Xnke

For a reliable streeter, I would start by using a long chucking reamer ream both bushings in the carb body at the same time, or if I couldn't get a reamer long enough, I would user some aluminum foil wrapped around the shank of the reamer, slip it through the "near" side bushing, with foil wrapped to make it a snug fit, and then ream the "far" side bushing. Then, turn the carb body end for end and do the same thing. This will help keep the reamer aligned in the bushings, but it likely won't be perfect. Ream the bushings to clean up, then hard chrome plate the shafts. If you have to go more than 0.012" on the plating, skip the plating and turn the shafts to 8mm, then press in a new 8mm bushing the the carb bodies and ream as per above to 8mm, to clean up. Any place that does hydraulic cylinders will know where to get the hard chrome done, and can finish the shafts back to 10mm (or whatever size you need them to be) easily.

At some point, they all are worth something to someone. Get in contact with the SCCA ITS guys or rebello and ask if they need/want any cores. The L24 block may be required for some racing classes...but that doesn't automatically make it valuable, just means someone may need it...and they are only getting rarer.

That's an easy fix, too. Keep the head on the shelf, if you just wanna bolt it back on again later use Maxal 4943 TIG rod to do the repair with. Grind out at least 1/8" past the damage, grind the crack all the way out, then just layer in the 4943 till you're a little proud of what you need, and re-machine. No heat treat required afterward, as long as you keep the casting temp under 300F. Localized heating will be unavoidable but the 4943 rod does not need a heat treat to maintain the strength, and if you DO heat treat it it reacts very close to A356, but untreated the initial hardness is high enough to hold a gasket and gets a little better with a few weeks aging. The 4943 is what I am using to do my 300 Ford I6 heads with, each section of head has to be welded back together and then the deck face is surface-filled to bring compression down for the turbo motors. When I was using 4047 I had to hammer-peen the welds to bring the harness up enough to hold a headgasket without deforming.

Not really. Best way to tell is bolt them on the car, and hit the throttle shafts with a little carb cleaner, just like checking for a traditional vacuum leak. The way I do it is just wiggle the shaft like you said-you should feel barely a perceptable movement-any play in them will introduce an air leak, but it's up to you to decide how worn is worn. For your needs, (SCCA ITS?) you're gonna want to either polish the shaft and have it plated back up to slightly oversize, and then just ream the bushings, or fit new bushings and turn the shaft down slightly. (Not enough to get you caught, anyway!) Although you did buy my old SU's with 8mm throttle shafts, so I guess the smaller shaft diameter is OK-or maybe those were just "runnable cores".

If you are looking for port work, plan on 2000$ for a quality job. Last I called Dave Rebello, he quoted 600 bucks for porting ONLY, no rebuild, no surfacing, no valve job, no parts. I don't know if that still stands or not.

Or you could, you know, look at successful L28ET powered racing cars (real, actual racing cars) and see what they've done and at what power level, and what level of competition. 1000+HP L28ET's were run in IMSA racing, even if they did "turn them down" to 700HP for the races. Look at those. You don't need forged pistons. You don't need *any* internal engine upgrades, persay-but rod bolts are a good idea. You don't need a ported head, or a cam, or even a new turbo or injectors for 200RWHP. You Don't need an aftermarket aluminum radiator-the stock ZX radiator cools better, in my experience. Heck, at 300RWHP, I can't get the engine more than 5 or 6 degrees above the thermostat's fully-open temperature, and that's when it's 120 degrees on the pavement. The car with the aftermarket aluminum radiator? 200-210 degrees on the same day, with the same 180* thermostat. To make a 200RWHP L28ET for racing, you need good, programmable engine management-of whatever flavor you want. That's all. Nothing else is *needed* to get to this level of power. They'll run literally hundreds of thousands of hard miles at this level-you'll find the limits of your oil pan before you find the limits of anything else. I'm not talking about a rebuilt or freshly machined engine-I'm saying a stock, 150-thousand-mile motor. There's NOTHING AT ALL wrong with them at this level. Keep the manifold air temperatures down, keep the engine out of detonation, and RUN THE SHIT OUT OF IT. The stock intake manifold will keep you from over-revving it, you'll notice torque falling off at about 5800RPM, and by 6500RPM you'll be shifting up anyway. Every time you rev it over 7000RPM, count that as 1 minute. After 2 hours, change your stock valve springs. They're on borrowed time, even with the stock cam lift. What you'll discover are the limits of the L28ET in road racing: Right off the bat: Oil pan. It's good to a point-then it'll bite you. Oil cooler. You need a good one, AND you need a good thermostat for it. The stock ZX auto-turbo one is fine if it's in good shape. Rod bolts. These might come before the oil pan, but they might not. Also dependent on driver and tune. Crankshaft Damper. These are *old*. All of them. They'll wear out fast at 7000+RPM, and will be a maintenance item. Get a good new one and check it often. Crankshaft Damper Bolt. Again, check it often. If it loosens up, the crank damper will start working the crank and shear the key. Engine management. You need some that can actually be adjusted to suit the engine and usage. 220RWHP: Stock turbo is done. You're out of air. Stock injectors are pretty much done-maybe 30HP more if your tune is spot on. The J-pipe is out. Too much heat, too many problems. Get an intercooler on it. Use 18 gauge aluminum tubing, it's a race car, not a nuke plant. Seriously, intercooler. You'll pick up horsepower AND reliability and the whole setup need not weigh more than 15lbs. 350RWHP: You're gonna want to start looking into ported heads and bigger cams here-you can get here without them, but it's harder on everything. Good intercooler. Doesn't have to be big, or thick. Does need to be ducted properly. Get it in the airflow and it'll do the job. Cover your whole radiator and watch everything melt down. Bearing clearances. Time to start doing regular inspections and looking at what kind of clearances, and what kind of oil temperatures you're running. Cooling system. The radiator is still probably just fine-but you're gonna want to look at the cylinder head cooling thread here to see what to do about keeping all six fire-rings round. 400HP: You *need* forged pistons at this point. The stockers can't hack it at this level, regardless of a good tune. The stock US-market exhaust manifold is going to be getting pretty tired at this point. It's fine, flow-wise, but the heat will be taking a serious toll on it due to thermal expansion. 450+HP: Beyond here, there be dragons. You're going to run into odd failures at this point. Weird stuff starts happening, and you will need good data and good people to really know what's causing problems, and what's just a symptom of a bigger problem. This is a road less traveled, and the map isn't well marked.

