LDT-465 back to multifuel

[zygomedic]

I just bought a 1971 M35A2 that has a Continental LDT465 converted to diesel only. I was wondering if I could and how difficult it would be to convert it back to multifuel? Not that I would ever want to do more than run used veggie or motor oil but you never know....

 

[skinnyR1]

FDC bypass to "convert" to diesel is a common misconception. It just turns the pump up so there is no more compensating or regulation.

Run whatever you want as it is, it is a multi fuel currently.

 

[cattlerepairman]

What skinny said. Look up "FDC - fuel density compensator". Bypassing this item eliminates a common source for internal fuel leaks. If yours had it done, it is an improvement, especially for non-cold-war-battlefield daily use.

 

[davidb56]

I just bought a 1971 M35A2 that has a Continental LDT465 converted to diesel only. I was wondering if I could and how difficult it would be to convert it back to multifuel? Not that I would ever want to do more than run used veggie or motor oil but you never know....

its ok to run New Motor Oil etc, but never run "used", unless you have a 1700$ extra IP on your shelf.

 

[Nomad1]

my understanding is that the fdc does make a difference. A wise man once told me just because something works does not mean it right

 

[doghead]

This topic has been covered completely, many many times.

The fdc simply tries to regulate power output with varied fuels that have more or less btu's based on viscosity.

It is not perfect but does "make a difference".

It is NOT what makes the engine capable of using a variety of fuels. That is done by piston and injector design.

After a while, the military discontinued the use of the FDC. Most likely due to it's frequent leakage of fuel into the engines oil.

You do not need it.

I would not recommend reconnecting it.

If you vary your fuels or want to turn up your fuel rate, you need to install a pyrometer. This is the only safe plan.

 

[Nomad1]

dogheads more complete answer reminds me that when doing modification one should do it correctly and that it may require to do other things as well for example larger tires may require different rims, heavy axlses and other things. I'll have to see if I can find something regaurding the military doing it and see how they went about it.

 

[silverstate55]

Doghead's more complete answer reminds me that when doing modification one should do it correctly and that it may require to do other things as well for example larger tires may require different rims, heavy axlses and other things. I'll have to see if I can find something regaurding the military doing it and see how they went about it.

Why not just spend an afternoon searching this site? There's a wealth of outstanding info here, the search function is fairly easy to use (Pro Tip: go into appropriate forum first, such as "The Deuce", enter your search terms under "Search Forum" drop-down tab). Probably better than anywhere else available on the interwebs, especially fakebook.

 

[zygomedic]

I have spent the last few days searching the forum but have not found anything on downgrading, and I am not confident that just reverse engineering the mod is going to be the answer. But maybe it would. Don't want to risk my investment on a maybe.

 

[porkysplace]

I have spent the last few days searching the forum but have not found anything on downgrading, and I am not confident that just reverse engineering the mod is going to be the answer. But maybe it would. Don't want to risk my investment on a maybe.

Running crap fuel will do far more damage to the fuel system and engine than worrying about the FDC bypassed . You can't filter out the super fine metals or acids in used motor oil.

 

[montaillou]

Why not just spend an afternoon searching this site? There's a wealth of outstanding info here, the search function is fairly easy to use (Pro Tip: go into appropriate forum first, such as "The Deuce", enter your search terms under "Search Forum" drop-down tab). Probably better than anywhere else available on the interwebs, especially fakebook.

The following is not meant as a rant, though it may seem that way. I really do appreciate all I've learned from this site...

I have spent hours and hours on this site in research. Some of it fruitless and down right frustrating. The search function doesn't work if you don't know the name of what you're looking for, it also doesn't help if you're searching for something so common that it's everywhere. I've found that often it's better to search in Google, which will bring posts from here, as well as others.

I've also found a decided lack of clarity in some posts. Want to know the exact number/length/amount? You'll find posts saying X should be good enough, or to read the TM. The TM's are great, but sometimes it just doesn't answer a question that wasn't meant to be answered off a military base away from a military supply chain.

I like to plan stuff out before I do it. Sure, crawling under the truck will sometimes get me the answers, but most times I'd rather have the parts on hand before I take something apart to know what I need to fix it.

This site is a great resource, but just be aware it's not the only one. I probably get 65% of my info here, 10% from a 4x4non-conformist-member-of-society web site and the other 25% through general web searches that can go all over the place.

Part of my issue is that I'm really taking the truck way out of stock. If I was just interested in keeping it stock, this site would probably work for 85% or 90% of what you'd be looking for, but my comment about finding hardcore number data still stands.

