Guest Anonymous Posted May 25, 2003 Share Posted May 25, 2003 Dude, I bet you'll be the first to buy one if/when they become avalible. Quote Link to comment Share on other sites More sharing options...
Sparky Posted May 25, 2003 Share Posted May 25, 2003 ya know, Ive been lurking in this post for a while now and i just finally got a chance to sit down and take a close look at those pictures of the RB20 head. bore spacing is the same?! I seem to remember asking this several years ago, to several different people. (some self proclaimed "experts" on the RB) they ALL told me that bore spacing was not the same..."not even close" as i recall, and here are the pictures to prove it other wise. I am all for this idea, but Alot of people ask "why not just go RB?" well, to be able to mate an RB head to the Lseries block, would be really nice. but the "OH-SH1T" factor would be even nicer. all, think of replacement costs for parts. the L series bottom end parts of fairly cheap and easy to get. and if you could use the stock L series head gasket as well...that would be sweet. also, Alot of us aleady have tons of money invested in our L bottoms. from 3 liters to worked DSL cranks, to forged pistons. wouldnt it be nice to still be able to use all that stuff, And not have yet another engine lying in our garages or backyards under a tarp (you know who yall are ) I say go for it! And for TBS, please consider the two options you have as far as water passages and oil galleries go. Maybe instead of working JUST the head to bolt on to the block. A closer examination of the block and the head might just prove to be a great thing. Think about the possiblilty of being able to work just a little of the head....then working on the block a well. putting all that machine work, into a alum head, sounds risky to me. imagine if you will. your car slightly overheats while tuning...and you crack the water passage...or two or three...all because they where worked so damn much....they are all too thin. BUT, If you worked the block insteadyou could possibly save yourself and your wallet..from having to buy another head to have machined. this will greatly depend on the bore of the block (with 3+ liters, this might be impossible) but with a nice 2.4 liter...or the high rev 2.6 that was mentioned on another board (this is the one im dreaming about) it might be the perfect combo! now I know what your thinking! "but now the head gasket has changed" well...your right. But how hard would it be to design a custom gasket? and how much would it cost? probably alot less than some of the other ideas youve had thus far. anywho, just thought id chime in with my twocents (I figured everyone else already has, i might as well too! ) laterZ and good luck. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted May 27, 2003 Author Share Posted May 27, 2003 If you must know. as for the RB head I've almost put that idea to rest unless I can find an oil pump that will bolt up to our bolcks but then in that event what about our distributor? how would I make it work. The reason is that the head over hangs to far because it uses the belt and not the chain. So for a head like that it would require a custom oil pump and a new way to hook up the distributor. And the skylines us a solid state ignition system so they can get away with just a CAS on one of there cams. If you look into it it gets more and more expensive and in the end a BR swap would be simpler and less costly. Now on the other hand I found a company that will cast me a head for 600 if I make the prototype and then mold it for them. Now for 600 bucks to me thats worth it plus I got the hook up at a machine shop that has a CNC Lathye and bridge port mill. tbs Quote Link to comment Share on other sites More sharing options...
johnc Posted May 27, 2003 Share Posted May 27, 2003 There's also the dry deck option when trying to mate different cylinder heads. You'll have to drill and tap the head and the block and run separate lines for oil and coolant. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted May 27, 2003 Author Share Posted May 27, 2003 hmm... that sounds interesting but my only concern would be thermal expansion and would would I use for lines, I amagine I would use flare fitting like whats used on the brake lines but would it really hold up to that much heat?? tbs Quote Link to comment Share on other sites More sharing options...
johnc Posted May 27, 2003 Share Posted May 27, 2003 All dry deck installations I've seen use AN fittings and braided lines. All are good to 600 degrees and 300psi with is more then enough for oil and coolant. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted May 28, 2003 Author Share Posted May 28, 2003 Can you point me in a direction to learn more about this dry deck set up. tbs Quote Link to comment Share on other sites More sharing options...
johnc Posted May 28, 2003 Share Posted May 28, 2003 Here's and example of one way to do a deck setup: http://www.turbomagazine.com/tech/0202tur_extremeedge/ In most dry deck designs there is no head gasket. The block and head are cut for stainless o-rings around the combustion chamber and also cut for special o-rings aroung the coolant and oil passages. I have seen some drag racing applications where the coolant and oil passages on the head and block are welded up and surfaced. The coolant and oil flow is routed outside of the head/block mating surface via AN lines with holes drilled and tapped in the appropriate gallerys on both parts. Both of the ones I saw were for extreme cylinder pressure applications (over 2,500psi). I assume the setups were very expensive. Sorry, I don't have any specific information to refer you to. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted May 28, 2003 Author Share Posted May 28, 2003 thank you for all this information I might be able to get this to work with the oil in our head and I have a friend that I'm helping out with trying to put an little nissan DOHC head on his mitsubishi four cylinder. tbs Quote Link to comment Share on other sites More sharing options...
TimZ Posted May 30, 2003 Share Posted May 30, 2003 All dry deck installations I've seen use AN fittings and braided lines. All are good to 600 degrees and 300psi with is more then enough for oil and coolant. Sorry to nitpick, but most plain stainless braided lines are only rated for constant operating temps of around 300degF. The braided teflon lines are good for 450 degF. Also, the psi ratings vary widely with the quality of hose and the size of the hose itself. 300psi is probably reasonable for this app with a good quality hose, though. 300 degF would still be fine for oil and coolant, btw. Quote Link to comment Share on other sites More sharing options...
