6BT swap into a P30 chassis RV

[Scott Iwen]

Hello gang,
I just joined the group tonight. Looking forward to chatting with all of you. I just acquired a 1985 Honey RV based on the Chevy P30 chassis for FREE. It has a 454 in it right now. It is very tired, has a dead cylinder (low compression) and runs like crap obviously. A sane person would probably send the RV to the scrap yard. Other people might rebuild the engine. Then there's me. I plan on buying a 1993 Blue Bird TC2000 in spring when the bus company decommissions it after this school year. The whole damn bus!!! It has a 6BT in it mated to an Allison AT545. 133K miles on it, so the rings are first getting seated in on the engine. Oddly enough, it does have a P Pump in it, which kinda throws me at the moment being it's a 1993 model. At the moment, I am game-planning and getting the tools I need to do this. I'm going to have questions as they pop up and hopefully tap into the knowledge contained within this group. The biggest question I have right now is whether I should use the AT545 or step up and use an MT643 instead. AT545 doesn't have a lockup converter where the MT643 does, plus it has more torque handling capability. I do plan on cranking up the HP, nothing outrageous, but I'm worried the AT545 might give up the ghost. Just wondering if there is anybody out there that might know first hand if the 545 can handle more torque than what they list it at. The only reason I'd need to keep the 545 is because there is a drive line parking brake assembly available, as where a similar option for the 643 is rarer than hen's teeth. I will need a parking brake because neither of these transmission have parking pawls. Anywho, more to come. I attached a few picks of the behemoth and the 5" side exit exhaust rendering I have planned for it....and the bus. It's going to be fairly "road kill", but probably more reliable.

View attachment 131047

 

[Scott Iwen]

Here's the bus.

 

[Timd32]

Welcome.

Can't help with the transmission stuff.

I don't know but I would be more inclined to gut the bus and tiny home that thing.

That is a really sweet bus, it's fairly impressive and unlike our buses here locally the cab over deal provides so much more room.

You can still do your 5" deal.

Either way you have a cool ride.

Keep us posted, hopefully some folks jump in on the transmission stuff for you.

 

[NIsaacs]

Industrial BT's had P-pumps in '93, Dodge in '94. As big as that bus is, it probably had at least the 210hp/520tq model and maybe the 230/600.

The P30 will have a Dana 70HD with 4.88 gears, so it will need taller gears installed.

 

[Scott Iwen]

Welcome.

Can't help with the transmission stuff.

I don't know but I would be more inclined to gut the bus and tiny home that thing.

That is a really sweet bus, it's fairly impressive and unlike our buses here locally the cab over deal provides so much more room.

You can still do your 5" deal.

Either way you have a cool ride.

Keep us posted, hopefully some folks jump in on the transmission stuff for you.

I've been told that a lot about converting the bus. I have my heart set on converting the RV for the following reasons: 1) lighter and shorter, 2) better fuel economy and 3) the cool factor. The bus will always be a bus and it's been done a million times. You don't see a Cummins swapped, old-ass RV very often. I'm pretty unconventional.

 

[Scott Iwen]

Industrial BT's had P-pumps in '93, Dodge in '94. As big as that bus is, it probably had at least the 210hp/520tq model and maybe the 230/600.

The P30 will have a Dana 70HD with 4.88 gears, so it will need taller gears installed.

Yup, I took a peek at the rear end. The tag says 4.56. I've narrowed it down to a D70 but I'm not sure if it's an HD. Either way, it will still need to be regeared. What engine RPM @ 60 MPH should I be shooting for? I also tried getting a picture of the engine nameplate but couldn't. It's too low in the chassis of the bus. My guess is the 190HP. The dude had 2 12 valves that were laying around and they were both 190's. I could be wrong.

 

[Tuesdak]

You don't see a Cummins swapped, old-ass RV very often.

And there is a reason for that!

Do you have the lift required to get the engine in and out of the P30 chassis? There is one P30 RV that someone put a P400 6.5 Diesel in. It's for sale via insurance auction as it had an engine electrical fire and burned. That would be an easier 454 to Diesel swap as everything would bolt up without mods.

Getting it registered and emissions passed could be a problem for gas to diesel swaps.

 

[Scott Iwen]

And there is a reason for that!

