GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » [GMCnet] GMC Coach - New Braunfels, TX
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77835 is a reply to message #77828] Wed, 24 March 2010 10:29 Go to previous messageGo to next message
Tim Conway is currently offline  Tim Conway   United States
Messages: 412
Registered: September 2005
Location: Long Island, New York
Karma: 0
Senior Member
On Mar 24, 2010, at 10:42 AM, D C *Mac* Macdonald wrote:

> I see from info that it requires 91 Octane fuel. Is this current
> 91 stuff
> or the OLD 91 stuff? If I remember correctly, current 87 or 88 is
> about
> equivalent to the old 91 stuff.


Congratulations on the new coach!

I'm not very comfortable commenting with all the knowledge here, but
I THINK I recall reading that the 455 needs 89 and the 403 - 87. I'm
sure some authoritative info will be posted...

Tim Conway
LI NY 78 PB
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77839 is a reply to message #76941] Wed, 24 March 2010 11:58 Go to previous messageGo to next message
rallymaster is currently offline  rallymaster   United States
Messages: 662
Registered: February 2004
Location: North Plains, ORYGUN
Karma: -4
Senior Member
Current version of regular works fine, Mac.
don't forget to check the age of the tires, and buy new ones if
necessary, before you start home. Tires on our coach were about 10 years
old, and looked pretty good. We replaced them before driving it the 50
miles to get home.
I had 4 tires (only about 5 1/2 years old) begin to separate last year.
One threw chunks of tread off, and only broke the bogey greaser. Really
lucky there. The other three began to separate and formed bumps.
Had to replace tires somewhere in New Mexico. Woulda been cheaper at
home.

ronc

On Wed, 24 Mar 2010 09:42:26 -0500 D C *Mac* Macdonald
<k2gkk@hotmail.com> writes:
>
> Well, I pulled the trigger last night, so I guess I have bought a
> coach.
> Now to get financing, insurance, etc. and retrieve it from over 450
> miles
> away from home.
>
> I see from info that it requires 91 Octane fuel. Is this current 91
> stuff
> or the OLD 91 stuff? If I remember correctly, current 87 or 88 is
> about
> equivalent to the old 91 stuff.
>
> Mac Macdonald
> Oklahoma City
>
>
Ron & Linda Clark
1978 Eleganza II
North Plains, ORYGUN
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ron & Linda Clark
North Plains, ORYGUN
78 Eleganza II
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77840 is a reply to message #77839] Wed, 24 March 2010 12:06 Go to previous messageGo to next message
k2gkk is currently offline  k2gkk   United States
Messages: 4452
Registered: November 2009
Karma: -8
Senior Member

Thanks, Ron.

There is a picture of one of the front tires
on the auction. Not detailed enough to see
the age data, but tread looks very good.

Mac


----------------------------------------
> To: gmclist@temp.gmcnet.org
> Date: Wed, 24 Mar 2010 09:58:30 -0700
> From: rallymaster@juno.com
> Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX
>
> Current version of regular works fine, Mac.
> don't forget to check the age of the tires, and buy new ones if
> necessary, before you start home. Tires on our coach were about 10 years
> old, and looked pretty good. We replaced them before driving it the 50
> miles to get home.
> I had 4 tires (only about 5 1/2 years old) begin to separate last year.
> One threw chunks of tread off, and only broke the bogey greaser. Really
> lucky there. The other three began to separate and formed bumps.
> Had to replace tires somewhere in New Mexico. Woulda been cheaper at
> home.
>
> ronc
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77847 is a reply to message #77828] Wed, 24 March 2010 12:44 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
k2gkk wrote on Wed, 24 March 2010 10:42


Well, I pulled the trigger last night, so I guess I have bought a coach.

Now to get financing, insurance, etc. and retrieve it from over 450 miles away from home.

I see from info that it requires 91 Octane fuel. Is this current 91 stuff or the OLD 91 stuff? If I remember correctly, current 87 or 88 is about equivalent to the old 91 stuff.

Mac Macdonald
Oklahoma City

Mac,

Welcome to the group/cult/asylum...

Octane numbers from years ago can deceiving as the recommendations are usually not specific as to Motor or Research number and the two are run at different speeds and temperatures.

To really answer your question, the Olds 455 was built with a CR at or about 8.5. That should not have problems with current regular grade fuels whether containing alcohol or not. If you hear it pinging, back off the throttle until you can get somewhere and back the distributor down a few degrees.

As to tires: There has been much discussion here and some have had failures such that the tire age was the major issue. It may cost a some serious coin to change out 6 tires, but it has a good possibility of being less expensive than the repairs that may be required after a tire throws its belts.

