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Yep, bored and sleeved. Might even go bigger on the bore, depends on what size the sleeves turn out to be. I've got all six sleeve blanks cast...

I like that hood. Looks pretty damn ugly to me, but the long vents on the sides seem to me like they'd shed heat well, and lower the pesky hugh pressure under the hood. Function over form, FTW!

Since it's an LD28 block, I'm using 150mm 4G63 turbo rods. used, but spotchecked, no cracks or porosity. all weights are within 3 grams before matching.

Ok, so I'm up late one night, after finding all six rods i need for my LD conversion, the block and crank are mostly lined up, and cylinder head choices are made. Here's my proposed setup, and the big question: Will my '72 roundtop SU's have enough balls to run this bastard? I already know i need richer needles, but if Rebello can run a 3.1 on SU's, surely I can run a 3.0. I'm looking to produce 200 N/A horsepower. Will probably run a Delta cams .480-282/282 cam, if not a little larger. Ported and Unshrouded P79 head. Compression about 9:1. Redline at 7000RPM. Home fabbed header, 2.25" exhaust. '72 E88 intake, port matched and "ported" as best can be done. I don't know if that's enough information, but I figure it should be a good start. I like the look of the SU stockers, and to me, it just feels right to have that orange air cleaner and twin SU's on the driver's side. (gonna have to vent the crap out of the hood, I'll bet...)

Funny, the only part of my Z that did work reliably was the rear defrost....

And a welded crank is a bad thing? If done properly, apparently it's good enough to be commercially made. VW nuts use them all the time. Only thing i see wrong, is that eventually you run into the bottom end of the cylinder... That's the problem I was gonna hit...

Search!!!!!!!!!!!!!!!!!!!!!1

Yeah, probably. But I know that 4G63 rods will THey handle quite a bit of power in stock form well, are 150mm long, and have a 5mm smaller bore...make that a 87.5mm crank throw...No welding needed.

Actually..that will not work. I need the studs to be able to bolt in my Raami-styled block brace. Great idea, but the reason for going to studs was not strength, but length.

I have had a slight change of heart here. I'm now thinking about a SOHC, crossflow head, due to the availability of the L series camshafts. Wait just a darn minute...what about the Chevy I6...what kind of cams could be robbed from that, and IIRC, it's not too much bigger than the L series in length...

What is the L24 main bearing stud size? I'm gonna be ordering new high-tensile rolled thread studs for my LD28 block conversion, but need to know what size studs to get. Knowing that they are metric, I'd imagine they are something close to M12-1.25, but i need to know for sure.

Really, 1fastz, you are the last one i would have expected that from...

Yes, getting any kind of prints would be helpful. I spent most of yesterday drawing an L-series headgasket in solidworks, just to get the hole pattern and such worked out. Lots of time with calipers and radius gauges... Anyway, the KA cylinder head seems to be a good base to start from, ad we already know that it can be made to flow really well. I'm a N/A guy, so un-assisted flow is a good priority for me, and my main reason for the whole thing. The next problem to correct is coolant flow through the head. I want to try to fix the temp problems on cylinder 5 and 6, because let's face it, that's a problem. Third, a good quench design is a realistic goal. I'd like to be able to use a flat top piston, with at most some valve reliefs cut in. Custom Pistons are not inexpensive, and I think that for *most* of our situations, they are not strictly needed. Also, what can we do about cams? I know 1FastZ has a solution, but as far as i am aware, they are JDM parts and thus, not widely available. I'm open to suggestions as to problems and solutions that we can incorporate into the design here. Now is the time to fix any faults that we can.

As I said before, get me a good set of solid models, and I can *probably* prototype a casting in 9-12 months. Nothing totally concrete, but I am no stranger to this kind of work. I pour the castings myself, so it's not as thought I can make a production run, but verifying patterns and ideas, I can do. I actually am already working on drawing up a KA24 cylinder head and then doing the cut-paste work to get as 6 cylinder version going, but it's slow work. If the thread drops back, i'll post an update as things happen, but as for now, 1FastZ's services are the best way to get a DOHC head.

Anyone got the exact section from that picture above? My Z had a run in with the PO's angry girlfrend..and she had a tire iron.