Do you have the lift required to get the engine in and out of the P30 chassis? There is one P30 RV that someone put a P400 6.5 Diesel in. It's for sale via insurance auction as it had an engine electrical fire and burned. That would be an easier 454 to Diesel swap as everything would bolt up without mods.

Getting it registered and emissions passed could be a problem for gas to diesel swaps.

I have a 4 ton (1 ton fully extended) super long engine hoist. It will come out through the drivers door. I am also ready to build a custom built gantry that will span from the passenger side and out the drivers door and use a chain fall to hoist it out. I'm in WI in the sticks, emissions and registration won't be a problem. We don't have emissions testing where I live. I have the RV registered with non-expiring "hobbyist" plates, which are for vehicles that are 20 years old and have been modified from stock. As far as why Cummins swaps aren't more common in a P30 is beyond me. I've seen YouTube videos of similar type RVs with similar chassis with 5.9s swapped in them The Cummins is going to fit. The 454 with that big ass air cleaner on top is every bit as tall as the 5.9. They are probably just as wide as each other. I understand that the Cummins will be longer, but I have a ton of room to move it forward a bit. These are assumptions on my part and may bite me in the ass in the end, but damn it, I'm pretty determined to get that wedged in there.

 

[Scott Iwen]

And there is a reason for that!

Do you have the lift required to get the engine in and out of the P30 chassis? There is one P30 RV that someone put a P400 6.5 Diesel in. It's for sale via insurance auction as it had an engine electrical fire and burned. That would be an easier 454 to Diesel swap as everything would bolt up without mods.

Getting it registered and emissions passed could be a problem for gas to diesel swaps.

I did a little research on the P400. Is it out of production?

 

[SnoKing]

Like TimD32, my first thought was you are going to wrong direction. Gut the RV stuff from the MH and reuse what in reusable in the bus. Bus looks so much better that the POS MH, and the bus body will take a cool paint job much better than the MH.

 

[NIsaacs]

Yup, I took a peek at the rear end. The tag says 4.56. I've narrowed it down to a D70 but I'm not sure if it's an HD. Either way, it will still need to be regeared. What engine RPM @ 60 MPH should I be shooting for? I also tried getting a picture of the engine nameplate but couldn't. It's too low in the chassis of the bus. My guess is the 190HP. The dude had 2 12 valves that were laying around and they were both 190's. I could be wrong.[/

Okay, 4.56 were used too, in the lighter GVW class. Do you know what yours is? My 33', 1983 P30 that I bought for salvage was 14k I think. I installed the engine (454) and turbo 475 transmission in a '66 4x2 GM that was converted to 4x4. The 70HD has 4" axle tubes. Does yours have 19.5's?

I installed a 1990 6BTA in a 1974 F-350 4x2 in 1990 that turned out nice. Then a few years later a logger friend of mine installed one in an older Dodge Motor Home, I think it had a 413. He used the early Dodge 4 spd auto, (727) maybe? He had trouble with the flexplate. He also installed a 3spd aux, 5531 I think.

 

[NIsaacs]

Like TimD32, my first thought was you are going to wrong direction. Gut the RV stuff from the MH and reuse what in reusable in the bus. Bus looks so much better that the POS MH, and the bus body will take a cool paint job much better than the MH.

Did you read post 5? The OP already answered you.

 

[Scott Iwen]

Okay, 4.56 were used too, in the lighter GVW class. Do you know what yours is? My 33', 1983 P30 that I bought for salvage was 14k I think. I installed the engine (454) and turbo 475 transmission in a '66 4x2 GM that was converted to 4x4. The 70HD has 4" axle tubes. Does yours have 19.5's?

I installed a 1990 6BTA in a 1974 F-350 4x2 in 1990 that turned out nice. Then a few years later a logger friend of mine installed one in an older Dodge Motor Home, I think it had a 413. He used the early Dodge 4 spd auto, (727) maybe? He had trouble with the flexplate. He also installed a 3spd aux, 5531 I think.

View attachment 131068 View attachment 131069 View attachment 131070

The GVRW for the RV is 14,500. And yes, it's on 19.5's. I'll get a calipers on the axle tubes tomorrow to see what the OD is. Thanks for the info. I'm having a hard time getting info off the internet, other than it's a D70. I can't find any stamps on the axle tubes other than the MFG date stamp.

