jmortensen

I've swapped 2 cams into 2 L engines without changing rocker arms. So far so good. The first engine had a stock cam, I swapped in a mild cam and ran it for 10K miles, then I got a bigger cam and changed lash pads and ran it for another 30K miles. Then I built a new bottom end when the crank pulley came apart on the first engine and that same head went onto the new engine. It now has about 40K on it and it has no problems with the rocker arms whatsoever. Nobody I know has replaced rocker arms when swapping a cam and I used to hang out with a bunch of 510 autoxers, and nobody I know has had a rocker arm failure at all. If you include all of their cam swaps I would guess that would be at least 5 more cam swaps without replacing rockers. Take that for what it's worth. Lift over about .470 or .480 requires new springs because stock springs coil bind right about there. The other thing that happens is that the retainers will hit the valve stem seal. I installed a .490/280 cam into an E31 with Schneider springs and retainers and found that even with the aftermarket retainers they still hit the valve stem seal. I had my retainers turned down by a machinist to give .050 clearance. Then later on on another forum someone else found that Ford 2.9L V6 valve stem seals fit right onto an L and give huge amounts of clearance. Viton is just a better material for seals anyway, and I don't hear too many people proclaiming their love for Nissan's valve stem seals. This is a great way to go. Here's the details on this: http://forums.hybridz.org/showthread.php?t=90825

ZSaint is thinking of an entirely different LSD. The VLSD that started this thread won't use 280ZXT CV's, because the VLSD has more splines on the inner end of the CV. It just doesn't work. You'll have to have the original VLSD CV's, or if you don't have them then you might have to get some from another Nissan with VLSD, like a 240SX or a later 300ZX. I think the 88 CV's are the right length, the others ARE TOO LONG. Definitely get the 88 CV's if you can. If you're really lucky, these will work and it will bolt straight up: http://www.modern-motorsports.com/catalog/product_info.php?manufacturers_id=&products_id=56 I don't know for sure if it's as easy as that or not, but a lot of guys are running the VLSD on hybridz.org so you might search over there and see if you can find the info. ZSaint, why wouldn't this have worked for you? http://www.modern-motorsports.com/catalog/product_info.php?cPath=32&products_id=5 Sounds like you went about it the hard way unfortunately...

Unless there is something wrong with the REAR toe, front toe shouldn't cause an issue under "dynamic braking" unless maybe it is WAY off to begin with. The reason is that the wheels will center themselves and you'll have an equal amount of toe in or toe out on both sides. The steering wheel might be offset to one side to compensate, sounds like you've already experienced that. But unless you hold the steering wheel where it started out, the wheels are going to go as straight as they can down the road just because the force of them driving forward will make them want to go straight. Why not run a tape measure across and see where the toe is? Just hook into a particular tread on the tire, then measure to the same tread on the tire on the other side. Do this as high up as you can on the front side and the back side. Subtract the difference, there is your toe. If you're all stock then front toe is your only adjustment you can make. You can get it close enough without having the car aligned by a pro. If you want to know where caster and camber and thrust angle are, then you'll need a real alignment. To fix the steering wheel issue there are a couple of things to take into account. Most important, did you get the tie rods on evenly? Is one tie rod threaded in 3/8" more than the other side, or did you put them on evenly? If not, go back and even them out before you adjust the toe. You can see if they're even by the number of threads showing on the inner tie rod. If you don't even them out you'll end up with the ability to turn farther left than right, or vice versa. Once you have them even, you lock the steering wheel in place (always nice to have a helper to just hold it straight). Then you adjust the toe as necessary, toe in of about 1/8" on front is pretty good for street. Then you lock everything down and drive. If the wheel points slightly left or right, you move the tie rods, not the steering wheel. If it points left you need to move the tie rods left, meaning you need to lengthen the right tie rod and shorten the left. As long as you do this in an equal amount the toe won't change. So you can go 1/8 turn on both sides, lock it back down, drive again and see what happens to the wheel. Should take about 20 minutes to adjust front toe. It's pretty easy, and every time I've done it with a tape measure I've been within 1/16" on the alignment rack. The rest, caster and camber can be done with a modest degree of accuracy with a bubble gauge, but REAR toe is very hard to adjust without an alignment machine, because the tires could have 0 toe but still be pointing off slightly one direction or the other, making the car crab down the road. If this happens on the front the steering wheel turns to compensate. No steering wheel to compensate in the back, so it will actually drive the wheels to the left or right. You might have seen a Volvo crabbing down the road, they're notorious for that problem. Unfortunately in a stock Z only front toe is adjustable, so anything out of whack on the caster, camber or rear toe is going to require some pretty big modifications to fix, probably adjustable camber bushings at the least. EDIT-Your shimmy is probably loose wheel bearings, or warped rotors. Could be wheel bearings are too loose, I would also say that bad tie rods or ball joints could cause this but that shouldn't be the problem in this case.

