engine swap to diesel

[fleamarketer]

Lets just say that I update the current 350.Maybe a .030 over bore and fresh bearings,updated/upgraded oil pump with a external oil cooler.Change the cam for a better torque curve,maybe a conversion to hydro rollers.I then upgrade to Racing Head Service heads that have a 180cc intake runner toped off with a Edelbrock EFI system which is known for fuel mileage and torque/hp gains.The best long tube Headman headers I can buy for long life.

I do all this and I am still having a hard time convincing myself that I will get the same or better fuel mileage as the turbo 5.9 diesel and I am pretty sure I wouldn't get the same torque rating.Hummm.

To do all that to the 350 might be very close to the costs of this swap with no sure outcome.And the possibility of needing to run the higher cost of 93 gas.The diesels live off high compression,so that is kind of a no brainier.

Please keep the input coming.I am merely explaining my thoughts.

[blackf3504dr]

Originally Posted by fleamarketer

I do all this and I am still having a hard time convincing myself that I will get the same or better fuel mileage as the turbo 5.9 diesel and I am pretty sure I wouldn't get the same torque rating.Hummm.

To do all that to the 350 might be very close to the costs of this swap with no sure outcome.And the possibility of needing to run the higher cost of 93 gas.The diesels live off high compression,so that is kind of a no brainier.

Please keep the input coming.I am merely explaining my thoughts.

If your only target is fuel mileage you will never recoup your costs in fuel savings. But on the other hand, if you are doing it because it's just plain "KOOL" and different and you can get it done..... I say GO FOR IT !
There's no doubt this is something a lot of us would love to do with our own Motor homes (I know I would) ...... You sound like you're trying to justify doing the diesel swap over a rebuild and I don't think you'd be happy with a rebuilt 350 when you really want the diesel.

[SteveLevin]

I wouldn't even get into EFI or anything for the rebuild/reman engine. IIRC Jasper has an "RV" build with a cam aimed for low end torque, etc., and it's literally only like 2 grand. We put one in our '78 Chevy crew cab and it's a stout motor for towing, hauls a 33' TT (not on of those fancy featherlight ones) without issue. Your coach would really haul the mail with one of those installed. And it runs on 87 octane.

As far as fuel savings you have to total up the savings and figure out how many miles you'd have to drive before "breakeven" -- and then, IME, at least double that figure to reflect all the "surprises" you might get along the way with the conversion (not the least of which has been that at times, at least out West, diesel has been 30% more than 87 octane.

The other thing you should do is weigh your coach as it sits, and make sure that you've got the front axle capacity to do this. Even if you go, if you are 16" tires and have to put them right up at 80 pounds to have the load capacity post conversion, you are going to really notice the ride quality degrade, for example.

Steve

[RedneckExpress]

All this talk has me dreaming of an old Chrysler 413-3 from 1972-73. Crazy HP/Torque without drinking the gas like a sailor, pre-smog, of course .

[fleamarketer]

Originally Posted by SteveLevin

I wouldn't even get into EFI or anything for the rebuild/reman engine. IIRC Jasper has an "RV" build with a cam aimed for low end torque, etc., and it's literally only like 2 grand. We put one in our '78 Chevy crew cab and it's a stout motor for towing, hauls a 33' TT (not on of those fancy featherlight ones) without issue. Your coach would really haul the mail with one of those installed. And it runs on 87 octane.

As far as fuel savings you have to total up the savings and figure out how many miles you'd have to drive before "breakeven" -- and then, IME, at least double that figure to reflect all the "surprises" you might get along the way with the conversion (not the least of which has been that at times, at least out West, diesel has been 30% more than 87 octane.

The other thing you should do is weigh your coach as it sits, and make sure that you've got the front axle capacity to do this. Even if you go, if you are 16" tires and have to put them right up at 80 pounds to have the load capacity post conversion, you are going to really notice the ride quality degrade, for example.

Steve

Steve the Chevy spec sheet is front 4,300lbs and rear 6200lbs.The heavy duty spec is 5,000lbs for the front and 7500lbs for the rear and with a dual rear axle conversion for the rear is 9840lbs.The heavy duty is using 19.5 tires.

