New member working on a vintage class C RV
 

Hello,

I have been lurking here for years and silently cheering on everybody who's working to get better F.E. out of their rides, and I finally have a project worthy of tackling.

It's a 1980 American Clipper 21' Class C RV. Super cool, a one family owned timewarp. The plan is to make it reliable and fun, and make some modifications along the way to help improve it's efficiency.

I have amazing records from the first owner of nearly every fillup which average out to 7.5 MPG over 76,000 miles. He never did anything to improve the FE other than trying to keep it in good shape.

As for me, I'm a lapsed Engineer, and was on the first Super Mileage Vehicle team at UC Berkeley back in 1992. I think we were averaging around 3000 MPG before we broke due to lack of testing. The team the next year finished and put in a respectable result if I remember correctly.

I'll get a build thread started soon, but thought I'd introduce myself first.

Thanks!
Ian

I'm glad you signed up.

Wow, you've got a lot to overcome there:
http://www.americanclipperownersclub...eds/parker.jpg

I'd probably start with fairing the top with coroplast and doing as much of an aero tail as is practical:

http://gajitz.com/wp-content/uploads...ilertail-1.jpg

On the plus side, every smidgen you gain is a huge percentage gain!

Holy COW. Now...THAT is an uphill battle.

When you start your build thread, I'm going to definitely subscribe to that. And, FC was right on the button. If you get it to 10 mpg, looked at one way it's a mere 2.4 mpg improvement, looked at the other way it's a 33% improvement.

Hmm. I don't think the EPA posted ratings for RVs, so we're just going to have to go with the vehicle's own history as a baseline.

Thanks for laughing with me guys, yes uphill battle is an apt analogy. Just thinking of driving this uphill over the coast range gives me goosebumps. We've delayed a maiden voyage twice now as I haven't been ready.

Last night I dug out a great article I found a few months back about trying to improve fuel economy on an 80's 4x4 dually Ford with a 460. They didn't touch aerodynamics, but did improve FE significantly with small, but measurable improvements. So I'm starting with that approach, find stuff that's measurable and make small improvements.

I also have other goals such as keeping the engine heat managable, making it handle better (no swaybars from the factory, ah the 70's), tightening the steering, etc.

And of course I know that driving it at 55 vs 65 will make the biggest difference. Thankfully for now with a 3 speed, unlocked transmission she's probably pulling 3000 RPM at freeway speeds. That's loud when the big block is sitting next to you. Putting in the overdrive trans will be more for livibility than actual cost savings.

We also did the calculation of car/hotel, vs truck/trailer (we had a 2004 Tahoe and 66 Streamline trailer previously that averaged 12 MPG towing, not bad), vs an old RV vs. a newer RV. We decided the $10k we saved going with the cool, old RV bought a lot of gas, as well as lots of room for upgrades. Plus we don't have as much money sitting in the driveway depreciating.

elhigh, I think most people just look at 1 MPG as 1 MPG. But for me it's all about the relative increase. While I probably won't notice the difference between 25 or 26 MPG in our Benz, going from 7 to 8 in the RV would be over a 10% difference, possibly up to $10 off a typical $100 fillup.

It's a 50 gallon tank, most gas stations cut you off at $75. Fun.

Anyway thanks for laughing along.

I think a 7004r or what ever has replaced it would be a good place to start, had a 350/350 turbo in a S-10 blazer 4x4 (3.73s), went cheap to get it running and upgrade later with a fresh 350/700r4 went from 12-16 mpg. $700 tranny never did pay for itself but made it a more pleasant drive.

Or really update it and find a wrecked truck for donor engine and tranny.

Exactly. I don't expect the trans swap to pay for itself, it's more the point that this thing is designed for road trips, so we need to make it road trip friendly. The options are either a Gear Vendors OVerdrive, which I would LOVE. But costs about $3000.

Or find an A518 out of an early 90's van, rebuild it, shorten the shaft in the RV and install it. Not plug and play, but we can make it work. My understanding is the A518 is basically a 727 with added overdrive. I'm not planning on climbing hills in OD so I'm not worried about blowing it up. Plus I think I can get a used trans, rebuild it and install it for $1000-$1500. Half the cost of the GV overdrive.

