Home » Public Forums » GMCnet » Re: [GMCnet] Primary venturis fuel drip at idle... and now HEI distributor issue?
| Re: [GMCnet] Primary venturis fuel drip at idle... and now HEI distributor issue? [message #333751] |
Wed, 20 June 2018 13:30  |
Dave Stragand
Messages: 307
Registered: October 2017
Karma: 0
|
Senior Member |
|
|
Today's findings...
Fred, you were spot on with the worn bore at the throttle shaft.
There's a noticeable bit of play. The single return spring is also way
too weak to serve any purpose, and the throttle cable stud is some
homemade deal involving a fuel line fitting and a bolt, so a whole lot
of wrong going on. I'll button it up as best as possible for the time
being, but it would need the bores sleeved at the least, if not rebuilt
or replaced with EFI.
But I don't think that's the only issue. I pulled the cap and rotor and
changed those, and tried a test on the advance/rotor arm assembly. I am
able to twist it from side to side as if under advance, but it takes a
good amount of force. Also, when released the shaft only returns half
way. I put a little movie of it up at
http://forwardlook.net/images/gmc/img_3913.mov I am guessing I will
need to pull it, strip out the shaft and give it a good cleaning, if not
a total R&R. Has anyone had the shaft 'stick' like that on an HEI
before?
-Dave
1978 Transmode near Pittsburgh
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Dave
Stragand
Sent: Wednesday, June 20, 2018 10:31 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Primary venturis fuel drip at idle
Thanks to all for the responses. I'll be stopping by today at lunch to
do some checks.
Fred -- I will check the throttle shaft bore by spraying carb cleaner on
the outside base at the shafts while it's running. Thanks for the
reminder as I have run into that before.
I'm leaning towards Bill's suggestion of a timing issue being the cause.
I recall that the rotor shaft was pretty sticky when twisting the rotor,
so I don't fully trust that all is well there. I have a new cap and
rotor so will check the shaft, vacuum advance and advance weights while
I'm in there.
Sammy -- I have had great luck with the Edelbrock (and Carter AFB's)
over the years, but if I was going to change, I would probably lean
towards Gerald's suggestion of EFI. The difference in price would be
well worth it. This is the first time I dragged out a timing light
instead of a laptop to tune a car in many years. It's nice to just turn
the key and go.
While very tempting to pour out upgrade money from the start, I am
holding off on the upgrades until we are sure she has enough 'good
bones' to continue moving forward. At present, the most I have driven
is about 20' backwards and forward -- but when she passes my wife's
"try driving it for 2 hours around the storage facility to make sure
it's in okay shape" test, my wallet will open a bit.
I will keep everyone posted with our progress!
-Dave
1978 Transmode near Pittsburgh
_______________________________________________
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
1978 Transmode (403)
Pittsburgh, PA
|
|
|
|
| Re: [GMCnet] Primary venturis fuel drip at idle... and now HEI distributor issue? [message #333753 is a reply to message #333751] |
Wed, 20 June 2018 13:54  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Yes, the hei, and to some extent, most distributors, collect iron powder
from wear of weights, springs, pins, etc. The strong magnetic fields of
rotating parts attracts this powder and gums up the mechanical advance and
rotor pieces. Combine this with long intervals between maintenance, and
eventually problems arise. Blame it on the specific ignition if you want
to, but it boils down to lack of maintenance. Spray some contact cleaner,
or brake kleen in there once in a while, follow it with compressed air, and
when it is free, lube with a non conductive lube like silicone grease or
engine oil. If you take the module out and clean that sticky stuff under it
out, be sure to replace it with heat sink grease made for that purpose.
Check the cap inside for carbon tracking, wipe it out with a clean, dry,
lint free cloth. You should be good for a long time, but nothing runs
forever without maintenance.
Jim Hupy
On Wed, Jun 20, 2018, 11:31 AM Dave Stragand
wrote:
> Today's findings...
>
> Fred, you were spot on with the worn bore at the throttle shaft.
> There's a noticeable bit of play. The single return spring is also way
> too weak to serve any purpose, and the throttle cable stud is some
> homemade deal involving a fuel line fitting and a bolt, so a whole lot
> of wrong going on. I'll button it up as best as possible for the time
> being, but it would need the bores sleeved at the least, if not rebuilt
> or replaced with EFI.
>
> But I don't think that's the only issue. I pulled the cap and rotor and
> changed those, and tried a test on the advance/rotor arm assembly. I am
> able to twist it from side to side as if under advance, but it takes a
> good amount of force. Also, when released the shaft only returns half
> way. I put a little movie of it up at
> http://forwardlook.net/images/gmc/img_3913.mov I am guessing I will
> need to pull it, strip out the shaft and give it a good cleaning, if not
> a total R&R. Has anyone had the shaft 'stick' like that on an HEI
> before?
>
> -Dave
> 1978 Transmode near Pittsburgh
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Dave
> Stragand
> Sent: Wednesday, June 20, 2018 10:31 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Primary venturis fuel drip at idle
>
> Thanks to all for the responses. I'll be stopping by today at lunch to
> do some checks.
>
> Fred -- I will check the throttle shaft bore by spraying carb cleaner on
> the outside base at the shafts while it's running. Thanks for the
> reminder as I have run into that before.
>
> I'm leaning towards Bill's suggestion of a timing issue being the cause.
> I recall that the rotor shaft was pretty sticky when twisting the rotor,
> so I don't fully trust that all is well there. I have a new cap and
> rotor so will check the shaft, vacuum advance and advance weights while
> I'm in there.