In fact, the 280ZXT was sold without an oil cooler. Many of them, actually. In the US, ONLY the automatic transmission cars got them. You can safely push 250HP on the stock injectors. I'd prefer not to, but it's been done that way for literally decades. On the stock computer, even! Is it the best route? Nope. Would I recommend it? Nope. Stock turbo will stop making power at 17PSI. Stock injectors will stop making power at about 16PSI. At 14lbs, with a stock cam and head, even with the best aftermarket computer out there you'll struggle to make 250HP at the wheels-but you can make it at the crankshaft and return 28-30MPG on the highway to boot. Best I've personally done is 219RWHP at 14lbs, stock cam and head, stock injectors, with MS1-extra controlling it. Had 88% duty cycle going there. I believe, if you go through your injector calculations, you'll find they are for flywheel horsepower, which in a manual car will be approximately 18% higher, and in an automatic approximately 22% higher. (Both of those are just approximations-driveline losses vary with the car's setup, wear, fluid viscosity, etc...without an engine dyno before and a wheel dyno after, you will never really know.) As to engine oils, Yes, synthetics are good. But you also need to realize you have a flat-tappet, solid lifter cam. These require oils with additive packages that have enough EP additives to maintain lubrication when the cam goes over-the-nose. Most modern synthetics DO NOT do this and so you need to take care when you're choosing an oil to get one that has an API rating of SL or prior-NOT SM or SN! SM and SN rated oils were not designed to handle flat-tappet cams and do not provide the protection needed. There's a long story behind it, dealing with catalytic converters, the EPA, rollerized valvetrains...long story and pretty boring. Suffice to say, I personally run Valvoline VR-1 Synthetic, and for break-in oils I use 4T motorcycle oils...many bikes still run solid flat-tappet cams, and so they still have a good EP additive package for now.

You can't wire the "L" directly to the switched voltage-You MUST use a resistor or an incandescent lamp. Not doing this creates exactly the problem you have. Same with GM alternators, and Chrysler as well. Some regulators can handle this, but none were really designed to-so you get an unpredictable problem. Sometimes it works, sometimes it doesn't. You're not helping things with the "no key" feature either-backfeeding the alternator is REALLY hard on the regulator.

What are you wanting done? Can't make a recommendation without knowing your goals.

Call Kelford for the cams. You're MUCH closer to MUCH MUCH hotter L-series engines than we are, right now in my opinion the hottest L-series engines are being built in NZ and AU. Especially the L-4's... . Yes, that is a roller cam, roller follower 2.0L L20B making in excess of 220HP...

Yeah, that fastener was cracked pretty deeply for a long time prior to the break-the steel being used is NOT adequate for the job. I'll bet it's 4140, and hardened up to about 40RC, which puts it into a brittle temper zone. Should be down to 34-36RC and my god, the threads...they're single-point cut but you can see where it's been cut with a manual threading lathe, and the safety net cut wasn't made deep enough. The threading tool was ground from a HSS toolbit, but the root radius wasn't cut large enough for this kind of loading. Also the shank of the fastener here, where you can see the threading was turned off to match the safety cut, needs to be cut smaller and with a larger radius in the corners, you want to completely clean up the thread root and do it with as large a radius as you can cut without chatter-chatter marks would simply induce the same stress risers you're trying to remove by undercutting the thread root. There is evidence of quench cracking on the face in at least three places, fatigue damage over about 40% of the face, so yeah, his heat treatment is way off here. Borrow/beg/buy a dye penetrant crack testing kit and test your newly heat-treated parts when they come in...if they fail, don't use them. Send them back with photos of the test and recommend he figure it out before he keeps selling dangerous parts. I'll try to get your photos edited with crack progression markers so you can see how and where it started and ended, and it'll be pretty clear what happened.

The turbo manifold IS stock...Or just swap the whole stock turbo engine. You're making it hard on yourself here, you'd be well within the rules. for 1500$ you could buy two complete turbo swap donor cars in some places!

Assuming my patterns aren't all warped and cracked from being in storage, I'll send 'em down to you, Derek. I just have to find them, and finish the core boxes first!

Ditch the 3800 and go with the 3500V6, it makes the same power as a stock 3800SC, with NO boost. 2004-2006 malibu/impala, dirt cheap. Lighter, stronger, smaller, better cylinder heads, and if you just need blower whine: SixShooter here has one in his Z, plus a GT3582R IIRC, and it scoots. I'm putting the one above into my pickup truck in a few weeks.

The reason isn't for any kind of combustion advantage, it's only to make it so the valves don't open up directly into the cylinder wall. Once you bore the block, it's a non-issue so he moved it back over onto the dowel pins. Bolt a head onto a block and look up through the bore while you move the valves, and you'll see that as the valve opens, it approaches the bore wall and thus shrouds the valve curtain area the further you open the valve.