zgeezer Posted March 26, 2007 Share Posted March 26, 2007 The swap is easy, but not a complete simple R&R. The 280 tank out of any 280 without the false floor and shallow spare tire well will work. The 280 tank is longer, it is deeper, and it lacks one of the tank vents on 240's. The 280 tank's fuel level sensor is interchangeable with the sensor and float of the 240. The 280 has an additional sensor, which I think is a pressure sensor attached to the fuel level float arm. The 240 fuel tank straps are both too short to mount the 280 tank. You will need 280 straps. I think 280 straps mount in the body in the same fashion as the 240s, but I'm not certain. The passenger's side fuel tank strap indentation on the 280 is located the same as the 240. However, the 280 strap indentation on the driver's side is located about 2 inches wider to the driver's side than the 240. A longer strap from the 240 mounts would secure the 280 tank, but will not fit into the 280's indentation. The 280 tank is well baffled. The 280 tank fuel feed and return are both larger than the 240 tank. The 280 return line is the same size as the 240 main feed. The 280 fuel feed line is substantially larger. I have a number of photos posted on my album under zgeezer that illustrate the differences. I'll try to mount them here. This shows the length, the lack of a vent, and the relocation of another vent. It's a little dark, but the depth of the 280 tank is a little less than depth of that block of wood. I think 2 inches. I think the 280 tank is well baffled. Here is the reason I'm attempting this installation. The fuel level senders are interchangeable between 280 and 240. The 280 has an additional sensor, which I believe to be a pressure sensor. I don't know if the ohm readings of the two sensors are the same. This depression in the bottom of the 240 spare tire well is shot from underneath and it matches a similar raised ring on the 280 gas tank. g Quote Link to comment Share on other sites More sharing options...
Dave Posted March 26, 2007 Share Posted March 26, 2007 If you remove the . (period) from the img statement they will show up. Quote Link to comment Share on other sites More sharing options...
ktm Posted March 27, 2007 Share Posted March 27, 2007 Also, Tony D indicated that you do not need to source different straps, simply use a longer J-bolt. I have not confirmed this myself. I just had my 240z tank modified by a local speed shop that specializes in custom fabrication. Quote Link to comment Share on other sites More sharing options...
Racin_Jason Posted March 27, 2007 Share Posted March 27, 2007 nice post. If I run into fuel starvation due to inadequate feed/return on my 240z8, I will be looking for a 280 tank Quote Link to comment Share on other sites More sharing options...
J__ Posted August 6, 2007 Share Posted August 6, 2007 nice post. has anyone put a 240 tank onto a 280? i have a 280 and theres a HUGE dent right in the middle of the tank, its ugly. also i think the 240 tanks look sleaker with their sloped bottom. would the 240 tanks be just as easy to fit onto the 280? Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 7, 2007 Share Posted August 7, 2007 Yes, if you look at the J-Bolts that secure the tank in the 280, you will see there is one that is substantially longer than the other. Two of those and you are set as far as getting it to work. Quote Link to comment Share on other sites More sharing options...
J__ Posted August 9, 2007 Share Posted August 9, 2007 sweet thnx. now i gotta go find a 240 tank Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 9, 2007 Share Posted August 9, 2007 Wow, seeing the two of them side by side really indicates some visible differences. Guess that 'shortness' has to do with the bumper shocks and extra shielding they put around the mufflers on the EFI cars... Anybody got some side by side shots of the 260 tank next to the 280? I have also swapped 260 tanks into 240's using the longer bolts...and from what I recalled the external dimensions were similar to the 240/280 tank comparo as shown above. On the 260 to 280 swap as I recall, all I did was back the nuts on the 'j' bolts out further to make the tank slip in, so the 260/280 tank may be external dimensional clones, the only difference being the pickups and possibly the baffling internally... BTW, the second sensor on the 280 tank sender unit is a capacitance unit that lights the red 'low fuel' light in the gas gauge on the later cars. A nice feature if you're like me, and know "I can go 72 miles from the time the light turns on in the Truck"... Makes a difference when Eherenberg is only 68 miles away, and that simply crossing the border from Blythe to Exit 1 on the Arizona Side means gas for 30 cents a gallon cheaper! LOL Great Photos, BTW. That makes explanations much easier! Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted August 10, 2007 Share Posted August 10, 2007 Wow, seeing the two of them side by side really indicates some visible differences. Guess that 'shortness' has to do with the bumper shocks and extra shielding they put around the mufflers on the EFI cars... Anybody got some side by side shots of the 260 tank next to the 280? I have also swapped 260 tanks into 240's using the longer bolts...and from what I recalled the external dimensions were similar to the 240/280 tank comparo as shown above. On the 260 to 280 swap as I recall, all I did was back the nuts on the 'j' bolts out further to make the tank slip in, so the 260/280 tank may be external dimensional clones, the only difference being the pickups and possibly the baffling internally... My late 260Z is carb'd and has a tank that looks identical to the 280 tank shown above. The fittings are in the same locations, but I cant verify the baffling or internal pickups as I havent dropped it from the car (yet). - Greg - Quote Link to comment Share on other sites More sharing options...
ZXRockie Posted August 10, 2007 Share Posted August 10, 2007 sweet thnx. now i gotta go find a 240 tank I just took one to the junk yard on sunday... I need a 75 280Z fuel tank... badly... anybody... Quote Link to comment Share on other sites More sharing options...
Nigel Posted August 10, 2007 Share Posted August 10, 2007 I hate to burst your bubble, but I don't think this swap is worth it if you're trying to combat fuel starvation in corners. I went through the trouble of putting a 280 tank in my 240, and with a high flow Walbro fuel pump, it was sucking air in hard left turns at not much below a half a tank. I ripped the 280Z tank out and put my 240 tank back in with a sump welded to the bottom. The best solution would be to run a surge tank which has been discussed extensively elsewhere on this forum. Believe me, I was extreemly frustrated after spending a lot of time and money to get the 280 tank in the car and still have starvation problems. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 11, 2007 Share Posted August 11, 2007 I hate to burst your bubble, but I don't think this swap is worth it if you're trying to combat fuel starvation in corners. I went through the trouble of putting a 280 tank in my 240, and with a high flow Walbro fuel pump, it was sucking air in hard left turns at not much below a half a tank. I ripped the 280Z tank out and put my 240 tank back in with a sump welded to the bottom. The best solution would be to run a surge tank which has been discussed extensively elsewhere on this forum. Believe me, I was extreemly frustrated after spending a lot of time and money to get the 280 tank in the car and still have starvation problems. Nigel '73 240ZT EXCELLENT POINT NIGEL! This is EXACTLY the phenomenon I was talking about in the 'build a nice surge tank' post! Just because you have a 280 Tank does not mean you can't run dry or that you don't require an external surge tank! I have said it before, even on triple Mikuini Cars, the Datsun Competition Manual used two fuel pumps and a surge tank to fuel N/A 240's in competition! The surge tank is more of an issue to solve cornering problems with fuel starvation, and it's combatted by making a vessel taller than it is wide so that during cornering the outlet (pump suction) is always flooded. The nice thing about the 280 Tank is that for a normally driven street car, it will perform satisfactorily for most of the people out there in daily driven activities. If you are racing, a Surge Tank is ALWAYS a good idea, EFI OR N/A! Quote Link to comment Share on other sites More sharing options...
ruggedbert Posted August 30, 2009 Share Posted August 30, 2009 So I'm installing the 280 tank in my 240Z. I have the passenger side strapped up, but I'm about an inch short on the drivers side. I tried both 240 and 280 straps and J bolts. Where can i find longer J bolts? Also, my filler neck barely touches my gas tank inlet. There is no way that I can clap it down. Are the 280Z filler necks longer? Thanks Quote Link to comment Share on other sites More sharing options...
softopz Posted August 30, 2009 Share Posted August 30, 2009 So I'm installing the 280 tank in my 240Z. I have the passenger side strapped up, but I'm about an inch short on the drivers side. I tried both 240 and 280 straps and J bolts. Where can i find longer J bolts? Also, my filler neck barely touches my gas tank inlet. There is no way that I can clap it down. Are the 280Z filler necks longer? Thanks I dont know about the filler strap but you can get a j bolt off a hardware store most likely or cut a batterey j bolt laying around if you got an extra. Nigel and TonyD thanks for that I recently got the l28et finally running in the 240z and I was contemplating the 280z tank or surge tank idea. Since my 240 tank is leaking at the sender (prolbally O ring) and is also leaking from pick up, return or vent (it looks like its crappily brazed on there) I know what I am going to do now. Dont want to hijack but I would like to ask a couple questions if I keep the 240z tank Is it a good idea to remove reserve tank and plug the vents?Theres too many! How about the reserve tank I saw a post here someone using the reserve tank as a surge tank. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 30, 2009 Share Posted August 30, 2009 It's not a reserve tank, it's a vapor/liquid separator. You can run without it, but I have it in most cars, I just convert to 3/8" vent lines from 15mm to keep good easily replaceable hoses back there. Some nylon couplers from 15mm to 10mm is all you need, and no more $100+ molded vent hoses needed! Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted August 30, 2009 Share Posted August 30, 2009 I hate to burst your bubble, but I don't think this swap is worth it if you're trying to combat fuel starvation in corners. I went through the trouble of putting a 280 tank in my 240, and with a high flow Walbro fuel pump, it was sucking air in hard left turns at not much below a half a tank. I ripped the 280Z tank out and put my 240 tank back in with a sump welded to the bottom. The best solution would be to run a surge tank which has been discussed extensively elsewhere on this forum. Believe me, I was extreemly frustrated after spending a lot of time and money to get the 280 tank in the car and still have starvation problems. Nigel '73 240ZT I didn't add a sump to my tank, but I did tap the drain plug for 3/8 NPT and added a fitting there to to pull fuel from, and have not experianced any issues with fuel starvation, when the tank is above about a 1/4, and I'm not corning hard. I haven't ran any track days yet, that's not really my thing, but for daily (spirited) driving and drag racing this seems to work well. BTW this is on the original '73 240 tank. Quote Link to comment Share on other sites More sharing options...
softopz Posted August 31, 2009 Share Posted August 31, 2009 I didn't add a sump to my tank, but I did tap the drain plug for 3/8 NPT and added a fitting there to to pull fuel from, and have not experianced any issues with fuel starvation, when the tank is above about a 1/4, and I'm not corning hard. I haven't ran any track days yet, that's not really my thing, but for daily (spirited) driving and drag racing this seems to work well. BTW this is on the original '73 240 tank. Thats exactly what I have a 90 degree 3/8 barbed fitting there. Problem with this is your picking up crud at bottom of tank> I dont know how long that walbro is going to last I should put an inline see through filter. Just dont know which to go with yet. Oh I thought it was a reserve tank what an odd thing. I got rid of it . Too many fuel vent hoses going into the car its bad enough with the l28et fumes and 240z holes that will be needing to plug. Quote Link to comment Share on other sites More sharing options...
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