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1971 240z rb25det build thread


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Ok here goes. I bought a 1971 240z about 2 months ago. I planned to swap the motor after freshening everything up. As fate would have it the motor seized on the 1st day I drove it. So now Im doing my rb25det swap a bit early. I have read a bunch of threads on this swap and even more threads on how much it costs. I had a hard time finding any info on how to actually do this and all the little items that were needed. So that brings me to this. I am gonna update as I make progress and try to be as specific as possible.


Any comments and criticizms are welcome. Also If it seems like Im doing something terrible wrong please let me know.


Here is the car. A rather rust free 1971 Datsun 240z.


post-11227-020055300 1280343975_thumb.jpg





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Step 1. Remove the old engine.


This part is about as self explanatory as can be. The FSM gives very good instruction on how to do this. My advice to everyone is Take your time be safe. Make sure you put a jack under the trans when you remove the crossmember. If you cant remove the engine on your own you probably shouldnt be installing the new one.


Step 2. (optional) Engine bay prep.


My engine bay looked terrible from the POs paint job. Heres a pic.

post-11227-070091600 1280344218_thumb.jpeg


I didnt like the way it looked at all so I decided to strip it down and paint it flat black so it would match any exterior color I chose to paint the car in the future.


1st I used chemical stripper aircraft stripper from home depot.

post-11227-018828500 1280344344_thumb.jpeg

it came off pretty easy.

Then I used a power washer to remove the loose paint and grease.

After that I primered the bay with rustoleum auto primer from home depot.

post-11227-007941100 1280344431_thumb.jpeg

And finally I painted the bay flat black. I actually used a high heat rustoleum black. Its designed for grills and can handle the very high temps on the engine heat. It is strange because it looks grey in some light and black in others. Very happy with the color so far.

post-11227-066765300 1280344571_thumb.jpg


Ok so I forgot to mention and this is very optional. I bought rust encapsulator and some pre from Eastwood.com.

I would definately recommend pre. It's amazing for removing grease. I rust encapsulated the engine bay before applying the primer. I plan to do the rest of the car with the rust encapsulator so I bought a gallon of both. I also did under the fenders while I had them off


Rust encapsulator. http://www.eastwood.com/rust-encapsulator.html


Pre. http://www.eastwood.com/pre-painting-prep-gallon.html


Ok checklist so far.

Chemical stripper from home depot. 1 can about $8.00

rustoleum primer from home depot. 4ish cans $20.00

High heat grilll paint from home depot. 4ish cans $20.00

Rust encapsulator 1 gallon $130.00

Pre 1 gallon $50.00

Total thus far $228.00


Next up fuel system.

Edited by 5thgenluder
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Fuel system. Stage 1


Well as most of you know the 240z is a carb setup. For the swap we are gonna need to change that to efi. I would like to thank rs speed and goodoldjam for all there help so far. I couldnt have designed this system without them.


Step one. Drain and remove the stock gas tank per the FSM. I also removed the expansion tank. You can keep it if you want. Remove all the factory fuel lines. This should be a pain in the butt if you do it on jack stands with no creeper like I did. ( The next day I bought one.)


Step two. Install the new fuel lines. I went with 3/8th hardlines. Some go with larger and others do flexible lines. I got a nice kit from Jegs that worked out pretty good. It can be found here. http://www.jegs.com/i/JEGS/555/63036K/10002/-1 As you can see it comes with 25' of 3/8 tubing. A cutter, a bender and a flaring tool. I followed where the factory lines were. I used jegs cushion clamps to secure them. They can be found here. http://www.jegs.com/i/JEGS/555/82032/10002/-1. The tubing was flexible enough to bend small bends by hand and I used the tubing bender for the rest. I did not like the 3/8npt connectors that the kit came with. They did not fit snug for me. I am using all -6an braided line for all the other connections so I did earls -6 tube nuts and sleeves on the ends. They can be found here. http://www.summitracing.com/parts/EAR-581806ERL/ and here http://www.summitracing.com/parts/EAR-581906ERL/. I then used male to male -6 fittings to make them a male connection. They are here. http://www.summitracing.com/parts/EAR-981506ERL/. I found a lot of really good info here. http://forums.hybridz.org/index.php?/topic/91311-connecting-stock-hard-lines-to-an-hoses/page__p__865552__hl__%22fuel+lines%22__fromsearch__1&do=findComment&comment=865552


Here are a few pics of the setup.

