Home » Public Forums » GMCnet » First outing 77 Royal, 403, with 307 gears (power in mountians)
| First outing 77 Royal, 403, with 307 gears [message #346860] |
Sun, 25 August 2019 21:31  |
Lhockman
Messages: 5
Registered: February 2019
Location: Alamogordo NM
Karma: 0
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Junior Member |
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WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was a shake down to find any problems. We live in southern NM and were going to a campground near Timberon NM. We had a huge climb from Alamogordo NM to Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
Ok now for our problems along the way. We had not gone too many miles when our fuel pump went out. Since these RVs need fuel we replaced it on the side of the road. My wife was following me with her car for a backup AND A GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This took some time, to get the part and travel up and down the mountian for the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed and we were off again.
Next big thing was we did not have much power to make the climb up the mountian. This is time to let you know I was towing a heavy car trailer with a Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch Campground.
Now that you have a quick synopsis of our first time out camping with our GMC. I could use some advice on getting more power for us out west and in the mountains. I think a popular option is to change gearing from 3.07 to 3.70. , this is an expensive option, but could be the best. I could also change the front tires to a smaller diameter, has anyone done this, I am running 16" wheels.
1977 26 foot, royale
Alamogordo NM
[Updated on: Sun, 25 August 2019 21:33] Report message to a moderator |
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346864 is a reply to message #346860] |
Sun, 25 August 2019 22:07  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Lennie,
Welcome aboard, and congratulations on your first trip. Glad you were able
to overcome the little problem.
A few ideas:
If you don't KNOW that all rubber components, especially the rubber fuel
and vent lines, including on top of the gas tanks, have been replaced with
modern barrier hoses, do so NOW.
You were apparently lucky and didn't have vapor lock problems. To ensure
that you don't in the future, as you're especially prone to do in that
area, eliminate that mechanical pump and the trouble-prone tank selector
valve. Replace all that with an electric pump for each tank (I like Carter
4070's). Mount them either just ahead of the forward tank or on the
outside of the left frame rail. Outside the rail is best except for the
possible hazard in a side collision.
Electronic fuel injection will further improve your vapor lock protection,
MAY give you a little more fuel mileage. And, especially if you use a
system with spark control capability, may give you slightly better
performance.
Definitely the simplest, probably cheapest route to improved performance is
that 3.70:1 final drive upgrade.
While I live in the rather benign SE USA, our X-Birchaven has been from Key
West, FL to Fairbanks, AK, so we've covered just about all weather &
terrain (except snow I have, and will ALWAYS have, very little GMC
experience with that!).
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com
On Sun, Aug 25, 2019 at 10:52 PM lennie l hockman via Gmclist <
gmclist@list.gmcnet.org> wrote:
> WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was
> a shake down to find any problems. We live in southern NM and were going to
> a campground near Timberon NM. We had a huge climb from Alamogordo NM to
> Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
> Ok now for our problems along the way. We had not gone too many miles when
> our fuel pump went out. Since these RVs need fuel we replaced it on the
> side of the road. My wife was following me with her car for a backup AND A
> GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This
> took some time, to get the part and travel up and down the mountian for
> the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed
> and we were off again.
> Next big thing was we did not have much power to make the climb up the
> mountian. This is time to let you know I was towing a heavy car trailer
> with a
> Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch
> Campground.
> Now that you have a quick synopsis of our first time out camping with our
> GMC. I could use some advice on getting more power for us out west and in
> the mountains. I think a popular option is to change gearing from 3.07 to
> 3.70. , this is an expensive option, but could be the best. I could also
> change the front tires to a smaller diameter, has anyone done this, I am
> running 16" wheels.
> --
> 1977 26 foot, royale
> Alamogordo NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
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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: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346865 is a reply to message #346860] |
Sun, 25 August 2019 22:11 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Call me fortps to get more power at high elevation as I go from sea level
to 8,000 few times a year.
On Sun, Aug 25, 2019 at 7:52 PM lennie l hockman via Gmclist <
gmclist@list.gmcnet.org> wrote:
> WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was
> a shake down to find any problems. We live in southern NM and were going to
> a campground near Timberon NM. We had a huge climb from Alamogordo NM to
> Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
> Ok now for our problems along the way. We had not gone too many miles when
> our fuel pump went out. Since these RVs need fuel we replaced it on the
> side of the road. My wife was following me with her car for a backup AND A
> GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This
> took some time, to get the part and travel up and down the mountian for
> the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed
> and we were off again.
