Guest Won'tletmyzDie Posted March 30, 2005 Share Posted March 30, 2005 hey guys I got a hold of a representative of OS Giken, the people who made the original DOCH setup for the 280z they sell a kit for it. Currently It is discontinued but maybe if we get enough interested people *hint hint* they would make the kit again. E-mail this guy and tel him that you are interested in it and we may be able to get that DOHC l28 we have always wanted. rod@rbmotorsport.co.uk Tell him mechwarrior5@hotmail.com told you to send him the e-mail so he knows what is going on. Quote Link to comment Share on other sites More sharing options...
EZ-E Posted March 31, 2005 Share Posted March 31, 2005 If I remember though correctly the cost versus the gain from this head wasnt all that great, if memory serves correctly, and these heads were really quite expensive!! Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted March 31, 2005 Share Posted March 31, 2005 Especially compared to a RB25DET or even a '26 for that matter. I once had a conversation with a guy who was bum'd that no one made a canted valve head(like a big block chevy or Ford Cleveland) for his 440 mopar. After a few minutes of him ranting that the only thing holding a 440 back was the head. I confessed to him that I thought 440's sucked anyway and he should just build an engine with more potential to begin with. He has a 427 Big block chevy in his car now. My point is... If max power is what you desire, just start with a better platform. If you just want a strong engine, plenty of guys have done it with the stock L6 configuration. Remember, this forum is about making improvements to Zcars, no matter what the extreme is. As far and beyond as swapping engines. Don't settle for the datsun engine if it doesn't meet your performance goals. Quote Link to comment Share on other sites More sharing options...
Guest Won'tletmyzDie Posted March 31, 2005 Share Posted March 31, 2005 Maybe I am dreaming but I have no intention of putting in a skyline engine or a v-8 or anything like that for power, it is just to easy. I want to build myself an l28 from nissan and get 600 hp to my wheels with it Yeah I may be pyscho but hey, I drive a z I have the right to be. At any rate does anyone know where I can find one of these heads in a junkyard maybe? Also I have heard rumors of a rotary type cam setup for datsuns that allows tach range to exceed 9,000 rpm safely... I am quite skeptical of this anyone have experience in this area? Quote Link to comment Share on other sites More sharing options...
Mack Posted March 31, 2005 Share Posted March 31, 2005 well, if your power goals are 600rwhp, I don think the OS giken peice is for you. Stock for stock, they offered a marginal 5% gain over stock. They were a trick looking part, but they didnt flow very well and had very thin walled port castings, allowing for very littel porting. Mind you, this is what I have read of them and I have never seen one in person. As far as finding one in a junkyard?!? HA! thats all I have to say on that. As far as reproducing them? fat chance on getting the company to reporduce them, its been attempted many times over the years, and no such luck. Not to mention they cost $15,000 in 1980's dollars, god only knows what they would cost now. People scoffed at the idea of a $5000 bolt on DOHC head that flows 250CFM STOCK, and you think anyone would shell out 15K? DO some reading on some of the work being done by myself and 1 fast Z. we are actually making a DOHC head for the L series. McAdam Quote Link to comment Share on other sites More sharing options...