Guest vodkaboy Posted May 31, 2003 Share Posted May 31, 2003 also I can't forget about a matching exhaust. From what I understand the molds are iterth destroed or damaged thus they could remake them bolt but maybe something else' date=' if this doesn't work then I'm going to just enginer my own and I found a company that can cast the for 600 each but I will need some one to sand mold it I can deffintly machine it out but I need some one to mold it. Is there any one that can help? If all goes good then one protype will be made and from there on out I will test it and see how it preforms. I can't do this alone and will need help to get the project done. tbs[/quote'] only $600? you sure you arent missing a figure there? christ, the heads on my t-bird are worth around 650-800 in their own right, and they arent even the greatest heads available (D0VE-C came in almost every BBF passenger car for the years 1970-1973, police interceptor or SCJ heads cost up to 2K!) when/if you get this project done, i want to hear about how well it does, and perahps i'll send you a fat cheque for a head of my own Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted May 31, 2003 Author Share Posted May 31, 2003 yes 600 bucks to cast a head with my molds. thats from bermag that will be doing the casting. Then there is the cost of machining, valve seats, cams,ect.... but I would like to make it use some of our parts to keep cost down. tbs Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 11, 2003 Share Posted June 11, 2003 My mechanic has quite a libary of old Z material. He once showed me a drawing/photo of a twin cam L28 so I know it has been done before! I will ask him if he still has the artical. Scott Quote Link to comment Share on other sites More sharing options...
johnc Posted June 11, 2003 Share Posted June 11, 2003 Ooops. Don't know where I pulled 600 degrees from. Maybe my a$$? Quote Link to comment Share on other sites More sharing options...
jeffp Posted June 11, 2003 Share Posted June 11, 2003 Has anyone ever contacted Gikkin to see if they would be willing to part with their drawings? I mean, if you are going to start this thing from the dround up, then whay not see if you can get their engineering drawings for the head. As I understand it, they have no intensions of ever building the head again. Quote Link to comment Share on other sites More sharing options...
DAW Posted June 26, 2003 Share Posted June 26, 2003 Obviously, chasing down an RB engine would be easier and cheaper, but that's not the point, is it? The pics of the RB20 head alongside the L28 block pics make it look challenging but definitely a reasonable and do-able project. Many race L4 and L6s ran externalized valvetrain oiling supply systems but I don't think this may even be an issue because it looks like the RB head has one oil supply hole at the front of the head that apparently supplies the oiling demand for the entire head. A short groove (passage) would need to be "routed" (milled) in the aluminum head to connect the block oil supply hole up front to the orfice in the head (think antfarm). The block hole fixed orfice would need to be increased in size. The mid-block L6 oiling hole gets blocked off by the RB head and no oil passes through. The semi-misalignment in water passages is not a big deal except that the RB head passages are too close to the L28 cyl bore (forget about any overbores) and this is probably due to the smaller bores of the RB20 vs those of the L28. Coolant leaks/blown headgaskets/hydro-locking all could result. The edges of the head passages closest the bore would need to be welded closed and the edges more distal to the bores opened up, even if at an angle to permit flow with the main passages in the head. So, what about other RB series heads re bore spacing AND size? For that matter, what about any potential donor DOHC inline 6cyl head? Volvo, Toyota, Jaguar, BMW, Mercedes (I'm not sure about this one), may all be potential sources. It seems far-fetched but until you compare some specs you just don't know. As to making new castings, there are some interesting technologies there but I think you should reconsider that approach because you may go broke trying to reinvent the wheel vs just buying an RB engine. DAW Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted June 26, 2003 Author Share Posted June 26, 2003 Has anyone ever contacted Gikkin to see if they would be willing to part with their drawings? I mean, if you are going to start this thing from the dround up, then whay not see if you can get their engineering drawings for the head. As I understand it, they have no intensions of ever building the head again Jeff since I can't speak japaness I can't talk to them and no one there speaks english. I tried and we made got TC24-B1, no english, send fax. So I sent a fax to them asking them if they would reproduce it or sell the plans for it. What I got back was they were unsure to remake the head and they wanted me to meet them at the salloo autoshow in Califorina. I posted trying to get someone to go out there and talk to them for me. No one here, at Nismo, Motorsport Auto, or Top End would go. Top End was being A$$ holes to me saying it's not there concer to find parts the parts need to find them. DAW your right on the money for my game plan to set up an RB20 head. Tomorrow I'm going to get a VG30 oil pump and see if I can mount it to our L6 blocks. if it all works out then I'll be able to fabercate an new engine cover/ timing cover and order an RB head for it. Wish me luck tbs Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted June 26, 2003 Author Share Posted June 26, 2003 sorry about my last post the quote and message is back wards. sorry about that. tbs Quote Link to comment Share on other sites More sharing options...
ToplessZ Posted June 27, 2003 Share Posted June 27, 2003 Well this post definatly makes for some interesting reading. Just noticed you were from ohio turbobluestreak. Good luck on this venture I cant wait to see how it all turns out. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 27, 2003 Share Posted June 27, 2003 I've read that the people who designed the L6 motor also designed an inline six for Mercedes before Nissan bought the company. These engines are said to be very similar. I don't know if these engines were ever fitted with a twin cam head, but it's worth looking into... Quote Link to comment Share on other sites More sharing options...
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