My Engines
I'm building 2 types of motors for my '71 S30. The first is a F54 based L28ET. The second is a V07 based custom engine. The '74 S30 is getting a V07 based LD28
Engine One 1971
The F54 block is from a '83 280ZX turbo. It's got the stock internals minus the pistons. The block will be bored to 89mm. I have yet to order pistons for either of my engines. It has a P90 head. I will be installing aftermarket valve springs on the engine. The head is from a '81 280ZX turbo. A "C" stamp cam will be utilized. The head will get a 3 angle valve job, port, polish, and resurface. I will be installing a set of Schnider valve springs that I have already purchased. The turbo will be mounted to a custom turbo header that locates the turbo in the stock position. The plan is to use a T3/T4 hybrid with a 60:1 compressor trim. This engine will use the same FI system as the second, but it will have a different program. The Injectors on this engine are 500cc RC engineering injectors. I was lucky enough to find at a local Pick n Pull. The intake manifold with be the stock 81 manifold with the 60mm KA24 series throttle body. This engine will be with the exception of 89mm pistons, bore size and turbo a stock 1981 turbo motor.
Engine Two 1971
The V07 block is from an unknown application. It was equipped as a mid-sump engine from Nissan. It was purchased from All Engine Dismantling in Fresno Ca.. It has since been converted from diesel fuel to gasoline. After doing much research I found that the LD28 is a closer realitive of the L20B. It's a L series engine with a taller deck height. It's approx a 1/2 inch taller than other L series. The idea being that you can slow the speed of the piston down when stroking the engine by changing the rod angle. This is critical when building a stroker engine. To much rod angle and the engine will be prone to early failure. It hasn't been a real big topic with the stroker engines, but I feel it is a big deal with the 400+hp stroker community. Most will disagree. The next big thing about the V07 block is the cylinder wall thickness. It's pretty much the same as the F54 blocks. The stock bore is 84.5mm. Finally the V07 block uses a larger head bolt 12mm, that can be torqed to 120lbs of torque verses 10mm @ 60lbs. Several points to make about this block. The water passage that is drilled into the front of the block on the outlet side of the water pump is missing. This is no big deal. There are passages that go to the head on the deck that need filled in. I plan on using 5 pipe plugs to do this. Most V07 blocks are a front sump design. The oil pan will need replaced and the oil pickup will have to be replaced as well. The old pickup point can be plugged like I plan to plug the water passage, but I would cut the pipe off of the old pickup and weld it up. Then just bolt it back into place as a cap/cover. The new pick will have to be drilled through and the bolting points drilled and taped. Because of the larger head bolts the cam towers will have to be modified to fit them. Like below.
The "Long Rod I6 Hybrid" quote***
"In the spirit of Hybrid Z I'm offering some food for thought. The problem with putting the LD28 crank (stroke =83mm) into the L28 block is that it's too cramped in that vertically-challenged block. The standard conversion uses Z24 or KA24 pistons (modified) with L24 rods (133mm). This gives a rod/stroke ratio of 133/83 = 1.6024, which sucks. I'm not going to go into rod/stroke and performance here, read-up on your own, but that;s good for a truck, not a performance unit that could hit the track.
OK..so here's the crux, I crunched the numbers prior to taking this project on and decided it was worthwhile, I consulted NISMO and they said "forget it".
So, take a LD28 engine and get rid of the cyl head, cast iron and it weighs a ton! Get rid of the diesel fuel pump and front cover (keep the water pump), keep the oil-to-water cooling unit on the oil filter assy. Massive alternator unit has an integral vacuum pump on its tail-end, could be useful if going turbo. Specs on internals: 84.5mm bore, 140mm rods, massive, with 1" floating wrist pins (not unlike a set of rods available from NISMO). Compressio ht of pistons = 46.5mm and that's alot. Block ht is the same as L20B and that's where the front cover is going to come from for out hybrid engine. So, the firstphase of my experimentation was to put a N42/N47 series cyl head onto the LD28 block. This requires the aluminum head to be drilled for a 10mm headbolt to a 12mm headbolt. Nothing special here, most of it was done by hand. Headbolts were from BMW, some washered, 3.0 inline 6 cyl or 2.5 4 cyl (I think): but they were the right thread pitch and length, and 12mm dia. Reuse the diesel head gasket. Said head makes about 9.8:1 as I recall. L20B front cover and LD28 water pump will go together with a bit of grinding to the water pump.
...
So, rod/stroke @ 140/83 = 1.686, better already than the L28 block/LD28 crank hybrid, and that's with huge compression ht of 46.5mm on those diesel pistons."***
I don't recomend using the Diesel pistons for this conversion. Replacing the rods and pistons with custom or L20B rods and pistons will work much better.I made an inquirey about a conversation I had with another Zer. It was about the possibility of a 4L stroker and if/how it could be made. *"I HAVE personally SONIC tested two LD blocks, withmy Certified Sonic Tester. I was getting a .150" reading in ALOT of areas of the cylinders, and that is towards the top of the bore, and in the middle, there is NO way, atleast on the two blocks I have tested that you can bore 7mm!! Ok, so to bore 7mm, That means that the walls need to be a MINUMUM of .093 thou for a cyldinder wall thickness, AFTER boring. So 7mm/2= 138 thou of wall thickness removed. Therefore, you would need .138" so your talking atleast 267 thousnads of an inch for cylinder wall thickness as a MINUMUM in ALL bores. Yea folks thats not gonna happen, I have like 5 blocks now, I don't want to tear down three of them as they are COMPLETE right now, and noneed to tear them down for checking as Ive already checked two. Only way this can be done, is for sleeves to be installed. Now what is the Bore centers on a L series 96mm on 1-2, 2-3, 4-5, and 5-6. And On 3-4 is 98mm. So stock bore is 84.5 on Ld Correct? So your talking 7mm over is 91.5mm bore, and 83 stroke, that puts you at 3.27 liter. Where is the 4mm Com into play? Yea see, just doesn't add up.
