46RH (A518) Conversion project

Started by Sasquatch, November 13, 2017, 02:27 PM

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That is one of those injuries that they tell you to come back in two weeks to get the stitches out and I would always take them out in ten days and they go back in the two weeks and get yelled at because I ' Don't know how to take out stitches". Well, Been doing it for 50 years now with no ill effects. By the way, My mom was a nurse so yes, I was taught the right way. LOL. Thats a bad spot though, I hope you are not left handed.


I did not.  I was so driven to get it done that I did not take photos.  I will take some as I fit the new TC and bolt it up.  It is due in by Thursday.

I guess I did take one photo....

Dont worry, it'll buff right out.  ;)

Going the route of installing the new bellhousing will ease my thoughts and concerns.  The broken flex plate has me second guessing all my calculations and measurements when I did the welded bellhousing.  I know that with the new one I can not just travel and not worry if it will break in the middle of nowhere.  The new flex plate (B&M race certified one) and the ultra bell are so overbuilt for my application it should never fail.

Speaking of fluid capacity, with all the coolers, filters, etc., it held almost 4 gallons of fluid.  I was going to put a deep sump on the transmission for an additional 4 quarts, but I really dont need it.  It stayed plenty cool and 4 gallons is enough.  That reminds me though, I need to order a weld on drain pan drain bung to put on the transmission pan.  It makes changing the oil much easier....


Did you get any pictures of the cutting and installing of the new bell housing  (Sorry to hear about your accident) ?  Another bonus is it will need less fluid ! Good Luck !
"The Journey is the REWARD !"
Member of 15 years. We will always remember you, Frank.


The rabbit hole keeps getting deeper.  Due to the broken flex plate I decided to replace my welded bellhousing with an Ultrabell to make sure that everything was right.  Cutting off the old bellhousing again I proceeded to try and cut off my finger.  That set me back some time to heal.  First time I have had stitches like that.

Finally last week it was going back together but my torque converter would not fit in the new bellhousing (it is much thicker than original).  Come to find out my coach has a 12" torque converter and the ultrabell only accepts 11" or smaller.  Ug.

Spent some time with the fine folks at Precision of New Hampton and settled on a 11" low stall RV torque converter.  Stall speed will be a bit lower than original which should help with mileage a bit and keep the tranny cooler (not that I had a problem) as well.  It has some nice performance upgrades over stock that I am quite sure I will not notice at all when driving except for a lighter wallet.

The saga continues.


Yes, I updated my thread on the trip reports.



Been following this and am interested in the post-trip report.  Drive safe.


Holy Crap! Don't leave us blowing in the wind. You can lay over in Walmart parking lots and use their free wyfi or MacDonalds or ???? Geeeeezzzzzz. Now yeah got us following along we got to know how the trips going. D:oH! i?? :)rotflmao :)rotflmao :)rotflmao


This is my last posting here unless someone has questions.  I am leaving Friday, March 22nd for Las Vegas.  This is it, to see if everything I did is sorted and working well.  Prayers happily accepted.  :)ThmbUp

Took it down to get propane yesterday and it drove as she should.  Overdrive kicked in and out just fine, my hopes are rising.  I will start a thread in the travel section to give a trip report as she unfolds.


I remember your mods and they were pretty much the same specs that I use for the Chevy engines.


Quote from: Rickf1985 on March 11, 2019, 11:12 AM
Best of luck and I am really looking forward to your report on the mileage. I have tons of data on big block Chevy engines and mileage but when people ask me about big block Dodges all I can offer is the Chevy info and tell them it should be similar. I am curious to see if I am right.

Before the overdrive install I would average about 7 mpg.  Sometimes into the 8's, sometimes as low as 5.5 if I am beating on her in the mountains or high winds.  I am not the slowest driver.  She is most happy between 65-70 on the freeway and 60-65 on secondary roads.  She has plenty of umph to carry those speeds and all the suspension upgrades as well.  I posted somewhere all the 440 mods I have done and what worked and what was a waste of time.  But long story short, she runs infinitely better than she did when she was completely stock.  The three biggest upgrades were 1) Fuel injection, 2) proper cam for torque/efficiency, 3) Headers/exhaust.


