RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 08-12-2017, 07:19 AM   #1
1 Rivet Member
 
1991 35' Airstream 350
Georgetown , Kentucky
Join Date: Aug 2017
Posts: 5
Engine in 91 350 LE question

Hello all. I recently got a 91 350 LE CLASSIC that has 46000 miles on it and at about 30000, the engine was changed from the 454 to a large block 502 with a supercharger. My question is what is the performance like of the 454 that required this upgrade? I drove this RV back across the states and even with the 502 and the supercharger, it could only maintain maybe 25 to 34 mph over the mountains and I didn't expect that. Is that better than the 454 performance??!!! If this vehicle is just to heavy, should I consider a diesel conversion and if so any ideas on what such a conversion might run?? Thanks to all in advance. Brad Bentz
Bentzb02 is offline   Reply With Quote
Old 08-12-2017, 07:22 AM   #2
Rivet Master
 
ALANSD's Avatar

 
1966 26' Overlander
Woodstock , Georgia
Join Date: Feb 2002
Posts: 8,523
the 454 is a semi reliable gas sucking hog that developed lot of heat. Your motorhome is large and heavy and might benefit from a Cummins diesel conversion. There are other here that have done that and you can read their journeys.
Use the search to find them.
I'm a former owner of a Classic 82 28 footer with A 454, but there are owners of your model who will add to this.
__________________
1966 overlander..sold
AIR #005
Please visit our blogs and web pages:
OUR AIRSTREAM PASSION! BLOG
RESTORING AN AIRSTREAM
retired!
ALANSD is offline   Reply With Quote
Old 08-12-2017, 07:49 AM   #3
Rivet Master
 
jdalrymple's Avatar
 
2009 27' FB Flying Cloud
1991 35' Airstream 350
Jay , Oklahoma
Join Date: Oct 2006
Posts: 1,695
As I mentioned in your previous thread, I own the same coach.

Mine is stock, and it's performance is about the same as you describe.

Assuming the rest of your drive train is unmodified, I would say that is about as good as it gets. The P30 chassis these motorhomes are built on was designed in the days of 55 mph speed limits and the 350LE body was pushing the upper limit of the chassis.

To make them travel at 75 mph and climb hills in the fast lane, one would need to replace just about every part of the drive train and steer axle. The stock transmission is just 3 speeds so it is hard to keep the engine speed in the power band in all situations. The front axle was nearly overloaded, so new steering components and heavier springs would be required to keep the thing in your lane at higher speeds.

It is difficult to balance the desire to improve the performance with remembering it is 30 year old machine.

We learned to take our time and enjoy the trip.

If we are traveling a long way or need to make time, we take the trailer.



Regards,

JD
__________________
Jeff & Cindy
'09 27FB Flying Cloud
'91 350 LE MH
jdalrymple is offline   Reply With Quote
Old 08-12-2017, 10:56 AM   #4
Rivet Master
 
ALANSD's Avatar

 
1966 26' Overlander
Woodstock , Georgia
Join Date: Feb 2002
Posts: 8,523
well stated Jeff. These are older bread trucks basically. Imagine driving a bread truck over the mountains.
__________________
1966 overlander..sold
AIR #005
Please visit our blogs and web pages:
OUR AIRSTREAM PASSION! BLOG
RESTORING AN AIRSTREAM
retired!
ALANSD is offline   Reply With Quote
Old 08-12-2017, 05:21 PM   #5
1 Rivet Member
 
1970 27' Overlander
b enzonia , Michigan
Join Date: May 2015
Posts: 19
Cool 345 performance

I have a 345 which we tookoout west with the 454 engine. Going out of Bullead City Arizona the big hill. I hit 30 mph. with the temp gauge at 400 degrees. The unit is radically underpowered. I don't thhink the P32 front chassis can take the weighht of a heavy diesel engine. I would suggest that you do what I did & park it in the woods. Buy a nice airstream treailer & pull it with a diesel pici up truck Preferrabaly a Cummins engine.
rem3006 is offline   Reply With Quote
Old 08-12-2017, 06:41 PM   #6
4 Rivet Member
 
chriscraw's Avatar
 
1991 35' Airstream 350
Austin , Texas
Join Date: Dec 2014
Posts: 298
come'on chaps!

