RV motors..What's the deal?

[66plysat]

I'm looking around to change out my 318 for a 383 or 440. I see engines that have been pulled from RVs. How are they different from an auto engine. Do they make good donor engines or should I stay away from them, what changes need to be made to make them work in a car? Thanks

 

[iraqivet01]

an RV 440 engine will work. I do know you have to change some things out. Not really sure, just know that others have used them in other B bodies.

I'm sure someone will chim in and tell you that has done it.

 

[Pistol Pete]

Just make sure if it's a 440 you want, it's a 440 you'll get. Many rv's came with 413's up until the mid '70's.

 

[Furyman1966]

gotta change oil pan, heads have more cooling passages I believe, so ya gotta be careful when getting head gaskets, maybe somebody can elaborate here, and they all have low compression, but have alot of torque, some have 6 pak rods if I remember right.....

 

[The 500 Foundation]

Most were cast crank rather than forged
check the balancer to see what you have

 

[Deleted member 214]

I'm wondering how much wear per mile a motor home engine would get vs. a car motor considering the weight of an old RV. Add to that the aerodynamics of a brick, and the motor home 440 would have to do some huffin' and puffin' to get the motor home up to speed. Think of the hills! To me, it would be like buying a used motor that I knew was used to tow a heavy trailer every time it left the driveway. Anybody have any feedback on that idea?

 

[Furyman1966]

Yeah I hear you on that. It seems like all the RV's that I stubble across are low mileage, less than 50K, and free, but you gotta take the whole thing. I have one at a friends house, only has 30k on it, but I will strip it down to check it out and put gaskets in it at a minimum when the time comes. They are definitely a low rpm motor, tiny cam, but actually move the 25 footer pretty good. To think, some rvs had 318s in them!

 

[66 coronet]

I bought a 72, the pan needs to be changed out the heads have a different bolt pattern on the exhaust side so the car manifolds will not bolt on and the truck manifolds will not fit into any car body. the intake manifold is water heated, the heads and manifold are not configured for exhaust crossover. The water pump housing is totally different. The pistons are dished for low compression regular fuel use. Some have cast cranks some are forged, mine is cast. About the only thing usable is the block which is the high nickel content.

 

[dbc105]

I have a buddy that has bought a couple of 413 motor home engines and is making street engines from them to go into a couple of '62 Darts he has. One engine was a good running one so he is going to keep the stock low compression pistons for now. The pistons(low comp), heads(smaller ports, heavy duty valves, different water passages), water pump housing & pulleys and brackets are all the external parts he is having to change. He is using a set of early model closed chamber heads, with hard exhaust seats installed, to help on the compression and stock RB intake & water pump housing. He did change the cam but it is pretty mild, a Lunati comparable to an old RR cam. Since this is not a race app it should be just fine.

Hope this helps,
DC

 

[Uncle Don]

i too have ran across a rv 440 engine. this one comes with 906 casting heads. that is not a stock rv engine head is it? i know the 906's are pretty good heads to use so my mopar gurus tell me. this one is a 68 model rv engine. with all this heat passage, water intake talk...how would you know what aftermarket intake to use? and the engine not overheat all the time? what do you do in this case with a rv engine?.....

 

[Nate Yi]

I recently dropped a 440 from a 1979 Sportsman into my 1969 Coronet. I don't know too much about the engine itself as far as internals go but the engine swap itself isn't too bad. Like some members already mentioned, oil pan/pick up and exhaust manifolds are different and will need to be changed if you want to clear the crossmember.

The biggest thing is the wiring, any motorhome engine you pull will more than likely have factory electronic ignition. You can do what I did and hack the huge motorhome harness and wire all the ignition bits yourself using the factory wiring diagram for the motorhome you pulled the engine from or source the harness and various bits from Ma Mopar.

Another thing is the torque converter from my 383 would not fit the 440 so I used the motorhome TC. I don't know if 383 and 440 converters are just different or if there's something else going on, but I'm a college sophomore learning as I go so forgive me for my ignorance

Oh, and check the throttle kickdown too. My motorhome engine used a large contoured metal rod for a throttle kickdown as opposed to the complicated series of linkages used on standard passenger car drivetrains.