Here are the hard lines through the tunnel.

post-11227-018002000 1280377075_thumb.jpg

Here they are at the rear of the car. ( Old 3/8 fittings that have since been changed to -6)

post-11227-002011700 1280377262_thumb.jpg

Here they are at the front of the car with the -6 fittings and adapter.

post-11227-030199700 1280377243_thumb.jpg


Well that takes care of the hardlines. Lets add it up

3/8 tubing kit with cutter, bender, and flare. $87.00

cushion clamps. 2 packs $18.00

-6 tube nuts. 2 packs $6.00

-6 tube sleeves. 2 packs $4.00

-6 adapter fittings. qty 4 $12.00

Total for fuel hardlines $127.00

Total so far. $355.00


up next fuel tank.

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Im going to be doing the fuel lines soon. I really hate messing with the tank because it always ends up being a pain in the butt, should be fun haha. Ill certainly be following this thread. I didnt really know a whole lot way back when I got my fuel pump, it was one of those Summit Racing ones thats a little better then the stock RB25 one. I wish I would have bought a Walbro one though...

Edited by jakeoster
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Jake. Best of luck to you. I can tell you that from what I've done so far. Which isn't much. Everything is a pain in the butt. I spend all my free time working on this project. I have a lot of parts and pieces gathered. The biggest pita for me was the down time and ordering wrong parts and waiting for the right ones. I have already begun my tank and am almost done. So that post should be up soon. I've only been working on this project for a few weeks and have developed a huge amount of respect for all the pioneers and those that have completed it. I hope that this post will help everyone like me that doesn't want to make mistakes and order the wrong parts. I have zero mechanical background so I will be farming out some of the work. But hope to help some of the people that need a little guidance. I see too many posts of people wanting to do this swap for $3k. It's much more than buying an engine and a weekend of wrenching. Like I said earlier the tank is almost done and I will have pics and a tutorial up soon. As far as pumps go I was recommended and will be using a Bosch 44 as my high pressure pump and a Carter as my pickup. I have em both already and my surge tank. That writeup is about a week away if my work schedule allows.


Ps Pat1 thanks for the kind words. You will be getting a pm about an oil pan from me soon.

Edited by 5thgenluder
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I am right in the middle of modifying my tank for efi (rb25det on stand) as well. At this point I can either install the stock rb25 intank pump (I have installed a blind plate on top of the tank) or I can go with an external in-line pump like a Walbro. It sounds like you are planning to use two pumps. Is your plan to have one in-tank (Carter) and one in-line (Walbro)? Is your reasoning for using two pumps surge protection or another performance issue? I am trying to add surge protection by putting the efi pick-up in the taller side of the tank with a one-way valve in that direction mounted on the baffle wall. I will post a few pics tonight.





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Bonk. I have to pumps both are external inline pumps. The 1st pump is a carter pump and it feeds an external surge tank. Its like a small extra fuel tank. The bosch pump then pulls from the surge tank to feed the fuel rails. That way no matter how low the fuel gets or if you are cornering hard enough for the fuel to pull away from the pickup in the tank you dont run the rails dry. Depending on your setup you may just want to add baffles to your tank and just run the 1 pump. Here is a pic of my surge tank.

post-11227-033183000 1280423242_thumb.jpg


Jacob, Thanks for the compliments. The lines are pretty easy to bend and if you are carefull they wont kink. I had no kinks in mine when hand bending the lines but I did kink one when doing one of the 90 degree bends. I went to far with it :(



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Fuel system. Stage 2 ( The fuel tank.)


Step one. Remove sending unit and check tank for rust. Mine was really bad inside. Heres a pic of the rust.

post-11227-075392100 1280531016_thumb.jpeg

If your tank is rusty were gonna take care of that in step 2. First we need to get the tank ready. I am running a surge tank in my setup. If you arent planning on running a surge tank you may want to get a baffled tank. First thing I did was have a friend cut off and weld shut the stock fuel return line and all the lines that went to the expansion tank except for the 5/8th on the top of the tank at the rear of the car. Next I used a tap where the stock drain plug was for my new feed line. I used a 3/8NPT and it was hard to find. I got mine here for pretty cheap. http://www.harborfreight.com/6-piece-pipe-tap-die-set-91395.html. Make sure to use cutting oil and frequently spin the tap in reverse to clear the threads. I then got a 3/8th to -6an 90degree adapter for my newly tapped hole. http://www.jegs.com/i/JEGS/555/100146/10002/-1.