HS30-H Posted March 31, 2005 Share Posted March 31, 2005 ....Stock for stock' date=' they offered a marginal 5% gain over stock......They were a trick looking part, but they didnt flow very well and had very thin walled port castings, allowing for very littel porting...... Mind you, this is what I have read of them and I have never seen one in person......[/quote'] Every time the O.S. GIKEN TC24 B-1 is discussed on this site I feel as though I am watching the Hindenburg coming in to land in New York. I just know its going to crash in flames. Oh the humanity! Mack, I can't see how you can talk about a "stock for stock" parts comparison? The TC24 B-1 had dedicated inlet ( triple side-draught type ) and exhaust manifolds, as well as special pistons and rods. They were usually used with a different crank too, so when you compare it "stock for stock" what exactly are you comparing it to? And is that "5%" in comparison to a stock engine? If not stock, then what spec? Precisely where did you read it? I'm sorry, but that figure is ridiculous. People scoffed at the idea of a $5000 bolt on DOHC head that flows 250CFM STOCK, and you think anyone would shell out 15K? Speaking only for myself here, and no disrespect intended to yourself or the others working on the 'Frankenstein' head, but how can you compare your project with the TC24 B-1? Your "$5000" figure is a GUESS ( OK, maybe a *target* figure.... ) and you have not got anywhere near finishing a prototype yet, let alone testing it, developing it and productionising it. If anyone is "scoffing" at you then maybe it is because a price has been tagged on to your product BEFORE many other questions have been answered. O.S. GIKEN on the other hand designed their conversion, made all the patterns and moulds and cast the things from scratch. All of this was done when the L-series sixes were current and popular - more than 20 years ago - and in the HOME market for those engines. Even if it was done on a small scale it was carried through with big scale values and standards. The price at the time reflected what they had invested in the project, and even then they were probably not charging enough for them. Please don't compare your project to theirs. You are not even on the same page yet..... If I were you I would have tried to resist the temptation to publicise the project until you were a bit closer to completion of a running prototype. Don't you think you might be showing your hand too early? Mr Won'tletmyzDie, Did you try using the SEARCH function here? If you had typed in 'O.S. GIKEN' you might have learned something about what has been discussed here before. Rod Bell is a busy guy, so I would recommend that you don't waste his time by getting him to look into this any further without looking through the old threads on this site. Other similar ideas have come to nothing, and all for the same reasons. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted March 31, 2005 Share Posted March 31, 2005 Turbo and Nitrous... That's the ONLY way you'll get streetable(barely) 600 horse power from an L6. Then it will still only be good for drag racing or GTU racing(sans nitrous). Why do you think people started doing engine swaps in the first place? Is it worth $20 thousand dollars to say you have a Nissan L28 that makes 600HP? $15K for the head, AT LEAST $5K for the bottom end and HUGE turbo. How much for a transmission capable of handling it? $1500... Either you've won the lotto, or your dreamin'. I have about $20K in my whole car(maybe alittle more), But that's for the entire car, not just an engine. Open your mind... Let me guess... You also want to keep the stock non LSD rear and the trans that came in your car? Quote Link to comment Share on other sites More sharing options...
Mack Posted March 31, 2005 Share Posted March 31, 2005 as far as the "figures", I was just going off of what others here have said as well as what has been stated in the "how to hotrod and modify" book. also, when I said stock for stock, what I meant was just bolting an OS giken head onto an L28 engine that was already running tripples and a header. basically, doing nothing to the bottom end, specail cranks, pistons and rods be damned! lol The head I am building will work. I have condfidence in my mechanical abilities, as well as my engineering abilities. Perhaps we should have waited until we had a finished product, but we figured the Nissan community would respond favourably to it, which most have. as far as designing everything from scratch and what not, thats the beauty of the frankenstein head. Nissan did most of the engineering and it is a proven design. Shims on buckets, cant go wrong. The head flows phenominally (well, when compared to L series stuff, lol) and we know it supports high HP applications. ( I know of a few 500+rwhp KA24DE-T's) Ill compare the project to the OS giken head all I want because unless you have an OS giken head, it may as well be our head. The fact of the matter is that I am 99.999999% sure that NO ONE on this board has ever owned or worked on an O.S. giken head, so its all speculation anyway. Do you have access to some Dyno charts for the head? Do you know where I could find some? I would LOVE to see them! Im not trying to be a smartass, I really would love to see them! Im not trying to belittle the O.S. peice, god knows I would LOVE one, if for nothign more than an "era correct" conversation peice. But the fact of the matter is, no one will ever touch one for under $20K, even if they did reproduce them. Adjusting for inflation, how much would those 15,000 1980 dollars come out to be? Im guessing AT LEAST 30K. And how much does a used one fetch, if and when the owner decides to sell it? It just comes down to what people are dreaming about and what people could have. Im a helluva lot closer to my frankenstein head running than I, or anyone else I know, will ever be to even owning a TC24B1 head let alone having one in their daily driver. And that, unfortunately or fortunately, is a fact. McAdam Quote Link to comment Share on other sites More sharing options...
