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My 1980 Datsun 720 diesel dually

Posted: Sat Jul 05, 2014 9:43 pm
by wayno
I am changing out my diesel engine this weekend.
Basically I started with this in the 720, sorry I forgot to take a before photo.
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This is the donor car, a Volvo with a Nissan SD25 turbo diesel.
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I started pulling the front off the Volvo to make it easier to remove the engine.
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I started with kinda a mess, it was very dirty in there.
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It's a little cleaner now.
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More tomorrow :)

Re: My 1980 Datsun 720 diesel dually

Posted: Sat Jul 05, 2014 9:59 pm
by wayno
Oh and I did get it in the truck today.
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Re: My 1980 Datsun 720 diesel dually

Posted: Sun Jul 06, 2014 12:54 pm
by DRIVEN
Should be a nice improvement.

Re: My 1980 Datsun 720 diesel dually

Posted: Sun Jul 06, 2014 4:11 pm
by wayno
Well I have it installed for the most part, now I have to do all the gauges, boost, oil pressure, oil temp, EGT(exhaust gas temp), and do little hoses like the engine case vent, and what I am going to do with it, I also could not use the exhaust system that was built for the Volvo, so that is going to have to be made from scratch, I might have to move the brake booster back about 5 inches, I used the 1982 version, I might have to go back to the smaller 1980 version.
I started today on the power steering, had to make a new mount, as this engine was different, it actually was easier this time.
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Then I piped the fuel system.
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Everything after that stuff was done, BTW it is starting to get hot outside.
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Then I put the radiator in after doing a whole lot of little stuff.
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Fan looks good.
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Now the hood is on and it closes, but..............
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I had to cut a hole in it, so I grabbed a hood I had in storage that was not so nice.
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I think I will make some sort of bubble that covers it, or put a backwards scoop over it.

Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 09, 2014 3:16 pm
by 510freak
Looks like it was there from the factory Wayne :thumbs:

Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 09, 2014 5:25 pm
by wayno
510freak » Wed Jul 09, 2014 4:16 pm wrote:Looks like it was there from the factory Wayne :thumbs:

Well, aren't you being nice. :)

I am trying to decide if I want to keep it propane injected, or go back to the way it was before without the propane, he changed everything when he installed the propane, it's really complicated, I just want a little more power on the freeway.
It was quite simple when he had it set up at first, a BOV between the throttle body and the turbo that was controlled by the vacuum created by the venturi in the throttle body, that has all been deleted, and the throttle body was modified somehow, and now the [propane is injected when a vacuum is sensed between the airfilter and the turbo inlet, the way I see it, the dirtier the air filter, the more propane that gets injected, which is not a good thing for me, as I rarely even check the air filters in my vehicles.

Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 09, 2014 5:32 pm
by izzo
The install looks good dude. Very impressed. You get a lot of shit done. Most people day dream of doing all that. You did it.

Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 09, 2014 5:39 pm
by wayno
izzo » Wed Jul 09, 2014 6:32 pm wrote:The install looks good dude. Very impressed. You get a lot of shit done. Most people day dream of doing all that. You did it.


To be honest, I bought this running, although I am the one transferring it over to my 1980 Datsun 720, I am going to take my time, I don't want to forget something and screw it up somehow.
The exhaust is going to be an issue, there was a lot of room in the Volvo engine compartment, not so much room in the 720 engine compartment, I might have to go out the driverside fender well with the exhaust, or make it a RHD. :rofl: :rofl: :rofl:

Re: My 1980 Datsun 720 diesel dually

Posted: Sat Jul 12, 2014 8:40 pm
by wayno
Well I started it today, except for the fuel pump not working, it seems to run fairly good.
It's in there now, but I deleted the propane injection for now.
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Everything is either tight or actually rubbing.
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The exhaust pipe is really close to everything, including the steering shaft.
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Re: My 1980 Datsun 720 diesel dually

Posted: Sat Jul 12, 2014 10:46 pm
by RedBanner
Thay cleaned up great, impressive.
"Everything is tight or rubbing" lolololol

Re: My 1980 Datsun 720 diesel dually

Posted: Sun Jul 13, 2014 4:28 pm
by wayno
I took it for a 5 mile drive today, the fuel issue seems to have fixed itself, I hate it when it does that, cause I don't know why, so inevitably it will happen again.
So I was doing all right till I hit the freeway, that is when I started having an issue, I could not get it up to freeway speed, and it does have the power to go way past freeway speeds, but the exhaust gas temperatures were getting to high, it got to 1200 degrees once, most the time I let off at 1000 degrees, but that one time I was going up a slight grade at 40/45mph and I wanted to get to the top.
I am going to install an inner-cooler next, I will move the radiator towards the fan just over a half inch, and I think that might just make the room I need to fit it in front of the radiator, the engine did not run hot at all, but the EGTs were way to high.
I also think the guy has this set up way to lean, he was into the fuel mileage thing I think, if I can make it run richer, it should cool it down, I also think I will be putting in another EGT gauge/sensor next to the turbo itself, that is a couple feet away from the first sensor that is right at the exhaust manifold outlet.
So here is how it sits right now.
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Here is one of them rubbing points I was talking about.
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Here is the front half of the exhaust, I cut up the pipe that was under the Volvo, and put one together that worked for me.
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The middle,
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and the end.
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I need to find out how hot the EGTs can be, as I cannot even drive on the freeway right now.