> Next big thing was we did not have much power to make the climb up the
> mountian. This is time to let you know I was towing a heavy car trailer
> with a
> Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch
> Campground.
> Now that you have a quick synopsis of our first time out camping with our
> GMC. I could use some advice on getting more power for us out west and in
> the mountains. I think a popular option is to change gearing from 3.07 to
> 3.70. , this is an expensive option, but could be the best. I could also
> change the front tires to a smaller diameter, has anyone done this, I am
> running 16" wheels.
> --
> 1977 26 foot, royale
> Alamogordo NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346869 is a reply to message #346865] |
Mon, 26 August 2019 06:16 |
mjbourgon
Messages: 259
Registered: May 2010
Karma: -1
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Senior Member |
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Good morning from Santa Teresa, NM. I have a 28 footer with 455 engine. You must remember you have a large auto engine powering our coaches. I looked at going to cloud croft also but the climb would be a challenge just for the coach not pulling any thing behind that is heavy.
Cloud croft is over 8000 ft and is a challenge. The other thing to remember is we have old units and this type of elevation is a challenge. I might try next time going to Ruidoso and then taking the road between ruidoso and cloud croft. A bit less of a climb.
Marcel in El Paso
> On Aug 25, 2019, at 9:11 PM, Jim Kanomata via Gmclist wrote:
>
> Call me fortps to get more power at high elevation as I go from sea level
> to 8,000 few times a year.
>
> On Sun, Aug 25, 2019 at 7:52 PM lennie l hockman via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was
>> a shake down to find any problems. We live in southern NM and were going to
>> a campground near Timberon NM. We had a huge climb from Alamogordo NM to
>> Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
>> Ok now for our problems along the way. We had not gone too many miles when
>> our fuel pump went out. Since these RVs need fuel we replaced it on the
>> side of the road. My wife was following me with her car for a backup AND A
>> GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This
>> took some time, to get the part and travel up and down the mountian for
>> the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed
>> and we were off again.
>> Next big thing was we did not have much power to make the climb up the
>> mountian. This is time to let you know I was towing a heavy car trailer
>> with a
>> Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch
>> Campground.
>> Now that you have a quick synopsis of our first time out camping with our
>> GMC. I could use some advice on getting more power for us out west and in
>> the mountains. I think a popular option is to change gearing from 3.07 to
>> 3.70. , this is an expensive option, but could be the best. I could also
>> change the front tires to a smaller diameter, has anyone done this, I am
>> running 16" wheels.
>> --
>> 1977 26 foot, royale
>> Alamogordo NM
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
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| Re: First outing 77 Royal, 403, with 307 gears [message #346872 is a reply to message #346860] |
Mon, 26 August 2019 07:28 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Lhochman,
Welcome to the group, family, cult, asylum.
I am very happy to hear that your first excursion was so successful. If you keep up with the regular maintenance, it can be this way a long time.
One of our early excursions was to Santa Fe and Albuquerque. I thought about starting east through Cloud Croft. I changed my mind when I saw the elevations and the road that looked like it had been scribbled on the map. We have since encountered both higher and more twisty roads. I now might drive though there without any trepidation.
Thank you for starting a good sigfile, but I will ask that you add your name to it. What ever you like to be addressed as will be good. This is largely because we really like to know who we are helping. It is also more convenient when you meet other owners (and you will). (You can change the alias easily.)
If you work the web just a little, you should be able to discover that there is a local chapter of GMC owners. Get hooked up with them as the support will be of great value. There is a Western States Rally coming up but I fear that might be farther than you might like, but look for GMC rallies that are closer and try to get to one.
You will soon discover that the coach is more than just a new big toy, but has much more value in the community that it connects you to. This is a community of supportive and helping people that is very rare in the world. We all want to see that you get to enjoy what the coach can do for you as well as the community that it connects you to. We have members here that total to millions of miles and centuries of hands on experience. The advice given here should be valued. As the only other community like this that I know of is that of the watermen that are my world. For this very reason, I like to welcome new owners here much as one would be welcomed there. So,
May the Good Lord bless this coach and all those that set forth within her.
