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Swapping in an LD28 for a while...


Guest vodkaboy

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Guest vodkaboy

well, my Z's EFI is SNAFUed to the point that it is geting 8mpg, and spitting out black clouds of smoke, and im seriously worrying about fuelwashing the cyls. meanwhile, i have an LD28 laying on my garage floor, that was planning to be converted to grease, then find its way into a maxima/810/Z/ZX for my senior project. I think, however, that plans are changing. Since i am currently down to my last $$'s and cant afford to drive at this mpg, and i cant afford to screw up my engine by having gasoline wash oil off of cyl walls, so I am thinking about killing 2 birds with one stone. toss the Diesel into my Z, finish my senior project, do some work on the Z's current engine while its out (upgrade++), and get good gas mileage on free gas (WVO).

what am i going to need to do?

i know im going to need to change the flexplate on the Diesel for a Flywheel off of my L28, and i should get a computer for the diesel to cycle my glowplugs, going to remove the AC and PS pumps from the diesel (nothing for them to go to anyway). finally, the diesel is going to need a starter, so i should be able to swap the one on my current engine in... is there anything else i need to worry about? fuel pump maybe? any relays that are controlled by the EFI computer that im going to need? is a gas fuel filter essentially the same as a diesel, or should i pick up a new filter? how much trouble am i about to get myself into? am i committing blasphemey?

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Diesel fuel filters are HUGE, and with good reason. The starter is probably not going to be able to turn over a 20:1 compression diesel motor (maybe a gear reduction unit might, but diesel starters are HUGE). Fuel pumps are totally different. It would be much better for you if you had more than the engine, but maybe a whole diesel Maxima to start with.

 

A friend of mine converted his Rabbit Diesel to grease, and that is a whole other ball of wax. You have to preheat the fuel so it doesn't coagulate in the fuel lines, and he had a dual tank system so he could switch back to diesel before he turned the car off, because the grease will coagulate in the fuel system and you won't be able to start it back up. The grease tank had 2 fuel pumps. 1 to run the fuel thru a copper pipe that was wound around the radiator hoses and then back to the grease tank to preheat it, the other to actually fuel the motor.

 

He also had a fairly elaborate paper towel filter to filter the grease he was getting from the local fast food joints before it ever went into the tank, because chicken McNugget bits will quickly clog your fuel filter and pump. :wink:

 

Biodiesel has none of these problems, but then you're stuck with fairly large quantities of chemicals in your garage (methanol, lye, etc), and I heard a rumor that they were trying to make producing biodiesel at a residence illegal in CA.

 

Good luck.

 

Jon

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That is the 1st question I had for my friend when he did his, and he said that the tubes are too small. He ran a 5/8 ID copper line to preheat, IIRC.

 

The other option was a blanket heater on the bottom of the grease tank, but he didn't have the $$$ for one.

 

His new setup has the exhaust going thru a pipe that he welded into the grease tank. :!: Hasn't got it running yet, but I have no doubt that he will.

 

He told me he was going to do it on the Rabbit, and I called him crazy. A couple months later he drives to my house and rolls down the window and says "Runs great! Only problem is it is making me hungry all the time. Every time I decelerate it smells like french fries!" And it did. :D

 

Jon

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. A couple months later he drives to my house and rolls down the window and says "Runs great! Only problem is it is making me hungry all the time. Every time I decelerate it smells like french fries!" And it did. :D

 

Jon

 

ROTFLMAO!! :D:D:D:D:D:D

Now that's funny. Could be a fix for the Z car's fuel fume smell......

 

Very interesting project though...very cool.

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You'll need a rear-sump oil pan because the Maxima is front-sump. I'd recommend getting an oil pan from an L28ET because the turbo oil drain tube is already on the pan and can be used in place of the drain tube that's on the LD28, on same side of the engine, for the drain oil from the LD28 vacuum pump driven off the back of the alternator.

 

The LD28 starter is a hefty gear-reduction unit. The a/t uses a lower stall speed torque convertor than the na L6s and a different pitch on the gear teeth of the flexplate and starter drive. I don't know if there were LD28 m/t cars, there may well be, I just haven't noticed any. If there aren't any, then I'd recommend using the LD28 a/t. It's better than the 240-280Z a/t's because it has a lock-up convertor that the Z cars don't.

 

There is an LD28 280Z in a magazine I've seen before, I think it was a history of 240-280Z's type magazine from over 10 years ago.

 

I think what would make your project even more interesting would be to add an intercooled turbo setup to your LD28. The L28ET exhaust manifold and turbo appears to be a bolt-on and you could use an intercooler from a Saab, Volvo or Starion to keep costs down. You will need stronger front springs if you install the diesel engine as it is a lot heavier than a na L6 due to the cast iron cyl. head and injection pump.

 

Good luck! DAW

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Important fact here. DAW mentioned the Maxima sump is in the front. The oil pickup of the Maxima block is located in the front also. You will find when you go to put the rear sump pan on the Maxima block, it will not fit because the pickup will be hitting it. You need to take off the pickup, and weld an extension on it to reach the rear sump. FYI 8)

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