I have heard the tern RV cam from "hot rodders" for years. What is the origin of this cam ( were they factory cams used in RVs) and the specs?
Its a cam designed more for torque, and yes they were used in RVs and trucks. Specs would vary depending on the engine and the cam. They also have a nice minor lopey idle. For example, here are some specs for a 302 RV cam vs like .368"/.381" lift and 270/248 duration for a stock cam. Valve Lift (INT/EXH): .448/.472 ADV Duration (INT/EXH): 280/290 Duration @ .050" (INT/EXH): 204/214 Centerline (degrees): 107/117 Power Range (RPM): 1200-4700
They are cams designed for low RPM power and torque. Great for towing ect. They work as an upgrade in a stock type motor. Usually have no big change in idle sound, good vacuum, (power brakes work). I am not a technical guy so someone else will have to give the specs. They do change with every engine.
The first so called RV cam I delt with was made when $1.25 gas came in 74, put one in a big block motor home and it got 2 MPG less than the factory cam. Maybe it was for a different RV, I always thought they were a joke after that.
I don't think RV cams were advertised to increase mileage, they were advertised to increase power and you generally can't make more power without using more fuel or at least using it more efficiently. Following the Arab Oil Embargo, several cam manufacturers stepped up with mileage cams. I remember the Iskenderian Mile-A-Mor cam from the early 70's and I think Crower still makes a mileage grind.
If a guy has a low static compression ratio, he cannot use a hot rod cam with long duration. It'll make the motor soggy by lowering the dynamic compression ratio. What he can do though, is use a little more lift and duration, in a cam called an "RV" grind and the motor will have a little more power than it did with the stock cam. It's all a matter of matching up the static compression ratio with the intake valve closing point. For instance, with a SCR of 8.5:1, I wouldn't use a cam with any more intake duration than about 200 to 205 degrees @0.050" tappet lift.
I bought a beat up one ton Chevy van with a rebuilt 305 Chevy engine. 40,000 miles and built by the local speedshop mechanic. Most everyone who needs real engine work goes to him. Before I bought the ratty van I talked to that engine builder. Said it was a 305 with an RV cam and reworked 305 good heads. He calculated from odometer it had 40,000. Owner said 20,000 and a 350. Shelled out $500 and put engine in my 55 Chevy. Hey, every retired guy can't afford a crate motor or custom built one. That engine has performed great with a mild lope over five years. 20 to 22 MPG with a 2004R I added. Peppy little mouse and nice idle. Plus I got a 22 foot storage box out back.
it depends on how you plan on using it....if you are not racing and just want to drive it normally it is a good choice
In the gas crisis seventies a lot of rodders revised their whole line of thinking when it came to building an engine. Gas mileage suddenly became a big deal. Getting an engine to run on lousy low octane lead free gas. Not burning your valves up etc etc. One popular part was the "RV cam" originally designed for recreational vehicles namely conversion vans, motorhomes and trailer towing. It was designed for max power in the middle of the rev range. You could take a seventies 350 smog motor, give it a 3 angle valve job, add an RV cam, a single 4 barrel aftermarket intake with Quadrajet carb, and a set of headers and pick up about 50 HP and 3 or 4 MPG over a stock engine. A lot of guys built motors like that for their everyday go to work vehicles, pickup trucks and street rods.
As in post #12, I got all of that and a good running engine for less than the cost of a set of rebuilt heads. It gets us to the car shows, cruise-ins, and the grocery stores. What more do we need? Not out to beat ya to the next traffic light or pull stumps. An RV cam adds just a little lope and a slightly unsmooth idle. Or maybe that's bad plugs!
The RV cam will make 3/4ths the amount of power that a 3/4 cam will. If you really want to kick ass you need a "full race" cam, or 4/4 cam. I think Dave Bruebeck had a 5/4 cam at one time.
Anyone else remeber the "kits" that were sold for SBC engines that turned them into a V-4? 4 of the cylinders were "deleted", and when those 4 cylinders wore out, you could switch to the remaining 4 and start over. I wonder how many people actually bought into that modification? Oh, and I have an "RV cam" in my DD pickup, but I don't go camping or anything, so it was probably just a waste of money. Butvch/56sedandelivery.
RV stands for Radical Vibratones....they sound so ultra dude, kinda like the new mother thumper cams man!!! Just like the fine print on the box, if it don't go fast, chrome it.
This really was a great kit, what I did was use the four deleted cylinders as air compressors....a mobile air compressor that got great mileage. WOW MAN, back then I was already going green!!!!