Welcome Lhockman
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
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346873 is a reply to message #346869] |
Mon, 26 August 2019 07:43 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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Marcel,
Some points to respond to. First is that we have a gasoline engine, but it
doesn’t know it’s a car engine. The standard tow vehicle back in the day
for a 5-ton Airstream trailer that was a Delta 88 or station wagon, with a
tow package and the same 455 engine. And many commercial delivery trucks
have smaller and lighter engines than the 455.
The 455’s horsepower peaks at 3600 RPM. We normally cruise at highway speed
at 2600 RPMs or thereabouts. We may need peak horsepower for a climb, and
there are two ways to get it. A 3.70 final drive will increase that highway
cruise RPM to a little over 3100. That will help with driveability, and
will without doubt make climbing easier. But it still won’t get us to peak
power at climbing speed.
But for really big climbs, we can put the engine in the middle 3000’s at a
reasonable climbing speed in S (Super). Shift manually—that’s easier on
the transmission than using the kickdown (Manny disables the kickdown for a
reason).
Truck engines turn slower because they have to (as a result of rotating
mass), and so are designed for massive amounts of torque to make up for
their inability to spin. The 455 is closer to a truck engine in that regard
than a modern gasoline engine with a light design and a horsepower peak at
6000 RPMs or more. Even if we built a 455 that could turn and breathe that
fast, we’d never run it at those RPMs on a climb.
GM designed the carburetor to provide acceptable service from Death Valley
to Pike’s Peak (14,000 feet elevation), when in a state of good repair.
Fuel isn’t what it used to be, and that favors a switch to fuel injection,
but it’s a fact that we can make the coaches serviceable at 8000 feet
elevation even with a carburetor, especially fed by an electric pump
pushing from the rear instead of a mechanical pump pulling from the front.
Rick “start with a state of good repair and go from there” Denney
On Mon, Aug 26, 2019 at 7:16 AM Marcel Bourgon via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Good morning from Santa Teresa, NM. I have a 28 footer with 455 engine.
> You must remember you have a large auto engine powering our coaches. I
> looked at going to cloud croft also but the climb would be a challenge
> just for the coach not pulling any thing behind that is heavy.
> Cloud croft is over 8000 ft and is a challenge. The other thing to
> remember is we have old units and this type of elevation is a challenge. I
> might try next time going to Ruidoso and then taking the road between
> ruidoso and cloud croft. A bit less of a climb.
> Marcel in El Paso
>
> --
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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| Re: First outing 77 Royal, 403, with 307 gears [message #346876 is a reply to message #346860] |
Mon, 26 August 2019 08:22 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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Senior Member |
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Happily, the PO for my coach blessed it with a set of Thorley headers, a massive 3" exhaust system, and put in some 3.42 gears. I was impressed with its ability to cruise up hills, often passing "lesser" motorhomes and semis with ease.
Then I did my first drive from the Phoenix valley to Flagstaff. This involves climbing 6-8% hills at 6,000 - 7,500 feet. My mighty 403 struggled mightily over 5,000 feet, and a lot of the climbs were completed in first gear with my right foot planted in the carpet. Since then, I installed a throttle body fuel injection system, and the difference is pretty amazing. What used to require winding out the engine in 1st gear now just causes a kick-down to 2nd without drama. It also starts easier and looks like it's getting better gas mileage (had some other fuel issues that made it impossible to know for sure). But the coach is just SO much easier to drive at altitude.
I'd echo what others have said about making sure the rest of your fuel system is intact. I did have some strange problems on the last drive "up the hill" to Flagstaff, but when I got home I saw that the body spacer (rubber "hockey puck" between the frame and body) nearest the fuel tank vent lines had slipped out, pinching the vent lines, causing a LOT of pressure in the fuel tanks. There's almost no clearance from the vent lines to the fuel tanks and body with a good body spacer, and if it gets compressed (or goes missing) things are going to stop working right in pretty short order.
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: First outing 77 Royal, 403, with 307 gears [message #346877 is a reply to message #346860] |
Mon, 26 August 2019 08:23 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Mease to Winslow running bobtailed, mine walked over the mountains and down the crooked roads without any histrionics - it has MSD Atomic injection.
