Daeron

You and the Cap'n make it happen!!

Quote of the Month!!!!!!!!!

If the car runs good, and feels strong, I would look more at how close the numbers are to each other than to how "low" they are. They aren't THAT low, certainly not for a turbo engine. Was there any reason you ran the compression check, other than just a check-up? If not, I would not be concerned.

For oilpan gaskets in general, (as well as valve cover and similar situations) I have always liked to take a cork gasket and spread RTV on both sides of the gasket, and then let it set up to dry for 12-24 hours. Then I use the gasket on a clean mating surface. To be brutally honest, I don't think I've done this with a Z oilpan, but it works well in all other situations I have tried it in (including sheetmetal oilpans on Roadster engines.)

Sounds like someone is using too long of a connecting rod...... GROAN...... I wouldn't bother trying too hard to press this point. The more people you convince, the more people you will be competing with for pistons. Kinda a lose/lose situation.

You haven't the foggiest idea how badly I needed that one. Passed along, and re hosted.

So a pair of these twin blade bodies would be more than enough breathing for a good, hi-po motor, AND it would make drivability much nicer if you had, say, an SU manifold altered to use fuel injectors, and aforementioned pair of siamese throttles. (Nicer compared to "some huge by large affair" that only has max HP in mind.) This makes me have ideas about a plenum to toss onto this setup that I don't want to talk about for fear of being beaten to the punch. I've already said too much.

Sorry if I am nagging, but I would presume that you have, then (in the context of this thread) "the throttle body on the left?" What size are the butterfly bores? "About the size of a dime.. [or a] ..nickel" is vague to say the least, and it would be nice to get better data.

Wow. That thing could almost be stock plus full moons and headlight covers. A buck sixty. That sends a charge down my spine:burnout:

I do not think the LD28 block can even come close to an 89mm bore. I haven't got a moment to look for posts to show, because I am speaking from what I have read (and not first hand knowledge) but I am still pretty sure your ceiling on an LD block is significantly less (in terms of potential bore diameters) than the gas L6 blocks. Sorry I can't recall specifics, but I know I have seen multiple threads where brian (1_fast_z, the guy who built his own DOHc head for the Z engine out of 240SX heads) repeatedly stated over and over that the block he sonic tested couldn;'t be bored out to over 83mm? Again, I am fuzzy on the details, but I know I have seen pipe dreams of 3.4 liter engines based on that super tall block with an 89mm bore, but it just aint going to happen.

One word of advice when playing around with soobies: NEVER underestimate the possibility that a Nissan part might fit. Tony D has told me a couple of times that Fuji Heavy Industries was actually subcontracted by Nissan to do alot of component manufacture, including (possibly) some L6 cylinder heads (!); I have seen time after time similarities between my old 87 GL-10 and datsuns/Nissans in general; so.... what I am saying is, you never know. Both cars use Hitachi transmissions and final diffs, (the auto gearbox in the 240SX and the pickup are RWD variants of the same 4EAT that Subaru has used in their cars since around 88) both used Hitachi-mock-Bosch EFI through the 80's at least... You neeever know when a Datsun bit might fit. In a way, a Subaru is what happens when a Volkswagen and a Datsun have a postwar reunion and things get a little out of hand... Drinkin all this modern Ethanol fuel, inhibitions are lost, and O2 sensors get preheated.... Steamy. Edit-> Advance apologies, but I really couldn't delete that once I typed it. I never claimed sanity or tact were my strong points.

That is the truth of the matter, but if you could assign a number to "how much easier" and then factor that into the equation, more power will almost always be capable with more displacement. Changing the r/s ratio and making it "easier" is an exercise in tweaking your powerband to be what you want it to be, with the equipment you want to use. Now, to know what you are doing with that, requires about 10-20 different iterations of you L-motor with differing strokes and differing rod/piston combinations, as well as piston crown/head combustion chamber combinations, and induction combinations. I am saying about 10-20 longblock combos, plus the added complications of the induction setups (camming and portwork included with induction) and then make about oh, 50-100 dyno runs comparing your numbersfrom each change. (Finding a good dyno, good operator, who can keep his machine somewhat consistent for this project, etc etc... ugh) It is something that takes DEVELOPMENT. Les Cannaday burst my bubble on this idea by telling me that electromotive did something similar to this at one point, nd did durned good with it.. after they dialed it in to a T. Using resources that pretty much NOBODY here has. Did it kill my interest in the project? Heck no, it made me want to do it to study it. It made me certain that I was wrong in thinking it'd be some whiz-bang junkyard combo that no one had found that screamed in a way that convinced you to chuck the practicality of the stroker out the window. I thanked him generously for bursting my bubble. But if you take a block, bore it out to 89mm, and get some LD28 rods and an L20 crank, youre around 2.6 liters and you are at one end. Get an LD28 crank, and L24 rods, and the KA pistons and you can re stroke your de stroker. I think the de-stroker might require a slight alteration of pin height from the standard KA, but at most two sets of custom pistons, two different cranks, one block, and one head (unless you wanted to have two heads ready to go, so you wouldnt have to change cams.) All it takes is an L28, an L20 crank, L24 rods, and an LD28 reciprocating assembly. Plus the pistons, so maybe 1K for the stock parts and maybe 1K for two set of pistons (could be cheaper.) All that needs to be done is to try it and you start building the experience that you need to REALLY know this stuff. The important part is empirical records tracking improvement.

