Engine swap question

Jakespeeds · December 05, 2014, 01:45 PM

I am looking at a 71 Brave. I also have a complete 8.1 Vortec with an Allison transmission from a 2WD GMC truck. I have looked around but cannot find any info on if these engines will fit inside that motorhome. Has it been tried or is it a known no fit situation? Anyone have the measurement of the width of the frame rails from inside to inside at the engine location?

Jake

eXodus · December 05, 2014, 02:35 PM

more information needed,

which year of the Vortec and which Allison ? (makes a difference, later 8.1 have the same outer dimensions as the 7.4) Which chassis length has the 71 Brave ? Chassis type ? Dodge or GM ? What was in there before ?
Pretty huge engine what you are planning to get in there. Not very fuel efficient or even very power full.

Could probably work but a lot of custom fit to be done.

Jakespeeds · December 05, 2014, 03:14 PM

2002 GMC 8.1 with the Allison 1000 from a 2WD Sierra.

I beleive its a D18 Brave. The engine looks like a 318 or variant. Defiantly a small block. Dodge chassis. It is as fuel efficient as anything else gasoline powered I can imagine. I have it in my 2002 GMC 2500hd 4X4. It gets 12 to 14 mpg and it weighs 6250 with half a tank of gas. I would argue the lack of power. That engine has not come up short in my 4x4 and that is when I was towing a 12000 pound trailer.

Jake

Rickf1985 · December 05, 2014, 03:24 PM

You are putting a late GM computer controlled engine and transmission in an early Dodge chassis. Good luck! Everything and I mean everything is going to have to be fabricated. ALL of the wiring and controls from the donor will have to be transferred to the Winnebago. That includes any gauges or lights pertaining to the engine and all OBDII controls. Plus you are trying to shoehorn a big block where a small block used to be and unless a big block was an option there may not be enough room in the frame. With torches and welders anything can be done.

Jakespeeds · December 05, 2014, 03:32 PM

I have an aerospace sheet metal and machine shop. So the fabrication is not a problem. Done quite a bit swaps of this nature. The last was a Lexus 1UZFE into a Merkur XR4Ti. And that required an oil pan to be built from scratch. The computer wiring on that engine is surprisingly pretty simple. I won't even have to use an aftermarket computer. If the frame rails are wide enough or at least similar to the vehicle I removed it from then I can't imagine there is an issue. The opening in the body and floor looks to be a bit wider than the frame. I am guessing this has not been attempted as far as anyone knows.

Jake

eXodus · December 05, 2014, 05:50 PM

since the fuel prices where high since lately most people opt for a diesel swap and not put in a giant gas engine.

Yeah, the weight is for fuel economy interesting enough not that big of an issue. It's mostly the aerodynamics and the square feet of space which is in the wind. This is the problem with the gas engine, they run pretty inefficient at high drag.

I can tow with my Dodge 5.4l Hemi almost everything heavy with a good mileage. But as soon as I tow a big empty camp trailer the mileage goes down.

You understand what I want you tell ? In an old not aerodynamic Motorhome the mpg will be not nearly good as your Pickup.

Since this is a Dodge chassis and the 440 was maybe an option and has about the same size as the 454 (and yours should also have that size) - but please doublecheck. You could fit in the 8.1.

If I would go all the hassel I would try to get a newer 5.9 Cummins and do this. With the 8.1 you are looking at 8-10mpg the diesel should get 14 or better.

But if you just want to do this for fun and tune the 8.1 and make something like a burnout car out of the winnie - that would be fun.

DaveVA78Chieftain · December 05, 2014, 09:56 PM

The M300/M375 chassis in 69-73 was designed to accept either a 318 SB or 413 RB.

The 73 and later RM300 (M300), RM350 (M400), RM400 (M500), and M500 will accept a 318, 360, or 440-3.

http://www.allpar.com/mopar/383.html

Dave

Jakespeeds · December 06, 2014, 09:14 AM

Gas mileage is not a high priority for me. I was bringing that up to make a point about the engine.

