Tim240z Posted October 28, 2002 Share Posted October 28, 2002 Quick poll: HP difference (real life) between 2.4 and 2.8. Is it worth the effort changing my 2.4 in my daily driver to 2.8? I have dual down draft webers on my 2.4 and would transfer them over to the 2.8 (if I went that way). Nothing wrong with my 2.4 (runs like a top), just a bit lazy. Would like a little more......(or maybe I should just wait for the LT1 Z to be finished to get my power fix from) Tim BTW, I have a second, complete 2.4 in the garage. Should I use those rods on teh 2.8? Quote Link to comment Share on other sites More sharing options...
Mike C Posted October 28, 2002 Share Posted October 28, 2002 What year is your 2.8? If it is a flat top motor, I would get an N42 donor head and do it in a hearbeat! If it is a dish piston motor, I still think I would do it. Using your 240 head so you can keep the square port 240 exhaust manifold. I think the 240 rods are a different length than the 280 rods and are not interchangeable. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 28, 2002 Author Share Posted October 28, 2002 Mike, Thanks for the quick reply. I don't have a 2.8 yet. If I was to go this route, can you recommend an appropriate year to pull from? Aren't the valves in the 2.4 head smaller, and thus a restriction point on the 2.8? Thanks, Tim Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted October 28, 2002 Share Posted October 28, 2002 I've got ya covered. I ran a 2.4L with an E31 head and a 262 /272 cam and that combo would run 9.45 @ 73.5 mph I switched to a 2.8L with an N42 shaved .040" and the 262/272 cam and only ran 9.25 @ 75 mph. I could have shaved the E31 .040" and almost ran the same time. Later on I shaved the N42 another .030" and installed a 272/282 cam on the 2.8L and ran the 1/4 mile at 13.4 101. After breaking the crankshaft from powershifting on that motor I reinstalled the 2.4L with the the same N42 head and cam and turned a 13.6 @ 99 mph. As you can see it wasn't a huge difference. The main advantage is in everyday low end torque with the larger motor. If you like to rev the poop out of your engines you could get a more aggressive cam and turn the 2.4L safely to 7500 rpm or maybe even 8000 rpm and run the same or faster times than a similiar 2.8L. Its really up to what you want. later,norm Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 28, 2002 Author Share Posted October 28, 2002 Thanks Norm. Can I assume that the inlet and exhaust systems were identical on both engines? That is surprising that the differences are so slight. So maybe I'm better off just pulling the spare head off the other 2.4, port it a bit and get a cam? Tim Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 28, 2002 Share Posted October 28, 2002 Tim.. here is a better L6 website I came across on about everything you want to do: web page example: the F54 is the better 280 block becuz it has additional webbing cast between the cylinders for better cooling and rigidity. etc. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 28, 2002 Author Share Posted October 28, 2002 Larry, Page was 'not found'. Is the URL correct? Can you get to it..... Thanks, Tim p.s. Do you still want all the stuff you have paid for? I absolutely don't mind holding on to it until you're ready, but if you have changed your mind, don't be shy....I'll refund you man. Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted October 28, 2002 Share Posted October 28, 2002 '81-'83 280ZX non-turbo L28s had flat-top pistons, which you want. Next step is to up the compression, via modifying the stock cylinder head or using an earlier one from a dished-piston motor. Plenty of recent discussion on both of these methods. Stock compression ratio is abysmally low, you should be able to get at least 10% more torque and power by upping it from ~8.5:1 to ~10:1. O' course you'll be using premium pump fuel then, but hey, it IS a sports car. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 28, 2002 Share Posted October 28, 2002 The url may be entered correctly now.The website is comprehensive at 14 pages and I printed it all I still want the stuff but my prodigal brother is in the Phillipines and Nate sez he will be in the LA area around Christmas. I still need the tranny since the my gut reastion on the current one is not good besides I actually want about 3 of them. The price was good to begin with. I will have a lot of parts in that Tomahawk from a lot of members. Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted October 28, 2002 Share Posted October 28, 2002 Just wanted to clarify that my suggestions were based purely on keeping it inexpensive. If you don't mind the work and cost involved then by all means upgrade to the 2.8L as it will make more HP even if its just a littler more. Just so you know I only kept the 2.4L in for 4 months and then went with a 2.9L stroker motor as I like torque as well as HP! You could build a cheap stroker like mine and run circles around about anything on the road. Later,norm Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 29, 2002 Author Share Posted October 29, 2002 You could build a cheap stroker like mine and run circles around about anything on the road. Details please...if you don't mind..Tim Quote Link to comment Share on other sites More sharing options...