--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] First outing 77 Royal, 403, with 301 gears [message #346879 is a reply to message #346873] |
Mon, 26 August 2019 08:33 |
mjbourgon
Messages: 259
Registered: May 2010
Karma: -1
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Senior Member |
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Good morning Denney. I agree the 455 is a good powerful engine especially when in good tune. You are right about dropping the beast into second gear for hills. This area is steep enough and long. I live in this area and I hesitated to run my old beast up that hill. Here in the desert southwest, it gets very hot and dry and I was also concerned about the heat situation for the old girl. It is a long hill just probable a mid way stop for a minute to let it cool down. The other thing we sometimes forget that these coaches were built in the mid seventies and we do not want to beat them too hard. I tow a Suzuki Vitara with no problems at all. I just do not want to push her to her limits and maybe hurt the old girl.. Mine does have an electric fuel pump also, great idea. If in the midwest give a call and we can have coffee
Marcel in Santa Teresa, New Mexico
> On Aug 26, 2019, at 6:43 AM, Richard Denney via Gmclist wrote:
>
> Marcel,
>
> Some points to respond to. First is that we have a gasoline engine, but it
> doesn’t know it’s a car engine. The standard tow vehicle back in the day
> for a 5-ton Airstream trailer that was a Delta 88 or station wagon, with a
> tow package and the same 455 engine. And many commercial delivery trucks
> have smaller and lighter engines than the 455.
>
> The 455’s horsepower peaks at 3600 RPM. We normally cruise at highway speed
> at 2600 RPMs or thereabouts. We may need peak horsepower for a climb, and
> there are two ways to get it. A 3.70 final drive will increase that highway
> cruise RPM to a little over 3100. That will help with driveability, and
> will without doubt make climbing easier. But it still won’t get us to peak
> power at climbing speed.
>
> But for really big climbs, we can put the engine in the middle 3000’s at a
> reasonable climbing speed in S (Super). Shift manually—that’s easier on
> the transmission than using the kickdown (Manny disables the kickdown for a
> reason).
>
> Truck engines turn slower because they have to (as a result of rotating
> mass), and so are designed for massive amounts of torque to make up for
> their inability to spin. The 455 is closer to a truck engine in that regard
> than a modern gasoline engine with a light design and a horsepower peak at
> 6000 RPMs or more. Even if we built a 455 that could turn and breathe that
> fast, we’d never run it at those RPMs on a climb.
>
> GM designed the carburetor to provide acceptable service from Death Valley
> to Pike’s Peak (14,000 feet elevation), when in a state of good repair.
> Fuel isn’t what it used to be, and that favors a switch to fuel injection,
> but it’s a fact that we can make the coaches serviceable at 8000 feet
> elevation even with a carburetor, especially fed by an electric pump
> pushing from the rear instead of a mechanical pump pulling from the front.
>
> Rick “start with a state of good repair and go from there” Denney
>
> On Mon, Aug 26, 2019 at 7:16 AM Marcel Bourgon via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Good morning from Santa Teresa, NM. I have a 28 footer with 455 engine.
>> You must remember you have a large auto engine powering our coaches. I
>> looked at going to cloud croft also but the climb would be a challenge
>> just for the coach not pulling any thing behind that is heavy.
>> Cloud croft is over 8000 ft and is a challenge. The other thing to
>> remember is we have old units and this type of elevation is a challenge. I
>> might try next time going to Ruidoso and then taking the road between
>> ruidoso and cloud croft. A bit less of a climb.
>> Marcel in El Paso
>>
>> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
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Unsubscribe or Change List Options:
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346880 is a reply to message #346879] |
Mon, 26 August 2019 08:48 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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Senior Member |
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mjbourgon wrote on Mon, 26 August 2019 06:33Good morning Denney. I agree the 455 is a good powerful engine especially when in good tune. You are right about dropping the beast into second gear for hills. This area is steep enough and long. I live in this area and I hesitated to run my old beast up that hill. Here in the desert southwest, it gets very hot and dry and I was also concerned about the heat situation for the old girl. It is a long hill just probable a mid way stop for a minute to let it cool down. The other thing we sometimes forget that these coaches were built in the mid seventies and we do not want to beat them too hard. I tow a Suzuki Vitara with no problems at all. I just do not want to push her to her limits and maybe hurt the old girl.. Mine does have an electric fuel pump also, great idea. If in the midwest give a call and we can have coffee
Marcel in Santa Teresa, New Mexico
Reading your message brought back the genesis moment for my own GMC adventures. I'd been trying to talk my wife into getting an RV for years, but every time I pointed out a likely suspect, she'd comment that it was just an ugly white box on a truck chassis (which is correct).