preith Posted March 31, 2005 Share Posted March 31, 2005 Did a google search and found a pretty interesting pdf file. In 1998, shortly after a new employee joined, he found an L18 based one in storage, and got it up and running in a 510 bluebird. http://www.datrats.com.au/OS%20TWIN%20CAMS.pdf My thoughts were I'd seriously consider it if could be had for $2000 or less, and I had a place to race it. I doubt it would be allowed in a production based class. Also, it could probably be developed further, with different cams and what not, but who would make those, or regrind the originals? It would take a lot of R&D with nothing in return for the cam manufacturer. Quote Link to comment Share on other sites More sharing options...
HS30-H Posted March 31, 2005 Share Posted March 31, 2005 as far as the "figures", I was just going off of what others here have said as well as what has been stated in the "how to hotrod and modify" book. Mack, Here's the actual quote from the Honsowetz book: "The optional two-valve, crossflow six cylinder head is not available through Nissan Motorsports USA. The reason for this is it's not allowed in many racing classes. However, this isn't a major loss because the crossflow head will give "only" a 4-6% horsepower increase over a comparable two-valve, non-crossflow head" He is obviously referring to Nissan's 'LY' head ( a single cam, 12 valve hemi-chambered design ) and NOT the O.S. GIKEN TC24-B1. I don't know where Honsowetz got those "4-6%" figures from ( maybe from Bob Sharp? ) but since the LY used many other different parts from the normal L-series engine it is hard to know what spec is being referred to, and just how it can be compared to anything else objectively. But anyway - you get my point? He's talking about a DIFFERENT head... Honsowetz goes on to write a couple of paragraphs about the O.S. GIKEN head, but it is clear that he never saw one or had any personal experience of one. He never quoted any performance figures. ... also' date=' when I said stock for stock, what I meant was just bolting an OS giken head onto an L28 engine that was already running tripples and a header. basically, doing nothing to the bottom end, specail cranks, pistons and rods be damned! lol[/quote'] But that would be pointless. How can the 'ideal' piston for a two-valve non-crossflow engine be the 'ideal' piston for a hemi-chambered four-valve crossflow engine? You can't just take off an N42 / P90 or whatever and throw on a TC24-B1. It's not a valid comparison unless you use the correctly-matched parts. I presume you will be using special pistons for your KA-based head, no? Quote Link to comment Share on other sites More sharing options...
Mack Posted March 31, 2005 Share Posted March 31, 2005 preith... I read that article as well, it was a nice write up. It would be a nice period peice! GREAT for historic racing! I did read that the cams they used were something on the order of 296 for the street and 306 for race!! thats INSANE! Lots of L series heads rarely go above 300, even for race! just tons of lift. IF you were looking for a DOHC for a 4 cylinder, the KA24DE will actually fit on an L series 4 cylinder. there was a guy a while back running a KA24DE head on a KA24E block (11.7:1 compression KA24E = flat tops, KA24DE = 10.5cc dish) and the KA24E headgasket is a spot on match for a Z20/22/24i headgasket, and we all know about interchangeability between L and Z series engines. I think a KA24DE head without the 96mm stroke could be made to scream. HS30-H forgive me on the quote, it has been a while since I read the "How to Modify" book as my ex roomy stole it! lol I should know better that to trust that book anyway. A LOT of his piston specs have been found to be innacurate. Have you ever seen an O.S. giken head running on a car? Im sure it would be a sight to be seen! I plan on using KA pistons for a KA head! lol. Actually, i was looking at some custom pistons to be able to use the LD28 rods, unless you know where I could get a set of FJ20 rods or perhaps L20A (139mm, correct?) rods? Im going for improving the rod/.stroke ratio for some high RPM's. was even contemplating an L24 crank/89mm bore/LD28 rod. R/S of 1.9. ultra tough, but man, those LD rods are H-E-A-V-Y. yes, it would be optimal to run a domed piston on a pent roof head! I was looking at these wave roller pistons. It looks as though this place has a good idea of whats going on, as opposed to just being a marketing tool. Quote Link to comment Share on other sites More sharing options...