 

[porkysplace]

The following is not meant as a rant, though it may seem that way. I really do appreciate all I've learned from this site...

I have spent hours and hours on this site in research. Some of it fruitless and down right frustrating. The search function doesn't work if you don't know the name of what you're looking for, it also doesn't help if you're searching for something so common that it's everywhere. I've found that often it's better to search in Google, which will bring posts from here, as well as others.

I've also found a decided lack of clarity in some posts. Want to know the exact number/length/amount? You'll find posts saying X should be good enough, or to read the TM. The TM's are great, but sometimes it just doesn't answer a question that wasn't meant to be answered off a military base away from a military supply chain.

I like to plan stuff out before I do it. Sure, crawling under the truck will sometimes get me the answers, but most times I'd rather have the parts on hand before I take something apart to know what I need to fix it.

This site is a great resource, but just be aware it's not the only one. I probably get 65% of my info here, 10% from a 4x4non-conformist-member-of-society web site and the other 25% through general web searches that can go all over the place.

Part of my issue is that I'm really taking the truck way out of stock. If I was just interested in keeping it stock, this site would probably work for 85% or 90% of what you'd be looking for, but my comment about finding hardcore number data still stands.

The biggest problem with the site search feature is crappy thread titles and people wanting the answer in the first post and not reading any farther.

 

[eagle4g63]

I have spent the last few days searching the forum but have not found anything on downgrading, and I am not confident that just reverse engineering the mod is going to be the answer. But maybe it would. Don't want to risk my investment on a maybe.

What are you going to be reverse engineering? Like has been said the FDC being bypassed is a great plus for these trucks. There is NO reason to ever put it back the way the government had it. It was used so the motor would have the same horsepower output regardless the fuel that was used. Now I'm not knocking anyone's taste in fuel to feed their truck as I have run almost anything I can get my hands on, but lets just say you are a purist and will only run "NEW Pump" fuel what ever it is that is approved by the government...WITHOUT the FDC the motor will have different horsepower depending on the fuel...that is it in a nutshell. No problems running it that way, just it will drive different, faster with better fuel.

I would NOT change anything on your truck and just drive it, IF you need to put something else in it than do it....it will run fine.....HOWEVER if you are absolutely convinced that you just have to put it back the way it was than look up the TM for the multifuel motor and run the fuel lines the way they were meant to be...just be absolutely sure to watch your oil level as if the FDC leaks it will fill the oil up with fuel and you WILL have a problem....IF for some reason your truck also leaks oil, you won't know for sure that you are diluting what oil you have and you will do even more damage....so as also said this topic is covered to every extreme and you will go dizzy reading everything OR you can just take the answers feed to you by guys that have been running these trucks and leave it alone and run what ever your taste in fuel is, the motor itself just doesn't really care per-say.

 

[silverstate55]

The biggest problem with the site search feature is crappy thread titles and people wanting the answer in the first post and not reading any farther.

Very true...the fakebook method.

 

[silverstate55]

The following is not meant as a rant, though it may seem that way. I really do appreciate all I've learned from this site...

I have spent hours and hours on this site in research. Some of it fruitless and down right frustrating. The search function doesn't work if you don't know the name of what you're looking for, it also doesn't help if you're searching for something so common that it's everywhere. I've found that often it's better to search in Google, which will bring posts from here, as well as others.

I've also found a decided lack of clarity in some posts. Want to know the exact number/length/amount? You'll find posts saying X should be good enough, or to read the TM. The TM's are great, but sometimes it just doesn't answer a question that wasn't meant to be answered off a military base away from a military supply chain.

I like to plan stuff out before I do it. Sure, crawling under the truck will sometimes get me the answers, but most times I'd rather have the parts on hand before I take something apart to know what I need to fix it.

This site is a great resource, but just be aware it's not the only one. I probably get 65% of my info here, 10% from a 4x4non-conformist-member-of-society web site and the other 25% through general web searches that can go all over the place.

Part of my issue is that I'm really taking the truck way out of stock. If I was just interested in keeping it stock, this site would probably work for 85% or 90% of what you'd be looking for, but my comment about finding hardcore number data still stands.

**ETA: I understand what you're saying and this reply isn't meant for you as much as the folks who don't want to do any research at all, as pointed out above & below. Few things are more frustrating for me than seeing a great thread posted with excellent info, and a week or so later someone comes along with a post asking the exact same thing...5 minutes browsing the appropriate forum would have found the solution to their problems. I used to do repairs on a truck for a guy exactly like that, he burned me out so badly that I hardly even want to work on my own trucks let alone anyone else's afterwards.**

I don't have any issues with the search functions on this site, whether built-in or google...if I don't know the nomenclature or name for something, a browse through the -34P or -24P usually finds me the answer.