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My parents just bought a very similar rv earlier this year and drove around the country with it over the summer. I think it was a 26' Shasta on a chevy chassis. 350 small block but with a 3 speed no o/d. I think they got around 6mpg.

Aero is going to be easy as cake to improve on that thing but i will say with that age, dont forget to fix the a/c.

What engine is in the camper? 400?, 383?, 360?, 0r 318? My bet is that it is a 360, which was a stroked 318. IIRC, those were carburated engines that tended to carbon up the intake manifold. Those are solid engines. Why not update it with port injection? I don't see why you need to replace the engine. Just update the torque converter with one that locks up (1982 or 83 model ?). What is the rear axle ratio?

http://www.americanclipperownersclub...eds/parker.jpg

My thoughts on RV aero include tackling the many protrusions that likely contribute to drag all out of proportion to their relatively small size, like roof a/c, roof racks and pods, that yuge canopy on the side, giant mirrors-on-a-stick, various antennae, and so on. Do some soul searching and decide if deletes are something you wouldn't mind?

The aero tail as Charlie mentioned should be an effective mod, perhaps the best one of all. Air dam could help too.

Non-aero thought: weight. Or more specifically, weight reduction. I've been to enough camper ralleys to know that many people pack everything including the kitchen sink. I think travelling light could only help. Things like, do we really want to fill the water tank when the destination has showers and whatnot? Lots of weight there.

Need to take it over to Hendersons Lineup. Mechanical rolling resistance issues plus steering/handling upgrades are their forte. National reputation. It's the biggest impediment to repeatable FE results at any step of the way.

A set of Doug Thorley Tri-Y headers and non-restrictive single 3.0" mandrel bent exhaust with resonator and chambered muffler. Engine fuel delivery needs to be refined with an O2 sensor on chassis dyno. Stepping up to even simplest TBI would be a benefit (but work with source as RVs have different fuel demand than cars. ) MSD distributor as its far easier to adjust total and initial timing.

A518 trans sounds good. I'd go with Bridgestone Duravis 500 tires. Will balance up with almost no weight and last longer than anything else. Dana 70 rear axle.

See threads by Orbywan. A boat tail would be singular plus effective.

I didn't follow reasoning, but that Streamline TT a better low cost and long term bet than this rattletrap. Wood framing?

An early 70's CAYO Motorvator (Avion) or Silver Streak Class C is a better choice. In which case leave aero alone except air dam, etc. Focus on RR mech issues and upgrade drivetrain. These are far better built. Past plumbing breaks, water damage unlikely.

These and yours are on either the CB300 or MB300 chassis, if memory serves. Traveling with full propane and fresh water is SOP. There won't be any FE gain by doing otherwise, plus they add stability and full practicality. An RV is an RV BECAUSE it has its own heating and power source (propane) plus an excess of water. There's never enough of either. The "benefit" of the coach electric is far less. In fact, it's a want and not a need.

Wall interior water damage is likely on almost all conventional RVs of gen years or more. Pick up a moisture meter with probe and start investigating floor. A long thread on WOODALLS re Dodge motorhomes has been running for years.

What is your projected percentage improvement goal?

I'm already researching a R12 to R134a conversion. Most folks just leave them dead, but again I can't imagine driving down to the Grand Canyon or most anywhere in the summer without A/C these days. It shouldn't be too hard, new o-rings, a new drier, new ports and a charge. If that doesn't work swap out the ancient compressor and try again.

It's a 440-3, and I haven't figured out the rear end ratio yet. I need to look it up.

I don't plan to replace the engine, just give it a good tuneup for now. A port injection swap would be fun as well, but I think the 4th speed would be a bigger result and help with noise etc overall as well.

Hey Slowmover, honored to have your input again.

We sold the Streamline because we were getting tired of maintaining a trailer and a tow rig, and when we switched from a Tahoe to a Roadmaster as a tow rig the towing wasn't so much fun anymore. We were done with the Roadmaster then got an offer for the Streamline we couldn't pass up and so we let it go.

Let's see, it already has a set of Thorley headers, but duals instead of a single 3". The exhaust is practically new so I'm leaving it alone for now.

