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Old 04-13-2004, 03:12 PM   #1
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Cincinnati , Ohio
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454 High Mileage

We are looking at an AS Classic with 100,000 miles on the 454. The motor seems to be running strong now. Could anyone give me an estimate or average service life. Also, has anyone replaced a 454 in a classic with a new crate engine? What kind of cost can I expect and what other things should be done if a new motor is installed. Thanks in advance.

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Old 04-13-2004, 03:40 PM   #2
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Welcome to the forum!

Your question actually raises other questions. How were the 100K put on the engine, and what year is the MH?

The biggest engine killer out there is lack of use. Let us say the MH is 10 years old. That means on average 10K per year. Not a bad thing, in fact that would be an excellent thing since it means it was used regularly. But if 80 K was done in the first 5-6 years and 20 K in the last 4-5 years you may be in for a replacement. This is why you see coaches with 70K getting new motors.

maintenance is also a factor. If it was used for 4-5 K each of the last 4-5 years, but the oil was changed at the proper intervals, the engine was run for an hour or so a month, gen set was run for an hour each month. Then you should not be too worried.

A few of us here ( myself included) have replaced the engine with a GM Crate 454. Long block cost is approx $2200.00. The labor is the killer. It was approx $2500.00 to do the R&R on the engine and do some additional drive-line work that I wanted done. So if you budget $5000.00 minimum for the job you will not be surprised. We went into the unit we now have wondering if we would have to replace the engine, we did, and we were somewhat prepared for it.

If you are buying for the original owner and can get service records then you will know what you are getting, If not all you can do is start with aggressive maintenance and hope for the best.

Brett G
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome

Wise men talk because they have something to say; fools, because they have to say something. -- Plato

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Old 04-14-2004, 01:13 AM   #3
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We bought an 84 AS with 46,000 (third owner) it used a quart of oil every 400 miles. At about 105,000 it started using a quart every 200 miles. I elected to do the overhaul myself. I found that one piston had two broken rings and a broken land between them. The only wear that I found was .002 at the ridge at top dead center. Conclusion: the excessive oil usage(?) slowed the cylinder wear to a minnimum. Since I was adding fresh oil every 400 miles, I did not change the oil at 3000 miles and only changed the filter when I got home. The oil cost was about the same, i.e., 7 quarts every 2800 miles or 7 quarts at oil change every 3000 miles and I did not have to crawl under the coach to change the oil or dispose of the used oil. We have EPA yests every two years and never had smoke or hydrocarbons approaching the limits. I now get 1800 miles to the quart and change oil and filter at 3000 miles. To change oil, I pull into a Walmart or other and ask how high their entrance door is (ITS ALWAYS LESS THAN MY AIRSTREAM HEIGHT). I cannot get inside, can I buy 7 quarts and borrow your sump bucket to change my own oil? If they do not have a sump bucket I buy one, use it, and donate ti to them so I dont have to pack it with me. I'm not saying this works for everyone but it has worked for me.
Ernie Preedy
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Old 04-14-2004, 05:58 AM   #4
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Oil Change -- and more.

"......I'm not saying this works for everyone but it has worked for me."


Welcome to the Forum! Your experience and knowledge will be valuable to us.

A novel approach to oil changes - especially handy when travelling!

Since you have put more than 60,000 miles on the 310, I suspect you may be the Forums "High Mileage Award" winner.

Could you share your other hints and setups and uses?

It sounds as if you might full time. Most of us MoHo owners on the Forum are working stiffs just dreaming about travelling as much as you apparently have.

I'm particularly interested in your mileage history, both before and after your rebuild. What was the best you ever observed? The worst? Do you pull a toad?

Anxious to hear more!

"Suck it up, spend the bucks, do it right the first time."

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Old 04-14-2004, 06:03 AM   #5
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Any service records, that will give an indication of condition and maintenance history. These had no OD trans, rpms are higher and more per mile than newer setups. Probably the quickest and easiest test would be to check compression, it also gives you a chance to look at the plugs. During the 60's to 80's when these were the standard design and quality I considered 100,000 the life. Some will get more but they are on borrowed time.

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Old 04-14-2004, 06:50 AM   #6
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my 1982 has just turned 100,000 but the engine was replaced by the original owner at 50. I suspect the lack of use was the issue as it was 8 years old when it had the new engine put in.

