fuel system basics -- converting FJ60 to diesel

[polarweasel]

I'm planning a Mercedes diesel conversion on my FJ60 for September. The main issue that I'm unsure about right now is the fuel system. A diesel obviously needs a return line to the fuel tank, and I've heard a vented fuel cap as well.

At a minimum, what do I need to do to make the FJ60's fuel system work with diesel? Ditch the charcoal canister and send a return line back to the overflow connection, and add an electric diesel fuel pump at the tank? Do I need a vented fuel cap, too?

I'm ignoring filters and the type of pump for now. I just want to understand the basic plumbing first...

There will be lots more questions to come in the weeks ahead, I'm sure...


Alex

[brownbear]

not all diesels run a return line. My 3b doesn't.

as well I don't have a electric pump. its all in the injection pump.

you need a water seperator. if you have the doner vehicle for you merc engine. have a look at the tank set up.

what engine are you planning on? also why go merc? how will you do the adapters to your tranny??

has there been any merc conversions for fj60's?

[beanz2]

Not sure about FJ60's, but doesn't the charcoal canister already has a return line to the tank? If the Merc uses a pump near the tank, I'd do the same.

Are you using 4x4Labs adapter? Is it ready finally?

Dave

[Eric Winkworth]

merc in a yota, why?

[VTCruiser]

brownbear is correct. not all diesels require a fuel return to tank. my 2H did not, however my 1HZ does.

Also, my fuel cap is not vented, the system actually runs on a slight vacuum, so it all depends on the set up.

[polarweasel]

4x4labs adapter... ha ha ha, very funny.

Nope, not using their mythical vaporware conversion kit. Gave up after three years of waiting, so we're gonna do it on our own...

AFAIK, there haven't been any Mercedes-powered FJ60s yet. We'll be using the OM617.95x engine, which is the 5-cylinder turbo model. We're giving that a try due to its small size, relatively good power output and good tuning potential, reputation for durability, and low price. We'll see what happens, but it seems like a pretty good match.

No tranny adapters required. We're going to divorce the t-case and use the Mercedes automatic transmission.

[brownbear]

ok now ya got to go in depth with an explaination on the tcase tranny, how you going mount a toyota tcase to the merc auto? of course if you havem pics are a must.

give some details on that specific engine.......

[polarweasel]

We're going to divorce the t-case, so instead of adapting the t-case to the tranny, we're just going to make a block-off plate for the front of the t-case, and then run a short shaft from the tranny to the t-case.

That means we'll need to actually bolt the t-case to a crossmember. Probably what we'll end up doing is make the divorce plate thick enough to provide support, and then bolt the plate to a crossbar of some kind.

The engine in question (OM617.95x) was used in 1982-85 300D sedans and wagons, and 1981-85 300SD sedans. This is five inline cylinders, indirect injection, and turbocharged. These cars (and wagons) are really popular with the biodiesel/grease-car crowd, because they're durable and cheap to buy.

Stock horsepower and torque ratings were around 120 horsepower and 170 lb-ft of torque. I've read you can wring substantially more out of it by turning up the fuel and boost, too. We'll see about that. At the very least, I want to intercool it. Propane injection is a "someday" idea at this point.

No tranny pics yet, but I have a couple of engine pics you can look at. I'll be updating that page as we go along...


Alex

[brownbear]

hey thanks for the info... one question slightly off topic.

I noticed there is a vacuum pump picture there. very hard to see.. what kind of drive does it use? belt?

if you can post of pm any info on this vacuum pump that would be great. I would love to replace the vacuum pump/alt combo on my 3b, where it is known to fail. instead run a hi output alt and a seperate vacuum pump.

I have been trying to see a cummins pump. these vac/alt combo's on 3b are very pricey.

[panama]

the vacume pump on our benz is mounted to the engine, so no external belts, I think it is gear driven, but could be a chain, i will look @ the book

[polarweasel]

Panama beat me to it...