I know nothing about diesels. Never worked on them but more importantly I don't have one laying around looking for a home.

It may not be a 318 but I know the difference between an LA and an RB by sight.

Jake

GONMAD · December 07, 2014, 10:41 AM

I say go for it. As I recall a quote..."Success comes in CANS not in CANTS" Zig Ziegler. Since you have a complete FAB shop the only thing to slow you down would be the wiring & that's not much of an issue if you do some homework. Make sure where the oil pan sump is, front or back. The early D chassis has a straight axle, does it not so the front cross member (if it's there) shouldn't be an issue. You'll have to run larger fuel lines & a return line along with a high pressure fuel pump & pressure regulator. As for the power just look to an aftermarket "E" prom or an on the fly re calibrator such as Bullydog or something similar. Also you'll need the computer for the Allison. Gale Banks makes a good computer Add on for the intelligent management of the overdrive & they work very well. Be sure you have a good fuel filter & water separator BEFORE the pump assembly. This saves the devices downstream from an early grave. I hope some of this helps. Have a good Thrash doing this, I'd be interested in your success. GONMAD

FastGlassman69 · December 08, 2014, 12:49 AM

Quote from: Jakespeeds on December 05, 2014, 01:45 PM
I am looking at a 71 Brave. I also have a complete 8.1 Vortec with an Allison transmission from a 2WD GMC truck. I have looked around but cannot find any info on if these engines will fit inside that motorhome. Has it been tried or is it a known no fit situation? Anyone have the measurement of the width of the frame rails from inside to inside at the engine location?

Jake

No it won't fit , no way at all, but I will gladly take them off your hands! LOL! Seriously, what do you have in their now for an engine, I have done many swaps over the years and think you should be able to do this if you have a big block in there now, as from what I have seen of the 8.1 they are fairly compact with the way they package the accessories. Good Luck! And if you run into another 8.1/Allison setup I'd love to put one in my Chieftain!

Jakespeeds · December 08, 2014, 10:32 AM

Thanks guys. I have made my final offer on the RV and we will see what he does. But now that I have researched this I actually like the idea quite a bit. So if the owner and I cannot agree on a price then I will be on the hunt for one of these. Unfortunately the Ring Brothers RV seems to have affected the perception of some peoples view on the worth of these rigs in like condition.

If anyone is looking for an 8.1 with an Allison combo they are not rare or expensive. They are available from many sources. An engine with all the accessories, computes, harness properly removed, and the Allison transmission (2WD) will only run 3500 to 4500 tops. Make sure its from a regular truck like a 2500hd. The ones used in commercial vehicles are not the same and run harsher.

Jake

Oz · December 08, 2014, 08:40 PM

QuoteIf anyone is looking for an 8.1 with an Allison combo they are not rare or expensive. They are available from many sources.

Can you list some of these sources, specifically? Would be good for people who have no clue where to start.

Oz · December 08, 2014, 08:45 PM

Quote from: Rickf1985 on December 05, 2014, 03:24 PM
You are putting a late GM computer controlled engine and transmission in an early Dodge chassis. Good luck! Everything and I mean everything is going to have to be fabricated. ALL of the wiring and controls from the donor will have to be transferred to the Winnebago. That includes any gauges or lights pertaining to the engine and all OBDII controls. Plus you are trying to shoehorn a big block where a small block used to be and unless a big block was an option there may not be enough room in the frame. With torches and welders anything can be done.