A thorough suspension refresh is on the list. A few bushings are new, most have 75k miles on them. It needs shocks, the typical steering box adjustment, will probably just redo the entire front end then get it aligned. I also found a sway bar for it to eliminate some of the sway I felt on the first few drives.

The Clipper is all fiberglass over a wood frame. They don't leak nearly as bad as most 70's aluminum/wood models. I looked at a few, all were total rebuilds. We also wanted something small like this one and loved the looks and fan base the Clippers have so we went for it.

As for % goal I would love to hit 20% once we do the 4-speed transmission. So that would put it right at 9 MPG. Since we'll probably only use it a couple thousand miles a year it doesn't make sense to throw $10k at it, but we'll see how much use it gets and adjust.

The 440-3 was produced by Chrysler Marine & Industrial. Far better than the competition as it is built to a far higher standard. It has a number of unique parts which do not interchange with standard 440s (mainly to do with engine front drive accessories). Best to do a compression test. Champion plugs

The drivetrain is set up to run the engine at just below peak torque at highway cruise. 27-2800-rpm as I recall. It'll do this for a few hundred thousand miles

I'd love to have one again

Be sure to keep the Thermoquad. Rebuild isn't difficult (leave choke strings alone), and it'll help. Except a hard to adapt GM QJet no other carb will give better performance or FE. As above, a TBI unit will help FE, but not deliver the same power at WOT. We used to add A on electric fuel pump near tank, upstream of mech pump to avoid heat soak.

I'd use Rotella T6 5W-40 oil and Baldwin oil filter. Look into the issue of adding zinc to preserve cam lobes.

Glad to read what you've wrote.

The dual exhaust will need a crossover. X-style. FYI: Press bends in a system reduce reduce TOTAL system to the worst interior diameter. This will matter when engine is under load. Heat will build in engine compartment. Answer is not larger diameter pipe, but mandrel bends. David Vizard is the expert, here.

Take it to Hendersons. Have them road test and write you an estimate. Their parts are outstanding (Super Steer). Do those installs as you will if DIY is contemplated.

Front and rear antisway bars must work together as to sizing. Get their rear axle Panhard Rod. I'd also go with every single front end part they have.

I haven't had a chance to run a compression check, but it runs great. It currently has nearly new Autolite plugs, I checked one and they look like they had just been changed. The original owner was very fastidious about maintenance. One of the last notes I read from about 1995 said it was burning about a quart of oil every 600 miles, which is good info to know.

Thanks for the info on the 440-3, it's been fun learning about it. I need to get a tach installed so I can see where it's running on the freeway, especially as we just installed new tires which were a slightly larger size (had to ditch the 16.5" wheels and finally found a set of 16" wheels with 225/75/16 tires).

I plan to keep the TQ for the foreseeable future. It sounds like the right carb for the job. I have considered adding an electric pump to make it start faster, as it is it takes a lot of pumping and cranking to start it since it sits so long between starts. A TBI swap would be fun someday, but is a much lower priority.

As for oil I was planning on changing it once with a 20W/50 then changing again with a synthetic, Mobil 1, Castrol or the Rotella. I know Mobil 1 has lots of Zinc already but a can of additive isn't a bad idea.

I'll do some more research on how I could improve the exhaust once I get through more pressing issues. Unless I'm struggling for power then it will probably get bumped up the priority list.

Hendersons is a good 2.5-3 hours from here, but if we plan to be down there I will certainly have them give it a look. I will also look through their catalog and see what they have for the old Dodge's.

Thanks!

Autolites for Fords. Dodge runs best on Champion. See PM sent.

The Rotella is diesel spec. A better choice as also gas compatible.

Choke should engage with following method: Slowly push throttle to floor. Pause. Even more slowly, let off to zero. Repeat once. (Or twice if testing finds it effective). To start, hold throttle open one-third. Allow high idle to run 1-2 minutes. Do not rev or change throttle position.

If it will not start with this method then something is off.

IMO, if Hendersons were six hours away from me I'd be grateful. I'm going to guess I know a bit more than you. Weigh that in consideration of time and money wasted versus expert opinion the first time. Your vehicle, so do as you will. But, it's frustrating to drag things out. Or learn on the road very far from home about problems that were more cheaply and effectively fixed early on. Not much scares me about running the country in a big truck. Even an old one. But only after an expert had been thru the front end.

