jmortensen

Those pistons work with the L24 rods on the diesel crank. They won't work on the L24 or L28 crank. You'll need custom pistons to make what you have work, and that's going to blow the idea of cheap out of the water. Why not slap the head on the block as it sits, with maybe just a hone and some new rings/bearings? A tight top end and a loose bottom end is a good way to make power.

Yes, there is a floor.

Yep. I didn't have that schematic and so when my brother in law bought a Z with rotted hoses we just hooked the top and side vents together and ran them to the filler neck. Worked fine.

Keep the stock tank. The fuel cell doesn't do anything for you, especially the plastic type shown above, except to make putting AN fittings on the fuel lines a bit easier. A good road racing fuel cell is a lot heavier than the stock tank and costs ~$500. The proper way to install it is to put it in and then make a barrier between the driver and the cell, so that makes the job doubly difficult. The main difference between the Z and the GN is that the GN has a firewall behind the rear seat, and the Z is open, so if you got hit in the rear and your plastic tank split, the gas is going to be right there with you.

There's your problem.

Glad to help. Hope it sorts itself out after some more hard driving.

There is no brake booster. It's a dual master cylinder non boosted setup (3rd reservoir is for clutch). The hoses go directly to the masters. FWIW, your brake booster shouldn't have fluid in it either. http://www.tiltonracing.com/content.php?page=list2&id=4&m=b

Usually valve stem seals give you a puff of smoke on startup. Haven't heard of valve stem seals leaking so much oil into the cylinders that it takes 15 minutes to burn off. In fact, having watched ATF literally poured into the carb of a running Honda to clean the chambers, I can tell you that even a large amount of oil in the cylinders burns off in a minute or two. Based on what you're describing, I think it's rings. Try wringing its neck a bit and see what happens. Worst that happens is you have a good time and burn some gas.

I'm going to guess that the rings just aren't sealing yet as well. A friend of mine has a great story about Z car engine rebuilds, goes like this: his friend rebuilds his L28 and fires it up and lets it idle for about an hour. Then he starts driving around and he's really upset because the thing is blowing a James Bond style smoke screen out the exhaust pipe. In desperation he comes to my friend who is the local Z guru and tells him what happened. My friend has an idea, so he takes the car out and just beats the hell out of the motor, revving to redline and decelerating over and over, just beating the wizz out of it. Comes back, no smoke at all. His conclusion was that the cylinders were glazed and he had to break the glaze in order to get the rings to seal. Tells the guy about working the rings on a new engine and how he needs to be constantly accelerating or decelerating on a new engine, no steady state. Regardless of whether his "glazed cylinders" theory is right, it shares a bit of similarity in that it was a new engine that was smoking and the smoke went away after working the rings a bit.

The only real adjustment on the Z in the front is toe. There is no camber adjustment and depending on the condition of your T/C bushings, you might be able to shim a bit of caster too, but its very limited. The rear, as you said, is totally fixed from the factory. You can make everything adjustable, but it takes varying degrees of modification. Probably the easiest way to make the rear adjustable is via camber bushings. http://www.thezstore.com/page/TZS/PROD/PSDC07/23-4171

If this post doesn't end this argument, nothing will. Well done.

Jan, did you look at his dyno plot? The motor that he showed the numbers for wasn't built for hp. It was built for torque. The hp peak is at 4430 rpm!!! It's no wonder that a stroker that has a low end cam and carb and exhaust to match puts out 50% more torque than a stock L20B. Why is this at all surprising??? Now if you put that same head/cam/induction system on an L20B, I suspect you would get other than stock numbers, and they would show much higher torque than stock. So his point that he got a 50% increase over a stock L20B really doesn't prove anything at all. He's attributing the power gain to the bottom end exclusively. His results are not about the bottom end exclusively. His results are a result of BOTH a bottom end change and a top end change. If you change the bottom end, you can expect an increase of roughly the value of the displacement. If you change the top end, you can expect an increase based on how you change it. In his case he put a stump puller cam in and got an extremely torquey and low rpm motor. No, it really isn't true, and you're wrong about strokers. Adding the stroker "kit" that you can buy doesn't require anything other than the crank, rods, pistons, rings and bearings. To emphasize the point made above about the top and bottom end having different results, what if you had this head on your L24? http://forums.hybridz.org/index.php/topic/95308-bsr-gtu-e31-head-images/page__pid__898296#entry898296 If you built a stroker bottom end and put this head and induction on it, it would not be a waste of time. It would make more power with the stroker bottom end because of the increased displacement not because the stroker fairy would come by and waive a wand giving you more power. There is of course a limit. If you take a tiny head and you put it on a bigger and bigger block, there is a point at which you'll get diminishing returns because the head simply can't flow enough for the displacement. I don't believe that you're getting there with ANY of the L series strokers I've seen with US market heads, whether it be a 2.3L L4 with an L16 head on it or a 3.2 liter with that BRE head on it.

This is the most retarded argument I can recall having in a very long time. You can build an engine to make more hp, or more torque. You can push them to the limits, or build them more mildly. On the crazy side, Rebello built a 225 hp L16 for Dennis Hale. Does that prove that non-strokers make more power per liter? Or if we looked at old CP cars back in the day were pushing 350 hp out of an L24, does that prove that strokers suck? Is it coincidental that both of those all out race engines put out about 140 hp/liter? Again, built like for like, you're going to get a fairly linear return in hp for displacement. You can ignore that reality all you like, but I'm done trying to convince you of what is so plainly obvious.