johnc Posted October 29, 2002 Share Posted October 29, 2002 Tim, If you don't mind rebuilding one, I'm probably going to sell the N42/N42 long block that was in my BSP 240Z. Static compression test after we rented a track to test the Penske's came back 185/120/185/180/120/165 so I pulled the motor planning to rebuild it. There's .010 room left for a rebore (if needed) but I was hoping that honing would fix the problem - otherwise its time for new pistons. The head needs refreshing too - 25,000 autocross and track miles kinda wears things out. The head and block have all the trick stuff from JG Engine Dynamics for IT/BSP and the engine had 9.6 to 1 compression even with dished pistons. Johnson Machine in Monrovia did all the work on it for Javier back in 1996 and they still know what they are doing. Figure about $500 for block machine work and $150 for pistons if you need them. The head would be about $400 also assuming the rockers and cam are still good - they still look fine. I was going to ask $1,200 without the rebuild and $2,500 to $3,500 with depending on what else I throw in (header, exhaust, SUs, intake, ignition, etc.). Just an option if you decided on a L28... Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted October 29, 2002 Share Posted October 29, 2002 Hey Tim, my setup is el cheapo in that the bottom end buildup has stock 280 rods and pistons with the addition of the diesel crankshaft. I'll send ya an email on an old write up about everything I did as it is too much to type again.LOL later,norm Quote Link to comment Share on other sites More sharing options...
inZane 240 Posted October 29, 2002 Share Posted October 29, 2002 Do you mind sending it my way too? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 29, 2002 Author Share Posted October 29, 2002 Thanks Norm....Great write-up!!! Mr Coffey, That is a seriously generous offer , and is highly appreciated. If this was my only car, I would be ALL OVER it, but I need to put those $$$ into the LT1 Z. I just want to do something cheap and nasty to give my daily driver a bit of pep since the V8 Z will only be a weekend and track warrior. Tim Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted October 29, 2002 Share Posted October 29, 2002 yeah everything alse was the same including the drivetrain. BTW it all depends on what ya want and how much money you have to spend. You will go faster putting your money into head work and a cam for your 2.4L than just swapping in a basically stock 2.8L. Later,norm Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted October 29, 2002 Share Posted October 29, 2002 If you do stay with the 2.4L I'd advise shaving the head for increased compression as you will lose too much low end torque with a performance cam unless you raise the compression. BTW, if you just shave .040" off your head you can get by without shimming the cam towers as there is enough adjustment left in the chain guides to take up the slack. If your chain is really old buy a new one as they do strecth quite a bit. You have three settings on the cam gear to make up for the retarded cam timing from not shimming up the cam towers and if you think the cam is too retarded then just run it in #2 or #3 slot. Although for top end power a more retarded cam timing setting is ideal. If I was on a limited budget that is exactly what I would do. And btw if you don't already have a 3.9 rear end upgrade to that also. Later,norm Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted October 29, 2002 Share Posted October 29, 2002 I'd say go with the 2.8. ~same hp as a lightly modded L24, but much more potential. Displacement is the foundation. Get as much as you can and build on that. Dan "preachin' what he practicin'" Baldwin Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 29, 2002 Author Share Posted October 29, 2002 Again, thanks for the info guys: I figured the 2.8 would be the way to go. The only thing that makes me hesitate is that I have a spare 2.4 in the garage (along with a 4 bolt 350) and various transmissions etc, so I would add another 2.4 to the pile if I sourced a 2.8 to swap in. (my wife is gonna have a kaniption) OH well, HP is worth the from the wife. Excuse my ignorance, but if I were to hunt down a 2.8 in the JY, any particular years better than another....keeping in mind that I will be keeping my dual weber setup. Tim Quote Link to comment Share on other sites More sharing options...
Guest Zpeed Posted October 29, 2002 Share Posted October 29, 2002 Hey norm Quick question, about the diesl crank does that just replace the orinaal 2.8ltr crank, without any other parts as the such. hoping to build a 200+hp L series soon.... 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.