Then one fateful day we were cruising across NM (in our car) on the way to CO from AZ, and we saw a beautiful GMC towing a matching (brown, IIRC) Suzuki. We were both thunderstruck by the style of the whole thing, and Carol said "I could see us in one of those". Well, that's all it took, and the nationwide search commenced when we got back to AZ. I ended up with a really nice '78 Royale Center Kitchen from west Los Angeles, and we've been enjoying it mightily since then.
I wonder if the coach we say might have been yours. If so, many thanks for being on the road that day!
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: First outing 77 Royal, 403, with 307 gears [message #346882 is a reply to message #346860] |
Mon, 26 August 2019 09:27 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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1) see if accelerator pedal is fully opening the carb so the secondary throttle plates are vertical. Most do not and need adjustment
2) if your distributor has not been disassembled, cleaned and relubricated there is a good probability that the mechanical and/or vacuum advance is not working properly. Continuing to operate the coach in severe conditions in this manner will kill the engine prematurely
3) not sure if your driving technique is the most optimal to put least stress on systems.
4) once all carb/ign is correct it's best to use WOT only as needed and for short intervals. Continuous WOT washes lube from walls and burns excess fuel and creates more heat load. Better to find the right speed /throttle spot and let it work there
For comparison I did the Phoenix /Flagstaff run in my 77 455 when it still had 3.07s and was able to maintain speed vs temp but if road was steeper would have been in 1st gear. Since then went to 3.42 and find it a good balance between speed and power with 455.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] First outing 77 Royal, 403, with 307 gears [message #346889 is a reply to message #346882] |
Mon, 26 August 2019 10:58 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I found an interesting problem yesterday during a black list service call
to a stranded couple in a Walmart parking lot 25 miles from my home. They
complained of backfiring through the intake, and as I was diagnosing the
problem, I opened the HEI distributor to check the cap for carbon tracks,
and the centrifugal advance weights to see if they were stuck. (they were) .
So, I removed the rotor, which was blue in color, and identified as a
"STANDARD" brand name. The weights responded to a bit of tweaking and
penetrate, followed by lubrication. But I noticed that the upper side of
one of the weights had a shiny spot on it. Upon observation of the rotor, a
matching spot was noted. It seems the molded rotor had some poor quality
control during manufacture, and it really affected the operation of the
flyweights, when the rotor was in place. As in, it locked them up.
So, I replaced the blue rotor with an "Echlin" brand from NAPA. No
more interference with the Echlin rotor. The advance worked as it was
supposed to.
The coil was the correct one for the application, as was the 5 pin
module. All connections were checked and found to be tight, bright, and
shiny.
The backfiring, however, persisted, accompanied by a mechanical
clicking sound. So, I referred them to a local repair shop for a
compression test and further repairs.
Jim Hupy
Salem, Oregon
On Mon, Aug 26, 2019, 7:34 AM John R. Lebetski via Gmclist <
gmclist@list.gmcnet.org> wrote:
> 1) see if accelerator pedal is fully opening the carb so the secondary
> throttle plates are vertical. Most do not and need adjustment
> 2) if your distributor has not been disassembled, cleaned and relubricated
> there is a good probability that the mechanical and/or vacuum advance is
> not working properly. Continuing to operate the coach in severe conditions
> in this manner will kill the engine prematurely
> 3) not sure if your driving technique is the most optimal to put least
> stress on systems.
> 4) once all carb/ign is correct it's best to use WOT only as needed and
> for short intervals. Continuous WOT washes lube from walls and burns excess
> fuel and creates more heat load. Better to find the right speed /throttle
> spot and let it work there
>
> For comparison I did the Phoenix /Flagstaff run in my 77 455 when it still
> had 3.07s and was able to maintain speed vs temp but if road was steeper
> would have been in 1st gear. Since then went to 3.42 and find it a good
> balance between speed and power with 455.
>
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #346891 is a reply to message #346860] |
Mon, 26 August 2019 11:04 |
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We were through Cloudcroft in late March, 2018 on our way to Tucson. It
was absolutely beautiful!
No problem for the Palm Beach with 455 and a 3.46 final drive. Sure, we
had to pull her down into 2nd a few times to make a summit and start a
descent, but that's just how ya drive a 12,000# vehicle pulling a 3,000#
car.