 

[Scott Iwen]

Like TimD32, my first thought was you are going to wrong direction. Gut the RV stuff from the MH and reuse what in reusable in the bus. Bus looks so much better that the POS MH, and the bus body will take a cool paint job much better than the MH.

Yeah, I hear you. You're not the first to tell me that. But like I said, I'm a bit unconventional, or weird, you make the call. I'm going to enjoy the challenge. And, yes, it's ugly................but that's part of it's "charm", in my eyes. I like the cousin Eddie look, or even the Breaking Bad vibe it's giving off. It makes people laugh. Nobody is talking me out of it, it's going to happen. LOL. And when it does, and all the bugs are worked out, my goal is to take it and my wife on a lower 48 tour...no interstates. 16,000 mile round trip. 15MPG can only help with that. The money I save in gas alone will pay for the bus I'm buying. Lofty goals, I know. But I'm goofy that way.

 

[Timd32]

I'm in full support of your RV project.

You have a plan and desire so that's a great first step.

 

[NIsaacs]

What engine RPM @ 60 MPH should I be shooting for? I also tried getting a picture of the engine nameplate but couldn't. It's too low in the chassis of the bus. My guess is the 190HP. The dude had 2 12 valves that were laying around and they were both 190's. I could be wrong.

You are probably right on the "190". I just looked up the Allison AT 545, that is all it is rated for. It is also a direct drive 4 spd.

Using your 60 mph cruise speed you will need a 3.50 gear @2100.

Link to the AT545.

https://r.search.yahoo.com/_ylt=Awr9Ik8VBGxh2MMAxwtXNyoA;_ylu=Y29sbwNncTEEcG9zAzEEdnRpZAMEc2VjA3Nj/RV=2/RE=1634497685/RO=10/RU=http://www.barthmobile.com/eve/forums/a/tpc/f/3731087061/m/6453935387#:~:text=ALLISON%20AT%20545%20SPECIFICATIONS%20General%20Purpose%20Truck%20and,kW%29%20Net%20input%20torque%20445%20lb-ft%20%28603%20N%C2%B7m%29/RK=2/RS=ulpgP3RTbGNT3Ww3P6Pb4Ww2UWc-

 

[Scott Iwen]

You are probably right on the "190". I just looked up the Allison AT 545, that is all it is rated for. It is also a direct drive 4 spd.

Using your 60 mph cruise speed you will need a 3.50 gear @2100.

Link to the AT545.

Thanks for the info. I looked on the Barth website. WOW! They really have a lot of good info on just about everything.

 

[Scott Iwen]

It's been confirmed. The axle on the RV is a Dana 70HD. It's casted into the front of the diff housing.

 

[Tuesdak]

And, yes, it's ugly. my goal is to take it and my wife on a lower 48 tour...no interstates.

Just so you are aware: Some RV parks (like in the homeless and LTR, long term resident, plagued California) have a 10 years old or newer rule. Exceptions to RV age are with a picture that frankly: isn't Ugly. Otherwise "You can't abandon it here! Get Lost!!!" Running into a problem like this after a long days drive will put a deep scratch into the charm that will not buff out. Some areas do not have alternative sites or they are full up. As noted the places have this rule for a number of reasons like the past rent due is more than the RV is worth.

 

[Scott Iwen]

Just so you are aware: Some RV parks (like in the homeless and LTR, long term resident, plagued California) have a 10 years old or newer rule. Exceptions to RV age are with a picture that frankly: isn't Ugly. Otherwise "You can't abandon it here! Get Lost!!!" Running into a problem like this after a long days drive will put a deep scratch into the charm that will not buff out. Some areas do not have alternative sites or they are full up. As noted the places have this rule for a number of reasons like the past rent due is more than the RV is worth.

That's crazy. I'm not doubting you, but that's crazy. The funny thing is, I was just out in Oregon near Portland and there are tent cities and homeless people everywhere. Those tent cities, and all the garbage and filth associated with them, are not nice to look at. So you are telling me some campgrounds will not allow me to stay because somebody might think it's ugly, even if it's just overnight? Well, I think it's beautiful, LOL. There's always the Wal-Mart parking lots I guess.