Your best bet is probably a Dodge/Cummins vacuum pump, but it could be that other diesels (Volvo? Ford? GM?) will give you other options. Talk to a diesel shop and ask how they all work, then go junkyard hopping. If you're lucky, the new price on a Ford or GM might even be low, assuming they even had vacuum pumps! Worth checking, anyway.

[svo_jon]

How long is the engine and how long is the tranny? I have been thinking of this for my fj40.
Thanks

[BURGER]

This vacuum pump thingy everyone talks about. What does it do and does my 12-ht motor have one off the back of my alternator?

[polarweasel]

svo_jon: Engine is 29" long, 24" high, 22" wide. I have no idea on the tranny, but it doesn't appear all that huge. We're doing my friend's 40 after we do my 60. If you want to wait, we'll have kits for both in a couple of months if all goes according to plan.

burger: Vacuum pumps are useful things. The Mercedes pump appeared belt-driven on the '85 300D I looked at yesterday, by the way. The Mercedes tranny is all vacuum-controlled, as are its door locks, brakes, and a pile of other stuff. I'm not sure what all is vacuum-controlled on your 12HT, other than the brake booster.

[svo_jon]

I would be interested in a kit for a 40 and maybe a 60 as well, depending on how much power it can be made to make. For my 60 I need something that make good power.

[polarweasel]

We shall see what happens in the power department. I know you can tune these up pretty far. I'd like to intercool mine eventually, but that's a while down the road. I want to get an engine and get it installed and working first. After that, I'll start messing around with making more power.

[Radd Cruisers]

Originally Posted by polarweasel

We shall see what happens in the power department. I know you can tune these up pretty far. I'd like to intercool mine eventually, but that's a while down the road. I want to get an engine and get it installed and working first. After that, I'll start messing around with making more power.

Not to burst your bubble, but I have heard the engine is underpowered for that size rig?

Andre was the person who has mentioned this time and time again, mind you he is running the 4BT, which is a monster in comparision.

Compared to a 3B I wonder how it would perform??

Rob

[svo_jon]

I did a little looking around and this is what I found:

2F 135hp 210lbft
3B 92hp 160lbft
13BT 120hp 210lbft
1HZ 135hp 187lbft
12HT 135hp 231lbft

And the Mercedes 5 cylender turbo diesel is 120hp and 177lbft. So, it fits in between the 3b and 13bt as far a the b engines are conserned and it insn't too far behind the 1hz or 2f.

It will be interesting to see how much power can be had from tweaking the Mercedes motor.

[polarweasel]

A 4BT is huge and expensive and seriously powerful. It's also an expensive pain in the ass to install, what with needing a springover for a good ride, adapter plates, NV4500 tranny, and on and on. On top of the expense, I wouldn't be able to register my truck -- installing that engine is against federal EPA emissions regulations, since it never came in a 1/2-ton pickup or smaller.

Here's the deal on emissions. When you do an engine swap, you must use an engine from a vehicle your year or newer, in your weight class or lower. The FJ60 (and presumably FJ40) is in the 1/2-ton pickup weight class, so we can only use a motor that came in a 1/2-ton pickup, compact pickup, or passenger car.

The other important EPA rule to note is that you have to use all the pollution-control and engine-control equipment that came on the donor vehicle. Catalytic converter, speed sensors, EGR, the whole shooting match.

If you don't follow the EPA rules, you can't get the official certificate from the smog police that lets you get your emissions test. No emissions test, no license plates. In my county (Larimer, Colorado) all diesel vehicles must be emissions tested once a year. Gasoline vehicles get tested every two years.

Fun stuff, huh?


Alex

[wesintl]

Originally Posted by svo_jon

So, it fits in between the 3b and 13bt as far a the b engines are conserned and it insn't too far behind the 1hz or 2f.

Personally at our altitude I doubt you will be happy with it. If it's in the 300 right now I would play with seeing how much you can boost the power. Otherwise the 3b is not a happy camper up here and adding a turbo I would suspect only gets it back to what it would be at sea level.. maybe a tad more. I still need to dive into my turbo project. Personally i'd want something with more known power if I were going to hassle with a conversion. Cool conversion though.