On Sun, Aug 25, 2019 at 9:52 PM lennie l hockman via Gmclist <
gmclist@list.gmcnet.org> wrote:
> WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was
> a shake down to find any problems. We live in southern NM and were going to
> a campground near Timberon NM. We had a huge climb from Alamogordo NM to
> Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
> Ok now for our problems along the way. We had not gone too many miles when
> our fuel pump went out. Since these RVs need fuel we replaced it on the
> side of the road. My wife was following me with her car for a backup AND A
> GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This
> took some time, to get the part and travel up and down the mountian for
> the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed
> and we were off again.
> Next big thing was we did not have much power to make the climb up the
> mountian. This is time to let you know I was towing a heavy car trailer
> with a
> Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch
> Campground.
> Now that you have a quick synopsis of our first time out camping with our
> GMC. I could use some advice on getting more power for us out west and in
> the mountains. I think a popular option is to change gearing from 3.07 to
> 3.70. , this is an expensive option, but could be the best. I could also
> change the front tires to a smaller diameter, has anyone done this, I am
> running 16" wheels.
> --
> 1977 26 foot, royale
> Alamogordo NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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bdub
bdub.net
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| Re: First outing 77 Royal, 403, with 307 gears [message #346893 is a reply to message #346860] |
Mon, 26 August 2019 11:44 |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
|
Senior Member |
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Lhockman wrote on Sun, 25 August 2019 21:31WE had our first outing with our 77 Royal 26ft unit with 403 CID. This was a shake down to find any problems. We live in southern NM and were going to a campground near Timberon NM. We had a huge climb from Alamogordo NM to Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
Ok now for our problems along the way. We had not gone too many miles when our fuel pump went out. Since these RVs need fuel we replaced it on the side of the road. My wife was following me with her car for a backup AND A GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This took some time, to get the part and travel up and down the mountian for the part and fix a fuel leak on fuel filter on carburetor. Well got it fixed and we were off again.
Next big thing was we did not have much power to make the climb up the mountian. This is time to let you know I was towing a heavy car trailer with a Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch Campground.
Now that you have a quick synopsis of our first time out camping with our GMC. I could use some advice on getting more power for us out west and in the mountains. I think a popular option is to change gearing from 3.07 to 3.70. , this is an expensive option, but could be the best. I could also change the front tires to a smaller diameter, has anyone done this, I am running 16" wheels.
I have a 403 as well. The two best upgrades I made to make the 403 come alive was changing the final drive to a 3.70 and installing fuel injection with good spark control capability (most aftermarket efi systems do not provide much help with spark control). I can out pull most stock 455 coaches on about any grade. When I approach a long 6% + grade, I will manually pull down to 2nd and can maintain 60 mph until the top. I usually pull a car weighting in at around 3000#. I know of another with the same configuration that I have who pulls gross weight of 17000# to 22000# without issue. Not sure you would gain enough with smaller diameter tires to make that a worth while approach - clearance of calipers might be problematic.
I love the 403 and will not change to anything else as I consider a rebuild. Currently have 165,000 almost trouble free miles and still runs strong.
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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| Re: [GMCnet] First outing 77 Royal, 403, with 307 gears [message #346894 is a reply to message #346890] |
Mon, 26 August 2019 11:54 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Probably a good bet, but they might get lucky and it will prove to be a
cracked intake manifold or a bent pushrod or failed rocker arm. In any
event, it is internal.
Jim Hupy
Salem,Oregon
On Mon, Aug 26, 2019, 9:33 AM John R. Lebetski via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Perhaps running retarded burned a valve. Unfortunately.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
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| Re: [GMCnet] First outing 77 Royal, 403, with 307 gears [message #346917 is a reply to message #346894] |
Tue, 27 August 2019 00:15 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
|
Senior Member |
|
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You are getting good advise here. If my beloved PO hadn't installed the Marvin Peck gears, lower gears would have been high on my list. I honestly think the best thing I've done is the Howell EFI and the spark controlled EBL. I have no experience with other EFI's but I'd take her up the grade at Baker going to Vegas any day. Heck, we came from Ohio to Fremont on Rt 80 that had some climbs, and we've been over the Grapevine many times without a thought.
So, Gears. EFI.