Hear, hear! Exactly why I want to do the LD block conversion.

Until midsummer at least, my stroker won't be taking much shape. I'll be able to purchase the Block soon enough, but with the modifications needed and sourcing other parts, I'll be a while. Anyway....What do liners (the physical part, not the machine work) actually cost, on average? It may not be worth my time to cast and machine my own...

Read through this thread again, and you'll see that a .120" wall thickness is considered to be the minimum wall thickness for a decent life. .120" is about 3mm. With the L28, you have a 96mm center distance between cylinders 3 and 4. between 1 and 2, 2 and 3, 4 and 5, 5 and 6, you have a slightly lesser distance, 94mm. Keep this in mind... If you look in your Nissan Factory Service Manual, you'll find the maximum permissible overbore in the L28 blocks is 2mm. Not that that stops anyone...

Josh, you are missing the main point here: Displacement. More displacement == more usable power. You are not gonna rev an L to 10K, not without spending a bucket of cash, no matter how short a stroke. Besides, in a daily driven car, high revs == shitty gas mileage. The stock L28 can rev to 6500 without many problems, slight modifications can easily get this up to 7000, with care, 8500-9500 can be done. Ask Tony D about the Bonneville cars... The goal here is to go for maximum displacement with maximum RPM ability. You cannot bore an L28 to 90mm and expect it to last more than a few thousand miles. You CAN however, offset grind a crank to gain a few mm stroke and not sacrifice structural integrity. As for higher torque and lower horsepower, remember that the Inline 6 is considered to have perfect balance at the first harmonic level, so revs are (relatively) easy to come by. (Torque * RPM) / 5252 = Horsepower. Higher torque will make higher horsepower, assuming revs remain unchanged. In reaility, I'm looking at this because it is feasible for me to do. I cast aluminum and iron all the time, have access to machine tools to do the major machine work. This means that cylinder sleeves are not out of the question, and if push comes to shove, pistons can be made on a temporary basis.

Well, to give you an idea, OS Geiken doesn't even have one. That's right, the OS Geiken company museum does NOT have one of these heads. So, you were gonna get one for 10K?

guess it's time to start casting 4" rounds of cast iron...

The machine work alone will run you close to a grand, if you are very lucky. Probably closer to 2K$. Derek is right, patterns like these are godawful to get right, even on a smaller scale. Let's look at what I figure I'd have to do to mold the "Paeco-Goerz" DOHC head: Patternwork: working from finished, error-free prints, 150 hours. Molding: with an error-free pattern, minimum cope, cheek, and drag mold, plus the multitude of cores needed. probably gonna have to use a two- or three-part pattern. probably 30 to 40 hours to figure out the molding, and practice to get it right, every time. Pouring: the easy part. 25 minutes to pour, 45 minutes to solidify and harden, 6 to 8 hours to artificially age, at least a month or two to precipitation harden, (Heh, iron is one to two years before you should machine it, depending on the size...) Machinework: probably 50 hours on the first head, after that, 4-8? lots of drilling, tapping, and precision work. I'ts gonna be a bit...Anyone got a KA head in solidworks? i could mod the design to be similar to 1 fast z's, and see about gettin patterns made up on the CNC machines at school...

Well, the DOHC problem could be solved, I use Solidworks. (hint, hint.) I guess I'll focus on that, because I actually currently have the equipment to cast those. A pour that size is easily handled by one person, and with the current molding abilities around here, completely doable once the patterns and core boxes are made up. If we can get some of the cylinder head gurus in on this, I'm up for patterning and casting them. Complexity be damned, i can manage that with time.

probably 300-500$ for the unmachined block casting. I dunno, hell, it'd be 8-10 months before I could get the main block pattern made, and probably a month for each of the core boxes..1.5 years to the first casting, if it wern't for my Z car restoration being in progress...indefinite at the moment. Anyone with Solidworks and an abundance of L blocks could be a real big help, though. Good 2d prints are a must, but excellent 3d prints could speed things up a lot.

I anxiously await your sonic test results, ezzzzzzzz. Pushing in a sleeve isn't as inexpensive as just boring it, but it's certainly doable. I pour cast iron every now and then, so casting a sleeve blank should not be a real problem.