Tony D

The vavle angles are not really that difficult. Another thing to consider from using the Honda's engineering is this: The valves are concentric to their pockets. All the pockets are already in-line. Indexing on a 5-axis CMM machine you find your origin off three valve pockets average locations using intake and exhaust. From that point you can sink your valve guide holes. From that point you can ream your guides to size and from that you have a concentric point for valves and valve seats. From that valve guide hole, since both rocker shaft and cam shaft is in the cam towers, the relative positions of their holes is set by calculation rather precisely. The head bolts are independent of those points, thankfully so that you can get your entire camshaft and valvetrain setup using only the head as a reference. Obviously the cams and rockers, as well as the lines of valves should all be longitudinal parallel lines through a centerline drawn through the head, as would the head bolt holes. Setting of the shuffle pins or reamed taper dowels for locking the cam towers in position is another machining step but once the relative positions of those three intake and three exhaust ports are determined--the relative position of the entire valve train can be determined. EVERYONE here I'm sure has seen valve seats in a head that looked 'off center' relative to the port--welcome to the world of 'casting core shift' --- the relative position really isn't that critical, and with the casting method Derek is now using the relative positioning of the ports, separation from centreline, etc should be VERY precise compared to an older head made with traditional casting methods. You just have to get the longitudinal axis for the line of valves determined using rough port diameters...you can adjust it quite a bit, relatively, inboard or outboard from centreline of the head to match the cam towers properly, and to make sure the valves are under the cam lobes (or more properly under the rocker arm tips) like they should be.

"Lastly, I (fondly?!) remember HybridZ threads of the dim and distant past that scoffed at the usefulness of a 24valve DOHC crossflow layout in comparison to the stock L-gata's 12valve non-crossflow layout. Looks like the zeitgeist is a little different these days...?" Remember a key point of those discussions was the ultimate power compared to a $2,400 non-crossflow ported head. $100,000? Forget it. Horsepower per dollar isn't anywhere close to comparable. Nick a zero off that price and suddenly 330+CFM of port flow aat under 0.500" lift (which you will simply never get from a non-crossflow head) becomes relatively affordable. There may be a class where it is race legal. That's being worked out as silently as the initial development was!

No, it will do the same thing as any other MC if the F goes to the R, or the R is going to the F. It would also be a 'late' configuration, reverse of the earlier cars. That has yet to be determined.

For the cost of mine, you could buy a damn fleet of used Ferraris. Hell, for the cost of mine, I could buy an OS Giken Engine complete, and the First Class Tickets to go talk to them in Japan several times while it's being built! I pretty confident it will be less than that!

I suggested the K20 Head since it replicates the S20 layout, so it will look proper. nobody is really going to need swappable left/right intake exhaust options, and the symmetrical ports are not flow proven. As nice a head as the Paeco-Goertz head was for it's time, the ports may not be optimal. Remember it never ran, and used who knows what for port design. The K20 is a 500CC per cylinder flowmonster compared to the L-Head, and the design is proven, and proven quite well I might add. Look at the numbers for even a stock Honda K20, and then look at the aftermarket support you have available. The idea here was to use something that has tremendous existing aftermarket support, or could be scrounged from a junkyard to complete a bare head and then upgraded later. Really the cams, rocker shafts, and drive were the big imponderables. One of the reasons for suggesting the K20 as Derek said was that we could flycut the head top and bottom on a mill, and simply bolt on the cam towers as is in the Honda. That means I could machine bare castings in the shed at my house (if I ever returned...) The rockers are available aftermarket to remove the odd lobe for the VTEC, and just run the aggressive profile which can be cut on a billet easily enough---remember they are ROLLER rockers, so a lot of that sliding friction goes away as does metallurgical issues. This head would really bring the L-Series into the modern day in terms of oil compatibility as well. All I can say is "I kept my mouth shut, wasn't me who leaked anything..." But if you search my posts, you will in retrospect see I was literally bursting keeping this under wraps! As for scrapped heads, Derek can attest that I offered up sacrificial L-Heads so we could do a pour and say "This is an L-Head, just recast a bit different" a melding of old and new. I'm happy to see it take shape and now have to turn on my iPad to get a look at the photos that must be residing there now!

At least to find out the A/R, for sure. It should be good with a 0.63, even an 0.82... but that 1.06 will suck donkey testes in terms of getting spool in any gear but when you got loads of load on it!

Yeah, but which one do you have?

But the bushings are not a quirk, it's concrete and solid. They went to the L26, they got the different crossmember. Yeah, there are other things that may be quirky, but the bushings are a rock solid "Late Model" since their introduction.

Nice shirt...