I've been using an air hammer with a chisel tip. If the rubber is hard it pops off pretty cleanly, but it leaves a bunch of little chips still stuck to the floor. The best thing I've figured out for them is to use a wire wheel to get most of it off, then some acetone to get the last little bit. It is VERY labor intensive. I had no idea what I was getting myself into when I started... I guess mine was more rubbery than yours or something.

The 3 or 4 or 5 valve per cylinder heads have a better combustion chamber shape and flow better than a 2V per cylinder head. That means they can operate better at high rpms, and the OHC cams have better control of the valvetrain. One more time comparing the OHV to the L series specifically just cause I like to beat a dead horse, then some efficiency stuff. The L6 doesn't have more than 2 valves per cylinder, newer DOHC heads have a very big advantage here that the L doesn't. Along with the number of valves the shape of the combustion chamber can be improved. The L also doesn't have the cross flow that a OHV V8 or more modern OHC head has, so it looses out on the scavenging advantage that the cross flow has. On the L6 the exhaust port is lower in the head than it would be in a cross flow head which makes the short side radius necessarily tighter which isn't good for flow. Now onto efficiency. More efficient doesn't mean less pollution. This was the reason that engines sucked so bad in the 70's. Look at the early V8 or even the early Z heads vs the ones from 75. They went from a shape we would recognize today (the closed chamber with lots of quench) to the "open chamber" in an attempt to cool down the combustion process. More efficient means more NOx which is the main contributor to visible smog. Also take a look at the compression ratios. The V8's were pushing 10:1, back in the hardcore muscle car days you could buy some hipo V8's with 12:1 right off the lot. Z's started out at 9:1, and lowered their compression to the low 8:1 range in the 70's. Lower compression = cooler power stroke = less efficiency = less NOx. EGR was added. Dump some exhaust into the cylinder to cool it off = less NOx. Here is a related link that tells what things happened, but it doesn't really compare the emissions equipment to an attempt to reduce efficiency: http://ca.autos.yahoo.com/maintain/answer.php?catalytic_converteranswer1.html Nowadays the car manufacturers have finally figured out how to get the high compression, powerful engines we want without all the smog. But the efficiency is in spite of the smog regulations, not because of the smog regulations.

I believe that my car doesn't have a soul. My car also doesn't have a name, and I don't talk to my car in anything other than a joking manner. I think it is an assemblage of parts that makes a machine. I control what parts go into the machine, and when those parts make a machine that pleases me, then that's when it's doing what I want. When parts break my car is not "sick" and since I have it torn apart right now it is not being "vivisected"... ;-) I don't want a Vette either. Too heavy. I do envy that assemblage of parts under the hood of a Vette though. Last time I checked it weighs less than my assemblage of parts under my hood and makes a good 75 hp and 100 lbs torque more than my current assemblage. So if you learn something from somebody on the internet and you implement changes based on what you learned... oh nevermind. V8 costs about the same as a turbo. I'd rather have the V8 personally. I can only tell you what I know, and since you've said you won't be reading this there isn't much point anyway. I've come up against a VG30ET 240, a couple L28ET 240Z, a Z31 Turbo and a couple of Z32 Turbos (one with over 500 hp) at autoxes and road courses. Haven't found one yet that was faster than my L28. I'm not saying that my car is the fastest thing on the planet, because it isn't and I know better. But I'd rather have 400 NA hp than 400 boosted hp just for the lack of lag and the linearity of the power. I've heard people say you can build a turbo without those problems, I just haven't seen it in a Z yet.