Step two. If your tank is rusty and your a DIY guy. I bought a tank sealer kit from eastwood. http://www.eastwood.com/ew-gas-tank-sealer-kits-for-cars.html It was a huge pain in the butt. The cleaning process went great for me. Youll need muratic acid and 2qts of acetone in addition to the kit. Clean with metal wash, muratic acid, fast etch, and acetone. Lots of shaking my arms still hurt. Then seal with tank sealer. I had trouble here because after I finished sealing I wasnt able to get the excess out. Plus my tank had a baffle so It filled that in in some spots. I spent all day with a razor on a stick and a hack saw blade on a stick reopening it. Then I used the supplied tank tone on the tank and then quickly changed it to flat black. I didnt like the silver.

Here is a pic of the tank flat black.

post-11227-033647800 1280531671_thumb.jpg

Heres a pic with the tap in.

post-11227-032747400 1280531680_thumb.jpg

Heres a pic of the damage I did while using a jack to hold the tank up while I attatched the filler neck:( post-11227-082271700 1280531781_thumb.jpg


comments. If I had it all to do over again I would have had a radiator shop boil and seal the tank professionally.


Lets add it up

Tap and die kit. $15.00

cutting oil $5.00

-6 to 3/8npt 90degree $10.00

welding shut plugs $? friend did it ( thanks Doug.)

Eastwood kit $50.00

Acetone $15.00

muratic acid $15.00

Total for tank prep $110.00

Total so far. $465.00

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Fuel system. Stage 3 ( the surge tank )


Ok I have been asked a few times now about this surge tank so here is the writeup on how I mounted it and a little bit of info on the idea of a surge tank. As most of you reading know the stock 240z tank is not baffled. So what that means is under hard cornering with a low fuel level the fuel can slosh away from the feed line. That in effect leaves the the fuel system dry which can in turn have harmful effects on the motor. The idea of a surge tank is this. You have a low pressure pump coming from the motor feeding and filling the surge tank. Then there is a 2nd pump from the surge tank to the engine. The return fuel from the engine also goes to the surge tank. This means that even if the feed line temporary goes dry on hard launches or long sweeping turns the motor is still pulling fuel from the surge tank. This prevents running the fuel system dry. ( any more questions or if further explanation is needed please let me know. )


This particular writeup is on mounting the surge tank. Hooking it up will be covered in an upcoming chapter.


Step one.

Find a location for your surge tank. This can be quite difficult depending on how big your tank is. ( Surge tank will be appreviated ST from now on. ) I was unable to find anyone in the USA that sold STs. I bought mine off of ebay. Just search "fuel surge tank" and you should find some results. Mine is made by autobahn 88 and was sold through Zenaracing. Heres a link http://cgi.ebay.com/ebaymotors/Fuel-Surge-Tank-Aluminum-2-Litre-Swirl-Pot-System-_W0QQcmdZViewItemQQhashZitem45f16c9fb1QQitemZ300403171249QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories. Its a 2 liter or about half a gallon. Heres a pic for all of you who look at this years from now and the link doesnt work. post-11227-012890500 1280544105_thumb.jpg .. Now came the hard part. Finding a location. Ideally most people put it under the car. I tried to think of a good way to make this work but with 2 pumps a fiter and a surge tank I just couldnt find a way to make it work. Or maybe Im just lazy. This car for me is not a daily driver. I chose to cut my wheel well and put my fuel setup in it. I will put a alluminum plate over the top of the wheel well when im done with the fuel setup.


Step two.

This is going to depend on where you choose to mount your surge tank but for me step 2 was prepping the wheel well. First I used my trusty Pre to clean up the well and my wire wheel to get all the tough spots. I even had the help of my lovely lady friend for this part. Heres a pic.

post-11227-033712200 1280544434_thumb.jpg

Then I rust encapsulated the wheel well. I then used my cutting wheel to notch out a square where I planned to have all my lines come through. Be carefull and mind where your fuel tank will be. I also notched out a square for my ST. Next I put dynamat thoughout the entire wheel well. ( fuel pumps are noisy.) I also used the dynamat to make sure there werent any sharp corners where my lines and ST are coming thru. http://www.abt.com/product/11695/Dynamat-10455.html . Next up mounting that dang ST. As I stated in a thread earlier I am in no way a mechanic so I cant weld and I just kind of make it up as I go. I set the St where I though it should go and started to make some alluminum brackets for it. I got the alluminum from home depot. I believe its 1.5" wide and 1/8th thick it came in an 8ft section. I bend the brackets using a wooden block and a 3lb sledge. A vice would have made life easier. Kind of just made it up as I went along. Heres what I came up with.

