Lockjaw

I would not worry about changing the head gasket, Nissan puts a good one on it from the factory. Sounds like a good deal. Hell the plugs are worth more than the motor. HAHA Have fun installing it. Not that big a deal. I could do it, but describing it is something totally different. Good luck.

If you like loudness get a flowmaster. Otherwise get a 2.5 or 3 inch set up with a straight thru muffler like a race magnum, hooker max flow, or walker ultra flow. You trying to outloud the Honda's with fart pipes?

http://geocities.com/zgarage2001/heads.html Try this link for more info. It has some good stuff on it.

ENGINE CASTING CODE L24 ('70-73 240Z) #P30 (flattop pistons) L26 ('74 260Z) #P30 (flattop pistons) L28 ('75-80 280Z) #N42 (dished pistons) L28 ('81-83 280ZX) #F54(flattop/dished pistons, siamesed cylinders Here is the block info numbers I have found. According to what I saw, the f54 block with a p79 head is the only one with flat top pistons, all other L28 engines had dished pistons.

Yeah I believe I read that in one of the Nissan hotrod books. That would be its compressed thickness BTW. Unless you went to a ZX shortblock, I am kind of thinking you have dished pistons. I am not an expert on this, but I know for a fact that the Zx engines with a P79 head were flat tops. Surely someone could tell from you block type. I think F54 is for flat top. Not sure about that. Either way, if you had dished or flatop, I doubt the thicker head gasket would hurt you. Ultimately you may be able to run more boost at the expense of a little response off boost. But it is like Corky Bell says, if you don't have boost, you don't have that huge torque increase to look forward to, and hence, no fun. You may be able to pull out a plug and scope out the piston top and tell, or stick something in thru the spark plug hole and check for a lip on the edge of the piston. I am thinking of something like a heavier zip tie or something that won't scuff things up, like say a coat hanger. The dish is pretty pronounced. Ah what the heck, boost it and see what happens, its only money right?

Hey sleeper, do you have a stock 280zxt ecu? If you do, I hate the way those shut down.I had a stock ECU that would go to 7k or better, but usually only right after I changed the cap and rotor. Go figure. The way those things shut down, you hit and you lose the race unless it is a really slow car. My JWT box has a 7k one, although Clark told me he could set it anywhere I wanted. I may change it a little if I get a larger cam. It is much softer when I hit it than the stock ecu.

OK, we will try to go in oder here. Yo2001, I odered an adjustable sprocket today for 93.00, and I posted the link to the place in the head gasket post. I sent you an email about the tps. As far as lobe centerlines, I need to do some research in that area because I am not a fan of a wide centerline. Of course most of my cam playing was done with normally aspirated Z motors, but I will look around some and see. I am not doubting you mind you, just one of those things if you know what I mean. I have seen the Scneider cam in the Motorsports catalog, but have never heard of anyone running the turbo cam. I have run two different NA Scneiders, and liked them both. I have heard bad things about Schneider from JWT people, mainly involving their customer service. I have seen in some of the old Nopi ads that Gude made a turbo cam for the z motor, but I checked his web site and did not see anything that looked good, and no real specs or stuff on the L series cams. Rocker arms are another issue. That is why I wanted to get a cam sort of larger that stock but on the smaller side so I did not have to get springs and retainers and lash pads too. If I got one ground on a billet, I could keep the same base circle as stock, and then i should not have to change lash pads. In reality though, if the cam manufacturer changes the base circle, it is pretty simple math to arrive at the correct lash pad thickness. I did it with a crower regrind and hit it dead on. I heard some folks we having some success retarding the stock cam some, like 30 to 40 hp worth, which is why I wanted the adjustable sprocket. I wish I had gotten my dyno pull on a disk so I could post it. I have larger injectors, and my torque and hp figures spiked pretty hard, and then torque dropped immediatley, while horsepower stayed pretty flat but declining thru about 6k. I make my major power between 3k to 4.5k or so. I would have been easier if the guy had me set up as a 6 cylinder rather than a 4. I was like, I know I wasn't turning my engine to 10k rpms. I think the cam would help extend the power band further, and especially once the torque and hp lin cross at 5250 or so. So lets say it hits hard about 3.2 k or so, and stayes pretty flat out to 6 or 6.5k. I could live with that. I don't want to be turning mine to 7.5k. I like my stuff to stay together and went thru enough piston rings when I was normally aspirated. What we really need is to get someone to make us some roller rocker arms, and a cam that will work with them. I think there is plenty of room in the head to do that. and probably power to gain, not to mention friction to lose. Imagine how quickly we could snap the valves open and closed with a roller profile. It can't be that hard to do for someone like crower. As you can see, I have a lot of time to think up idea's. If I hear anything, I will let ya'll know. I may have to break down and call Clark at JWT. It would be handy to come up with the spec's on all the L series cams though. I bet some people in SCCA would know or would like to know.