OK, you caught my math error. I suck at math, sorry about that. I still don't buy your parasitic loss argument. 32 valves, springs, retainer, and keepers is still a lot of mass. I'm fully capable of understanding the hypothetical, but I don't make my decisions on what engine to put in my car based on hypotheticals. If you want to that's just peachy. You can extend that theoretical advantage over a hypothetical pushrod L6 to theoretical infinity. ;-) As for me, I'll do what ACTUALLY makes the car faster. I don't need a hypothetical advantage, I need a REAL advantage. For this reason I keep comparing the engines that exist and get installed into cars that actually exist. Why do you insist on referring to a hypothetical advantage? Does that gain you any traction here on planet Earth?

Yeah, I had similar experiences. My Toyota P/U has 208,000 and my dad had a 85 S10 Blazer that broke down every 3 weeks that turned me off of American cars for a LONG time. My Z had ove 200,000 when I got it, but that's not a fair comparison since it's had 2 L6's, a tranny swap, 2 diff swaps, etc. The thing is that the 70's and 80's were CRAPPY for American car manufacturers. Quality was LOW. Very LOW. Power was down. Cars struggled under smog restrictions and plain ol bad engineering. The big 3 really didn't know what to do about smog. My friend's dad had a 78 F150 with a 351W or M or whatever engine in it, and we tried to pull his 510 to a race some 4 hours away. Took us 8 hours and we were doing 35 miles an hour up ANY sort of grade. What a horrible POS truck! During this time the Japanese cars had a major advantage in that they didn't try to redesign the same car over and over and over. They were able to make designs that passed smog but weren't quite as badly affected in the power or reliability areas, and they took over huge portions of the market share deservedly so. Even in the 90's American car manufacturers were still making pretty cheesy interiors, with switches and gauges that were cheap and crappy in aesthetics and functionality. Times are changed though. GM cars have come up significantly in quality and in design. If you choose to still remain wary of American cars, I can't say that I blame you one bit. But they are better and more efficient and more reliable and more powerful now than they have ever been. http://www.theautochannel.com/news/2005/06/30/136286.html This is one of the strongest selling points for an American V8. I can buy 8 forged CSB pistons for less than the cost of 6 forged Nissan pistons. I can also get 8 connecting rods for less than the cost of 6 Nissan rods. Everything in the aftermarket is geared towards the CSB in particular, and that is a huge advantage. Imports are getting increasing aftermarket support as time goes by, and I for one really hope that the Nissan 5.6 gets a wide array of aftermarket parts to choose from. We'll have to wait and see. If you're happy with your 200 hp more power to you. If I could be happy with that I would have saved 100s of hours in labor and 1000s of $$$.

It looks like a kick arse engine by all accounts. The issues that I can see are: cost, availability, aftermarket support, weight, size, transmission options. I'm sure the first three will be overcome with time, the last 3 might be a problem, might not. What engines are you talking about then? I thought we were talking about Z's. As I've pointed out several times, despite the theoretical advantage of the OHC L6, the L6 does not necessarily have a higher rpm limit than a Chevy V8. Both of these engines are commonly found in our beloved Z's. If you're back to theory that's fine. Theoretically I agree with you 100%, which is why I voted that I prefer the OHC design in the poll. If you are saying that there exist OHC engines which spin higher than the fastest OHV redline I would agree with you. Why that relates to somebody's choice about an L6 which doesn't have those characteristics is beyond me. Parasitic loss? How about having to spin 4 cams instead of one? Opening and shutting 48 valves instead of 16 uses less hp? How about the drag of the gigantic chain and the idlers and all that? Think of how much mass is in the chain(s) on a DOHC V engine, it's gotta weigh at least as much as all the pushrods put together, and thats not even counting the cams, cam gears, valves, springs, retainers and keepers. I don't know that I'm convinced on the parasitic loss argument. Maybe this is why OHC engines don't seem to have as much torque at as low an rpm as OHV (generalization). Maybe it's the parasitic losses from the valvetrain at low rpms that hold back the OHC engine, but it's higher rev capability and better chamber design and better flowing heads (another generalization) make up for these losses at higher rpms, not to mention VVT that some DOHC engines have. Could also have to do with the fact that the valvespring in the OHV engine is responsible for moving the rocker and the pushrod and since those pieces aren't in firm contact that makes keeping the valvetrain stable at high rpms is harder in the OHV. That's all pulled straight out of my butt, BTW, I haven't researched it at all, but I don't think parasitic loss from the valvetrain is an argument for OHC.

