Xnke

Going to the turbo cam will increase your detonation propensity. Reduced intake duration and wider lobe centers will increase cylinder pressures. Overlap does not reduce compression effects, intake valve closing does. Longer intake duration and narrower lobe centers generally means lower cylinder pressures. Exhaust recirculation can be increased with overlap, and *reduces* cylinder temperatures by reducing the amount of combustible material in the chamber at the time of ignition.

I'm not seeing anything on the T3 website in their product list that would indicate they have the shortened center bars, companion flanges, adaptors.... Enlighten us? EDIT: Must be thinking this package... https://technotoytuning.com/nissan/280z/complete-r200-r230-rear-end-conversion-z-car At $2780, that's only ~5.8 times the cost of buying the OBX helical diff that many of us run with the stock Z-car axles, or 300ZXT conversions. Doesn't seem like good value if all you're doing is fitting a limited slip differential.

At this point, Derek is glad he's not paying labor cost on these! To date I have 49 hours on the clock, so I'll have to pare that down if I am going to actually sell any of the production pieces...

You can do that, but you will need to get companion flanges to fit your outer stub axles, and the center bars to go between the CV joints. the 180SX axles will be too long to fit.

Checking clearances, I'll be able to weld the other two rearmost tubes in this evening. (they're tacked up, but I didn't fit them on in case I needed to move them a bit) Plenty of clearance here, so will be easy to use the same header on the Z-series truck bellhousing to get the engine standing straight up and down, and will be doable to use the KA housing...might be a bit tight on the steering shaft but very workable I think. The two rearmost tubes won't encroach on the stock bellcrank or the brake booster much at all. I was initially worried they'd be a difficult fit, but this header will still actually fit in a ZX with rack-and-pinion steering, I don't have a recirculating ball steering box to check against yet.

Side Note-It's a pretty simple job to fit these clips into the OBX diff while it's mounted in the car-much easier than removing them from the Nissan diff! I remembered installing the clips from the huge pain in the butt it was to do mine, which we did about the same time, just a year ago... To fit them in, a 21mm socket was the perfect OD to force the clips to compress, and still just slip through the splines. A 6" extension and a small hammer popped them in with absolutely no drama whatsover. After that, clipping the axles in was harder than putting the clips in!

The longnose R200 is fine...I'm sure you've seen the wheelstanding R200-diffed car photo here multiple times. For the money, the OBX helical is the way to go. The VLSD's out there all have high milage and are generally starting to wear out at best, or are worn out nearly-open diffs at worst. It's a direct fit, only need to check your gear mesh and possibly shim it side-to-side to get the lash set properly. It's not a hard job. That said, the VLSDs MUST use the stub axles that came with the diff, as the axle lengths are different. One stub is short and one is much longer. Generally these axles will be too long to fit under the back of a Z car, by several inches. You will have to dissasemble the axles, swap the center bars around, and figure out which center bars will be the proper length. All the information you will need is contained in the Drivetrain forum here.

You must wait for the head to cool completely. If you unbolt it hot, why did you bother to bolt it up at all? You are trying to constrain the movement of the head to certain directions only, so you have to keep it constrained until it stops moving. When I do an L6, I usually leave it bolted up to the block until completely cold (24hrs) then unbolt it, check the un-welded surface for flat, and peen the welds if I am using 4043/4047 welding rod, or I do nothing if I use 4943 rod. Either way the head sits for a minimum of a week before machining. This "rest period" makes it significantly nicer to machine flat later, much less tearing/pulling/gouging of the welded material. Don't let your welder use 5356 filler rod. It's great for castings, but only castings with a working temperature below 200*F...above that temperature it tends to stress crack. 4043, 4047, and 4943 do not have that limitation. Of those three alloys, I use 4047 for the majority of my head welding, and I am really digging the 4943 for the same purpose. 4943 is quite spendy though but it doesn't need peening because the weld deposit is hard enough to hold a headgasket without any further work. You don't warp the head from the *heat* of welding, you warp the head from the weld deposit shrinking as it cools. Hot straightening a head is not really desirable. Straighten the head cold, pre-bend it in a screw-type press until it's "flat" and then heat the spot opposite the bend with a rosebud until you're 600-800F in that one small section, then let cool. You can't use a hydraulic press with this method because the heat will cause it to increase pressure, and it will bleed down over the long cooling period. By doing the straightening cold, you don't cause nearly the same level of damage to the heat treatment of the casting.

Offerings To the God Of speed...

1/4" is a LOT... When I weld up the chambers in the L-series 6-cylinder head, I use a 0.040" flat washer in the middle two headbolt holes, and tighten the two ends till they just barely touch the jigging block, so pre-bending the head that 0.040". Occasionally this isn't enough. For the 4-cylinder heads a 0.020" shim is enough. I'm talking about adding a few CC's of metal here or there to get your chamber volume down, not repairing a broken cylinder...For more drastic modifications, you'll need to prepare for more warpage. The more metal you add, the more shrinkage you get-regardless of how hot you work the casting, this will always be true. Also watch for the manifold face going banana-shaped too, although I've never had a head move from just welding up the injector notches. Also, this is going to depend heavily on your welder, his technique, how he jigs the head, what school of heat control he subscribes to, etc. Plan on doing two heads if you're doing the work yourself and you've never done it before. There is a lot more to it than just plop the filler in, skim it flat, and calling it job done...

You're already shrouded with the stock sized valve. Look at the way the valve moves into the bore, and it doesn't even start in the middle. As the valve advances down and into the bore, it gets closer to the bore wall the whole time. Going to a bigger valve can show some gains IF the port is worked to support it AND you have 89mm+ bores. Want more than that? Move the valve centerline over so as the valve opens, the valve head moves AWAY from the bore. It's not exactly trivial, but it's certainly doable.