So you are saying the 83 cam had 4 degree's of advance ground into it? Is that right? See I am thinking I could send the factory cam to crower and have them grind me a new billet cam with more lift and duration, without getting to the point where it lopes. Then it should pull cleanly to about 6500 or so, with good power when the cam came up and the turbo spooled up. I would go up to about 420 or so lift, maybe as high as 450, and add about 15 to 20 degree's of duration, and leave everything else alone. What I don't want to do it get some big old cam that lopes and kills the response down low. Maybe I should short shift my car at the drags next time and see if it runs better.

Oh I forgot to add. You can have your stock turbo upgraded. If you change to a hybrid, you will have to do some wastegate actuator modification, which is kind of a pain. I ended up sending my turbo (hybrid) out to Top End to let them fab up a bracket after I clocked the turbo properly. When John Meyers was alive, he would mod the stock turbo by having both housings machined so he could fit larger compressor and turbine wheels in them. They worked pretty well, particularily if you used the GN wheels. The plus to that is the turbo is physically the same size, but it just makes more power due to the larger wheels. I would think any of the shops could mod your stock turbo. I would get the super 60 compressor wheel, and go to a stage II or Stage III turbine wheel. That is if you stay with the stock turbo. If you go to the hybrid, you have to make some modifications. I had to change how my oil drain line ran, and the inlet of T4 housing is bigger than a T3, so you have to get that plumbed. I used 3" pipe, and went to a truck shop and got some different 3" nitrile connections and plumbed mine that way. I had a slight bend put in one but if I had to make any bends more than 30 degree's, I would get some mandel bent elbows and cut and splice them and have a muffler shop weld them together. Then just prime and paint them. You will also have to get a down pipe made if you use a hybrid, and I would have a 3" one made. There is a lot to consider. And it gets more expensive as you go.

Yes 307hp to the wheels. The engine is basically stock with the exception of forged pistons and I used 240 rods instead of 280 ones just to be different. Actually I used the 240 rod since it is slightly longer in an attempt to improve the rod to stroke ratio and lessen detonation potential. Don't know if it helped or not. I have no porting, stock cam, head etc. I had it all balanced, used ARP rod bolts, and did a lot of rod work like polishing and shotpeening and having the two oil holes drilled in the small end like in the Hotrodding a nissan engine book. The rods should be good for a lot more HP. My number is pretty good, but there are plenty of guys out there making more. I am hoping to get up close to 400. I think that would be brutal. My next engine will be much more modified. I will likely bore it out a little, I have a friend who has a diesel crank he said I could have, I just have to pull the engine out of the car, so I may do that. I want to port the head mildly, and use a little larger cam. I will likely use some of those coatings, and want to get some stuff extrude honed as well. It would be easy to stick 5k in an engine. Machine work is really expensive if the people are good. I guess I should start ordering stuff someday. I could probably put one together over the course of a year or two that would be pretty wicked. With my luck, I would have to take it back down for an oil control ring, which I had to do on this engine. Sucked. Ran great for about a hundred miles and then started doing the oil puking thing. Number 6 cylinder. I was really careful too. Let me know what you come up with, I would really be interested.

Well I sent an email off about the cams so we shall see what I get back. I also ordered the NISMO adjustable cam sprocket, and am going to try retarding the cam and see what happens. I can retard it up to 9 degree, or advance it up to 12 degree's in increments of 3 degree's. I think retardation is the way to go. Not very PC was it?

http://nismoparts.safeshopper.com/7/cat7.htm?482 Try this one for head gaskets too. They have a 2mm thick one. Not cheap though. But neither is the HKS unit. I am sure I did not drop that in there right, I am not a computer geek. Sorry.

You can run any cam in the "non-hydraulic" head, it doesn't matter if it is the hydraulic cam. I will see what I can find out, and I will post the results. I would like to know the spec's so I can have a larger one made.