I get it. I'm just presenting the opposing viewpoint. You say again that OHC will rev higher than OHV, and again I have to say that this is not correct with regards to all V8's vs the L6 stock vs stock or modified vs modified. LS7 or 1968 Camaro 302 (that one takes care of the modern vs old part of the debate) have redlines of 7000, and I'm not a pony car guy but I'd guess that there were others. I love that Kameari chain tensioner. What a great idea. I think Alan HS30-H has said that they tested it on a machine to 13,000 rpm, not on an engine BTW.

Christopher, it sounds like the struts are too stiff on 4. If the strut overpowers the spring then it does something called "packing up" where every bump you hit compresses the strut but the spring can't overcome the rebound damping. When this happens you hit bump after bump after bump until the suspension is bottomed out. I'm running the Illuminas on 200/250 springs and I haven't had that problem personally. I pretty much agree with everything else Christopher says though. Great struts, aren't stiff enough for slicks. I drove on the street on 1 or 2, switched to 4 or 5 at the track.

I drove a Titan and was VERY impressed with the engine. What exactly did you want to compare Jason? Redline? 6100 in the Titan. HP is 305, torque is 385 IIRC, and that's in truck tune. I'm sure it will be capable of a heck of a lot more. I hope they put it in a car and develop it some more for that application. Cg will be higher due to the DOHC, weight of the engine ??? uh, what else should we be comparing...

No need to get nasty. I wasn't trying to get nasty with you. Emotional argument: "I'm gonna go with it's a "Nissan Thing". Personally I never said I was a purist, I consider myself a loyalist." Being loyal is a fine and good characteristic, but it isn't a logical argument. "I'd much rather drive a Nissan than any Chevrolet or Ford" is not logical either. WHY would you rather drive a Nissan? If there is not a logical reason, then it too is an emotional statement. Chevy motor or Nissan motor makes no difference to the car, as long as the car goes. Both are clearly capable of making the car go. That's why it's not a logical argument. Similarly Chevy vs Ford is not a logical argument. Also "I hate Camaros" is a statement, not an argument. "I hate Camaros because they're overweight and undersuspended and have a tendency to explode the tiny 7.5" differential." Now there's an argument. We can break that down and decide whether these points are true or not. If they're not, then the argument isn't a very good one, so the best thing to do is either to re-examine why you don't like Camaros, or consider changing your point of view. I don't know why you're here or why you like Z's. If you like Z's because someone told you when you were a child that Z's were great and Chevys suck, then I guess that would be illogical too. I personally like the Z because it is a great inexpensive lightweight car to modify and race. The emotional part for me is that I like the way it looks (see, I'm not a Vulcan either ). If the emotional part for you is an attachment to the L6, that's fine. I'm just pointing out that it is an emotional argument, and much like the theoretical arguments of why the OHC is superior to OHV it isn't rooted in facts. On a personal note, I love to argue and I'll do this all week if you want to keep going, but I don't want to hurt your feelings. We can stop whenever you want.

Right. Not a logical argument. I did mention my truck which has a 5.3 liter based on the LS1, but that doesn't have to be the V8 example. I believe everything that I've stated holds true for the old V8 a la 283, 302, 327, 350, 377, 383, etc with the exception of the redline, which moves up and down depending on the build of the motor and the car it was put in. I'm pretty sure that Busch car runs the old style V8, which is concurrent with the Z as far as age goes.