Let's understand that even at 341/2 feet the 454 was at it's limit. Adding another 6" and a 1000 lb of Corain counter-top and oak cabinetry just to round out the weight to 16,000 lb did not help the situation. As an owner of a 350LE, I've learnt to live with a drastically under-powered leviathan meaning take hills as gently as your first kiss, keep the revs under 3500, sit back and just enjoy the experience of owning the pinnacle of American RV engineering albeit 30 years ago.
I must say reading of a supercharged 502 makes my eyes water as I looked closely at an upgrade to a 502 before sinking $7500 into rebuilding my 454. Of the $7500, around $2000 was labor. I seem to remember that the 502 crate motor was priced at around $6300 ($6500 with shipping) so running the numbers and being a cheap-skate at heart,I stayed with the 454. I would think that a supercharged 502 is producing more horsepower and certainly more torque than a stock 454 so my guess is your gearbox and differential ratios could be upgraded. You could also lash-out on a Gear Vendor's overdrive unit as around $3500 to take advantage of the 502. Maybe other, more erudite Forum Members can comment but stay with the plan and cherish that 35 feet of unsurpassed 1991 luxury, preferably sitting beside it as the sun sets on some idyllic spot that warms the Jack Daniels in your goblet! Cheers!:lol
chriscraw is offline   Reply With Quote
Old 08-13-2017, 10:33 AM   #7
Rivet Master
 
ALANSD's Avatar

 
1966 26' Overlander
Woodstock , Georgia
Join Date: Feb 2002
Posts: 8,523
true! I used to enjoy the cruise up mountains, slowly with my 454. And a shorter motorhome. You can actually take in the view and stops at a scenic overlook.
WHat scared me more was when the thing stalled or cut off while on the highway. Had to replace all the wiring in the engine compartment.
__________________
1966 overlander..sold
AIR #005
Please visit our blogs and web pages:
OUR AIRSTREAM PASSION! BLOG
RESTORING AN AIRSTREAM
retired!
ALANSD is offline   Reply With Quote
Old 08-13-2017, 11:07 AM   #8
Airstream Driver
 
PeterH-350LE's Avatar

 
1994 30' Excella
1992 35' Airstream 350
Austin , Texas
Join Date: Feb 2002
Posts: 4,394
Images: 51
I have taken my first Classic Motorhome (1979 28' with a 454) on a big trip in the Colorado Mountains and going over 3 10k plus passes. Max speed was about 25-30mph uphill using tremendous amounts of fuel. Downhill was just as exciting, since second gear would redline the rpm.
I never was tempted to take my other classics (a 345 and a 310) on that same trip and frankly don't recommend it. Todays technology has vastly improved and the Classics were not build for this new and "improved" speed and environment. Enjoy them in the flat lands.
__________________
1994 30' Excella Front Kitchen Trailer
1992 350LE Classic Touring Coach
AIR #13
PeterH-350LE is offline   Reply With Quote
Old 08-13-2017, 09:32 PM   #9
Rivet Master
 
Smartstream's Avatar

 
1982 28' Airstream 280
Port Angeles , Washington
Join Date: Aug 2008
Posts: 1,888
I look at the speed, power, mountain climbing situation a little differently. I have a 280 with the Isuzu which is no ball of fire by any means. I have driven the old stream from coast to coast and back so I have encountered a few grades. The interstates aren't too bad being basically limited to 6%. The state highways on the other hand can be more interesting. Heading to the Grand Tetons we encountered 10 miles of 10% grade up and another 10 miles of the same down. I don't remember the elevation. We hit a grade in Wyoming that was 7% to 8% for 9 miles. That one got up to 9600'. There was another in Nova Scotia that was 13% but only 3 km long.

We certainly didn't set any records on the grades but we did do 16000 miles in 4 months. The relatively few minutes spent going slow in the hills was nothing compared to the many hours we enjoyed touring the countryside. If you consider the amount of time at stop lights, in construction zones or city traffic, the time on grades means even less. It's what happens when you travel and it's all part of the experience. I just sit back and enjoy the ride and at the end of the day I grab a cold one.
__________________
Cheers, Dan
________________________________________


"Socialist governments traditionally do make a financial mess. They always run out of other people's money. It's quite a characteristic of them."
~ Margaret Thatcher ~
Smartstream is offline   Reply With Quote
Old 03-02-2018, 07:26 AM   #10
3 Rivet Member
 
OttawaValleyGuy's Avatar
 
1991 35' Airstream 350
Beachburg , Ontario
Join Date: Aug 2008
Posts: 153
I have owned several 454 powered motorhomes
I am an older laid back kinda guy
I love and respect my 454
It is not the fastest on steep inclines but the torque is awesome, I let it drop to about 2200 rpms and enjoy the scenery
If you are the kinda guy that needs to be the first one to the top, you are not a good RV er
__________________
Howard and Ann Schutt
OttawaValleyGuy is offline   Reply With Quote
Old 03-03-2018, 10:08 AM   #11
4 Rivet Member
 
chriscraw's Avatar
 
1991 35' Airstream 350
Austin , Texas
Join Date: Dec 2014
Posts: 298
Enjoy the limitations