If a thread is useful, I Subscribe to it and save it in the appropriate folder I created; I have many folders for saved threads, as do most others I'm sure. I know I have over 1K threads saved in total....I've also searched the interwebs extensively and there is no other resource like this one. It's not that hard if one is willing to devote the time necessary to do proper research.

But the most important one is what Porkysplace was talking about: you have to devote the time to read through associated threads (it helps to scroll all the way to the bottom of each page and look at "Related Threads") in order to find what you need. I also modify my trucks and the best info is still found within this site. There is a wealth of info and technical specs archived here and it's a shame that so many don't take the time to really delve into it.

 

[silverstate55]

Running crap fuel will do far more damage to the fuel system and engine than worrying about the FDC bypassed . You can't filter out the super fine metals or acids in used motor oil.

To get myself back on topic, this right here should be the final answer necessary. In the end, it's your motor and your $$$ if you don't believe us "naysayers." I've gone through a couple sets of injectors and IPs, even after running used motor oil through centrifuges, super-fine filtration and water removal methods, polishing, and the like...save the used motor oil for your shop's heating system. Run your Deuce on fresh, clean diesel from a commercial station, with your preferred lubrication added for your IP & HH.

You'll spend large sums of money to come to the same circularly-logical conclusion that myself & others have: it saves money to just go to the fuel station and fill it with pump diesel.

I know because I logged every gallon of "bio-diesel" and alternative fuel I processed over 5 years, including time & labor necessary to process it. I was the only person for several years licensed & registered in Nevada to process "bio-diesel" for PERSONAL use (NOT commercial). What I found was that for each gallon of "bio-diesel" I processed, it cost me on average $4.82 per gallon...not including the County & State fuel taxes I was required to pay monthly based on my reported production. I tried to be meticulous, as since I was the only person in Nevada licensed to this for personal use, I didn't want to set a bad example. The State paved the way for me to do this, as they were only set up to do it for commercial enterprises and I was the test bunny. So I made sure to document everything as best as I could, anticipating scrutiny from the State.

It's cheaper by far to create your own EPA-approved storage facility on your property and buy diesel in bulk for long-term storage and use, than it is to really get involved in running PROPERLY PROCESSED alternative fuels in your Deuce. But, your truck, your $$$, do as you think is best.

The "Alternative Fuels" sub-forum should have all the answers to your original questions and more.

 

[frank8003]

its ok to run New Motor Oil etc, but never run "used", unless you have a 1700$ extra IP on your shelf.

I was gonnah write something like that but your post is my thoughts exact.
No matter what, well, maybe the best of the best triple stage power-plant lube oil filters, one CAN NOT get the soot out of diesel crankcase oil. That oil does not get burnt in a multifuel or any kind of diesel engine unless one likes to buy and install parts that are difficult to acquire.
Kaydon top of the line filter rigs and power-plant centrifuge sets are few and far between.

I must say that the diesel fuel one buys at the pump now is NOT like these engines are meant to burn. The lubricity is gone. I don't know what would be the minimum motor oil to "new" diesel fuel mix. I just used 80% NEW motor oil and 20% pump diesel.

 

[montaillou]

It's not that hard if one is willing to devote the time necessary to do proper research.

Please find a thread for me (that's wasn't started by me) that tells how long the battery cables should be. You'd think it would be easy "battery cable length", yeah, no. I spent 5 years in university and my specialty is research (history major).

 

[silverstate55]

Please find a thread for me (that's wasn't started by me) that tells how long the battery cables should be. You'd think it would be easy "battery cable length", yeah, no. I spent 5 years in university and my specialty is research (history major).

OK you win, you are right & I am wrong...I'm wrong much much more than I'm right so I should know better by now....

Since the Search functions are mostly user-driven, they leave A LOT to be desired...

 

[frank8003]

Please find a thread for me (that's wasn't started by me) that tells how long the battery cables should be. You'd think it would be easy "battery cable length", yeah, no. I spent 5 years in university and my specialty is research (history major).

This post in wrong place but......................
I spent all my time working.
You want lead, electrical
TM 9-2320-361-24P WP 0193 00
WP is work package see figure 192
page 00193 01 indicates the NSN and the part numbers of the original
They can be used as a search in Part Target which will give the particulars


If you want to find how to find anything in a TM FAST send me a PM and I will tell you.