karay240 Posted March 31, 2005 Share Posted March 31, 2005 The OS head was made during a time period where none of the major manufacturers (OEM manufacturers like nissan) were affraid of ppl thinking that they were wasteful during the time of the oil shock. OS made those heads w/ simple hand tools, and that's why they are so rare, and soooo expensive (yes, the whole thing is practically hand-made.) This is also the reason that they utilized rockerarms, instead of using direct acting cams (they didn't have the tooling to do it.) Anyway, OS had really good success w/ these heads in racing. They were able to get well over 320hp (w/ no forced induction!!!) After their success, and the oil shock became less of an issue, Nissan's racing dept (I think it was called Nismo then, too) came out w/ their version of it w/ a 2 valves per cylinder (the OS one is 4 valves per cylinder, and the conbustion chanber looks like that of the RB26.) I'm not sure how well it would be w/ forced induciton, but I know that w/ NA trim, it's not 5~6% gains. I think that it's a neat idea to have a twin cam head from OS, but the cost performance just isn't there when you compare it to swapping another motor in it, whether a V8, RB, 1J, SR, or whatever. Kenny http://www.rbmotoring.com Quote Link to comment Share on other sites More sharing options...
HS30-H Posted March 31, 2005 Share Posted March 31, 2005 Have you ever seen an O.S. giken head running on a car? Im sure it would be a sight to be seen! Yes, I have. Been in a car equipped with one too. Take a look at this old HybridZ thread: http://forums.hybridz.org/showthread.php?t=76847&highlight=TC24-B1 .......unless you know where I could get a set of FJ20 rods or perhaps L20A (139mm, correct?) rods? Im going for improving the rod/.stroke ratio for some high RPM's. You can still get L20A and FJ20 rods in Japan, last I looked. Its the FJ24 that you can't find anywhere. Used L20A and FJ20 rods are very cheap out there, but surely getting some custom-made rods will be better and not that much more money. The USA is just about the best place to order a set of custom-made rods, I think? Quote Link to comment Share on other sites More sharing options...
HS30-H Posted March 31, 2005 Share Posted March 31, 2005 Anyway' date=' OS had really good success w/ these heads in racing. They were able to get well over 320hp (w/ no forced induction!!!) After their success, and the oil shock became less of an issue, Nissan's racing dept (I think it was called Nismo then, too) came out w/ their version of it w/ a 2 valves per cylinder (the OS one is 4 valves per cylinder, and the conbustion chanber looks like that of the RB26.)[/quote'] Kenny, No disrespect intended, but I think you have the sequence of events all wrong. You can't seriously be suggesting that the O.S. GIKEN twin-cam conversions predated Nissan's two-valve SOHC 'LY' head? That's way out. Nissan were using the 'LY' from late 1972 - way before even the four-cylinder OSG design. You can't say that Nissan "came out with their version of it" - you have the cart before the horse. Nissan had four-valve DOHC crossflow engines way before all this anyway. How about the 'UY' DOHC inline six fitted to the 'Fairlady S' race car in the late Sixties, or the S20 DOHC 24-valve six ( developed from the Prince GR8 race engine ) as fitted to the Skyline GT-R and Fairlady Z432 from 1969? Look at the port shapes and combustion chamber design of the S20, and you can see similarities to the FJ, and then the RB. OSG were doing what they did, and people were taking notice, but times were changing anyway after the "Oil Shock" faded and the Japanese "Bubble Economy" boom started to get into its stride. A return to performance-oriented niche-market high perf engines was inevitable...... Quote Link to comment Share on other sites More sharing options...