Best of luck and I am really looking forward to your report on the mileage. I have tons of data on big block Chevy engines and mileage but when people ask me about big block Dodges all I can offer is the Chevy info and tell them it should be similar. I am curious to see if I am right.


I am gearing up for another trip, hopefully this time all the problems are sorted and will have real numbers to report.  I am leaving in 2 weeks to travel from Boise to Las Vegas for spring break.  Other things I found after my last disaster trip to Arizona last year was that I had a shot rotor in the distributor, all my spark plug wires were arcing, and the plugs more worn than I would have thought for how many miles were on them.  I also replaced two failed engine mounts.  Now all that is new, the engine is purring nice and smooth.

The transmission worked perfectly on the 90 mile or so test run after finding and repairing the warped valve body.  Shifted better than it ever did since starting this project.  So, combined with the engine repairs, I am hoping for a smooth run and some good fuel mileage numbers.

Regarding mileage, I am going to have to learn when to shift out of OD on hills.  During my test run I pulled a couple of moderate grades, just left the cruise control on at 65 and let them pull in OD.  It pulled the hills just fine only loosing a couple of mph.  But, I am sure that it was using more fuel than it would have been had I downshifted to 3rd and let the motor rev.  I also wanted to beat on the OD to see what temperatures it would run at.  Now it was a cooler day, in the 50's/60's if I remember right, but the hot side temps never even hit 200 on the hills and stayed in the 150-160 range on the flats.  So this is perfect. 

I am going to keep my computer hooked up on the trip so I can watch the fuel usage from the fuel injection system.  Watching the gallons per hour (GPH) reading under different driving situations I will be able to quickly figure out optimal shift points for economy.

Keep in mind, all the problems I had on this transmission were due to MY mistake rebuilding it the very first time and the damage that occurred to the valve body that was very hard to catch, which caused all the future failures.  Anyone else wanting to do an OD swap would probably not run into these issues if you have someone QUALIFIED to rebuild your transmission.  Have it rebuilt, and then use a bell housing adapter kit or plate and you will be off and running.  How I did mine with welding on a 727 bell housing and making the rebuild mistake turned a mole hill into a mountain of problems that never should have happened.

When I start my trip I will start a thread in the travels section and report how well the transmission is doing and how the trip went.  If anyone is located in Las Vegas and wants to get together to swap stories, shoot me a PM.


Which is why I undertook this challenge...


(2.Noise.  One of the huge benefits of doing some of my mods was to reduce cabin noise while driving.  It is pretty darn quiet now.  Stuffing an older 12 valve in there would be quite a bit louder, and I am liking the relaxed feeling that the quiet cab gives me now).

This is one example of how sweet an FMC coach is, engine is in the back! Nice and quiet up front......BUT with stock gearing, my 440 is screaming 3,400 rpm's @60 mph....AND very thirsty :'(
Never get crap happy with a slap happy pappy


No Rick, I am not going to do a motor swap.  :P   I seriously considered a Cummins swap years ago before I invested a ton in my drive train and there was two major reasons I decided against it. 

  • Dual fuels.  I use my generator quite a bit while driving in warm weather to operate the air conditioner.  I did not want to have to add a third fuel tank and have to deal with filling two different fuels at gas stops.  I know I could probably find a diesel generator, but the smaller, older ones are horribly loud and I just did not want to deal with that.
  • Noise.  One of the huge benefits of doing some of my mods was to reduce cabin noise while driving.  It is pretty darn quiet now.  Stuffing an older 12 valve in there would be quite a bit louder, and I am liking the relaxed feeling that the quiet cab gives me now.
I know people have a hard time believing me, but I really do not need any more power than what I have.  It cruises effortlessly at 70 and will pull any hill I encounter with ease.  When I first acquired the coach, climbing over the Blues eastward from Pendleton, OR I would top the summit at about 40 mph having to climb it in 2nd.  I did it a couple of years ago and never even needed to take it off cruise control and topped it at 54 mph.  That is plenty fast enough for me.  I could have even gone faster if I really laid into the throttle.  (my original cruise control would only pull on the throttle about 5/8, so it would not see full throttle on cruise)

As far as drive train is concerned, I have only one more project to do and that is to come up with a more permanent parking brake solution.  I will probably find a drive shaft mounted cable operated disk brake setup, or something of the sorts.  I looked at the drum brake setup off of the original 727 and I just do not think there is any way to really make that one work without a ton of fabrication.