I have had my set up for about 3 years. When I talked with JWT, what they told me was to send them a 84 to 85 300ZXT ecu and they would mod that. My impression was they could not mod the 83 box. They ended up deciding the 88 thru 89 NA 300 box was a better choice, so they just swapped me out even. They used to use the MAF off the 300, but the cost to replace one is expensive, and they did not like the way Nissan set up the hot wire in there. I guess every time you shut the car off, the ecu would send a nice voltage spike thru the wire to clean it. I was the second person to use the cobra MAF set-up. They were in development stage with it when I talked with Clark. The car they were doing was an auto with a big stall, so I was the first 5 speed person. I went thru about 6 chip revisions with Clark since I was esentially R&D'ing the set up for them. At first my car was slower than with the factory set-up. What I noticed was the car would not really rev over about 5k, so we started adding some timing. Every chip I got with more timing made an improvement. The chip I have now rocks. The Ecu is set up with a 7k rev limiter, I have 420 cc injectors, an HKS intercooler, big fuel pump, and a hybrid turbo. The car runs high 12's with drag ta's on the back, and I have run a high 12 once with street tires and using pump gas. Since I don't drive the car everyday anymore, I usually always have some racing fuel in the tank, mixed with super unleaded. My best pass so far is a 12.77 at 113.75. I have run an 8.39 1/8th at 89.25. I have a fully loaded 83 280ZXT, and when I had it on a dyno last fall it made 307 hp to the rear wheels. It is very responsive and the drivability is way better than I could have ever gotten with the stock set-up. If your car is being painted right now, I would snatch the ecu out and send it to Clark at JWT. Have him check it out for you. I only deal with Clark out there. I think Jim is a jerk and he doesn't like to talk to people unless they are a technician. Clark usually only takes calls in the morning, and he does programming in the afternoon, so you won't be able to talk to him after lunch. If there is something funky going on, Clark will take care of you. He's a nice guy, and truth be told, he is probably the brainchild for the operation. Does it have a sticker on it? Mine has a sticker on it from JWT saying what it is. You should see about getting them to upgrade you to the cobra maf set-up. Much better way to go. The MAF is only about 200 bucks, the nissan one is well over 400. It sounds to me like you may have a Motorsports modified ecu. Could that be possible? They are the only people I know of that were ever modding the stock 280zxt box. It should have a sticker on it if from Motorsports too. Check it out and let me know. I will check the board periodically to see what you found out. Good luck.

HKS offers a head gasket that is 2mm thick, which is roughly the thickness of two factory head gaskets. You should be able to get one from NOPI or TOP END. I am not sure I would recommend two stock ones to gether. The HKS one is supposedly reusable too. What pistons does your engine have? If they are dished, I doubt you need a thicker head gasket, if they are flat tops, I would recommend the thicker gasket. If you have a good intercooler, then it may not matter what piston head gasket combo you run. I have flat top forged in my turbo engine, and they are about 10 thousandths down in the bore at tdc, and my P90 head has been shaved slightly and I use the stock head gasket and I can run 18 psi with my hybrid on pump gas.

I put my AFM out in front of the radiator to have more room before I put the JWT system in, and I liked the room, but the AFM did not like being that far away from the turbo. I had a hardtime when it was cold and I first started the car, and response problems also. I can say that having the MAF vs the barn door is a night and day improvement. the responsiveness that I gained was well worth the price. You could also consider swapping in the harness, MAF, injectors , and ecu from a 300 zxt and run that. I am sure it would offer better drivabiity than the 280zx stuff. Stand alones are great, but you have to know what you are doing to have one. If you don't, you will have to pay someone everytime you have a problem, and you have to have a laptop to tune them. An upgrade to a different ECU and MAF will easily compensate for different conditions, will have stock like reliabilty, and will run fine. Mine has compensated for everything I have done to it, and when I upgrade my turbo, it will compensate for that too. I have no piggyback things on my car, but I do have a Bosch adjustable fuel pressure regulator that allows me to change the fuel pressure while maintaining the factory set 1 pound increase in fuel pressure for each pound in boost. So far I have not adjusted it from its stock setting though. JWT has lots of cars out there that freakin haul ass with ecu's they have modded with different MAF's. If you want bigger injectors than what they typically offer, just tell them and they will work with you. I may upgrade to 550's one of these days. I would go after one of the infinity boxes now that has two timers in it so you can run sequential fuel injection on 3 cylinders. My box is like quasi sequential in that under 50 percent, it fires the injectors 3 at a time, versus 6 at a time in the stock set up. Since it only has 1 timer, when it reaches 49 percent, it fires all 6 injectors. A box with two timers would still onluy fire 3 injectors all the time, which would give you better mileage, and drivability. They have done an infinity box on a 300 single turbo. If you call out there and want to know, talk to Clark. Forget Jim and those other guys, Clark is the guy who will break it down for you and tell you the straight scoop. That is my .02. Feel free to send me an email any time about the setup I have or what it runs thru the 1/4 mile. It is not slow.

Well I am not sure, which is why I would like the spec's. I know they went to the trouble to stamp 3 different letters on the backside, and I have heard the 83 cam is the best one, but without having the 3 cams and sending them to Crower or somebody, I don't know. My friend has a shop with lots of Z cams laying around, and I could not find a single J grind, I found a few F's, several M's, and a B, which I put in my car. I had an old BAE kit with a rotomaster turbo, and I knew it would not spool very quickly, so I wanted a cam that had more bottom end. I figured since it went in the auto, it had to be slightly milder. I have tried a regular stock ZX cam, and did not like it, and I tried a Schneider cam that I had for an NA engine, and it sucked as well. But you have to have the specific specs on the cam to dial in the desktop drag program, and I have no idea what the specs are. I just would like to play around with the thing and see what it thinks I need to try for more power. I guess I could call Nissan Motorsports, but that is always such an ordeal. It took me forever to convince the guy I spoke with last time that there were different cams. He said they were all the same. I told him politely that he was mistaken. Anyway, just thought I would take a shot before having to waste my major long distance talking to Nismo.