post-11227-071062800 1280544977_thumb.jpg

post-11227-069471500 1280544993_thumb.jpg

post-11227-046248900 1280545008_thumb.jpgpost-11227-032411000 1280545078_thumb.jpg

post-11227-099553700 1280545107_thumb.jpg


Ok I think you get the idea. I bolted it all down and Im good to go. Oh and I also put a little piece of dynamat betweent the ST and the brackets to keep vibration down.


Lets add it up.

Surge tank. $100.00

Dynamat. $200.00 Optional and plenty left for the lid.

Alluminum for brackets. $20.00

Mounting the ST. $320.00

Total so far. $785.00

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Pat1 thanks again for the kind words. So far its been a real pain making this surge tank work but I wont have to do it again I hope.


Goodoldjam thanks again for all your help. Im glad you found this page because you have been a huge help so far.


Trying to get a little more work done tonight. I spend most of my time looking at everything and laying it out in my head. Do you guys think I should mount the 1st pump down to the right of the surge tank? Is the wheel well to far away? The instuctions say to mount it close to the fuel tank and no more than 24" above the tank. I dont think its 24" above it but in the wheel well it will be more than 24" away. Let me know what you think.

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Fuel system stage 4. (filter, pumps, and connections.)


This Is where it gets tricky and Im going to try my best to explain it all as best as I can.


Ok first thing first. I did all my connections with jegs stainless steel braided line. Here it is. http://www.jegs.com/i/JEGS/555/100912/10002/-1. I bought 10 feet and It was just enough if I could do It again Id get more because I still need to do the engine bay. I did Jegs straight fittings here. http://www.jegs.com/i/JEGS/555/100001/10002/-1 and here http://www.jegs.com/i/JEGS/555/100021/10002/-1.


The first thing I connected was the overflow. It is a 90degree fitting that comes off the top of the ST that way any excess fuel in the ST will flow back into the fuel tank. The other end of that hose is attatched to the original feed line off the stock fuel tank.


The next thing I connected was the line that connected the return line from the engine bay to the ST. I used straight hose ends on both end of this hose.


Next up I connected the line from the bottom of the tank. I unsed a straight fitting on the bottom of the tank and a 90degree to connect it to the fuel filter. The fuel filter is a 40 micron in-line filter from Jegs. Here it is http://www.jegs.com/i/JEGS/555/15032/10002/-1. From the filter I connected the Carter fuel pump. It didnt have a -6 an fitting so I just clamped on the stainless line. Heres the Carter pump. http://www.jegs.com/i/Carter/180/P4070/10002/-1. From the Carter pump I connected it to the top of the ST using a 90degree hose end.


The last thing I connected was the outlet from the ST to the Bosch fuel pump. The Bosch pump is a 044 inline pump. I bought it on amazon.com. The inlet of the pump needs an adapter. http://www.summitracing.com/parts/FRA-460618/ and an outlet adapter http://www.summitracing.com/parts/RUS-670510/. From the outlet of the Bosch we go to the feed hardline we installed in fuel system stage 1.


This is all very hard to explain. Maybe so pictures would help. This one explains most of it.

post-11227-021906400 1280717088_thumb.jpg


Here are a few more shots of the setup.

post-11227-088559100 1280717169_thumb.jpg

post-11227-077193800 1280717224_thumb.jpg

post-11227-031259400 1280717276_thumb.jpg


Ok so you can tell I still need to mount the Bosch pump, Put some grommets in where the fuel lines come in. I also want to tidy up the lines a bit. I also need to wire up the pumps and do the filter in the engine bay as well as the Fuel pressure regulator. That is all coming in a future writeup.


Lets add it up.

10' stainless braided hose. $40.00

qty 7 an straight hose ends $35.00

qty 4 an 90degree hose ends. $42.00

JEGS 40 micron inline filter $30.00

Carter fuel pump. $70.00

Bosch 044 fuel pump. $180.00

Bosch inlet adapter. $4.00

Bosch outlet adapter. $5.00

Total for filter, pumps and connections. $406.00

Total so far. $1191.00

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