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-   -   Diesel conversions (http://www.risingsun4x4club.org/forum2/showthread.php?t=16798)

PhatFJ 11-07-2011 01:32 PM

Diesel conversions
 
So, I have been reading up a bit on different diesel conversions and thought I would start a thread on the subject. My 1970 FJ40 has an GM 5.7L, is mated to an SM465 and 3spd. Transfer case, runs ok, does great on the trail but, I am not thrilled with the gas mileage and subsequently the range even when I have 36 gallons of fuel capacity. I have been looking into diesel conversions not only for the mileage but the longevity of the motor and potential of using bio-fuel. I have read many posts about the "B" series Toyota motors and have come to the conclusion that price and parts availability is the biggest drawback to this choice. The Cummins 4BT seems like a good choice, good price and parts seem very available, I am not sure that they will have the necessary power but maybe. The last but not least is the MB OM617 (300TD) like Justin put into one of his customers. Very available at a good price, parts are also very available; the motor puts out good power and will run for a very long time. Many people have converted these motors to bio-fuel as well. The other thing I like is that Luke over at 4x4 Labs makes an adaptor plate to bolt up to a GM transmission like my SM465. Luke also states on his site that I can reuse fuel tanks and lines in place. In conclusion, I am thinking that this conversion could run somewhere around $2500.00 with me doing all my own fabrication and setup, I would double my gas mileage and the motor will last a very long time. At the price of fuel these days I think this may be a good way to go. Any thoughts?

subzali 11-07-2011 01:35 PM

I would think a 4BT would have all the power you would want.

What about the Isuzu diesels?

PhatFJ 11-07-2011 01:41 PM

Quote:

Originally Posted by subzali (Post 196050)
I would think a 4BT would have all the power you would want.

What about the Isuzu diesels?

Although it seems parts are quite available for the 4BT, I have had problems finding a 4BT running at a reasonable price, seems most want around 3K just for the motor (well used). The adaptor is going to run around an additional grand.

I have not looked into Isuzu at all and know nothing about them. Do you have any information or experience with them?

corsair23 11-07-2011 01:48 PM

Quote:

Originally Posted by PhatFJ (Post 196047)
In conclusion, I am thinking that this conversion could run somewhere around $2500.00 with me doing all my own fabrication and setup, I would double my gas mileage and the motor will last a very long time. At the price of fuel these days I think this may be a good way to go. Any thoughts?

The :cool: factor aside, how long would it take you to recoup the investment based on the gas savings?

I don't DD my 40...Actually I rarely drive my 40 :( - Is the 40 your DD?

I guess what I'm saying is basing the decision on the fact that you will get better gas mileage might not be the best business case :hill:

If you get 10 mpg now and bump that up to 20 mpg with the conversion, and using $4/gal as the average for fuel...At 10 mpg a mile costs you $.40 vs. $.20 with a diesel. My math is probably wrong but break even doesn't come until 12,500 miles. Of course if gas stays lower than $4/gal it will take longer to pay off the cost of the conversion - @ $3.50/gal the payoff comes after about 14,300 miles...Then again if gas goes up to $5/gal the payoff comes at 10K miles. I know I'm not taking into account the price difference of gas vs. diesel so that would play in there a bit.

Now if the 5.7L V8 dies and you need to replace the engine anyway :D

subzali 11-07-2011 01:56 PM

Quote:

Originally Posted by PhatFJ (Post 196055)
Although it seems parts are quite available for the 4BT, I have had problems finding a 4BT running at a reasonable price, seems most want around 3K just for the motor (well used). The adaptor is going to run around an additional grand.

I have not looked into Isuzu at all and know nothing about them. Do you have any information or experience with them?

No, but here's after a quick search where I have seen them talked about:
http://forum.ih8mud.com/diesel-tech-...bd1t-swap.html

Isn't the Mercedes engine a car engine?

art hog 11-07-2011 04:04 PM

My 4BT in my 55 gets about 24-mpg driving from Rollinsville to Boulder on average. On the hwy it is closer to 30-mpg. I have plenty of power. You will not get that kind of mileage with a 4sp. You need an overdrive. I have a NV4500. You will also need to do a spring over and switch to FJ60 axles or mod the oil pan. There is a 3.3 cummins that is very nice but $$$$$$. Also from what I understand to run biofuels, ie: veggie oil you will need an aluminum fuel tank. Steel creates a scale on the inside of the tank and flakes off and messes everything up. So I have been told. I would go with the 300-td.

Woodsman 11-07-2011 05:08 PM

You can't always justify dropping a diesel into an older rig with just fuel numbers. You get the benefits or better low-end power, more mileage per tank and you'll be able to do many trail runs without taking any extra fuel where you may have taken 5-10 extra in gas.

When dealing with a new vehicle, IMO, it is very easy to justify the extra purchase price (if you have that kind of extra changing in your piggy back) because the "diesel option" is generally about how much more the vehicle will be worth even when used. In other words, you'll get your money back.