Howard...I agree wholeheartedly with your comment.
To reflect the "on the go" engineering limitations inherent in my vintage Airstream motorhome, I've learned to sit back and simply enjoy the scenery, leaving the overnight at first light and cruising to the next stopover at around 3 pm and opening the bar. As the evening wears-on, relaxing over a meal cooked in the spacious 350LE kitchen and dining area, then a hot shower in the expansive bathroom area (with that unique double opening door). Finally, heading to dreamland lolled by the gentle hum of the airconditioner curled-up in the huge rear bedroom surrounded by a vista that can only be experienced from those wrap-around windows. C'est la vie!
cheers
Chris
chriscraw is offline   Reply With Quote
Old 03-04-2018, 09:30 AM   #12
3 Rivet Member
 
OttawaValleyGuy's Avatar
 
1991 35' Airstream 350
Beachburg , Ontario
Join Date: Aug 2008
Posts: 153
Right on Sir
A great way to enjoy life
__________________
Howard and Ann Schutt
OttawaValleyGuy is offline   Reply With Quote
Old 03-04-2018, 09:35 AM   #13
Rivet Master
 
mayco's Avatar
 
1982 31' Airstream 310
champaign , Illinois
Join Date: Oct 2012
Posts: 3,887
If you don't enjoy the journey as much as the destination then these rigs probably won't meet your desires. the journey will eventually include breaking down and making repairs on the road. They need lots and lots of love, they give it back!
mayco is offline   Reply With Quote
Old 03-04-2018, 10:41 AM   #14
Rivet Master
 
1989 34.5' Airstream 345
Ebro , Fla Panhandle
Join Date: Jul 2013
Posts: 1,206
It's fun reading above of the folks that have settled into the relaxed pace of classic cruising. Well put guys!

It's such a big adjustment from modern motoring. It clearly takes a change of traveling attitude, one that in my mind brings many rewards in the experence for those that can manage to make it.

As a former sailor of an engineless sailboat for many years and thousands of miles, I was well on the way to enjoying classic ( spell check said I meant cursing, Ha) cruising.

Cheers Richard
tevake is offline   Reply With Quote
Old 03-04-2018, 10:56 AM   #15
Dazed and Confused
 
Isuzusweet's Avatar
 
Currently Looking...
1983 31' Airstream310
Hillsburgh , Ontario
Join Date: Sep 2012
Posts: 3,805
I'm just curious as to...

1) What style supercharger you're running? Roots or Lsyholm?

2) Was the motor set up for an RV application? This can have a dramatic effect on how the power (torque, not hp) is delivered. Does it produce power down low, middle or upper rpm ranges? What kind of camshaft is in the motor?

3) Is the fuel management system able to cope with.....

A) The right size pump in the tank to push the right amount of fuel? Or did they place a lower rated fuel pump outside the tank on the frame rails. This lack of fuel could have an effect on motor performance when you need it most, like climbing hills.

4) Is it possible one or more of your brake callipers is seized a bit and causing your brakes to drag?

5) Are the sparkplugs, wires, coils insulated against heat, and are the correct heat range for the motor?

6) What kind of transmission are you running and does it have the correct torque converter specifications to better transfer power from engine to running gear. Has the fluid been changed recently?

Many things can negate performance; go through this list and more that others can suggest before throwing out the baby with the bath water.

Cheers
Sidekick Tony

PS It would be cheaper for you to buy a later diesel pusher than convert the P30 to diesel........less noise too.
__________________
Per Mare, Per Terram and may all your campaigns be successful.

Its a recession when your neighbor loses his job; its a depression when you lose your own. "Harry S Truman"
Isuzusweet is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
1991 350 LE Engine ? Bentzb02 General Repair Forum 2 08-11-2017 10:09 AM
E250/350 vs F250/350 kb0zke Tow Vehicles 10 05-21-2016 04:41 PM
Argosy 20' MH Chevy 350 - engine soft plug? ViewRVs Mechanics Corner - Engines, Transmission & More... 19 02-23-2012 09:34 PM
Airstream Classic 350 LE Motor Home 1992 Orig. Owner SAirstream Classic 350 LE Motor eBay Watch Airstreams on eBay 0 11-28-2010 11:00 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 10:44 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.