[svo_jon]

So is the 29" length including the fan or without the fan?

Do you have an overall length figured out for the engine, trans, and tranfer with the devorced shaft?

I am geting exited about this as a posibility.

Also, do you know what the first gear ratio is in the trans?

Thanks

Jonathan

[polarweasel]

I haven't a clue what's included in the length, sorry. I suspect that is without the fan. I'll know more in a while, when we actually get an engine and get it on a stand.

3.98:1 first gear in the Mercedes auto.

[svo_jon]

Dose the auto have an over drive? What kind of rpms are you looking at?
Thanks
Jonathan

[polarweasel]

I forget if the auto is overdrive or not. Either way, they're very high-revving engines. The cars do 3100-3800RPM at 110 Km/h. Redline is 5000RPM or so, 4500RPM under full load.

We're not going to re-gear my truck, at least not yet, so I'll be turning the same RPMs as with my 2F, assuming no overdrive.

Off to test-drive another one...

[polarweasel]

Quick update: I'm taking delivery of a 1985 300D on Monday afternoon. $933 with tax, and it runs and drives well. It even looks semi-decent.

I'm going to leave the car intact for a bit, clean the engine, tune it up and get it to pass emissions, and maybe service the tranny. That way, when we do the swap, we'll have a lot less to worry about.

At this point, how soon we pull the engine/tranny and start swapping depends on how many parts I need to get, how quickly and cheaply I can get those parts, and of course how much free time I've got in the next week or two...

And in the meantime, the nasty-ass driver's seat will keep me from getting too attached to the car. Chop chop, kill kill kill!

[iceneweb]

yep the 617 is a great engine: i also own a 300D (turbo), and love it. however, it is no 3B style torque monster, but performs really well when thrumming along on the freeway at 120km/h plus . . . .

as an aside, the 617 was also installed in the Mercedes G-Wagen and certain Unimogs . . . .

[Gumby]

The 60 has a return line plumbed into the tank. It's a vary simple conversion. At least it was on my 6.2. You will have to open up the filler neck.

The diesel exemption certificate was very easy to get in IL. No more emission testing once they confirmed it was a diesel engine.

[Grease Cruiser]

Originally Posted by polarweasel

A 4BT is huge and expensive and seriously powerful. It's also an expensive pain in the ass to install, what with needing a springover for a good ride, adapter plates, NV4500 tranny, and on and on. On top of the expense, I wouldn't be able to register my truck -- installing that engine is against federal EPA emissions regulations, since it never came in a 1/2-ton pickup or smaller.

Here's the deal on emissions. When you do an engine swap, you must use an engine from a vehicle your year or newer, in your weight class or lower. The FJ60 (and presumably FJ40) is in the 1/2-ton pickup weight class, so we can only use a motor that came in a 1/2-ton pickup, compact pickup, or passenger car.

The other important EPA rule to note is that you have to use all the pollution-control and engine-control equipment that came on the donor vehicle. Catalytic converter, speed sensors, EGR, the whole shooting match.

If you don't follow the EPA rules, you can't get the official certificate from the smog police that lets you get your emissions test. No emissions test, no license plates. In my county (Larimer, Colorado) all diesel vehicles must be emissions tested once a year. Gasoline vehicles get tested every two years.

Fun stuff, huh?


Alex

Sounds like you need to move out of Larimer county! Here in Garfield county, no emissions, no safety inspection, no nothing.

Personally, I think Rob and some of the others are right about being underpowered. Both my 3B's are choked out at my elevation (6,000 ft +/-). Your turbo'd Mercedes is a good motor but I think in a heavy 60, it will be fairly weak. It might be much better in a 40. Anyways, interesting conversion. Good Luck.

[polarweasel]

Hey Gumby, by "open up the filler neck" you mean remove the unleaded restrictor plate, right? Or do you have to get access to the filler neck in order to sort out the return line?