Mark VIII Diesel conversion

[Ed Hall]

Fuel keeps going up and according to many predictions, crude is destined to go to $150 per barrel real soon. Too bad, Lincoln dropped the diesel option that was available for the Mark VII. How feasible it would be to transplant the diesel engine from a Mark VII into the VIII? From what I understand, the VII with the BMW turbo diesel would get around 40 mpg which would be nearly double the gas mileage of what I'm getting.

Here's a Mark VII that has the BMW Turbo Diesel engine.

http://austin.craigslist.org/cto/2495016241.html

 

[Icarus]

Try it an let us know.

 

[LowLincoln]

Could be a fun project. Is the engine in your car toast or something? I would find another VIII with a bad engine, etc. and use that as the project car.

 

[Ed Hall]

Could be a fun project. Is the engine in your car toast or something? I would find another VIII with a bad engine, etc. and use that as the project car.

Nothing wrong with the engine in my Mark other than it being hard on fuel. The conversion would definitely be done on a VIII with a bad engine. In fact, right now I'm in the process of converting a 1999 Chevy Tahoe with a blown engine to diesel.

 

[driller]

Nothing wrong with the engine in my Mark other than it being hard on fuel.

Dude with 4.10s I could drive 150+ miles thru the mountains to the track, race all day and drive back home and still average 19 mpg. If you're only getting 20 mpg, there is something wrong with the car.

No way in hell will any diesel transplant could be cost efficient with today's diesel prices higher than premium gas. The return on investment would take years to payback the capital costs before any benefit is realized.

You payed low dollar for a low mileage luxury coupe. Drive it, enjoy it and get over the mpg you think you are loosing. Even if you double the mpg, it would take years to recoupe the cost of doing so.

 

[zmt325]

seriously.?.?.? the m\20 diesel is bulletproof, but a complete boat anchor. the only good thing about it is you can steal the forged crank and put it in a petrol m20 as a cheap stroker, just buy a 524td and enjoy the better build quality and cheaper parts. WTF

 

[Ed Hall]

If you're only getting 20 mpg, there is something wrong with the car.

The computer spits out no codes and the engine runs very smoothly. The spark plugs were recently replaced and it did not improve fuel economy. I pumped up all the tires to 40 psi and it has helped a little. The engine feels a little sluggish for 295 hp. My Cadillac with the poorly designed Northstar has exactly the same power and feels a lot faster.

 

[98lincmk7lsc]

If you think spark plugs are all you need to do, you may want to Roma little more research...

 

[87TTOPGT420]

Maybe pulling a 6000lb load with it is killing your Milage....just saying

You want a fuel efficiency buy a fuel efficient car....once again just saying

People who bitch about fuel Milage need to stfu

You sacrify so much driving a fuel efficient go cart, I'll take my 24mpg and smile and enjoy cruising in a car that I actually enjoy driving....still just sayin'

Anyone remember the 80mpg fox mustang with 400hp Nuff said :q:q:q:q your fuel sipping diesel

 

[LaserSVT]

I...... but...... you're such an ........ 40 psi?....... buy a truck...... I quit.

 

[Ed Hall]

If you think spark plugs are all you need to do, you may want to Roma little more research...

I've done a bunch of research but don't want to throw more parts at it. When it gets bad enough, it'll throw a code then I'll know what is wrong.

 

[My Great 8]

Ed,
I bought a 93 from Jamie about a year ago. He installed a 98 LSC exhaust system on it and hacked off the mufflers. I drove this car from Ft. lauderdale to New Jersey and set the cruise at 72 mph. I achieved 28.6 mpg with the car loaded with luggage. I have since then given the car to my 20 year old lead footed son. I found two flowmaster 40 mufflers in the junkyard. Since the install, the car is now getting 24 mpg with him driving it 60 miles a day at 80+ mph. Strictly highway driving, I got 30.3 mpg!! Maybe a set of Flowmasters will increase your mpg. My son only got 27 hiway mpg with his previous Honda Accord. Enjoy the car for what it is! I certainly do!

 

[Ed Hall]

Maybe pulling a 6000lb load with it is killing your Milage....just saying

You want a fuel efficiency buy a fuel efficient car....once again just saying

People who bitch about fuel Milage need to stfu

You sacrify so much driving a fuel efficient go cart, I'll take my 24mpg and smile and enjoy cruising in a car that I actually enjoy driving....still just sayin'

Anyone remember the 80mpg fox mustang with 400hp Nuff said :q:q:q:q your fuel sipping diesel

It's getting 24 mpg at 65 mph. I feel it should do better than this.

 

[Ed Hall]

Ed,
I bought a 93 from Jamie about a year ago. He installed a 98 LSC exhaust system on it and hacked off the mufflers. I drove this car from Ft. lauderdale to New Jersey and set the cruise at 72 mph. I achieved 28.6 mpg with the car loaded with luggage. I have since then given the car to my 20 year old lead footed son. I found two flowmaster 40 mufflers in the junkyard. Since the install, the car is now getting 24 mpg with him driving it 60 miles a day at 80+ mph. Strictly highway driving, I got 30.3 mpg!! Maybe a set of Flowmasters will increase your mpg. My son only got 27 hiway mpg with his previous Honda Accord. Enjoy the car for what it is! I certainly do!