[RustyJC]

Just for your reference the actual front axle weight of our 2002 Dodge Ram 3500 dually with the Cummins 5.9HO/NV5600 6-speed when loaded with passengers, the 5th wheel in tow, full fuel tank, etc. was 4,350 lbs.

Rusty

[fleamarketer]

I have made up my mind and it is on with a diesel 5.9 1994 or 1995 47 tranny swap for this motor home and that might include up to a 6" welded pipe spacers for the body mounts to lower the frame to help make it work.I'll use the engine combo that is in for now while I wait for the right donor truck deal to come along in my area.I will continue to restore the rest of it in the meantime.Certainly it is by far the biggest bang for my buck.

[Hoverbug]

I'll agree with pwk16129 in his 1/29 post. My Airex that I purchased last spring has a GearVendor which was installed just after it was purchased new. I couldn't be more pleased. It pulls like a diesel in the Cascades and gets 9-10 mpg with power to spare on I-5. The only maintenance a GearVendor needs is an occassional oil change. Happy Trails!!

[Mikakuja]

Fleamarketer, I would really reconsider the body lift.......Really Bad Idea......

[fleamarketer]

Originally Posted by Mikakuja

Fleamarketer, I would really reconsider the body lift.......Really Bad Idea......

We have done those successfully on Astro van sub frames and V8 conversions.

[Mikakuja]

I wouldn't mind seeing a sketch of what type of body mount/frame drop you are planning as it is possible I have a different picture in my mind than what you have.............What I see right now is way to much flex with a mount up to 6" tall which would only be amplified with the weight of the coach especially in windy contitions, harh cornoring or braking....
An Astro van is much lighter and would have no where near the stresses on the mounts that your MH will have.

[fleamarketer]

The pipe spacers are the same ID as the lower body mount.The pipe is welded to the frame mounts on center and is capped off at the end.Then the capped ends are bored out the same as what was on the frame mount.The frame mounts are now bored out to pass the lower body mount/bolt up into the pipe spacer and that duplicates the same thing that was on the frame mount.Schedule 40 is the pipe material used.It is a really strong part.

I do agree that raising the body on a M/H does effect the cg.I would want to beef up the sway bars to help that out.Adding one in the rear.This M/H did come as a option with dual rear wheel axle and a move towards that would also be a consideration along with a rear end gear change to about 3.42's to the lower 3.23's for the diesel turbo's torque range.

The steering intermediate shaft would need to be looked at and a find from another vehicle would be needed to be sure enough of it is seated.

The kind of swapper I am is the end product does look factory installed.All I am saying at this point is IF it looks like a ton of the body is going to need cutting,than I would look to those pipe spacers to relieve some of that.

[fleamarketer]

There is no way to justify the Gearvendor tranny behind a engine with only 165 hp and only 230lbs of torque.With the costs of their tranny alone,it would be 2/3's of the costs of the diesel swap that is a 4 speed tranny with a lock-up converter.The biggest bang for my buck is the turbo diesel.



Thank you For Your Suggestion.

Gary

Here is the best part.I am pretty sure to find a crash donor truck with the yr range of 1994 to 1995,it would cost from $2500 to $3000. because I priced the engines alone from junk yards at that price.That engine in this M/H I would predict mpg of from 12 to 14 and it would out last me owning the M/H.Those 5.9's will go easy 250,000 to 300,000 miles.Lastly it would pull the tusks off a elephant.

Originally Posted by Hoverbug

I'll agree with pwk16129 in his 1/29 post. My Airex that I purchased last spring has a GearVendor which was installed just after it was purchased new. I couldn't be more pleased. It pulls like a diesel in the Cascades and gets 9-10 mpg with power to spare on I-5. The only maintenance a GearVendor needs is an occassional oil change. Happy Trails!!

[Gary - K7GLD]

The most popular Cummins 5.9's seem to be the '98 or so - largest and most reliable injection pump, and purely mechanical - no electronics gadgetry to have to modify and adapt - powerful stock, and easily modded for added power as desired...