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 14, 2014 8:46 pm
by wayno
Well I took the front off the truck this evening, I moved the radiator closer to the fan, within a quarter inch or less, I am trying to make room for the inter cooler.
I am not sure if this is the way I should go, what I really need is an inter cooler with both outlets on the side/same side that is a little thinner, if I do a lot of cutting on the sheet metal, I can make it fit, but I think it would be better if it fit without the cutting.
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I looked on ebay, but nothing seems to be the size I need, I will keep looking.

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 14, 2014 8:56 pm
by draker
how big of an intercooler do you actually need? That looks pretty big. I don't know what size of turbo that is but maybe something like this could work:

http://www.ebay.co.uk/itm/RENAULT-SCENI ... 1c3c7208d0

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 14, 2014 9:08 pm
by wayno
draker » Mon Jul 14, 2014 9:56 pm wrote:how big of an intercooler do you actually need? That looks pretty big. I don't know what size of turbo that is but maybe something like this could work:

http://www.ebay.co.uk/itm/RENAULT-SCENI ... 1c3c7208d0

That one looks kinda small, I want to get the maximum cooling I can, the engine did not have any cooling issues, if anything it was running a bit cool, but the EGTs were not making me happy, so the cooler it goes in, the cooler it comes out.
The biggest issue is that the one I have is 3 inches thick, I need one that is 2 1/2 inches thick with the outlets pointing sideways instead of up.
I am looking for something that is about 21" x 13" x 2 1/2" thick, so far the closest thing is over $300.00, that is a couple hundred higher than all the rest of the coolers, they are averaging just under a hundred to $150.00, but that one size is double the price.
Also a lot of them are 3" thick, I want 2 1/2 inches thick, the one I have is 3" thick, and it is going to cause a lot of extra work if I use it.

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 14, 2014 9:28 pm
by draker
The twin turbo Z32 uses two side mounts similar to those. Too big and I'd worry about lag.

I'm sure you'll find something that'll work.

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 14, 2014 9:59 pm
by wayno
Right now I have something going on, when I was driving down Mill Plain going about 40mph, I could not find a sweet spot, either I was accelerating or I was coasting/decelerating, I could not find a smooth even speed.
I am not sure that I have everything set correctly, but I just drove it for the first time yesterday, and I went backwards to a setup that he had before the propane injection with a BOV in between the turbo and the throttle body, not sure if that BOV is set correctly, I cannot tell if it is even working.

Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 16, 2014 9:24 pm
by izzo
I know not enough about shit to make anything of it.

paging Micro... Micro machinery....

Re: My 1980 Datsun 720 diesel dually

Posted: Sat Jul 19, 2014 6:39 pm
by wayno
I drove the truck again today, this time my threshold for EGT was 1200 degrees, which I hit easily.
I have come to the conclusion that I do have more power getting up to speed, but I have no more power on the hiway.
I will look into the airfilter condition(dirty/clean), I hope that is the issue.
I have had the frontend apart, and have come to the conclusion that the intercoolers I have are not going to work, and the stuff on ebay is not the correct size either, it's not thin enough unless I spent a lot of money, and I have decided that I need to find something cheap, so if it doesn't work, I will not be out a lot of money.
The engine doesn't like to rev up, my 521 kingcab engine doesn't like it either, but it revs higher than this turbocharged engine, I need to drive it more to understand I guess.

Re: My 1980 Datsun 720 diesel dually

Posted: Mon Jul 21, 2014 8:04 pm
by wayno
Well I finally convinced myself that I had to start cutting, I was not happy about it, but it was time to move forward.
So I cut the bottom core support brace, I cut the top and front out, and then welded in a stiffener, and the bottom support for the intercooler, I had to get it in there deep enough to keep the grill and bumper.
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Here is the lower sheet metal, at least what is left in position.
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And here it is installed, I have to clean a lot of things up, so I have not installed the radiator yet.
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Re: My 1980 Datsun 720 diesel dually

Posted: Wed Jul 23, 2014 9:06 pm
by wayno
It's coming along, I made all the connections except one today to complete the intercooler setup, hopefully it won't leak, two of the connections are ABS to ABS fittings, and I did not glue them at this point, they are so jammed in there, I am not sure it can actually blow apart, but maybe it could leak.
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It is just tight, everything is on one side.
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I do have a possible issue, very little of the radiator has free flowing air now, either the intercooler is in front of it, or the piping is in front of it, the engine was running cool, so I hope this continues.
I will see about getting the last rubber piece I need tomorrow, but I doubt I will have time to install it and drive it, that might have to wait till this weekend, sometimes I find time, and if I do that will be great.
The Volvo is gone, I got $223.00 for it without an engine, transmission, radiator, or the wheels, they have good tires so I was happy to keep them.