I've been trying to find a page that quotes the redline of a NASCAR V8. Man is that tough to find! I did find this one: http://www.fittipaldionline.com/current_season/buschcar.shtml but I believe this is a Busch series car and that they are less prepared than the full on NASCAR cars. I am not a NASCAR fan, so I might just not know where to look. Even so, 9000 rpm is the quoted rpm limit here for a Busch series car. I would swear that the major leaguers are pushing 10,500, and I got that from flipping past Speed channel and thinking, "Holy crap, 10,500 rpm!!!" That is correct, but the V8 still has a 150 hp advantage over a stock L6. So you can take the 1000 rpm, but I'd prefer the 150 hp. I was trying to compare a NASCAR engine because it does have to live through qualifying and the race, and is not simply a 1/4 mile engine. Keep in mind, NASCAR races at Infineon Raceway and a couple other road race tracks, so it IS a circuit racing series at least for a couple races per year. I agree that comparing an engine that gets rebuilt every 1/4 is not fair, which is why I never brought up the 7000 hp of a top fuel dragster. A top fuel dragster isn't even remotely related to a Z car. OK so your ARBITRARY line is that the engine should be a Nissan engine. Other more severe purists' arbitrary line is that the engine number should match the chassis number. It is a purist thing, and you're just a little less of a purist than some others. A short story: My roommate was selling chassis #472 about 7 or 8 years ago. A guy drove 7 hours to come take a look. He gets there and is checking it out. My roommate says, "You want to see a nice Z, you should look at Jon's Z over there." The guy walks over looks in the window of my car and almost wretches, I mean he looked physically ill. He then told me that I "ruined" a classic Z. What he saw was Recaro seats, Autometer gauges, and aftermarket carpet kit, camber plates, and a strut tower bar. That was enough to make the man physically gag. How do you think that guy would feel about my F54/E31/Mikuni/header engine? Something tells me if I had actually showed it to him I would have had to wash puke off of it. So what makes his level of purism wrong, but yours correct? Where is the arbitrary line correctly placed? Matching #'s? Same manufacturer? Period correct induction? None of the above? I firmly believe that an engine is an engine. You may want an engine to perform a specific task, or produce a specific amount of power, or have a specific torque curve or whatever. I do not believe that an engine that says Nissan on it or has a particular cam configuration is automatically superior to any other. There are many engines that are not built by Nissan that have characteristics that would suit the Z well, and I'll stand by the idea that the engine that is easiest and cheapest to build and does what I want is the one I should buy. I understand you do not agree, and I'm not trying to make you. You have an emotional argument (am I mistaken?) and I'm just trying to point out the rational point of view.

Heh. Maybe I'll sell you mine when I swap to V8...

The most common swap is the 350, followed by the LS1 or the 302, so that's probably why we're talking OHV V8s. I believe the Ford 4.6L OHC V8 is too wide to fit in the engine bay, not to mention it's a dog anyway so it would be a waste of time/money. Not too many other options for OHC V8's that would be readily available IMO. I haven't heard of anyone swapping in a BMW M5 engine, but that's probably because the engine would cost 5 or 6 times the price of a decent Z. I thought we already did on the other thread. The 350 has a higher potential redline than an L6. OHC in theory has more potential for higher rpms, but the L6 in particular can't handle the extreme rpms. I don't know whether that's because of the non crossflow head or the crankshaft harmonics issue or what. Regardless of why, V8s actually can do better than an L6 at high rpms and that's the truth. If you're going to push either to that kind of limit you're already talking about a high dollar engine. Most people use these arguments when talking about relatively stock engines, where the V8 might have a rpm limit somewhere in the 500-1000 rpm slower than the L6. IIRC my original L24 had a redline of 7000, and the L28 I replaced it with had a redline of 6500 from the factory, my new Sierra pickup has a readline of 6000. So then you're talking about the relative benefit of another 1000 rpm and 150 fewer hp than the V8, which again leads me to believe that the advantage still goes to the V8. Now we're talking about a displacement thing more than anything else, but the power advantage is there for a rpm disadvantage that's pretty minor. You're talking boost, so are you swapping in an L28ET or are you driving a ZX Turbo? If you're swapping the motor into an early Z, then I really don't see the distinction between doing that and putting in a V8. Is it a Nissan thing? If someone swapped in a Nissan V8 (the old 70's pushrod limo engine for instance) would that be "better" than a 350? If so why? Just trying to understand. The L28ET is a MUCH better match up to a V8, and it makes a lot of sense to do a turbo swap IMO. Obviously you've seen the limitations of the NA L6 and chosen to do something about it. In that sense we're in agreement. Your taste is your prerogative. Taste is subjective, and there certainly is no need for anyone else to tell you how to build your car. You like the L series, build an L series. I would still argue that an early Z with a ZXT engine is also a "mongrel" in technical terms. If it ain't stock, it's a mongrel, right? Isn't that the purists' credo? I followed Auxilary into the argument on the other thread because I used to argue the purist case until I realized that ALL of my preconceived notions about the pushrod V8 were incorrect. It took me years to rid myself of the prejudices I had built up.