Wow, that's impressive fuel economy especially at 72 mph. I hate loud cars but if loud mufflers increase fuel economy that much, I may be willing to listen to the noise.

 

[My Great 8]

Wow, that's impressive fuel economy especially at 72 mph. I hate loud cars but if loud mufflers increase fuel economy that much, I may be willing to put on a set of ear plugs when driving.

Ear plugs are not necessary. At highway speeds the car had a nice tone. I couldn't take a 20 hour trip with a lot of noise. Now with the mufflers, it's a bit quieter. It really sounds great! Also, the car just turned 145k.

 

[LaserSVT]

It's getting 24 mpg at 65 mph. I feel it should do better than this.

No reason it shouldnt get 40mpg? There are several. Its a decient HP V-8. Its a 3800+lb car. It only has four forward gears. It has a CD of .33. There is a loose nut behind the wheel.

While it should do 24-26 on the highway at 65 with a proper load the fact yours still gets 24 after such abuse it kinda impressive.

Now stop trying to turn a two door luxury sports car into a fuggin truck!

 

[driller]

No reason why a car like this can't get 40 mpg.

Really? Have you driven any car that gets 40 mpg? :shifty:

If so, how would you compare it to the Mark VIII???

You're chasing a dream if you think a 4000 pound luxury coupe is going to get 40 mpg.

 

[UltimateSVT]

Enough with the blabbering! If you don't like it's fuel economy sell it! You won't economize much more with a diesel engine! PLUS diesel is more expensive than midgrade now-a-days!

 

[MediumD]

I get over 40mpg...

In my SOHC Saturn SL2.

As for diesel swaps, I've seen plenty of 4BT and 6BT swaps into various vehicles, but they're pretty damn heavy. Even the 4BT is at least 300 extra pounds in the front of a Mark VIII. But one swap I haven't really seen is the OM612 2.7 I5 diesel from a Sprinter van. That would add maybe 100lbs.. IIRC around 150hp and 240ft.lbs. stock, might be able to be turned up a bit... And over 20mpg in a huge ass van.

 

[87TTOPGT420]

Lol ban this guy already his posts make my brain hurt jk

your posts are useful....for the noobs...what not to do with your mark viii

I'm sure I could do better then 24mpg on a long trip but I seldomely ever stray more then 75 miles from home generally through out the week about a 10min drive one way to work I only put about $40-50 a week at a $1.27/L there is 3.78L/gallon

 

[Coherent]

To start with try replacing your O2 sensors and airfilter. On my mark VIII the O2s were going bad and absolutely killing my mileage, but they never got to the point where a check engine light or anything came on. Just because there's no codes doesn't mean they're still good.

Also some exhaust work like cutting out the third cat and some free flowing mufflers like magnaflows can give you a bit more mileage without being stupidly loud.

My Mark VIII can average around 28 mpg on the highway if I stay around 70-75 mph and use ethanol free gas. My performance mods are headers, new O2s, super high flow cats, magnaflow mufflers and a K&N air filter.

 

[Ed Hall]

Really? Have you driven any car that gets 40 mpg? :shifty:

If so, how would you compare it to the Mark VIII???

You're chasing a dream if you think a 4000 pound luxury coupe is going to get 40 mpg.

Yes, a Mark VII with the BMW diesel option.

 

[Ed Hall]

To start with try replacing your O2 sensors and airfilter. On my mark VIII the O2s were going bad and absolutely killing my mileage, but they never got to the point where a check engine light or anything came on. Just because there's no codes doesn't mean they're still good.

Also some exhaust work like cutting out the third cat and some free flowing mufflers like magnaflows can give you a bit more mileage without being stupidly loud.

My Mark VIII can average around 28 mpg on the highway if I stay around 70-75 mph and use ethanol free gas. My performance mods are headers, new O2s, super high flow cats, magnaflow mufflers and a K&N air filter.

Thanks for the excellent post. The O2 sensors have never been replaced so I'll start with that. I would be happy if it got a few more mpg's and had the power of my dieselbomber. Now, I'll get busy on my other diesel conversions.

 

[kaha]

With the cruise control set to 80 and the fuel economy function on the infocenter reset, my '96 averaged just a hair over 30mpg on a trip to Helena. No passenger or luggage, but plenty of grades (both up and down, the highway runs through the Rockies).

I consider that AWESOME mileage for this class of car.

Then again, around town I usually get 12-14 because I drive it like it's got a pair.

 

[kaha]

Thanks for the excellent post. The O2 sensors have never been replaced so I'll start with that. I would be happy if it got a few more mpg's and had the power of my dieselbomber. Now, I'll get busy on my other diesel conversions.

Another thing, Ed: have you cleaned your MAF sensor? If it's filthed up, it will also reduce your fuel economy considerably. Just a shot of CRC MAF cleaner should be all it needs.