Rebello seems to think that output is linear with displacement: http://www.rebelloracing.com/enginebuild.htm 2.7 makes 270 hp 3.0 makes 300 hp 3.2 makes 320 hp Coincidence??? BTW I believe that refutes the "answer" to the question which you've asked me. SCCA seems to think that there is a linear relationship. At least they write their rules based on that assumption. There are probably 20 examples of this, but I'll give you the one that affects my car. In X Prepared the formula for weight is as follows: Minimum Weight Calculations All listed weights are without driver. All weights are calculated based on displacement as listed per Appendix A, 10.a. Example: weight for a 1837cc RWD car is 1200 + (1.837 x 200) = 1567 lbs. RWD: 1200 lbs + 200 lbs per liter FWD: 1200 lbs + 150 lbs per liter AWD: 1200 lbs + 250 lbs per liter

Don't look at the psi number. In fact, if the motor doesn't start and you can't warm it up before you test, don't bother testing compression at all. Read this, and look at what his compression test showed without a warm up first: http://www.classiczcars.com/forums/showthread.php?t=39578

You didn't understand them.

I missed the bit about having a poly bushing in there. If that's the case then I think it will probably hold up for a long time, and it may be that limiting the movement with the stud makes it so that the stock mount lasts indefinitely. I would say that the single hole in the sheet metal crossmember is going to be the weak link in that chain, so if there are problems they are going to be happening there. For a similar amount of effort, the clamshell design with a strap of metal that bolts to the stock mount and wraps underneath the crossmember with a rubber or poly pad on it seems like a more surefire method, as I think it's less likely that one would tear out the whole diff crossmember.

If I may get on my high horse for a second, there is no way in hell that a stroker crank alone is going to net you a 50% increase in torque when you're comparing an L28 and an L31. Now if you have a really big cam in the L28 and you put a small cam in the L31 and play with cam timing, etc, I could buy that. But for engines built similarly, no way. I think the math on the stroker is the best way to estimate what you're going to get. It's not always that simple though. Running the exact same setup before and after, Tom got 0 hp and 10 lb/ft of torque. My guess is that there is more to be had there and he'll probably end up with about 12% more power and torque, you can stay tuned to the thread to find out. http://forums.hybridz.org/index.php/topic/94521-hbzers-guess-my-31-rwhp/ Mark's original stroker put out a whopping 137 hp and 157 lb/ft of torque: http://forums.hybridz.org/index.php/topic/38495-31-stroker-horsepower-rating/ And in its latest iteration it puts out 267 hp and 250 lb/ft to the wheels through 40mm carbs: http://forums.hybridz.org/index.php/topic/24798-na-31lhead-camshaft-questions-no-shortcuts-max/page__st__140 As you can see, a stroker isn't a guarantee of anything, and I think a similarly built non stroker will put out very similar numbers when measured by hp/liter. IMO if you're looking for a fast car, build the non-stroker. There comes a point at which it is cheaper to go with the stroker than it is to keep going on the non stroker to increase hp, but I don't think most people get there. When you do get there, consider that I bought a 315 hp V8 motor with 320 something lb/ft of torque for $1100 with 30K miles on it. It looks brand new inside. When you get down to it there are far less expensive ways to get power than by building a NA L series. In autocross, having the stroker puts you into XP if I'm not mistaken. That's a pretty tough class to compete in if you want to be really competitive.

For low budget I'd suggest as new a Honda as you can afford. The Z is a 35 year old car and will nickle and dime you to death if you want to keep it properly maintained. They run forever, they're good cars, etc, but most any car that old is going to need some attention.

If you've got poly in the mustache bar, I don't think the mount is taking that much weight in the front (take the front crossmember completely off and the front of the diff is still pretty horizontal), but regardless, due to the interlock design it really can't come apart. If it gets loose, replace the cheapo poly mount. Your welded stud should work OK, but if the diff mount fails you're putting all of the vertical load into a pretty small area on the diff crossmember, and I think you're likely to find it failing there. There is a thread on hybridz.org showing solid diff mount failures and one in particular shows the hole in the diff crossmember tore open, and I think that's likely where you'd end up with yours if the diff mount failed. Once the rubber fails I think they'd act the same way on the diff mount for all intents and purposes.

You can always have some steel wheels made. In the USA they're popular with the circle track crowd. Not sure how available they are in AU.

Best bang for the buck on a bone stock Z with 40 year old parts? Handling: 1. Ball joints/tie rod ends/alignment 2. Wheels/tires 3. Springs/struts 4. Poly bushings Interior: 1. Steering wheel (can't stand the stock wheel) 2. Seats 3. Gauges that are accurate Engine: 1. Tune up 2. Exhaust 3. Camshaft Brakes: 1. Replace rubber hoses (stainless?) 2. New pads/shoes 3. Rear disk upgrade What is the most important? First thing IMO would be to replace all the rubber fuel and brake lines and check the pads and shoes. Then I'd go for the ball joints/tie rods/alignment. Then the tune up. After that I'd work down the lists in whatever order I could.

Eyebrowing the block is REALLY easy if you have a die grinder and can be done with the head off of the engine if needed. There is a write up in How to Modify Your Nissan/Datsun OHC Engine by Honsowetz.

It's not the stacked dead coils that are the problem. Eibachs have that on their progressive springs and I have explained to people numerous times that it's normal and not to be concerned about it. On the Tokicos, it's the WHOLE spring that is nearly bound with just the weight of the car on them. Start going over bumps and you have to wonder what's going to hit first, the coils or the bumpstops. You're right though, the 280Z linear springs don't have the problem. I think that's because they're stiffer.

Is there no issue with using the larger valve on an L24 block? Can't recall for sure. Regardless, you'll get a slight drop in compression, probably not enough to notice if you're just driving around, might be noticeable at a drag strip or a race track.