7.5-mpg sounds right. I'll bet it's also 55-58/mph for that. Consistent with what we saw with a bigger Moho in the 1970s. Also consistent with other carb'd big blocks pulling trailers from then. 9-mpg sounds like a nice goal.

But dropping cruise rpm may not work as well as you think. TQ is needed to maintain headway, and gearing must be effective. Keeping motor up near peak torque is how that happens.

As iv tried to emphasize, mech condition will mean most. And steering wander is what I'd attack. Slop in the column itself (rag joint) out to wheels. It's not just the steering box. (Lee Power Steering is who I used years ago on Saginaw problems. A blueprinted box is your friend).

In same way, chassis to body bushings. Rubber doesn't last forever, and fresh will keep movement -- affecting steering -- to a minimum.

I'd imagine you've read Orbywans great threads on Class C aero as some inspiration. Only approach "reasonable " to 20%, IMO.

Start with little stuff such as replacing all exterior lamps with LED fixtures. It's a safety issue. (Interior, see LEDRV; Dan). Grote or Trucklite for exterior and FMVSS approved. I'd want to convert to 7" round headlamps as on older units as LED replacement is huge gain. Otherwise, see Barry's vehicle lighting pages on altering headlamp wiring to achieve 13V at lamps. I've done four vehicles this way.

After that I'd dig into battery problems. House versus starter problems. Usually new cables and switch needed. Alternator upgrade as the old MoPar piece is weak compared to today. New grounds with braided only. There is method and procedure here which needs be followed. Dodge Factory diagram out there some where, maybe the WOODALLS thread.

Won't hurt to weigh it. Full fresh water and propane plus gear always aboard. CAT Scale. Get all four corners separate, not just axles. Mohos have a tendency to be "off" at one corner or another. Among those serious, this is an ongoing topic (handling and braking). See also Rogers blog "RV Tire Safety" and chase all his Moho tire posts.

12-13k total weight is about where a low compression big block is still a comfortable performer.

Electrical refurb is huge for reliability. AGM batteries a good choice and a compatible charger (see Randy, "Best RV converter"; no matter what's present it's probably obsolete). It's the least needed system for camping, but the main source of aggravation and the most likely to cause hair tearing and breakdowns while en route. Fuel system hoses, etc, are second.

Propane system is simple, but tank likely needs recertification. New tank not terribly expensive.

As to appliances, the stove and reefer can be used as is (past fire safety issues on latter; today's units expensive and not as well built). But water heater and furnace should really be replaced. No parts, and safety has precedence. If you are considering a catalytic heater, then get the brand which uses external air for
Combustion.

Roof AC upgrade is Coleman Mach 8. 15k unit. Lower profile.

PPL Motorhome site is who I use for all this. Reputable and knowledgeable. And that means more than last couple of dollars.

Maxxair roof vents versus Fantastic Fan. Lower profile, not just better otherwise. TV antenna should be crankdown type. Avoid omnidirectional. Wastewater tank vents should be metal, IMO.

EternaBond tape should be part of your supply kit. And RV specific sealants. Not silicone. ***Buy Bed-It Butyl Tape*** another. Captain Tolleys Creeping Crack Cure may be applicable.

FE will come. Reliability and safety are hand in hand with it.

This will be an interesting thread to follow, I have a a horse transport that was based on the dodge trucks, so hopefully I'll be able to pick up a few hints.

This is my old girl
http://i132.photobucket.com/albums/q...13538210_o.jpg

I get about 12,5 l/100 km (19 US MPG), the figure changes a little with two fat ponies in the back, but not by much.

I haven't done anything to mine apart from maintainance, mechanical fan to electric and a rev counter. Oh and slow down I normally cruise now at about 50 mph.

I do have plans to change the gear box and axel oil from mineral to synthetic. Also very soon I need to pull the turbo off and get that re-sealed, not sure if it will do much, but it should keep the engine cleaner.

Installing underpaneling would help the aero a lot and reduce road noise. The underside of a Class C RV with all of its storage tanks and structural members makes the underside of a pickup truck look aerodynamically clean.

Camping season is upon us.

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