And as always. . .

May the Good Lord bless this coach and all that set forth within.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77850 is a reply to message #77840] Wed, 24 March 2010 13:17 Go to previous messageGo to next message
van.one is currently offline  van.one   United States
Messages: 70
Registered: March 2010
Karma: 0
Member
Mac,

I expect your email was about the N.B. unit. I stopped bidding at $7,000.
last nite, tried to phone Steve Allen at noon to see how much I missed it.
Glad I missed it, I probably would have stayed in NB and played golf a few
days. And my golf game is not what it once was.
I still hope to get out east to see the GMC that was on Craigslist, but the
owner bought it at auction in Edmond several years ago, and is not ready to
sell at a sacrifice price. So I will keep looking for a bargain.

van.


----- Original Message -----
From: "D C *Mac* Macdonald" <k2gkk@hotmail.com>
To: <gmclist@temp.gmcnet.org>; <rallymaster@juno.com>
Sent: Wednesday, March 24, 2010 12:06 PM
Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX


>
> Thanks, Ron.
>
> There is a picture of one of the front tires
> on the auction. Not detailed enough to see
> the age data, but tread looks very good.
>
> Mac
>
>
> ----------------------------------------
>> To: gmclist@temp.gmcnet.org
>> Date: Wed, 24 Mar 2010 09:58:30 -0700
>> From: rallymaster@juno.com
>> Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX
>>
>> Current version of regular works fine, Mac.
>> don't forget to check the age of the tires, and buy new ones if
>> necessary, before you start home. Tires on our coach were about 10 years
>> old, and looked pretty good. We replaced them before driving it the 50
>> miles to get home.
>> I had 4 tires (only about 5 1/2 years old) begin to separate last year.
>> One threw chunks of tread off, and only broke the bogey greaser. Really
>> lucky there. The other three began to separate and formed bumps.
>> Had to replace tires somewhere in New Mexico. Woulda been cheaper at
>> home.
>>
>> ronc
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.437 / Virus Database: 271.1.1/2765 - Release Date: 03/23/10
07:33:00

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77852 is a reply to message #77835] Wed, 24 March 2010 13:29 Go to previous messageGo to next message
van.one is currently offline  van.one   United States
Messages: 70
Registered: March 2010
Karma: 0
Member
Mac,

If it pings a little on 87 octane then put a few moth balls into the gas
tank. That is what I used to do when I wanted to soup up my model A ford
(when I was in Jr. High).

van


----- Original Message -----
From: "Tim Conway" <mactac735@mac.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, March 24, 2010 10:29 AM
Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX


> On Mar 24, 2010, at 10:42 AM, D C *Mac* Macdonald wrote:
>
>> I see from info that it requires 91 Octane fuel. Is this current
>> 91 stuff
>> or the OLD 91 stuff? If I remember correctly, current 87 or 88 is
>> about
>> equivalent to the old 91 stuff.
>
>
> Congratulations on the new coach!
>
> I'm not very comfortable commenting with all the knowledge here, but
> I THINK I recall reading that the 455 needs 89 and the 403 - 87. I'm
> sure some authoritative info will be posted...
>
> Tim Conway
> LI NY 78 PB
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.437 / Virus Database: 271.1.1/2765 - Release Date: 03/23/10
07:33:00

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77856 is a reply to message #77829] Wed, 24 March 2010 13:51 Go to previous messageGo to next message
van.one is currently offline  van.one   United States
Messages: 70
Registered: March 2010
Karma: 0
Member
Mac,

Me too, on the congrats. If you are serious about the financing I have
extra cash that is looking for 2.5% interest for 6 months (or one year).

I doubt that I will buy one in less than a year, but who knows?

van van.one@gmail.com



----- Original Message -----
From: "Bryan Hayes" <hayesnet1@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, March 24, 2010 10:04 AM
Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX


> Congrats, Mac!
>
> On Wed, Mar 24, 2010 at 8:42 AM, D C *Mac* Macdonald
> <k2gkk@hotmail.com>wrote:
>
>>
>> Well, I pulled the trigger last night, so I guess I have bought a coach.
>> Now to get financing, insurance, etc. and retrieve it from over 450 miles
>> away from home.
>>
>> I see from info that it requires 91 Octane fuel. Is this current 91
>> stuff
>> or the OLD 91 stuff? If I remember correctly, current 87 or 88 is about
>> equivalent to the old 91 stuff.
>>
>> Mac Macdonald
>> Oklahoma City
>>
>>
>> ---- Original Message ----
>>
>> From: k2gkk@hotmail.com
>> To: gmclist@temp.gmcnet.org
>> Subject: GMC Coach - New Braunfels, TX
>> Date: Wed, 17 Mar 2010 12:49:43 -0500
>>
>> eBay # 250598570191
>>
>> (
>> http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250598570191&viewitem=&sspagename=STRK%3AMEWAX%3AIT
>> )
>>
>> I have submitted the opening bid on this coach. I have no idea as to
>> where the reserve is set, but figure I'm pretty safe at opening level.
>>
>> I wonder if any San Antonio GMCers might be familiar with this coach
>> and/or its owners.
>>
>> I will be asking for more info and more pictures, but it seems to be
>> in pretty nice condition and the interior decor does not totally
>> scream 1977!
>>
>> Mac Macdonald
>> Oklahoma City
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.437 / Virus Database: 271.1.1/2765 - Release Date: 03/23/10
07:33:00