Yes but it is two strokish in that it does a power stroke with every revolution.

EXACTLY MY POINT!!! Nothing wrong with an L6, unless you want the most power you can get for a given displacement. Suddenly it appears the L6 may not be the answer... OHC or OHV...

About 2 miles from my house a guy was cut off during the morning commute by an older lady. He ran her down in his pickup, hit her and turned her sideways. She went across the center divider and her car rolled into oncoming traffic. Apparently the guy was so pissed that he got out of his truck and was yelling at her while she was dying in the car, upside down. When I was younger I had a bad attitude but at some point I figured out that you don't know what the other guy is cutting you off for. Maybe he's trying to get to the hospital. Maybe he's a raving psycho. Maybe he's on drugs. Maybe he never even saw you there. I take it to the track now and try to leave people alone on the streets.

Yeah, Nissan wouldn't do anything like that. It's not like they had the L16, then L18, then L20B, then NAPZ22 then NAPZ24, or the L20A, then L24, then L26, then L28, or RB20, then RB25, then RB26. Too bad them good ol' Japanese get so caught up in bigger is better, eh?

That's funny, I thought you in particular had a thing AGAINST the L6. Didn't you go RB just for that reason? Just out of curiosity what does the RB weigh, and how much $$$ do you have in your swap, and how much hp does it have. I'm betting that you could have done better with an LS1 swap. For those who haven't yet seen it, here's the newest low tech POS: http://www.superchevy-web.com/technical/engines_drivetrain/completebuilds_testing/0504sc_ls7/

Hehe. I voted for OHC. I DO prefer it purely from a design perspective. When you translate that into L6 vs V8 you'll get a different result. I'm leaning away from OHC and towards OHV, because in the commonly available options, the OHC has a hell of a lot more hp potential. Oops, that was supposed to say OHV has a hell of a lot more hp potential...

Well I think we've thoroughly hijacked this thread by now, huh?! :stupid: The point I was making was that the L6 has none of the commonly touted advantages of a OHC engine over a V8, except 40 lbs less weight. Other than that slim weight advantage, there really isn't an advantage in rpms, cg, weight distribution, hp per liter, etc. For people who want big hp it is clearly easier to do with a V8. And the main thing that sucked me into this argument was the dino engine, weight distribution, cg arguments. Those are all fallacious arguments. Maybe we should just try to get back to who has a cool looking Z, or start another thread where we can continue arguing the merits of OHV vs OHC. EDIT: That was exactly my point. I don't have the chassis to use it. I don't know why you picked that number, but it's not a very realistic number for a Z anyway.

You still have to put this in context. What's the highest revving L series you've EVER seen? For me, it's 9000 rpm. That is a full on Rebello L16, not an L6. How about the highest revving pushrod V8? How about 10,500 rpm. I change the channel on 50 of them every day on Speed channel when I flip past to see if there is something worth watching on. To me circle track is like watching an aquarium, but the engines are there and they're spinning very high rpms every weekend. Your example may work for the S2000 or the BMW M3 or something like that, but the L6 doesn't have a huge rev advantage over a V8 in either stock or modified form. What's next, hp per liter? Tell me you can't get find 1000 V8's that put out 570 hp for every L28 that puts out 280 hp. The L6 is a good solid engine. I still have one in my Z. But the high tech vs low tech or high revving vs low revving or weight or cg or hp per liter arguments just don't stand up. If you hate V8's in a Z it's probably an emotional thing. Something like "the L6 is the heart of a Z". I used to think that way too. Now I just want some cheap power that I can find parts for at the local auto parts store. I can only think of one L6 that ever made that kind of hp, and that's the Electromotive ZX. If you've been to a hot rod car show you've probably seen a few V8's that make that kind of power in that one place. But even still when you put it in context, do you need 700 hp in your Z? I wouldn't even want 700 hp in mine. I'd spend more time replacing stub axles and differentials than driving the thing. My $.02, Jon