So long as everything else is safe - brakes (including brake lines), suspension, tires, fuel lines, wheel bearings. Safety is first. The rest is improving on the original design.
Man we're lucky to have these worries!
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] First outing 77 Royal, 403, with 301 gears [message #347441 is a reply to message #346891] |
Fri, 06 September 2019 16:15 |
Vern Crawford
Messages: 81
Registered: August 2016
Karma: -1
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Member |
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Howdy Lennie and family,
Welcome to the asylum! You are now part of an amazing bunch of wise, warm,
and talented GMC Motorhome aficionados.
All of the comments by others above are worthy of consideration.
We just got home in Texas from our 4th annual 6,000 mile pilgrimage to the
Pacific Northwest with our standard carburetor 1973 Palm Beach with its 403
cubic inch engine, and a standard final drive. We have never avoided any
mountainous climbs along the way. Heck, I seem to go out of the way to
tackle a beautiful new winding mountain drive (like the "Lost Coast Loop"
in Northern California).
We always return via the Colorado Rockies, with friends in such places as
Carbondale, Creede, Leadville, and camping along the Continental Divide.
To make life a bit easier on her next time she meets a long steep climb at
high altitudes I'm going to treat her to a final drive upgrade [Jim K, are
you going to the Spring GMCMI Conference in Lousiana?]. But so far she has
pulled us through whatever we have encountered, with the occasional hick-up
some refer to as vapor-lock.
Previous owners Billie and Mike Kelley had called her "BUC" for Back Up
Coach. When I first brought her home Lenore nicked named her "AaRVee."
After all of the places she's taken us I want to suggest a new name for
her:
"Billie D. Goat!"
Hugs,
Vern, Lenore, and Knibbles D. Kat
On Mon, Aug 26, 2019 at 11:05 AM Billy Massey via Gmclist <
gmclist@list.gmcnet.org> wrote:
> We were through Cloudcroft in late March, 2018 on our way to Tucson. It
> was absolutely beautiful!
> No problem for the Palm Beach with 455 and a 3.46 final drive. Sure, we
> had to pull her down into 2nd a few times to make a summit and start a
> descent, but that's just how ya drive a 12,000# vehicle pulling a 3,000#
> car.
>
> On Sun, Aug 25, 2019 at 9:52 PM lennie l hockman via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> WE had our first outing with our 77 Royal 26ft unit with 403 CID. This
> was
>> a shake down to find any problems. We live in southern NM and were going
> to
>> a campground near Timberon NM. We had a huge climb from Alamogordo NM to
>> Cloudcroft NM, at least a 4000 ft. climb in about 15 miles.
>> Ok now for our problems along the way. We had not gone too many miles
> when
>> our fuel pump went out. Since these RVs need fuel we replaced it on the
>> side of the road. My wife was following me with her car for a backup AND
> A
>> GOOD THING. I found that Auto Zone in Alamogordo had one in stock. This
>> took some time, to get the part and travel up and down the mountian for
>> the part and fix a fuel leak on fuel filter on carburetor. Well got it
> fixed
>> and we were off again.
>> Next big thing was we did not have much power to make the climb up the
>> mountian. This is time to let you know I was towing a heavy car trailer
>> with a
>> Polaris RZR. The camping was great, we stayed at the Circle Cross Ranch
>> Campground.
>> Now that you have a quick synopsis of our first time out camping with our
>> GMC. I could use some advice on getting more power for us out west and in
>> the mountains. I think a popular option is to change gearing from 3.07 to
>> 3.70. , this is an expensive option, but could be the best. I could also
>> change the front tires to a smaller diameter, has anyone done this, I am
>> running 16" wheels.
>> --
>> 1977 26 foot, royale
>> Alamogordo NM
>>
>> _______________________________________________
>> 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
>
--
Vern Crawford (and Lenore Langsdorf)
155 JJ Lane
Center Point, TX 78010
(618) 203-8296 Vern's cell
(830) 928-5550 Lenore's cell
VernCrawford@GMail.Com
LenoreLangsdorf@GMail.Com
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| Re: First outing 77 Royal, 403, with 307 gears [message #347444 is a reply to message #346860] |
Fri, 06 September 2019 17:24 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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If you were to change tire diameter, understand that that changes steering axis., as the point where the imaginary line through the ball joints intersects the pavement moves.
John Lebetski
Woodstock, IL
77 Eleganza II
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