Converting gas to diesel
July 19, 2004 - 11:28pm
Just wondering what it takes to convert a gas car to a diesel engine....because, I'm looking at buying an rv but id need to replace the transmission and probably the motor, and i was thinking i could amybe get a diesel motor and transmission to match, but i don't know if id need to do anything else.
July 22, 2004 - 6:18pm
#2
I would never (well, hardly ever) buy a vehicle with the intention of converting from gas to diesel. BUT, many RVs are based on the Chevy P-30 chassis, and there are many used engine/trans combos around that will drop into that frame. Suposedly the 6.2 GM is not rebuildable, but Jasper does it. It would have to to be really cheap to be worth buying and converting, and even then I would not be to eager to take it on. Remember, the tourque curves are diferent between gas and diesel, therefore the trans/rear ratios will have to be taylored to fit. Lotsa project. It might be easier to get a diesel bus and convert it to an RV. (Or perhaps use the bus for a doner drivetrain). I have found it to be a problem insuring old school busses, evn though they are a great deal, and a lot of vehicle for the money.
Just my thoughts on the matter.
July 23, 2004 - 8:33pm
#3
I've seen the question asked before and wanted to ask it myself. The problem is, nobody answers it and says "don't do it." "Buy a diesel."
That's great, but I can't buy a 70's Winnebago that's already set up for diesel and I don't want to burn up more fossil fuels. It's not about the time or the money, it's about sustainability folks.
Can anybody answer the question?
no reason that suspension and brakes should have to be changed (maybe the power assist in a turbo application), But I'm interested in the wiring and plumbing of it all. If you start with a fairly complete donor and an engine based on an engine that might have originally come in a vehicle...what's the problem? I know it's a big project, but so will be dealing with $10/gallon gas!
Thanks for any help
Alex
Columbia MO
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If the inventor of the hammer were alive today, he'd be penniless as a result of liability claims.
July 24, 2004 - 12:36am
#4
I think the question was just answered. It was "lotsa project". Is sustainabilty your goal, or a several month long project? It may be less work to buy a schoolbus and convert it to an RV than to change over the drivetrain and engine in a winnebago. I personally would rather spend several months above the chassis than below it. And I've found, in my quest to rig things all hoopty-like, that to rig bells and whistles is one thing, to rig the workhorse is quite another. (hey, if sustainability is your goal, get a workhorse. Grass and water and love is all they take, no grease or anything to mess with.)
But if you take it on, tell us about it, all the do's and don't's. Who knows; we may just be naysayers, like those who told columbus that he'd fall off the earth.
Sorry but I must end with more naysaying... if the whole world were to convert to grease burning, I don't think we'd be that much better off than we are now. We're still burning something to get around. And think of all the land it would take to produce that fuel... monoculture is not good for the earth either.
I just think it's silly for us greasers to think we're actually helping the planet, we're burning carbon based fuel just like the rest of them. It helps that grease is a closed loop, but we're still dragging around hundreds of pounds of metal everywhere we go.
Enough. That "sustainability folks" quip just got to me. If you want to be sustainable do it on your own time, I'm trying to have a good time here.
July 24, 2004 - 10:11am
#5
There's not much sustainable about driving, agreed. I'd have a horse, but I live in town where I can pedal most places. That leaves me with a small enough lot that I don't think the neighbors or the city would go for a horse :). (actually I know it...I checked into it:)).
I guess my real point is that on message boards all over, people ask a question to have it sidestepped with "forget about it." The original poster seemed to be aware that it isn't an easy swap but wants to know what is involved...some basic considerations.
I know I've got my agenda, and don't mean to come along stirring things up. Sorry for that, but it touches home because a lot of the vehicles I'd like to use aren't diesel powered, but I think they could be with a fair amount of work.
So. Help me out here. It seems some considerations are
Physically bolting the engine and transmission in. Purchasing, fabricating, or designing and having made mounting brackets for the engine and transmission in question.
Fuel system...duh. What components are necessary for running a diesel engine?
Electrical and electronic. Fuel management systems. What ball of wax could we get into here?
Cooling system. Would an upgrade possibly be in order?
Ancillary things like gearing, torque converters, belt driven accessories, added weight, ect.
What about anything else? Any thoughts on the considerations I posted?