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77860 is a reply to message #77828] Wed, 24 March 2010 13:59 Go to previous messageGo to next message
van.one is currently offline  van.one   United States
Messages: 70
Registered: March 2010
Karma: 0
Member
Mac,

Closer to 500 miles (I made the trip many, many times). But it is downhill
going (but uphill coming back). My recommendation is avoid going through
Austin during the busy time of day.

Reason I use gmail, you can save your email to gmail, get it off your PC,
yet retrieve it whenever you want to. I save my books on gmail.

van van.one@gmail.com


----- Original Message -----
From: "D C *Mac* Macdonald" <k2gkk@hotmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, March 24, 2010 9:42 AM
Subject: Re: [GMCnet] GMC Coach - New Braunfels, TX


>
> Well, I pulled the trigger last night, so I guess I have bought a coach.
> Now to get financing, insurance, etc. and retrieve it from over 450 miles
> away from home.
>
> I see from info that it requires 91 Octane fuel. Is this current 91 stuff
> or the OLD 91 stuff? If I remember correctly, current 87 or 88 is about
> equivalent to the old 91 stuff.
>
> Mac Macdonald
> Oklahoma City
>
>
> ---- Original Message ----
>
> From: k2gkk@hotmail.com
> To: gmclist@temp.gmcnet.org
> Subject: GMC Coach - New Braunfels, TX
> Date: Wed, 17 Mar 2010 12:49:43 -0500
>
> eBay # 250598570191
>
> (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250598570191&viewitem=&sspagename=STRK%3AMEWAX%3AIT)
>
> I have submitted the opening bid on this coach. I have no idea as to
> where the reserve is set, but figure I'm pretty safe at opening level.
>
> I wonder if any San Antonio GMCers might be familiar with this coach
> and/or its owners.
>
> I will be asking for more info and more pictures, but it seems to be
> in pretty nice condition and the interior decor does not totally
> scream 1977!
>
> Mac Macdonald
> Oklahoma City
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.437 / Virus Database: 271.1.1/2765 - Release Date: 03/23/10
07:33:00

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77862 is a reply to message #76941] Wed, 24 March 2010 14:10 Go to previous messageGo to next message
David L Greenberg is currently offline  David L Greenberg   United States
Messages: 899
Registered: January 2004
Location: Port St Lucie, FL
Karma: 0
Senior Member

On Wed, 24 Mar 2010 13:29:40 -0500 "J. Leon Van landingham"
<van.one@cox.net> writes:
> Mac,
>
> If it pings a little on 87 octane then put a few moth balls into the
> gas
> tank. That is what I used to do when I wanted to soup up my model A
> ford
> (when I was in Jr. High).
>
> van
>
I know there are 2 kinds of mothballs on the market today; ones with
naptha and the others with parafin. I don't imagine parafin is good to
your system.

David Lee Greenberg
Port St Lucie, FL
Dedicated to the Preservation of the Classic GMC Motorhome
http://GMCmhRegistry.com
http://www.picturetrail.com/gmcregistry
____________________________________________________________
Home Improvement Projects
Click here to find experienced pros to help with your home improvement project.
http://thirdpartyoffers.juno.com/TGL2141/c?cp=_2YAd76VgCh5AuMUjG4rXwAAJ1Csyv5OnZl2mKFYY98JLnqKAAYAAAAAAAAAAAAAAAAAAADNAAAAAAAAAAAAAAAAAAAShAAAAAA=
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Dave Greenberg
Dedicated to the Preservation of the GMC Clasic
http:GMCmhRegistry.com davegreenberg1@juno.com
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #77929 is a reply to message #77828] Wed, 24 March 2010 21:39 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
k2gkk wrote on Wed, 24 March 2010 09:42


Well, I pulled the trigger last night, so I guess I have bought a coach.
Now to get financing, insurance, etc. and retrieve it from over 450 miles
away from home.