Clifton Posted April 1, 2005 Share Posted April 1, 2005 I want to build myself an l28 from nissan and get 600 hp to my wheels with it Yeah I may be pyscho but hey, Not a psycho, but a dreamer. 600 rwhp can be had easily but not so easily, cheaply, or reliablly with an L28:nono:. An RB26 with a stock block and head could do it, 2JZ could almost do it on pump gas but that would be too easy. Quote Link to comment Share on other sites More sharing options...
preith Posted April 1, 2005 Share Posted April 1, 2005 preith... I did read that the cams they used were something on the order of 296 for the street and 306 for race!! thats INSANE! Lots of L series heads rarely go above 300, even for race! just tons of lift. I'm a little confused by this statement, I hope you're talking about duration, and if so that's not entirely correct. Almost all full race N/A motors use a 300 duration or more (slightly). The lift is usually .560 or .620. Anyway, OS had really good success w/ these heads in racing. They were able to get well over 320hp (w/ no forced induction!!!) It's not that uncommon for an all out race L28 to get around 320 hp. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 1, 2005 Share Posted April 1, 2005 Go Alan! Mack, he's got valid points. The quote was referring to LY -vs- L on the 4-6% range. The OS claimed 12% bolt on in literature of the day compared to L. This is akin to Mikuini claiming 22% by a set of 44PHH's on the L24, and 12% on the 280 mill running EFI (they even had dyno graphs with no scales on them to prove the point!) But as for this quote: "The fact of the matter is that I am 99.999999% sure that NO ONE on this board has ever owned or worked on an O.S. giken head, so its all speculation anyway." I would take the member list, divide that number into at least TWO and revise that ".999999%" figure to more accurately reflect the realities of the situation. Just as an aside, the TC24B1 that was tested at JG Engine Dynamics in Alhambra actually made less horsepower than the JG-Ported head on a similar engine. This was using a SOHC cam grind similar to what the two OS cams were ground to---they did have the advantage of trimming lobe separation easily on the dyno. Cam figures are about usless unless you ahve the cam in front of you and measure it yourself. Who is to say they were measured at 1mm valve lift, .015 or .050" valve lift or in CAMSHAFT lift. I have seen many cams advertised at 304 duration that when measured at .015 or .050" lift at the valve were only in the 280 range. So a 304 may sound radical or insane, it really only is a number. I have had real world 290 duration cams in vehicles, and they in no way compare with some advertised "310" grinds. At least nobody called it a 3/4 Race cam... :Rolls Eyes" Get it? 3/4 Race because it's 270 degrees duration... now you know the rest of the story! But I digress... Now keep in mind, Javier used one of his 3.2L engines, and that required changing pistons and rings between the tests. I begged Javier for the old head, but unfortunately he tried porting the OS head to get comparable numbers and found the casting was much thinner than stock Nissan parts, and the ports could not be reshaped for better flow or horsepower. Reading that, you can infer that he trashed the head cutting through the ports in more than one place. But L-Engines were on the decline, and Hondas were taking up more and more time in his shop... I still wish I had the old OS head just as an ornament. Cut ports or not... Quote Link to comment Share on other sites More sharing options...
Bluto Posted April 2, 2005 Share Posted April 2, 2005 Even though the topic gets brought up for all the wrong reasons it seems that we get a few more interesting tidbits of info each time. Thanks, Sam Quote Link to comment Share on other sites More sharing options...
slownrusty Posted April 2, 2005 Share Posted April 2, 2005 Tony - That is a very interesting comment on Javier's work on the TC24B1. Really confirms the power potential of a well ported P90. I remember back on the day when he used to spend alot of time messing with Datsuns.... Yasin Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 2, 2005 Share Posted April 2, 2005 Yes, I remember well. It was before the rage with Hondas. When nice rust free 240's would show up in the junkyards by the SCORE... WE had a chocolate river that ran through town, and little orange men who dumped sugar into it to make it sweet. Because as you all know, memories filtered through a choclate river are oh, so bittersweet! BWAHAHAHAHAHAHAHAHAHAHAHAHAHA! Someone can slap me for being off-topic when they see me! I hereby give you permission for that comment! LOL But yeah, I was suprised by his comments. And still shudder at the thought of having something like that and trashing it---such is the nature of the business during experimentation I suppose! In 30 years some people will lament what we are doing for our rides I suppose... Quote Link to comment Share on other sites More sharing options...
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