|
|
|
|
|
|
| Re: [GMCnet] Picked up a complete late 78- 2 compressor assembly at a salvage yard for $10. What's the option on it for? [message #316822 is a reply to message #316814] |
Sun, 30 April 2017 07:35   |
JohnS
Messages: 126
Registered: December 2014
Location: Vacaville, CA
Karma: -2
|
Senior Member |
|
|
I believe what you have is a Cinnabar Modification, designed by Wes Caughlin, to the EL II System, a pretty desirable mod. The 12 volt valve is actually an adjustable pressure limit switch. As designed by GM, pressure was limited only by what the compressors would put out. When new the pressure could go quite high in RAISE, resulting in problems. The switches were supposed to be adjusted to 120psi limit. This mod also replaced the shutoff solenoids with ones that did not allow leakage in either direction, & also added the pressure gauges. I have documentation for this, but won't be home to access it for several days. Then I'll try to put it on the photo site.
John Shutzbaugh, Vacaville, CA, ncserv@aol.com;
78 Buskirk stretch, "What were we thinking?"
|
|
|
|
|
|
|
|
| Re: [GMCnet] Picked up a complete late 78- 2 compressor assembly at a salvage yard for $10. What's the option on it for? [message #316835 is a reply to message #316814] |
Sun, 30 April 2017 11:37 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Bob, the EL II compressor/desiccant assembly was state of the art stuff
when they were used in the late 77 and 78 coaches. There are two weak
points (times two) The first one is the permanent magnet fields in the
motors. They fade away over time, and not much the average owner can do
about it. The motors just develop less and less torque as they age out.
Newer permanent magnets use some rare earth elements, and retain their
strength for many years. Like the ones used in the Vi-Air compressors. Get
a screwdriver near the motor and they will stick right to them.
The second weak point is the exhaust valves built into the compressor
cylinder head(s) They are not servicible and are a common source of air
leaks. Not much can be done for them, except, like Cinabar and some others
have done, add a downstream solenoid controlled valve. More complexity to
an already complex system. Not the way I like to go. I subscribe to the
K.I.S.S. principle. The least complex system USUALLY winds up being the
most reliable.
Both of those weaknesses I described are resolved by replacement of the
compressors, or a complex workaround. Compressors SIMILAR TO, but not
exactly the same, we're used in a number of Oldsmobile Silouette vans, as
well as Pontiac and chev vans that share the platform with Olds. No current
production vehicles that I am aware of use an exact replacement compressor.
Rotsa Ruck finding something. Same for the height control valves. Some are
close to the same, but not exact. They can be improvised to work. I have a
bunch of pieces for the EL II. Let me know if I can help you with used
parts. Shipping costs.
Jim Hupy
On Apr 30, 2017 9:10 AM, "Steve Southworth" wrote:
Bob - any other good parts on that '78 salvage coach?
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
|
|
| Re: [GMCnet] Picked up a complete late 78- 2 compressor assembly at a salvage yard for $10. What's the option on it for? [message #316872 is a reply to message #316861] |
Mon, 01 May 2017 06:48 |
JohnS
Messages: 126
Registered: December 2014
Location: Vacaville, CA
Karma: -2
|
Senior Member |
|
|
Yes, those wires are for the exhaust valve, actuated by the leveling sensor in the wheel wells or the "Lower" switch at the driver's control panel. The leveling sensors are active when the switch up front is in "Travel". These sensors then turn their respective pump on (thru a relay), or activate the exhaust valve, to maintain ride height. Only one line goes to each side, cutting down on the large number of leak sources of previous systems.
Not a bad idea at the time, but as James Hupy pointed, out those sensors & pump/valve units are now very expensive and there are no easily adaptable replacements available.
Hope your salvaged units check out ok so you can move on.
John Shutzbaugh, Vacaville, CA, ncserv@aol.com;
78 Buskirk stretch, "What were we thinking?"
|
|
|
|
| Re: [GMCnet] Picked up a complete late 78- 2 compressor assembly at a salvage yard for $10. What's the option on it for? [message #316877 is a reply to message #316872] |
Mon, 01 May 2017 07:29 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
|
Senior Member |
|
|
Sort of like this
http://gmcmotorhome.info/levelsch.htm
Schematics
On Mon, May 1, 2017 at 4:49 AM John Shutzbaugh wrote:
> Yes, those wires are for the exhaust valve, actuated by the leveling
> sensor in the wheel wells or the "Lower" switch at the driver's control
> panel.
> The leveling sensors are active when the switch up front is in "Travel".
> These sensors then turn their respective pump on (thru a relay), or activate
> the exhaust valve, to maintain ride height. Only one line goes to each
> side, cutting down on the large number of leak sources of previous systems.
>
> Not a bad idea at the time, but as James Hupy pointed, out those sensors &
> pump/valve units are now very expensive and there are no easily adaptable
> replacements available.
>
>
> Hope your salvaged units check out ok so you can move on.
> --
> John Shutzbaugh, Vacaville, CA, ncserv@aol.com;
> 77 Eleganza, bought it new, can't blame PO, and
> 78 Buskirk stretch, "What were we thinking?"
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