When I searched for the aftermarket parking brake setups, no one had anything for a Dana 70HD that I could find.  But I need to measure the yoke bolt spacing and look at them from that angle and see if I can find one that either fits or that I can machine a bit and make fit.  My redneck line lock works in a pinch, but it is not a long term solution.

I have two major projects left on my list for this coach.  One is a MAJOR undertaking and that is a new paint job.  But I want to do it right and pull everything off the exterior including the windows.  It will give me a chance to rebuild all the windows, put all new hardware everywhere, and make sure everything is screwed back together nice and tight after the paint work is done.  I am going to keep it the original color and graphics, just new shiny and fresh.

The next is to replace the air conditioning unit on the roof with a more modern one that is smaller in physical size and has a heating option.  It would be nice to use shore power when I am paying for an RV spot instead of burning through my propane.  My original Frigiking air conditioner, believe it or not, still works perfectly though.  But I know at 42 years, it's days are numbered.  It worked perfectly yesterday while I was on my test drive. 


Great to hear! You have closure for winter knowing that come next summer you will be able to just jump in and go. I guess I can forget about getting you to try the 671/Road ranger combo now. :)rotflmao :)rotflmao :)rotflmao  After this last trip with mine if I had a garage big enough I would be looking for that combo. Hm? N:(


Major update.  I finally had a chance to get her out and put 100 miles on it this afternoon.  This is my first main test of the repaired transmission and I am pleased to say she is working perfectly.  Did some city stop and go and about 70 miles of interstate with some hills (It is Idaho). 

Temperatures ranged from 160 to 190 max on the hot side output of the transmission.  Shifted perfect, ran perfect, no issues at all.  I set the cruise on the freeway at 70, threw her into OD and enjoyed the silence (well, almost).  Engine was turning a comfortable 2350 rpms at 70 and had plenty of poop to pull the minor hills I encountered.

So, she is home from work, winterized and tucked away for the winter's slumber.  I am looking forward to next year and taking some trips and enjoying the benefits of all the hard work and frustration I put into this project.


On a vehicle as light as a motorhome it would be probably 12-15. You could also hook it into an Allison 6 speed auto but Detroits were pretty sensitive to rpm, they had a pretty small range they liked to be in. Especially the 6 cylinders. I drove a 1971 Autocar heavy tractor with a 12V71 12 cylinder Detroit and that thing would pull like you would not believe between 1600 and 1800 RPM. It pulled hard all the way down to 1200 but at 1600 it would spin the tires with anything less than 10,000 lbs on the axles. But man it was a thirsty beast! It got 4-6 MPG at best. Being a two stroke they were not the most efficient fuel engine but damn they sound good! :D


What would the mpg be with one of those?  They aren't very fuel efficient are they?

Quote from: Rickf1985 on May 16, 2018, 06:35 PM
OK, OK, I will stop pestering you. Just hope I don't trip over a 671 Detroit laying around anywhere. That and a Road Ranger and MY wheels will be turning!


I know the feeling Frank, I need a few more replacement joints before doing anymore big jobs.


You get to a point where you do not want to work on the beast any more, I think I may have set my timing to late , But cant get up the energy to recheck it (it is not as easy as usual) I am happy to just get in and drive, With only checking fluids and air pressure ! Frank
"The Journey is the REWARD !"
Member of 15 years. We will always remember you, Frank.


Rick, there is an ice tea waiting for you if you ever make it to Idaho.....


It has been great following this, and all of the comments. Actually, it's been a hoot.
Keep up with us please, Sasquatch, regardless of and including your upcoming projects!
It is not our abilities that show what we truly are - it is our choices.
Albus Dumbledore


You KNOW I was interested in that project since it was so off the wall and technical. AND he had the balls to test drive it so far with little preparation. And on top of all that he put up with all of my crap! :D :D :D