For an excellent, detailed documentary of a 440 to 5.9 diesel swap which details what Rickf is talking about, give this a read. It may not be exactly what you want to swap with, or for, but it will definitely give you a clear picture of what's involved:

http://www.classicwinnebagos.com/forum/index.php/topic,6699.0.html

Rickf1985 · December 09, 2014, 06:51 AM

Oz, I appreciate the recognition but that would not really be a good comparison of the swap I was talking about. The 6BT Cummins is non computer and will run with one wire connected. About as easy as it gets. I am talking about having to swap out ALL of the wiring from a donor vehicle to support all of the sensors and gauges that control the OBDII computer system. One that I am thinking about sine I have one is a 96 Ford Powerstroke diesel into a 89 Chieftain. Same basic physical size as a big block Chevy, the turbo is mounted on the top rear of the engine where there is plenty of room in the dogbox. Have to do a lot more thinking about it before I do anything.

eXodus · December 09, 2014, 07:19 AM

Rick you know that a Turbo is producing massive amounts of heat, the metal is glowing red at medium loads. My Doghouse is made out of fiberglass and I wouldn't trust it with the heat of a Turbo.
Even if yours is out of metal, the carpet would probably melt

But the 7.3 Diesel is such a nice engine - I would love to see it in a Motorhome.

Jakespeeds · December 09, 2014, 10:07 AM

Quote from: Oz on December 08, 2014, 08:40 PM

Can you list some of these sources, specifically? Would be good for people who have no clue where to start.

Ebay is one of the best. The is from a 4WD but at least once a month a 2wd comes up "http://www.ebay.com/itm/02-Chevy-Complete-Stand-Alone-8-1-496-Engine-4WD-Allison-Transmission-Package-/271701374598?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f42a9f686&vxp=mtr

Car-part.com and junkyarddog.com is another good source. I am lucky (or unlucky depending on how you look at it) to have Sun Valley California very close to me. There are a lot of yards there. I was at one of them picking up a LS motor for another swap I was involved in. I noticed a complete takeout from a Sierra 2wd 2500hd. I have always liked this engine and the price was hard to pass up so I grabbed it. But if you have any yards nearby I would start calling and asking. Another place I search for drivetrains for customers are insurance auctions. Specially when I am playing with a drivetrain I have no experience with. You might be surprised at where those are held and you can search online for locations. Some even allow bidding online.

Jake

Jakespeeds · December 09, 2014, 10:09 AM

Quote from: Rickf1985 on December 09, 2014, 06:51 AM
Oz, I appreciate the recognition but that would not really be a good comparison of the swap I was talking about. The 6BT Cummins is non computer and will run with one wire connected. About as easy as it gets. I am talking about having to swap out ALL of the wiring from a donor vehicle to support all of the sensors and gauges that control the OBDII computer system. One that I am thinking about sine I have one is a 96 Ford Powerstroke diesel into a 89 Chieftain. Same basic physical size as a big block Chevy, the turbo is mounted on the top rear of the engine where there is plenty of room in the dogbox. Have to do a lot more thinking about it before I do anything.

Can the turbo be remote mounted at all? You might have to have a different hot side wheel installed to compensate for the temp drop in the exhaust. Depending on how far you have to go.

Jake

Rickf1985 · December 09, 2014, 12:46 PM

You can get turbo wrap that holds the heat in the turbo which has two functions, It keeps the heat in the turbo which produces more power and it also keeps the heat out of the engine compartment. In the pickup trucks that turbo is right against the firewall. You want the turbo as close to the exhaust manifold as possible.

TripleJ · December 09, 2014, 08:28 PM

The only thing that comes to mind is where you will be getting your vehicle speed signal from for shifting the trans. Many vehicles like to use a pickup in the rear differential or the ABS sensors at the wheels. Without a VSS the trans may default to 2nd.

There certainly should be somebody who has found a solution tho. The interwebs is pretty big

Jakespeeds · December 10, 2014, 10:16 AM

That was one of the concerns I had when I started looking at doing this. Luckily The 8.1, Allison combo in the Sierra 2500HD does not seem to require any inputs beyond the engine and trans. So dodged a minor bullet there. I was also able to power up the ECU and verify its from a Sierra 2500HD. Its an 2002 setup. So that means 345hp and 455tq. The redline is nice and low and 4700. Same as my 4x4. Even if I do not manage to get them one I am looking for. I will start hunting for another.

Jake