I have an Edelbrock Performer Plus cam in my Chevy 350. It is certainly a street cam which is OK if you don't want to take the motor to the next level. My roadster sounds good and runs good and I can drive it cross country in the fast lane without complaint. Edelbrock recommends it for a variety of uses including RVs. http://www.edelbrock.com/automotive_new/mc/camshafts/cams_chevy_sb.shtml Big cams require more spring pressure, more compression, more carb, head work, etc to run right. If you are not going to use it there is no need to buy it.
Back in the '70's they called them RV cams, the term stuck for 10 years or so. Then Edelbrock came out with the performer other cam companies used their own nicknames, Torker and variations. There is nothing at all wrong with low end cams. They are more for street driven cars. They are most known for their tire smokin starts. They kick ass stoplight to stoplight. I've seen more than one owner of a hot strip car get pissed because he looked bad in a block long race by a car with a low end cam. On longer runs and at higher rpm's the low rpm cams have a big disadvantage.
back in the late 70s Crower made a cam called the Baja-Torquemaster that made tons of lo-end. we used them in big and small block chevs and got really good results. Everyone compared this to a R-V Cam !!! Then comp came out with there 1st version of the 260 High-Energy cams and we could get them alot easier. And here is where it gets weird, I gave a 1st design Comp 260-H to a cam grinder to see just what he thought of it. Replie after he checked and compared it to something he used was "damn near a copy of the G.M. 300 horsepower cam" So all in all a good ol 300 hp cam wasn't such a bad idea !! >>>>.
well we are talking about replacing smog cams (OEM), made to pass emission test. they sucked gas and with the 8-1 compression made your '70s era engine a slug..no power, and sucked gas.
Wow, I think some folks are missing something here? Trucks and R/V spend very little time at "low speed". The motors are almost always spinning just to make enough grunt to move one of those things. I've driven commercial trucks, gas fire trucks, delivery vans, etc. Never seen one live at low speed speed. Most live on the governor all day long. That's so different than a passenger car, it's not even in the same league. OK, they don't turn 7K, but they do turn 4K all day long. I got a Chet Herbert RV cam in my BBC pick-up and I love it. Slight lope and it really runs between 3,000 and 4,500 - right where you want big torque on the street to haul your ass around someone. It won't win a race, but it works in the real world The thing about camming a motor is to match the profile to the displacement. In the old days we'd put 327 performance cams in 283's and they were pretty ragged on the street if you were cruising. Same thing with a big FE profile in a 352 - ragged. Most 383's would handle a 413 cam - sort of. Point being - that RV cams are a good thing. They're about right for street use, if you want performance and your wife wants to take the whatever to the store now and then, they do the job.
Just say no to a rv cam!!!! They are almost never as good as the stock cam. Its usually just a term somebody uses selling a cam they no nothing about. I have seen a couple that worked really good and a bunch of them that performed very poorly call a good grinder like comp cams and pick a good cam for your application cams are cheap do it right the first time
I always thought of and RV Cam as one for low end torque, the power range lower. That going to say it would have a larger lift and slightly longer duration. I have had a few in street cars, I can understand the race factor but people really push the "king of the hill" super lump cams WAAAY to much. Really, how cool is it to lump around your local cruise spot idling at $4-$5 a gallon..........but I digress. I have a "RV" type cam in my 390 now ('54 panel), great street and superior towing.
I bought an old '69 Chevy 1 ton (old county truck) to tow my '62 Nova race car to the track. It had a '327 and 4 speed. It smoked badly. over heated on hills and used a couple of quarts of oil to tow 75 miles. I had to down shift on hills too. I bought a 350 and rebuilt it with 9:1 compression, pocket ported the heads, used an old Edelbrock Street Master manifold with a Holley 650. I tried an "RV" cam since this rig was primarily for towing. I couldn't be happier. Instead of down shifting, I accelerated up hills, it ran cool and had more power than a new truck.
Bought a 78 f150 that had a RV cam in it and after I put a set of duals on it I could get close to 20 miles per gallon on the highway and could pull a full size car and not feel it behind the truck,it had the lowly 351-M.
Sounds like a typical smog era "street" build. I know today there must be better cams but back then the so called RV cam had its place. It really represented a change from wanting the most radical cam to the most practical cam. Then the pendulum swung the other way and everyone went back to wanting the biggest HP numbers even if they occurred at RPMS you never see except on the race track. With today's high cost of gas maybe we will see more attention to building practical, efficient motors that have some extra oomph without maxing out the old credit card every time they come near a gas pump.
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