Sorry, but that went up in the wrong spot ENTIRELY. Go back to the main sub forum branch, and go into Z31 subforum, and post a new thread of your own, there. You might want to search a bit before doing that, though.

The Cost method of deciding whether or not to DO this seems to be the consensus of many others with whom I have spoken about. However, whether or not it is worth it; ie, can I make more power per cubic inch to the ground, is a matter of tuning not just the engine and its powerband, but the gearbox and final drive ratios, all TO THE TRACK in question. In other words, Engineering a racecar is a tricky thing, and when you are "optimizing your rod ratio" you are playing in the sandbox dreaming of the day you will be a Big Boy. I say you, I mean "we" because I am right there in the sandbox with ya. Some of the guys here are Big Boys, and I haven't seen a single one of them maximize their rod ratio unless they were class-limited to be under 2 liters of displacement. If you can find a class where you don't have to keep the stock recpirocating assembly, but you have to stay within or below stock displacement, then this is an idea to bat around with. But nobody has done it and changed the world with it yet. It HAS been done, and the earth kept on spinning.

+20 bonus points for using the terms "crank" and "yank" so close to each other in a sentence, WITHOUT making it about... well, you get the idea...

That was back when they replaced them with those fancy backwards lowercase f's in script

I *did* know that, but couldn't find the specs anywhere (easily) so I just ignored it. Trust me, I was definitely aware of that one Its one of the reasons why, upon discovering a dearth of rods with 53mm BE bores, I still posted the info that I did up. tony, your comment about offset grinding is appreciated; when Komdotkom mentioned grinding the pieces to match something seemed odd, but I couldn't put my finger on it. Another Rookie mistake from yours truly The 1-3 mm potential increase in stroke can be taken care of using the VG piston now rather than the taller KA, and the honda (and 'yota) rods give us some real estate between 133 and 140 to play with. But I gotta say, Honda engines are some of the best damn engines out there, and for anyone to hesitate before putting a honda rod into their engine because of a bunch of idiot post-tweens with more spoilers than brains, really doesn't fit this website. Ever since I started driving my CRX HF about six months ago I've started taking affront to anyone who assumed Honda parts were crap because Honda enthusiasts are largely wasting skin... so I;ve been meaning to get that one off my chest.

Well, see, I was imagining a straight pull, not needing to modify the rod or your crank. But this discussion motivated me to look a little deeper and i found this... http://www.scribd.com/doc/7376862/Conrod-Application-July2408 It is a company's catalog in a digital, searchable document format.. I searched "53" and also "21" searching for rods that would only need to be altered at one end. Most (if not all) rods with 53mm big ends are too long to use, but there are some honda rods with 48mm big ends and 21mm pin journals that might work in the 136 and 138 range it looks like.. B16, B18, ans B20 motors.. Okay!! Listed: H23/B20A/F22 rod, 141.75mm length, BE is at 51mm, pin at 22mm, combined with a stock VG30 piston puts the piston .5mm above the block using that L20A crank, and the rod/stroke ratio is still above 2. Interesting document, I thought it might prove useful.

What toyota rods fit onto the L-series crankshaft? I did some googling and it seems like there is conlficting info out there.. the 3SGTE "crankshaft rod journal" is listed at 48mm, but the "" is listed at 51mm. The L-series rods are 53 mm. Also, 22mm wrist pins on the rods, which matches the Z31 piston but the Z31 rod BE is also 53mm. SR20 has a 51mm big end and a 22mm pin, maybe that is what you were thinking? Or am I missing something?

Wow.... nice photos!!!!! /sarcasm/ I think your throttle body might be a little on the small side.../sarcasm/

I kept shut because A: i didn't do any of this and B: I couldn't even come close to relating it all right anyhow, but I was hoping you would chime in after I threw your vid here. Looooong rod, over 2:1 ratio, tight tight tight tight ring pack on the piston. There are in fact, TWO replacements for displacement. One is boost... but the other is reciprocating frequency (RPMs) 2 liters at 9300 = 6 liters at 3100, right???

Thank you for clearing that up. I knew the points you brought up in response, but when I read your initial post it just... went over my head.

Huh??? How is the L20A crank compromised? (Aside from the two facts that A: I was just speccing out the furthest this gentleman's idea could be taken with existing parts, and B: ) Edit: 1. The question was a legitimate one, and not intended to sound as smart@ss as it might. 2. Point B above was just to illustrate how totally wicked-badass 9500 RPM sounds Don't take me TOO seriously.

Solid!

Yup!! Thats it, or it is as like it as two peas!!