 

[19Charger74]

I think with the RV engine depending on what your going to be doing to it these are the difference's.
1-heads (low flow,small valves)
2-low compression pistons (as always)(exceptions on a few motor homes with Hi-po 440s)
3-intake manifold, carburetor, linkage's
4- exhaust manifolds
5-cam shaft (they produce more low end torque over stock 440 cams or other engine cams)
6-i believe the water pumps have extra blades(bonus more cooling/Thats a fact on SB)
7- Torque converter in auto.
8- oil pans and pick ups are different from the cars.
9- Ignition/emission systems vary with the years of motor homes.

Thats about it from what i can remember.

 

[19Charger74]

If you putting a RV engine in your car. Check the Casting Numbers on the block for propper identification.
Also most of you want to get a little more HP anyways so just get a pair in #906 RB cyl heads, aluminum Intake, 4bbl Carb, new Ingnition, recurved dist, Headers.
Thats the typical conversion from RV to Car. You can get higher compression pistons and a bigger cam but the RV cam works well with a daily driven street car with cleaned up heads, Atleast thats how they feel to me lol

All in all pretty much the same damn engine except on the top end. Swap the top and go racing.

 

[66plysat]

Thanks for all of the useful info, its good to know how many smart Mopar guys are out there. I have alot to learn and hope to pick your brains for info.

 

[64BEL]

I recently bought a '78 440 MH engine for future transplant into my Belvedere. As far as I can tell, it's a fine piece to use, and I plan to do a Don Dulmage Old Reliable build with it. I got the complete short block with heads and intake (that I don't plan to use) for $100.

 

[scotts74birds]

I dont want to hi-jack this thread, cause alot of great info has been put out! There is another issue that is close enough to include in it, RV trannys. I've "heard" they are built to hemi specs, have HD band and clutches, some may be longer, some may have trans brakes. I dont want to booger-up this thread, but it may benefit others by having this info in the same place. Any experts out there?

 

[joemac1j]

gotta change oil pan, heads have more cooling passages I believe, so ya gotta be careful when getting head gaskets, maybe somebody can elaborate here, and they all have low compression, but have alot of torque, some have 6 pak rods if I remember right.....

6Pak rods are not the strongest. I worked as a mech for Melrose Motors and saw a lot of broken engines. Some rod failures, some do to pistons rocking at the top of the stroke and causing the piston pins to pull out and the rods cut the engine in half. Thats the way my engine in my 6Pak, Shaker Hood, In Violet Cuda died with only 8K miles. Put in a 440 with Stage 3 rods and raced it, drove it on the street and turning 11:90's. Never any trouble.
JOEMAC
:tongueflap:

 

[72 Charger SE]

I dont want to hi-jack this thread, cause alot of great info has been put out! There is another issue that is close enough to include in it, RV trannys. I've "heard" they are built to hemi specs, have HD band and clutches, some may be longer, some may have trans brakes. I dont want to booger-up this thread, but it may benefit others by having this info in the same place. Any experts out there?

I don't know about the internals of the transmissions from the motorhomes, but there is a very big difference externally. They have a shorter tail shaft housing than car transmissions, and have a brake drum at the rear that serves as a parking brake for the motorhome (I'm guessing that the internal sprag for the parking brake is not strong enough for holding a large motorhome on a hill, so they added the drum.)

I've got a couple of motorhome transmissions, just haven't opened them up yet.

 

[19Charger74]

Not sure the difference in MH transmissions either, But i would have to say they would be 727TF in the automatic department.

 

[BelvedereII]

I've got a 440 from a '73 Winnebago in my car, swapped on some ported 906's, aluminum 4bbl, TQ got a rebuild, first used a Comp Xtreme .488/.491 cam because of the factory pistons. Ran fine so I bought a Racer Brown .510/.510 cam which ran better (also swapped to 4.30 gears, though!) then went and had some 10.25:1 pistons installed.

Gotta say the car ran well enough with the factory pistons and with only 22k miles on the motor the shop told me it looked extremely clean when they tore it down--crosshatch bore finish largely intact. I'd buy another!

If you're gonna race a Winnebago motor, gotta give credit: