Guest Anonymous Posted May 5, 2003 Share Posted May 5, 2003 I have a stock 72 240z. I am thinking of upgrading to a V8, but before entertaining that idea, I was curious, what are some cost effective upgrades that I can use with the stock 240z motor? How much would it cost for me (in parts) to bring an L24 up to the 250HP range? If it comes in the $1500 range, I think I would prefer to go with a Chevy V8. Thank you for your time Quote Link to comment Share on other sites More sharing options...
Mike C Posted May 5, 2003 Share Posted May 5, 2003 250hp will be expensive. REAL expensive. But an electronic ignition conversion, new coil, good wires, 2 1/2" exhuast and K&N air filter makes a pretty darn big improvement. Follow that up with an early 5 speed and some 3.90s and you may change your mind on the V8! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 5, 2003 Share Posted May 5, 2003 I put dual KN filters, one on each carb and that did help alot (a while ago) I am new to the Z's and just remembered that the car does have a 5 speed in it. What is the best way to tell what car it came from? I am completely pulling the engine and tranny out to repair some frame rust under the battery. A couple of cylinders are burning a decent amount of oil, and I was thinking of rebuilding the motor (or replacing it with a V8). Are there any internal engine components I should replace to get better HP? I do not want to lose my low end torque, or spend alot of cash heh =) Thanks again Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 5, 2003 Share Posted May 5, 2003 Find an 81-83 280ZX engine and rebuild that and put it in there with your head (do a nice 3 angle on the head), add a header and exhaust and a camshaft, and you will be surprised how much more powerful the car will be. Put a 3.90 rear end in the car, and it will really move. Getting that kind of power out of a 2.4 is harder then a 2.8. If you have a 5 speed, the easiest way to tell is how much of an overdrive it has. If the rpms drop by about 25%, you have the ZX one, less drop then that, you have a Z transmission. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 5, 2003 Share Posted May 5, 2003 For about $500 I swapped in the 83 turbo engine. Thats pretty cheap I think for the way the car runs now. I am really surprised at how quick the car is. Just my 2 cents. Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 5, 2003 Share Posted May 5, 2003 I agree with Moby, despite my non-functioning ignition transistor A cam setup ALONE without even touching the head will border on the $500 area, much less header, different carbs if you chose, yada yada. Plus the turbo will have better driveability than a peaky NA setup, and with better low end has the potential for better MPG, plus its injected. If your 5th gear feels like 4th gear then you have the early 5 speed, 5th gear on those is .864, 4th gear is 1:1, making them so close together its hard to tell them apart. Quote Link to comment Share on other sites More sharing options...
Mike C Posted May 5, 2003 Share Posted May 5, 2003 I finally gave up on the turbo option. Around here I couldn't find a donor for less than $1500 and those were automatics. Like everything else, just depends on what you want to do. I agree with Lockjaw. Get a flat top 2.8 and try and find an N42 head. The FI longblocks are usually in excellent shape even with 150k plus miles. The N42 head is square port to use your stock exhaust and will have the bigger valves your E88 doesn't. I bought a 2.8 for my 72, wish it was a flattop, but it is a .040 over dished job. It does have an R&R'ed E88 that has had the bigger valves installed. The real bonus is the triple Del'Lortos. I'm going to run the Nissan T5 with the 3.54 that are in the car and see how I like it. I may eventually do the 3.90, but an LSD 3.70 would be perfect. I go back and forth on the V8 conversion thing, and right now I'm in L6 mode! Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 6, 2003 Share Posted May 6, 2003 My donor was an automatic, but I already had a 5 speed in the car anyway. Remove one simple peice from the end of the crank, voila ready for your manual trans. I lucked out on a $150 donor, 70k miles on the clock. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 6, 2003 Share Posted May 6, 2003 I appreciate all your help, I will look into the mentioned upgrades. My uncle has a 280 in his backyard so I plan on seeing what it has in it. I have not searched on it yet, but how hard is the differential upgrade? Is it just a simple swap of the diff, or is it multiple parts? Thanks again all Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 6, 2003 Share Posted May 6, 2003 That depends, if it has an R200 and you want an R200 of another ratio, its just a diff swap. If it has an R180 and you want an R200, its a little more involved. Quote Link to comment Share on other sites More sharing options...
Guest michael_240Z Posted May 6, 2003 Share Posted May 6, 2003 hey mike c, this is just what i heard but it sounds pretty logical but it was stated that you are better off getting one out of an automatic because automatics generally don't get driven as hard as a manual would and therefore the engine isn't as worn out. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 6, 2003 Share Posted May 6, 2003 Here is the list of MODS that made one of my cars run 186WHP... N42 head, 1982 ZX flat top pistons on a stock 280 block, stock rods and Crank, MSA header, Holley 390 Carb on a Sharp 4BBL carb. 2.5 inch exhaust with Dynomax muffler. It had 3:36 gears and a 5 speed sourced from god knows where... Ignition was a supercoil and an MSD box with NGK wires... That is real world, and was measured... NOT impressive based on the money spent to get that WHP... If you MUST stay L6, I'd find a factory Turbo setup, freshen and install it instead. Beware of seat-of-the-pants HP and Torque guestimates... John Coffey is a real good source for what combos are effective in the L6 configuration. Mike Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 6, 2003 Share Posted May 6, 2003 My donor was an automatic, but I already had a 5 speed in the car anyway. Remove one simple peice from the end of the crank, voila ready for your manual trans. I lucked out on a $150 donor, 70k miles on the clock. I hope you did not forget the pilot bushing in the crank. Autos don't normally come with them, and you will be rebuilding a tranny before long without it. Quote Link to comment Share on other sites More sharing options...
Mike C Posted May 6, 2003 Share Posted May 6, 2003 I think that autos aren't driven as hard may be a myth. One thing to beware, is that many auto cars are stalled up against the converter to build boost. This in turn forces the crank into the thrust bearing for extended periods which can lead to thrust bearing failures, crank wear, and excessive crank endplay. Missed shifts aren't a problem, but the auto car is not impervious to wear and tear and as noted, the wear can be more significant than with a manual. If I was going to spend $1500 plus for a donor, I would want a manual in order to a.) use it. or b.) sell it to recoup some of my investement. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 6, 2003 Share Posted May 6, 2003 If you rebuild the 2.4L make sure you replace the early 240 rod bolts with some better bolts. The 240 rod bolts were dangerously thin. MSA carries upgrade kits. The 2.8L swap is definitely the way to go, but sort of defeats your whole "cost effective" argument in that you could be well on your way to a V8. The differential swap, R200 or R180, is strictly a bolt in affair on a 240 so have to give it an "uncomplicated" rating. The only trick is getting all the parts you need with only a single trip to the wrecking yard. The real early 240's (like mine) had the diff mounted an inch and a half too far forward. This makes the upgrade very worthwhile since it noticeably reduces vibration. I think Nissan fixed this in mid 72 so it may or may not apply to you. The JTR manual has a complete shopping list. Quote Link to comment Share on other sites More sharing options...
Mudge Posted May 6, 2003 Share Posted May 6, 2003 I hope you did not forget the pilot bushing in the crank. Autos don't normally come with them, and you will be rebuilding a tranny before long without it. I will post a pic of what needs to come off the back of the Auto flexplate for those not aware of it what it takes to do the swap. We noticed that the hole sizes were very different, so there was no way the trans was just going in place like that Quote Link to comment Share on other sites More sharing options...
johnc Posted May 6, 2003 Share Posted May 6, 2003 (brake torquing an automatic) This in turn forces the crank into the thrust bearing for extended periods which can lead to thrust bearing failures, crank wear, and excessive crank endplay. Reving the engine with the clutch pushed in does the exact same thing. Quote Link to comment Share on other sites More sharing options...
Mike C Posted May 6, 2003 Share Posted May 6, 2003 But not to the same extent. You can't really build boost by free-revving the engine the same way as you can build boost by actually loading up the engine. Just pointing out that just because it is an auto doesn't mean it wasn't hammered on by a boost happy teenager. Since you can't have fun banging gears, all you can do is boost up on the launch! Quote Link to comment Share on other sites More sharing options...
DAW Posted May 10, 2003 Share Posted May 10, 2003 Here's my $.02: 1) Check around your area for a wrecked 280ZXT and buy the motor with the electronics/ECU intact with the motor. They vary depending on your locale I've seen an engine complete (except for an intact harness and ECU) go for $250 but you've got to be ready to jump on a deal like that. Put the engine in and hook up an intercooler and bump up the boost a bit, then take it from there. 2) Find a '75 (preferably, due to N42 head) or '76-'78 (second choice, due to N47 head) 280Z engine, locate a set of L24 (or L16) rods with 9mm bolts. Remove the dished L28 piston/rods and remove the pistons from the rods. Discard the L28 rods. Have a good machinist turn down the rim of the dish (converting it to a flat-top) just so that the Nissan markings in the base of the dome are barely visible on each piston. Weigh the pistons individually and the rods (L24) individually. Match the rods to pistons for the most consistant unit weights and have the pistons (pins) pressed onto the matched rods. Match piston/rod units by weight with the best corresponding unit matched to it according to how much the two will weigh when they are at TDC when their counterbalancing piston/rods are at BDC. That may be hard to follow but think dynamically about setting up the rotating mass. So, taking down the piston rim allows the use of the 2.6mm longer rods which restores the deck ht.; makes about 9.8:1 c.r. (vs anemic 8.3:1 stock); and converts your engine to a more favorable rod/stroke (133/79 vs 130.4/79). These changes will really wake up the engine, then come header/exhaust, camshaft and induction (look for 2" SUs, triple side drafts, or fuel injection with some mods). 3) There's another approach that involves the use of an LD28 shortblock, but that's a little involved for the stage you're at. Good luck and have fun. DAW Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.