I see from info that it requires 91 Octane fuel. Is this current 91 stuff
or the OLD 91 stuff? If I remember correctly, current 87 or 88 is about
equivalent to the old 91 stuff.

Mac Macdonald
Oklahoma City



87 is fine. If your hearing is OK, then listen for it to ping while you are driving. If you hear any pinging on heavy load, retard he timing 2 degrees. I do not know anyone personally that uses anything higher than 87. There have seen a few posts here in the past that say they use 89 or 91 but I do not remember who they were.

On the subject of pinging. Listen closely when you first drive the coach. Especially if it has been parked for a while. There have been a few cases of the distributor advance weights rusting and sticking partially or fully advanced causing pinging. Mine did it on time on a trip to my first rally. I stopped and temporarily fixed the problem until I got home. Then I bought a Dick Paterson rebuilt distributor to permanently fix it.

Ken B.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78011 is a reply to message #77929] Thu, 25 March 2010 10:23 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
Messages: 4442
Registered: January 2004
Karma: 13
Senior Member
The government has changed the way that companies post octane numbers.

The way it was done in the 70's gave a higher number so the numbers in
the GMC owners books are higher than the regular gas (about 87 now)
shown on the pumps today.

However 87 octane will work fine in our V8 GMC engines


Emery Stora

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78053 is a reply to message #77929] Thu, 25 March 2010 21:13 Go to previous messageGo to next message
roy1 is currently offline  roy1   United States
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
Senior Member
Ken
my hearing isn't all that great so I have an MSD spark control on my hei and an MSD knock sensor so I can retard the advance curve. I have found 87 to be good most of the time while towing my Toyota but I generally top the tank with a higher octane when I have some serious mountions to climb as the knock sensor will start to do a slow dance on 87 when I start climbing even when I retard the initial to 2 degrees.
Roy


Roy Keen Minden,NV 76 X Glenbrook
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78066 is a reply to message #78053] Fri, 26 March 2010 01:16 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
roy1 wrote on Thu, 25 March 2010 21:13

Ken
my hearing isn't all that great so I have an MSD spark control on my HEI and an MSD knock sensor so I can retard the advance curve. I have found 87 to be good most of the time while towing my Toyota but I generally top the tank with a higher octane when I have some serious mountains to climb as the knock sensor will start to do a slow dance on 87 when I start climbing even when I retard the initial to 2 degrees.
Roy

I have no problem with knock sensors. Installing one is probably a good move for us hard of hearing folks. I have a knock sensor in my coach sitting in the right seat. That is how I determined my static timing setting. I ran it up until it pinged and then backed it of 2 degrees. That is where it sits now several years later. Since I seldom go in real mountains I never need to change my timing. I did climb Trail Ridge Road in Rocky Mountain National Park one time up to the top at 11,000 feet and I have been through Eisenhower tunnel a couple of times which also is around 11 k. But other than those I I'm usually 5,00 or below.

But back to his original question, 87 octane should be just fine
for him in the Eastern areas. Since it is a new coach to him I just wanted him to listen to make sure his initial timing and advance were working OK.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78069 is a reply to message #78066] Fri, 26 March 2010 08:06 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
Messages: 4442
Registered: January 2004
Karma: 13
Senior Member

On Mar 26, 2010, at 1:16 AM, Ken Burton wrote:

>
>
> roy1 wrote on Thu, 25 March 2010 21&#58;13
>> Ken
>> my hearing isn't all that great so I have an MSD spark control on
>> my HEI and an MSD knock sensor so I can retard the advance curve. I
>> have found 87 to be good most of the time while towing my Toyota
>> but I generally top the tank with a higher octane when I have some
>> serious mountains to climb as the knock sensor will start to do a
>> slow dance on 87 when I start climbing even when I retard the
>> initial to 2 degrees.
>> Roy
>
> I have no problem with knock sensors. Installing one is probably a
> good move for us hard of hearing folks. I have a knock sensor in my
> coach sitting in the right seat. That is how I determined my static
> timing setting. I ran it up until it pinged and then backed it of 2
> degrees. That is where it sits now several years later. Since I
> seldom go in real mountains I never need to change my timing. I did
> climb Trail Ridge Road in Rocky Mountain National Park one time up
> to the top at 11,000 feet and I have been through Eisenhower tunnel
> a couple of times which also is around 11 k. But other than those I
> I'm usually 5,00 or below.


Ken - since I am living at 7200 feet and drive at even higher
elevations a lot, I can tell you that it is very difficult to get an
engine to ping at high elevations. One can actually advance the
static timing to 20 deg advance and still not get pinging but you get
a lot more power on the hills. However, when I did this I would have
to drop the timing back down at lower elevations in order to stop
pinging.