There is no 'quirk' for the early 260Z's. The rack bushings are for a 260/280Z. ALL 260Z's use the later 260/280 rack bushings. ONLY the 240's use 240 Bushings. This was easier in 1974 when there were only "240 Bushings" and "260 Bushings"... Which, incidentally, is the way it is in the entire rest of the world!

"The depths look the same to me, however the port for the front brake reservoir is located maybe half of an inch further than the old MC." As John C said, make sure you got the CORRECT MC... There are two, one with "F" in the front of the MC, the other with "R" at the front of the MC. If you swap them, you get the EXACT feeling you describe. The early cars had brake pipes from the MC that went straight down. Later cars had them "X" under the MC as the body tubing didn't change, but the location of "F" and "R" on the MC did. If you have a later car with an early MC, or an early car with the later MC, and hooked your lines up the way they were originally, you get absolutely NO pedal until the very bottom of travel and then it's almost like an on-off switch where there's nothing, nothing, nothing, brakes (but you have so little pedal travel left you bottom out and what brakes you get you get and pumping doesn't help it at all. Here, a photo would hit it right off. You can NOT go in and say "I want an MC for a 240Z" if you do, you will likely get the later assembly as it was 72-78.

Crossmember changed when the tail lights did...

"30k for a Z? What are these people on?" Vacation most of the time, playing golf... you know, MBA stuff!

" I can also say from experience if you spin a rod bearing with this clearance the piston will hit something. " Oh yeah, 'been there, done that!' Excellent point! "Clearances exist for a reason."

Now, about this: "im pretty new to EFI as i grew up with carbs (and im 21)." Uh, I'm 50 as of Friday. I grew up in the UP of Michigan. I truly grew up on carbs, and saw the transition to universal EFI. I watched domestics cling to old technology and imports embrace change. If you really did grow up on carbs, you would be RUNNING to EFI! I would NOT recommend turbo on your Mikunis, regardless of your 'growing up on carbs' comment. I would, however highly recommend the turbo blow-through ITB setup I describe in the prior post. The fueling will be FAR easier than with carbs. Search on Blowthrough Mikunis, and you will see! (You don't HAVE to go to EFI when you go turbo, but I'd highly recommend it!)

Strip out the venturis of the Mikuinis, buy some screw in injector bungs and put them in your existing manifold, make a matching Fuel Rail, and buy the TPS Adaptor for the Mikuni Body, and run what you already have. There are articles in Japanese Magazines doing this on dyno tested engines to see what they get, and they always get more! And the look in the engine bay is awesome. tone down the Injector Manifold and injectors painting them black and it looks like a vacuum rail... everything looks like your carbs are running, not EFI!

A GM HEI is not exactly an 'Aftermarket' system, it's just what another OEM uses. I have run an AFTERMARKET performance GM HEI since 2002, I can shoot a spark almost 4". Try that with a stock E12-80! It cost me a whopping $48 too... There are 'direct replacements' and there are performance improvements which sacrifice no reliability. The GMHEI module swap is one of them. Plus, the "TACH" terminal on the GM module comes in handy....for something...I forget what...

There is a "projects" forum, you can request to the mods it be moved there rather than doing it all over...

Because the 280 and the 260 are similar, incorporating improvements over the original 240Z design. One such improvement was the quicker steering rack ratio, which had a different set of bushings than the earlier 240Z's. That's why.

I've always stolen my sealants...

No thanks until its running right!

"It also confirms what I thought, that use of clay is most relevant for determining piston to valve clearances." How do you get that out of anything I said? The combustion chamber is not necessarily flat... the clay determines the exact clearance when installed. On pop-dome pistons and not simple flat tops, this is as good as you will get as most of the time these parts are hand-fitted to the combustion chamber in some places. The clay will show highs and lows. I don't have gaskets laying around, if I need one, there is a reason you trial assemble engines. As I said, "you will waste a gasket" ... Most people starting out and properly advised will have a gasket they install with anti-seize liberally applied, and run it through several torque/relax/retorque cycles and then wipe it all down and go to town with their new "checking gasket"... nice an reusable.