Yeah, Yeah, I know-No new photos of the headers yet. I have had to strip my own car instead of using another local guy's partially assembled Z to check fitup, so that's what's been the extra delay this month. I've got the SuperZ stripped down, the adaptor plate bolted up and the header bolted to it. Photos tomarrow when it's daylight. Part of the long delay has been making sure that when the engine gets rotated by using a Z series or KA series bellhousing, the header doesn't hit the steering shaft-but then Derek has no plans for that so I quit wasting time on that and decided to just build the header and get it done. I'm the guy holding up the show now. If the production head gets some orders, I'll have to buy one and jig it properly for all three bellhousings so there are no issues. Also, questions like "Will it fit a ZX?" All those questions I've just thrown out the window for this prototype header since I know the car and the position it'll be in...has taken me too long to quit jigging a production piece and just get on with it. I'll try to get you more timely updates on this, guys.

I will actually get thursday and friday off this week for some kind of holiday thing, so if it's not pouring rain again I'll be draining the coolant and stripping the supercharged Z's manifolds and thermostat housing so I can test fit your headers in the car. Need to make sure I don't hit the floor pan with the collector!

You *do* realize that the T5 is rated for 294ft-lbs of input torque, right? And that you're going to break it pretty much as soon as you crank the engine over? WHY????? Don't say "well they run 500HP through T5's in mustangs!", because they just don't hold up. In a street car, they might last a year at that level. I watch several a year break, every year. The only real solution is an aftermarket internal kit, which will run 600-800$ plus fitting. It's well worth the weight of a 125lb gearbox to not have to take it out every other week...

Is Rusch Motorsports still in business? I haven't heard from Paul in a long time.

Well, rain today has nixed the headers-in-the-bay shot. Hoping it lets up soon and I can get some of my manifolds removed tonight. I have tomarrow off too, so there is still a good chance.

The 1100HP modified standard production L-head...wasn't an LY. It will take about ten minutes after the first startup to wipe the color from the welds, and intergranular corrosion occurs at carbide inclusion sites, not over the whole surface. It's just normal oxidation corrosion that causes the brown color. The first 6-8" will show considerable coloring after a week of driving, excluding the first inch or so from the flange...that should stay bright a while longer. Not to mention those weld colors are actually detriminal to weld life...in industrial use they get acid washed to prevent corrosion and then the tube just looks like a single piece with a swirl in it. Examples: Will get acid washed to look like this, removing the corrosion. 321 won't look "better" any longer, it'll just last longer when it's glowing dull red in a high vibration environment. And 321 will always look better because it's hard to justify a 58$ U-bend over a 21$ U-bend on your street car if you can't at least say it looks better...321 is over double the price of 304 and really isn't needed until you go turbo/nitrous. Even moderate supercharged engines can run 304 without major incident.

Good news, I get sunday, monday, and tuesday off work-so I should get some good time in on the headers. I hope to get them fitted in my personal Z Monday so I can get the collector location locked down. (I belive in options...so there are two tuned lengths available here...Datsun style or BMW style) More photos monday, when I can get them actually down in the car for the first time in months.

Because wet liners leak. Eventually...all wet liners leak. Also removing the bore wall entirely weakens the block considerably, but brazing a sleeve back into the block would recoup the strength lost by machining the bores completely out. Also eliminates the liners leaking, so there's two birds, one stone. You bore the LD28, you hit water just over the stock L28 bore size. If you're going to spend the time and money to prep an LD28 block for big displacement, then get the big displacement. 90mm bore, 90mm stroke, 11:1 compression with a flat top piston and a P90 head...3.4L.

The LD blocks will bore to 86mm, but only just. They need sleeves to go any bigger. There are wet-sleeve LD28 blocks out there. I don't think they are Nissan Factory blocks though, I think it was an aftermarket thing. I've seen two, and have one sitting in storage, ready to fit 89mm liners in. The thought crossed my mind to braze the liners in, while stress-relieving the block as I've seen done in some Japanese builds...

Little update on the headers here, I had today off work so I have finish welded the front three tubes. Close up of some of the welds: Some people think headers are easy. I'm one of them...but stainless headers *are* a bit more trouble sometimes... That tube fit there two minutes previously...as the welds cooled it squrimed around quite a bit. By the time it was totally cool, it slipped right in. Plan is to have the back three cylinders tacked up this week, and be ready for finish welding.

I think people are confusing 3d printed sand molds with actual direct printed parts. This is a traditionally poured sand casting, with the actual moulding sand having been 3d printed. Not to mention that the 3d printed metal doesn't have the density of a casting, let alone a wrought part.

I think machining existing large A/R T3 housings would work. No need to do a new casting.

I use the Z22S truck piston in +1mm in my 2.9l supercharged engine. I run the L28 crank, L24 rods, and the ITM L22s piston, and compression is higher than you suggest. Total piston dish is 9.3cc, piston is +.010" out of the deck, and I run the fel-pro 0.040" head gasket. With my 40cc head, compression was 9.7:1, with my P90 head, compression is 8.0:1. Running your combo will net you 7.5:1 or so, using a P90 head, as you posted, and the ring pack is exactly the same as the L28et ring pack. Nissan Pistons moved to the that ring pack in 82, turbo or not, and even if the pistons you get are the older ring pack it is clearly not an issue...guys run stocker cast pistons up to 350-400hp all the time. EDIT: I have run cams up to 0.500" lift and 300 degrees seat duration on the exhaust side and still had adequate piston-to-valve clearance. I haven't run a lobe that big on the intake yet.

Not really. The gearset does not usually break first in the 71B/71C transmissions...it's the front countershaft bearing and then the rear mainshaft bearing that goes. The stock gearset is forged as well...