87 octane works fine in the mountains. It is the addition of 10%
ethanol that will drop the mileage and cause vapor lock problems in
hot weather at higher elevations.

Emery Stora
77 Kingsley
Santa Fe, NM


_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78082 is a reply to message #78069] Fri, 26 March 2010 13:27 Go to previous messageGo to next message
roy1 is currently offline  roy1   United States
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
Senior Member
Emery Ken:
Possibly my new high torque cam is entering the picture I just prefer not to see the knock sensor going past the green bars. The motor is new so it doesn't have any carbon on the pistons.
I only notice it starting to ping in 2nd gear pedal to the floor
and 3000 rpm and yes the distributor is curved. I agree carburetor engines (which mine is) run richer at elevation. After the hard pull I just reset the advance. Flat land and rolling hills are never a problem with 87 octane even with an aggressive initial timing setting. I can't imagine anyone needing more then 87 back east if they have 8-1 pistons.
Roy


Roy Keen Minden,NV 76 X Glenbrook
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78083 is a reply to message #78069] Fri, 26 March 2010 13:37 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
emerystora wrote on Fri, 26 March 2010 08:06


On Mar 26, 2010, at 1:16 AM, Ken Burton wrote:

>
>
> roy1 wrote on Thu, 25 March 2010 21:13
>> Ken
>> my hearing isn't all that great so I have an MSD spark control on
>> my HEI and an MSD knock sensor so I can retard the advance curve. I
>> have found 87 to be good most of the time while towing my Toyota
>> but I generally top the tank with a higher octane when I have some
>> serious mountains to climb as the knock sensor will start to do a
>> slow dance on 87 when I start climbing even when I retard the
>> initial to 2 degrees.
>> Roy
>
> I have no problem with knock sensors. Installing one is probably a
> good move for us hard of hearing folks. I have a knock sensor in my
> coach sitting in the right seat. That is how I determined my static
> timing setting. I ran it up until it pinged and then backed it of 2
> degrees. That is where it sits now several years later. Since I
> seldom go in real mountains I never need to change my timing. I did
> climb Trail Ridge Road in Rocky Mountain National Park one time up
> to the top at 11,000 feet and I have been through Eisenhower tunnel
> a couple of times which also is around 11 k. But other than those I
> I'm usually 5,00 or below.


Ken - since I am living at 7200 feet and drive at even higher
elevations a lot, I can tell you that it is very difficult to get an
engine to ping at high elevations. One can actually advance the
static timing to 20 deg advance and still not get pinging but you get
a lot more power on the hills. However, when I did this I would have
to drop the timing back down at lower elevations in order to stop
pinging.

87 octane works fine in the mountains. It is the addition of 10%
ethanol that will drop the mileage and cause vapor lock problems in
hot weather at higher elevations.

Emery Stora
77 Kingsley
Santa Fe, NM



What you say is entirely true. I guess I should have stated it a little differently. It is climbing large grades to get to those altitudes where my concern comes from. Operating at those altitudes actually takes lower octane fuel. That is why the gas companies get by selling lower than 87 octane above 4000 or 5000 feet and still calling it regular fuel.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78117 is a reply to message #78083] Fri, 26 March 2010 19:32 Go to previous messageGo to next message
roy1 is currently offline  roy1   United States
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
Senior Member
I had forgotten about that . That is why I notice the problem more so when I come down off this mountain with a load of high altitude gas to a lower level then start climbing again. After a couple of tank fulls of flatland gas I don't seem to have much action on the knock sensor. Dam I hate it when I forget stuff.
Roy


Roy Keen Minden,NV 76 X Glenbrook
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78118 is a reply to message #78117] Fri, 26 March 2010 19:38 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
I do not know at what altitude they start selling lower octane gas for all three grades. I know I always get it every time I go to Colorado. I have seen this in other states but never made it a point to keep tract of them. I have seen it as low as 84 somewhere. More common is 85 and 86. When I am there I have no choice and just use it.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78119 is a reply to message #78118] Fri, 26 March 2010 19:44 Go to previous message
roy1 is currently offline  roy1   United States
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
Senior Member
I'm at 5000 ft so what you say about the lower octane seems to ring true.
Roy


Roy Keen Minden,NV 76 X Glenbrook
Previous Topic: [GMCnet] Master Cylinder Pushrod Clearance
Next Topic: Excellent RV 12 volt battery information site
Goto Forum:
  


Current Time: Mon Jul 08 09:47:26 CDT 2024

Total time taken to generate the page: 0.03161 seconds