Of course, you could also be a dork like my cousin and sink over $24K in your Cummins for pulling at the county fairs. Of course, he's almost 27 and still living with mom and dad.

art hog 11-07-2011 06:15 PM

My reason to go diesel was to be able to run WVO. The 2f, V8 motors are not economically viable in this world IMO. who knows where the price and the availability of fossil fuels will be in the future. If the 1% have there way, I won't be able to afford it. So a diesel is a better option for me. Plus I have a 53 gal fuel tank, at 30 mpg I have close to a 1500 mile range. I have a map of every donut shop in the US and canada. I plan my trips by this map. If we could just go back to running hemp oil, We would not need all the forign oil.

PhatFJ 11-07-2011 06:17 PM

First and foremost, thank you all for the input!!

Quote:

Originally Posted by corsair23 (Post 196059)
The :cool: factor aside, how long would it take you to recoup the investment based on the gas savings?

I don't DD my 40...Actually I rarely drive my 40 :( - Is the 40 your DD?

I guess what I'm saying is basing the decision on the fact that you will get better gas mileage might not be the best business case :hill:

If you get 10 mpg now and bump that up to 20 mpg with the conversion, and using $4/gal as the average for fuel...At 10 mpg a mile costs you $.40 vs. $.20 with a diesel. My math is probably wrong but break even doesn't come until 12,500 miles. Of course if gas stays lower than $4/gal it will take longer to pay off the cost of the conversion - @ $3.50/gal the payoff comes after about 14,300 miles...Then again if gas goes up to $5/gal the payoff comes at 10K miles. I know I'm not taking into account the price difference of gas vs. diesel so that would play in there a bit.

Now if the 5.7L V8 dies and you need to replace the engine anyway :D

I agree, the return on investment will bee a while. I will be able to sell the 5.7 ready to drop into another project fairly easily which will help.

Quote:

Originally Posted by subzali (Post 196064)
No, but here's after a quick search where I have seen them talked about:
http://forum.ih8mud.com/diesel-tech-...bd1t-swap.html

Isn't the Mercedes engine a car engine?

Wow, that thread is big!! lot's of information.. I did do a couple of searches on CL and e-bay, it seems that the isuzu motor is quite pricey as well, if you can find a newer one with lower miles the price jumps way up. The MB 300td seems to be VERY available and affordable. I found one with 144k and can pick it up for $850.00, the rebuild cost of the 300td is high and some recommend that it is better to buy a used one OEM built rather than rebuilding one. The 300td is a car diesel and it has PS, Air cond, and other options that some of these industrial motors do not have on them as well.

Quote:

Originally Posted by art hog (Post 196074)
My 4BT in my 55 gets about 24-mpg driving from Rollinsville to Boulder on average. On the hwy it is closer to 30-mpg. I have plenty of power. You will not get that kind of mileage with a 4sp. You need an overdrive. I have a NV4500. You will also need to do a spring over and switch to FJ60 axles or mod the oil pan. There is a 3.3 cummins that is very nice but $$$$$$. Also from what I understand to run biofuels, ie: veggie oil you will need an aluminum fuel tank. Steel creates a scale on the inside of the tank and flakes off and messes everything up. So I have been told. I would go with the 300-td.

Thanks for the info!! I did not know that about biofule. Is the 4BT itself that tall or does the turbo extend up so high that you have to mount it lower in the frame?

Quote:

Originally Posted by Woodsman (Post 196079)
You can't always justify dropping a diesel into an older rig with just fuel numbers. You get the benefits or better low-end power, more mileage per tank and you'll be able to do many trail runs without taking any extra fuel where you may have taken 5-10 extra in gas.

When dealing with a new vehicle, IMO, it is very easy to justify the extra purchase price (if you have that kind of extra changing in your piggy back) because the "diesel option" is generally about how much more the vehicle will be worth even when used. In other words, you'll get your money back.

Of course, you could also be a dork like my cousin and sink over $24K in your Cummins for pulling at the county fairs. Of course, he's almost 27 and still living with mom and dad.

As far as value goes I think so too, I have owned several diesels including heavy equipment and they really hold their value as long as you take care of them.

Uncle Ben 11-07-2011 06:20 PM

Quote:

Originally Posted by art hog (Post 196088)
My reason to go diesel was to be able to run WVO. The 2f, V8 motors are not economically viable in this world IMO. who knows where the price and the availability of fossil fuels will be in the future. If the 1% have there way, I won't be able to afford it. So a diesel is a better option for me. Plus I have a 53 gal fuel tank, at 30 mpg I have close to a 1500 mile range. I have a map of every donut shop in the US and canada. I plan my trips by this map. If we could just go back to running hemp oil, We would not need all the forign oil.

That hemp oil is affecting your spelling! :lmao: :guapo:


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