.D.
Northeast Florida
77 ex-Palm Beach 403
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