So with a 96mm Bore center, 91.5 bore, you get 4.5mm/2= 2.25 bore thickness between cylinders, which is about 89 thousands of an inch, BETWEEN CYLINDERS, if ALL cylinders are Siameesed, And you CANT Siameese sleeves, and that is TOO thin for comfort. Doesn't add up does it.
So how did the 4 liter come into play? Ok so a reground crank say 1mm that is offset would give 84mm for stroke, then you would need 100mm bore, YEA RIGHT, You don't have me fooled for ONE second."*
This may not be necissary though. I am told by DAW of hybridz.org that certain BMW head bolts have the correct length and thread pitch, along with a hex head rather than allen to fit this conversion without extra machine work! DAW*** "..what I did was to use the LD28headbolts where ever I could, using extra washers were needed and used BMW bolts ()from JY cars, about midvintage, either 4 or 6 cyl are the same) for lengths where the LD28 bolts didn't work. Both LD28 and the BMW bolts are 12mm with same thread pitch. The BMW bolts have traditional hex-head and the LD28 are socket head. You have to drill all cyl head bolt holes out to go from 10mm to 12mm, but I'd advise that you not mill into the cam tower because it may crack during use after torquing down the head and the torque would be lost." *** This engine is using the LD28 crank shaft and the L20B connecting rods with custom pistons. The plan is to have either Wiseco, Ross, or JE build me some pistons. I've already spoken with Ross about some 89mm L20b based pistons. I'm looking at a 25.4mm bore for the wrist pin at a 40.05 pin height. Flat top style with releifs for the valves giving +5cc's to the combustion chamber. The rings and placement is subject to debate. I'm thinking of the following. 6mm down 1.5mm top comp ring. another 4mm down and a 2mm second comp ring. another 2mm down and the oil rings. NOTE: A big issue with both the L28 strocker and the LD28 stroker is piston slap. Offseting the wrist pin is critical along with getting good pistons. Forged pistons tend to slap when cold because the tollerences have to be less when cold and allow for proper expansion when the piston comes to full operating temp vs a hyperutectic or cast piston not needing the extra clearance cold reducing piston slap occurance. In forged pistons this cold period allows the piston to shift rather than fit snug in the cylinder causing a piston slap noise. Slap can also be caused by rod angle in combo with pin offset. Repositioning the pin will load the piston differently preventing as much piston slap. Rod angle has everything to do with how and when the piston is loaded. Therefore it also has as much to do with piston slap as the previous two points.<< I'm thinking of total seal rings as sugested by Ross, but I'm getting both good and bad opinions. I'm debating the use of the L20B stock rods. I'm thinking of using aftermarket rods that are forged and a little more heavy duty. Carrillo offers a custom forged H rod that I can have modified to fit a full float 24.5mm or 1" wrist pin. I'm afraid of bending the stock L20B rods.
The bottom end will then get ballanced. The P90a will get a 3 angle valve job, ported, polished, and surfaced. After saving a considerable amount of change I will consult Isky Cams for a cam shaft. Schinder Isky, or Jim Wolf Technology will provide the valve springs. A custom harmonic balancer will be in order. BHW maybe? Or possibly Zraceproducts? No ideas yet.
The clutch will be a custom stage 3 clutch provided by ACT. Utilizing the L20B timing cover and timing chain will button up the front of the engine. I plan on using an aftermarket timing chain tensioner. Something like the one below.
This will provide accurate timing under high boost conditions instead of letting the engine granade itself. 42 links is standard on typical L-series. 44 links is only for the L20B and similar deck height blocks such as the LD28. ***"...the LD28 block is 19.7mm taller than the L28, the same ht differencebetween an L20B and L18. So, you use L20B timing chain & front cover."*** The LD28 also comes with a oil to water oil cooler. I will be using this as well. The N42 intake along with a custom exhaust manifold will be used. The N42 intake will be ported and matched to the 60mm KA24 series throttle body. I will use the same 500cc RC Engineering injectors on this engine. I will be using a HKS 1mm head gasket. The oil pan from the V07 block has extra capacity so I will keep it. Baffling will be added to the pan! I am going to build a custom windage tray based on the RB tray as well. I have yet to decide on the turbo size for this engine.
courtesyparts nismo adjustable cam sproket
To the right is a "exagerated" picture of the water jackets of the LD28. If you were to cut the engine down the center this is what you would see. The blue is obviously coolant. Just beneath the coolant in this picture is a filled in space. This space would normally be also filled with coolant from the factory. In this case since we are going to be boring out to 89mm we have the option of stengthening the block. Filling the block is tricky. I have never done this before so this should be reguarded as a first attempt failure. We will see how well it works. I've been recogmended to use Pevcon steel epoxy to fill the space with. the steel epoxy should have very similar expansion rates as the cast steel block. I've been told that because you want the coolant to pickup as much heat as possible you shouldn't fill past the top of the top ring at BDC.
**Tolerances thrust surfaces non-thrust surfaces ideal cylinder wall .25" .1875" cylinder wall w/epoxy .1875" .125"
*Specs provided by 1 fast z.
**Specs provided by clark@jimwolftechnology.com. Please do not contact Clark to debate provided information. See Disclaimer for that.
***DAW provided the specs
1974 Engine LD28ET
The LD28 will be the base for a turbo charged propane injected bio fuel monstor. To see more on this engine click the link below.