It runs great, and I change oil every 6 months or 3000 miles using valvoline synth blend--a K&N Filter, do it myself cost me 15 bucks or so. I also lube the chassis with a hand pump, and keep shooting Marvel mystery oil into the gas tank every so often to freshen the gas supply. Seems to work out. Oh yeah I used Stabil when it was sitting for a while.
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Old 04-14-2004, 07:18 AM   #7
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fcycle - my 86 has 175,000 miles on the chassis. I suspect an engine rebuild within the last 30,000 miles (bought mine at 160,000 miles). I would certainly recommend a compression check and a good look at each spark plug. But if you can't do this yourself or get it to a mechanic there are a few other basic checks you can do yourself: record the oil pressure readings at cold idle, at highways speed and then again a warm idle. If you are getting below 40 psi at speed and below 20 psi at warm idle you could have a pretty tired engine (or just a tired oil pump). Look for oil in the air cleaner and air cleaner element. Excessive blowby can show up here. Also check the color and smell of the oil on the dipstick. If its clean and translucent it probably had a recent change, but look for water droplets or worse - coolant droplets in the oil. Also, check the transmission dipstick and look for that nice red fluid color. If it smells burnt then you could have a tranny rebuild in your future.

The best way to tell how a coach has been maintained is to look at it's service records. If they are not available then look at the coach itself. Properly completed repairs, new components, general cleanliness all can indicate the service philosophy (and the maintenace budget) of the previous owner(s). If things look half-a$% then they probably are.

Of course, mine was a bit of a basket case when I bought her so you can always find a diamond in the rough.
Steven Webster
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Old 04-14-2004, 02:56 PM   #8
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oil change and more

Thanks for the reply. We are not 'full timers', I would but my wife wont. Our first retirement trip was to the Maritime Provences of Canada and back in '97, about 13000 miles, several trips to Calif. and the Polar Bear Safari to Thompson, Manitoba actually went to Churchill but you cant drive there. It all adds up.
The problems that I have had: 1. On a trip to CA the starter would not turn at all---traced to a fuseable link in starting circuit (top of engine) the wire had become brittle due to time, heat and corrosion. Carry a spare? I dont know, if you carry a spare for every thing that could break you could build a new MOHO. 2. Tried to start engine to lead a caravan, engine died after 16 secs, tried an additional 4 times with same results. Wired around the safety oil pressure switch--ran for 30 seconds at which time I shut it off due to no oil pressure. I led to caravan (short one of 170 miles) with my toad. The nylon sleeve that aligns the distributer shaft into the oil pump had broken--no oil pumping!!! do not bypass that safety switch. 3. Could not travel over hills at decent speed, took 6 months to solve this one (see Steve Webster thread about MH cant climb hills) The push-on connecter at the oil pressure safety pressure switch had lost its spring effect due to high heat and age, the voltage drop across this connecter slowed the elect fuel pump effect to just enough fuel to slowly climb hills. The connecter finally disconnected itself and I saw it was open when I crawled under to inspect the fuel filters that I had replaced the day before. We do so many things at the side of the road. We had already called for a tow truck, so I had to pay him for his time anyway. 4. Crossed a railroad track at low speed, the front wheels shimmied so much that I had to stop. Start again and no shimmy. About a year later it happened again, consulting with a front end shop ( my brothers owned a tire shop and allignment), I examined the steering stabalizer, it had a worn spot near the center of travel replaced it and no problems since (probably 40,000 miles). If your steering stabilizer has any oil on the shaft or the rubber bushings just replace it. I store my big billboard (AS moho) in a garage. If exposed this billboard tells certain miscreants that Ernie is or is not home, nuff said. as to fuel mileage; at 46,000 miles and no toad about 7.5 mpg, with toad about 7.3 mpg this dropped down to about 6 mpg with toad at 100,000 miles. After the overhaul last August, I averaged about 7.8 mpg in the flat lands of midwest and abou 7.2 mpg at high elevation of WY I-80 where you do 80 mph in the slow lane( this was in my car on another trip)
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Old 04-21-2004, 02:42 PM   #9
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I appreciate all of the feedback. Without the benefit of a thorough mechanical inspection, I believe the addage regarding the mechanical condition mirrored my the cosmetics is good advice. It is always hard to tell if something is a diamond in the rough, or that beauty is only skin deep.

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