>
> Sammy -- I have had great luck with the Edelbrock (and Carter AFB's)
> over the years, but if I was going to change, I would probably lean
> towards Gerald's suggestion of EFI. The difference in price would be
> well worth it. This is the first time I dragged out a timing light
> instead of a laptop to tune a car in many years. It's nice to just turn
> the key and go.
>
> While very tempting to pour out upgrade money from the start, I am
> holding off on the upgrades until we are sure she has enough 'good
> bones' to continue moving forward. At present, the most I have driven
> is about 20' backwards and forward -- but when she passes my wife's
> "try driving it for 2 hours around the storage facility to make sure
> it's in okay shape" test, my wallet will open a bit.
>
> I will keep everyone posted with our progress!
>
> -Dave
> 1978 Transmode near Pittsburgh
>
>
>
>
> _______________________________________________
> 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
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Primary venturis fuel drip at idle... and now HEI distributor issue? [message #333757 is a reply to message #333751] |
Wed, 20 June 2018 15:41 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Dave,
The distributor rotor, when turned against the advance springs should move
freely, and snap back when released. Otherwise, the distributor needs to
come out, be disassembled, de-rusted, lubricated, possibly have bushings
replaced, and be "curved" (have the proper springs and weights installed to
achieve the correct timing advance curve).
The best way to achieve all that is to send your distributor to Dick
Patterson for a complete rebuild. However, you may get by with just the
"clean & lubricate" if you do it carefully and things are gone too far.
Or, just go ahead and install EFI and an ECU-controlled distributor (which
has no weights since the ECU controls timing).
Ken H.
On Wed, Jun 20, 2018 at 2:31 PM Dave Stragand
wrote:
> Today's findings...
>
> Fred, you were spot on with the worn bore at the throttle shaft.
> There's a noticeable bit of play. The single return spring is also way
> too weak to serve any purpose, and the throttle cable stud is some
> homemade deal involving a fuel line fitting and a bolt, so a whole lot
> of wrong going on. I'll button it up as best as possible for the time
> being, but it would need the bores sleeved at the least, if not rebuilt
> or replaced with EFI.
>
> But I don't think that's the only issue. I pulled the cap and rotor and
> changed those, and tried a test on the advance/rotor arm assembly. I am
> able to twist it from side to side as if under advance, but it takes a
> good amount of force. Also, when released the shaft only returns half
> way. I put a little movie of it up at
> http://forwardlook.net/images/gmc/img_3913.mov I am guessing I will
> need to pull it, strip out the shaft and give it a good cleaning, if not
> a total R&R. Has anyone had the shaft 'stick' like that on an HEI
> before?
>
> -Dave
> 1978 Transmode near Pittsburgh
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Dave
> Stragand
> Sent: Wednesday, June 20, 2018 10:31 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Primary venturis fuel drip at idle
>
> Thanks to all for the responses. I'll be stopping by today at lunch to
> do some checks.
>
> Fred -- I will check the throttle shaft bore by spraying carb cleaner on
> the outside base at the shafts while it's running. Thanks for the
> reminder as I have run into that before.
>
> I'm leaning towards Bill's suggestion of a timing issue being the cause.
> I recall that the rotor shaft was pretty sticky when twisting the rotor,
> so I don't fully trust that all is well there. I have a new cap and
> rotor so will check the shaft, vacuum advance and advance weights while
> I'm in there.
>
> Sammy -- I have had great luck with the Edelbrock (and Carter AFB's)
> over the years, but if I was going to change, I would probably lean
> towards Gerald's suggestion of EFI. The difference in price would be
> well worth it. This is the first time I dragged out a timing light
> instead of a laptop to tune a car in many years. It's nice to just turn
> the key and go.
>
> While very tempting to pour out upgrade money from the start, I am
> holding off on the upgrades until we are sure she has enough 'good
> bones' to continue moving forward. At present, the most I have driven
> is about 20' backwards and forward -- but when she passes my wife's
> "try driving it for 2 hours around the storage facility to make sure
> it's in okay shape" test, my wallet will open a bit.
>
> I will keep everyone posted with our progress!
>
> -Dave
> 1978 Transmode near Pittsburgh
>
>
>
>
> _______________________________________________
> 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
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
|
|
| Re: [GMCnet] Primary venturis fuel drip at idle... and now HEI distributor issue? [message #333863 is a reply to message #333758] |
Fri, 22 June 2018 15:19 |
Dave Stragand
Messages: 307
Registered: October 2017
Karma: 0
|
Senior Member |
|
|
Just to follow up for anyone who was following this thread now or for
later in the archives...
Before pulling the distributor, I tried slipping the red tube of a WD40
can in under the advance to put a drop or two of lubricant in above the
reluctor. Worked it back and forth for a minute or so, and it started
snapping back freely.
Started up again, and the idle is much nicer, revving up is much faster,
and now the carb has only a trace of a drip from the venturis at idle.
Both the carb (worn throttle shaft) and distributor (worn advance weight
posts and too much up-down play) should be rebuilt as part of the
restoration, but they should suffice for the meantime for the coming
endurance test.
-Dave
1978 Transmode near Pittsburgh
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
1978 Transmode (403)
Pittsburgh, PA
|
|
|
|
Goto Forum:
Current Time: Fri Sep 27 16:34:00 CDT 2024
Total time taken to generate the page: 0.02197 seconds
|
GMCforum
Search
Help
Register
Login
Home