Thanks,
Alex
Columbia MO
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If the inventor of the hammer were alive today, he'd be penniless as a result of liability claims.
August 27, 2004 - 1:30pm
#6
streetninja! This is Carissa with the Mercedes! I lost your number- email me!
August 29, 2004 - 10:28am
#7
I agree... the question posted was how to convert gas to diesel... regardless of logic, he seems determined... so lemme see...
Engine size/engine mounts. My guess is that you are better off replacing the entire transmission/bellhousing/driveline/differential with the engine. This will take a lot of the guesswork out offitting a square peg into a round hole, and should take care of any problems regarding power specs.
Another thing I thought of was suspension. As I understand it, diesels in general are much heavier than their gasoline counterparts, and therefore may require a tweak to the suspension. Even though the RV load is the same, you have potentiall added several hunderd pounds (if not more) to the entire chassis with the diesel components.
As an advantage however, (the silver lining in all of this), you will most likely gain a much heavier front end... which will help with steerability (is that a word?) and control... a common problem to many RV's that place too much weight behind the back axle, lifting the weight from the front wheels.
The biggest problem in all of this, of course.... is that you are going to have to find a "Diesel Fuel Only" sticker somehwere. That will most likely be your biggest challenge.
ns
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"That's right... keep eating...
... excellent..."
August 29, 2004 - 11:20am
#8
if you need motor mounts fabricated or anything else at all. i found a really cool website that may help you out
http://www.emachineshop.com/
you design what you need in thier fairly simple online cad and they give you an instant quote and if you want it they will make it for you as specified and deliver it to your door. havent used them but the work that they have as examples looks well done and they were good enough to get press in USAToday. its worth a looksee at least.
August 30, 2004 - 8:29am
#9
One thing to keep in mind along with the switch ( depending on what year/type the vehicle) is the power train control module it must be matched to the engine in order to perform well. take care ot get the wiring runs and other stuff along with the engine.
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KEEP ON GREASIN'
August 30, 2004 - 9:52am
#10
At the risk of sounding like a "nay-sayer".... I thought I would present this idea (since we are tossing $, time, and logic out the window)...
Can you find a same/similar model flatbed diesel truck, and just change out the RV "cube". (I assume that we are talking about a "Class C" RV).
Again, that gets dangerously close to "just get a diesel", but I was trying to think outside the box...
ns
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"That's right... keep eating...
... excellent..."
August 30, 2004 - 1:44pm
#11
This is why (though I have decided to get a diesel truck and jetta first now, only for practicality reasons and to get me up and... cooking? faster) I decided to just do a ground-up restoration when I get the diesel vehicle I want...
Take the shell of an old '69 camaro, one of the ones at a junkyard or something that doesn't have an engine in it anyway, and when I buy parts for it I can just buy parts from the car that has the engine I will end up using (hopefully going to go for one of the new mercedes CDI engines). That way it won't involve gutting the car, it will just involve changing what parts I buy, and, in effect, building a mercedes with the body panels, etc, of a camaro wrapped around it.
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- Windaria
August 30, 2004 - 6:31pm
#12
I have a 1986 Bounder 30' Class A (Chevy P-30 chassis) and have considered the same thing. At 5 to 7 mpg, I simply can't afford to drive it! But... with diesel/veggie its entirely different!
I have considered getting one of the newer Ford Transit (European) style vans and moving the "camper" stuff over there. Essentially, it would mean parting out a perfectly functional camper. Unfortunately, it has little value due to the fuel economy.
As for the transmissions and rear ends... my 2002 F-250 has the same 3.73 rear end as you would find behind a gas burner and I believe the same tranny. The engine/trans combination would be much better but I don't see a problem beyond that.
The front suspension is entirely different. As I understand, the reason Dodge didn't come out with a true crew cab with their Cummins diesel is frame issues. Diesel engines are so much heavier than gas its an entirely different engineering concern.
Diesels haven't been in RV's at great numbers until the past five or ten years. Those are still pretty pricey by my book.
But hey... let's keep exploring. There's plenty of imagineering that can be done!
Todd T
August 31, 2004 - 7:59pm
#13
You will need to provide more information for an accurate answer.
What make is the chassis?
What engine is in it?
What type of transmission is in it?
What type of transmission are you going to use"
What type of diesel are you going to use?