It's a virtual world now... I live in the Philippines, and source parts for my JDM (LHD Conversion) Suzuki Turbo Every from Canada, Australia, USA, UK, Holland, Japan, etc... Saying things are hard to obtain in the USA is laughable. The internet makes this a moot point. When I lived in Japan 20 years ago, guys were worried about living "out in the sticks" and my response was "you got a telephone and UPS Delivers" ... It's an instant virtual world these days. As noted above, try this kind of stuff 30 years ago and even then...parts were available just expensive. Remember the basic tenet of Nissan Corporate Headquarters Parts Department (Global Services): ANY NISSAN PART MAY BE ORDERED THROUGH ANY NISSAN AGENCY WORLDWIDE -- YOU JUST NEED THE PART NUMBER. If you don't have it, you can fax Japan, and they will fax you back the pages for the vehicle applicable and assist you in determining the proper part number to order (much like any Domestic Dealership with a NEW vehicle...) Secondarily, there is a large company in Yokohama which will get you ANYTHING for ANYTHING from the JDM. I'm talking Reman ENGINES ($2,200 for my Suzuki...) Shipping is not cheap...but the choices were not based here on Economics, were they? If you have adequate spares, expensive shipping can be avoided. I knew my turbo was going out...I bought a replacement for $249. I packed it in my luggage the last trip to USA and brought it back...only to need it (I think) just this past month. If I order it from Japan, it's $1,000 and takes five days plus customs duty (and the bribes...) My basic contention is that if you have ever read Smith's "Engineer to Win" you realize that preparation is the key. There are no unsuspected failures if you do it right. If something TRULY is unsuspected, something that could not have been inspected and prevented...it's a statistical outlier, and is likely something that will sideline you no matter WHAT engine you choose. If a Turbo F1 Engine can make 1700 HP for the duration of the race without failiing...I think the failures we will be presented with are easily forecasted.

I was using gross numbers.... I meant for sealants. They're not DIFM so no possible issues. There was a time during the diesel conversion that the MJ1 Bomblifts used Holley Red Pumps as the boost to the main. They were not DIFM, either. The vanes would go out and you just replaced the pump. AF Form 1000 was submitted and rejected to use the vane kit in them. So I happily took all those Holley Red's and put a vane kit in them, along with brushes and resold them to the Japanese. Knowing when "your crate of scrap" is clearing DPDO was really helpful (I guess thats DRMO now...) If you think $4 for sealant is too much, an RB20 will be excruciating.

In the end - when you do the final assembly of the engine, do you use a new head gasket? Yes, you use a new head gasket when assembling the engine the final time. The used gasket is only for setup and clearance checking. Nobody has said to re-use a gasket for anything other than a consistent known quantity to set clearances. If so, how do you know the compressed height of that new gasket will be the same as the used one you had for your measurements? You don't, that is why 'CLEARANCES' exist in a range. You can be sure the repeatability of crush on a given gasket will be within a 3-Sigma Limit and that if you used a compressed Fel-Pro, you can be sure that within a thousandth or so, the gasket will crush to that same area. Using a FelPro to check a Ishino--no use whatsoever. You may have to waste a gasket if you want to gauge the height correctly. Welcome to Proper Engine Assembly 101. The clamping forces are calculable, the engineering is sound...you can take 100 new gaskets, crush them down, measure the results and do your own research and come up with your own numbers to use...but given that this process has been used since before I started doing this, it's a sound and accepted way of doing it, your comprehension or agreement with it notwithstanding. The key is the VARIATION from gasket to gasket when compressed is 0.001" MAYBE. The variation of an uncompressed gasket is quite big as you aren't measuring the fire-ring when clamped. I know shops that keep a variation of gaskets to use for this setup, the compressibility and setting/gasket creep phenomenon is too much to enter into here, suffice to say once it's compressed, the change of compression is nil. Afterwards you can clamp and clamp and as long as the clamping forces do not exceed the original forces used, the gasket will not compress any further. If not, how many times can you re-use a head gasket? I thought it was advisable to use a new one every time. Nobody here has EVER said to re-use a head gasket. I think you are not comprehending that the used gasket is for SETUP AND CLEARANCE CHECKING and not for running the engine. Some gaskets are designed for re-use, you are not at that level where you are using one of them. Using a new gasket is mandatory for competent engine builders...again, we can get into the engineering discussion of engineering a jointed gasket and compressibility but it's not necessary... the clamping forces are present on the fire ring to seal combusion, but universally the issue arises of coolant leakage from the fiber compressed portion of the gasket when re-used. You can clamp the gasket all you want, but it will NOT compress further unless the fire ring embeds into the head....to allow further compression of the fiber portion and seal it upon re-use. The fire-ring is the limiting factor in combustion chamber clearance checking, and it will only go so far from new. The fiber outer section is another animal altogether, and it generally spent after first removal---it's condition doesn't matter in combustion chamber clearance checking, only the fire ring. It crushes to a known distance and physically stops due to the pressures exerted, and will not measurably change unless clamping forces are greatly increased. This is why you use the USED gasket to set your clearances, not a new one. You can waste a new gasket to check them (compress it, then throw it away) if you want to, but most guys just keep the old FelPro sitting on the wall to aid in clearance checking. There will be no measurable difference between clearances arrived at using a used gasket, as opposed to wasting a new gasket. You just save the cost of the gasket.