Hey, Does anyone out there have the spec's on the 3 turbo grind cams Nissan put in the ZX's. I think they are B, J, & M. I have the B grind, and I know the M grind is 83 only manual and auto. B grind is Auto 81-82, and J (not sure if right) is 81-82 manual. Any idea where I could find out? Need the specs to play around with the Drag program. Thanks.

Ok, you say you have a JWT modified Ecu. Which one? My understanding was that his set up came with larger injectors and a Mustang Cobra MAF. IS that the set-up you have? That is what I have in mine. I have an 83 ZXT with 89 ecu modded by JWT, larger injectors and a cobra MAF. I also have an HKS intercooler kit. Where did you get the set-up? Did you buy it from JWT or a private party? Sounds to me like you may be missing some of the stuff needed. Let me know and I will see if I can help

DO you have the factory waste gate actuator? If you do, it sucks. I have a dual port one from Top End on my hybrid, and it rocks. The only time I ever had a boost drop like you describe is when my turbo started going south. I had some contact between the compressor wheel and the housing. You may want to check that as well. I hope it is the actuator.

Anyone got a rec on a relpacement coil for my 280ZXT. Need one that can handle increased boost pressure. I currently am using one of the little first gen 300ZX coils. It works pretty well, but I think it may be going bad. Is there anyway to test it? If my coil wire over to the distributor was arcing on my intercooler line, would that cause the coil to overheat and quit working? That is what I suspect happened. The coil was very hot and the car just loaded up at idle like they do when the alternator is bad and the battery runs down. Tach started bouncing around some and then the car would just die. I have an old HKS twin power ignition that I had to completely disconnect to get the thing to start, and thought that was the problem until it did it again with just the coil running. Thanks

Getting rid of the door will probably help alot as far as responsiveness is concerned. I hated that big AFM, it was just tough to work with all that mess when you were trying to use a larger turbo and plumb all of that and intercooler lines too. I am not so sure that I still think the stock ZXT computer is not going to be a hinderance as well. What can I say, I am just not a fan of the stock set-up. I am sure some people have made thier cars plenty fast with them, and more power to them if they have. I like nice drivability, and I never got that with the stock set-up. I guess it all boils down to money, or in my case the lack of it. One of these days I am going to have a stand alone, until then, my JWT system will have to do. Good luck with your plans, which ever way you go.

I used a Conquest intercooler in my 240 when it was turbocharged. It is ok if you don't mind 5 psi worth of pressure drop. This is just my opinion because I know alot of people out there do things different and make it work, but a stock oem intercooler is not designed to work in the higher boost environment most of us run in. While it may work, you may have a lot of pressure drop, or low efficiency both of which are robbing you of power. I think the guy on here with the twin turbo 240 L engine will back me up. You will make more power and be ahead of the game if you spend the money and get a good intercooler the first time. Again IMO.

Hey, Does anybody know where I can come up with a matching pair of Epsilon 3 piece wheels? They would be 16" with the black mesh ceters. I need two center caps as well. Or I have 3 good one's and 1 bad one I would sell. 2 match (same width). I have two center caps. These were popular years ago. Thanks

I have the JWT conversion on my 280ZXT. It uses the stock harness with a couple of wiring mods, a MAF from a 93 Mustang Cobra, 420cc injectors, 89 NA 300 brain, and the chopper wheel from the 300zxt, although I don't think it matters as long as it is a V6 chopper wheel. I was the 2nd person in the US to use the set up and it took some time dialing it in. I had several chip revisions to adjust timing, and am very satisfied with it now. Not at first since my car slowed down, but it has always had outstanding part throttle driveability. My hybrid turbo spools faster than it did with the stock set-up, but best of all, there is not that distict change from no power to power that I always had around 3500 rpms with the stock ZX fuel injection. Clark at JWT likes the Cobra MAF since it is cheap in comparison to the Nissan unit, I think I paid less than 200 bucks for a new one. I have a T3T04B hybrid with the stage III turbine and an H3 compressor and I have full boost by 2800 rpms. It starts making boost around 1800 to 2000 rpms, and I could never get that with the stock set-up. The other thing I like about an MAF equipped car is that they compensate for mod's a little better. I have not had any troubles out of mine. Stand alone may be better, and I considered that, but at the time, I drove my car every day and wanted the reliability of having a factory ecu. And I did not have a laptop as I do now, so I may go to the tec unit one of these days.