5.9, 6.2, 6.5, 7.3?
The 6.2 and 6.5 mechanicals are slighly heavier than the big blocks. I am not sure how much heavier though. The 6.9 and 7.3 are extremely heavy. They weigh almost a 1,000 pounds. They are physically huge.
the 6.2 and 6.5 mechanical engines look good to me. Many people say they are crappy but I drove one last week with 350,000 miles on it and it was adequate to move a 4wd suburban. The rest of the truck was falling apart but the drivetrain was solid. The 6.5 and 6.2 were used in the hummers.
If you buy the engine I would get the engine and transmission together. You will also need to research the brake system before you buy anything. The 6.2 I was looking at didn't have a brake booster. Some might have a vacuum pump. It had a hydroboost system that worked off the PS pump (it wasn't working though.) Other diesels use a vacuum pump such as the 1.6 VW. some vehicles use the hydro boost type system for braking such as the Astro and Safari. The Mustang also uses this type of booster because there isn't enough room.
If you get an electronic diesel, you will need the wiring, PCM, all sensors and the original transmission and rear end. You can have you PCM custom reprogrammed to fit other transmissions and rear ends. Your speedometer will not work without a special kit to either convert the VSS to mechanical action or the tailshaft housing and output shaft could be modified to let the speedometer work by having a second place to have a gear. If some of your gauges are not hooked into the PCM (such as watertemp) you can look through a parts catalog that lists the thread and resistance values. The gauge sensors are calibrated to the vehicle not the engine. Get one that has the same values as was intended that will mount to the engine. There have been conversions where people hook up a temp sensor to a warning light and get a "bighter light" when the vehicle gets warm.
You will either have to lengthen, shorten, or leave the drive shaft alone. It depends on your situation. You will need to find a way to convert the tailshaft to mate with the driveshaft. Either with special U-joints or specially made driveshaft. You should have the driveshaft made professionally.
You may have to modify the transmission crossmember to accept the new transmission mount. The transmisison crossmember position may have to be changed. You will have to figure out a way to hook up the cable.
Exhaust. Stick some pipes on it, get to the back or at least the side.
The engine wiring should be easy on a mechanical diesel. Not many wires. You will have to wire in glow plugs with a relay. How you want to control them is up to you. If you want to use a controller that's fine but you will need to get to the water temp sensor. The Starter is no big deal. You will have to figure out how the old alternator was regulated and how the new one works.
The physical engine mounts might be a problem there are many engine mounts at the local parts store. The companies that make them have large books of different ones that can be ordered. You can also modify your old ones or the new ones you buy. You can drill new holes in the frame. You can have special ones made for you.
The oil pan is kind of a area I haven't looked into that deep. As long as it clears the K-member (big bar underneath the engine) you shouldn't have any trouble. You can also modify the pan or have one made. I guy i went to school with made his own. It was ugly but it didn't leak.
The radiator and hoses
You can try to use your old radiator. For a commercial chassis it should be fine for cooling. The hoses will have to be measured. Get a good idea of what you need and go the parts store and look through their hoses till you find one that looks right. T
October 18, 2004 - 10:34pm
#14
Here's maybe an easier question than the Winnie (by the way, I love those eyebrow classics but never checked out whether they made them in diesel)...
I want to drop a diesel into a VW convertible. Rabbit not Cabrio era. Classic 80's. The obvious donor is another Rabbit. On the other hand I see there are a lot of other potential donors out there... anybody know if the scirroco's or jetta's from the same era have donor issues?
Any other ideas?
I've seen at least one original diesel VW convertible, but they seem unlikely due to the odor... but french fries? why not?
April 25, 2005 - 11:19am
#15
Windaria,
Have you followed through on your Camaro project. I'd welcome your (and anyone else's) thoughts on converting my '68 Firebird to a grease car. See the link below.
http://www.greasecar.com/forum_topicview.cfm?frmtopicID=2319
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depends on what car you end up with but if you reckon on changing engine + mounts, gearbox, exhaust, fuel pumps, wiring, possibly brakes & suspension components etc then you won't be far wrong.
TBH, unless your car is an oddball or a rare classic that you want to keep going then it's probably cheaper & easier to sell it & buy a wheezil.
DD.
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It's a diesel thing - You wouldn't understand