Mack Posted September 4, 2005 Share Posted September 4, 2005 so, here I sit looking at all the pretty little bent valves in this RB25 head I have for parts, wondering how hard it would be to slap it on an L block, with external oil lines and maybe one or 2 external coolant lines. My mind begins to drift towards the semi complete LD28 short block with its BELT driven injection pump, I cannot help but wonder....... head bolt holes as well as bore spacing are DEAD ON as well as a lot of coolant holes around the cylinder bores. so, does anyone know where I can get a detailed coolant flow schematic for an RB25DET engine as well as an L series engine? I think I could pull it off if I could get my hands on some injection pump pulleys and just have them welded to the RB cam gears then find a suitable length belt and viola! well, besides putting some tensioners on teh outside of the timing cover and a few other hurdles. thoughts?? Quote Link to comment Share on other sites More sharing options...
twistex Posted September 4, 2005 Share Posted September 4, 2005 damn that would be sweet ... somthing i would like to do to my ld28i need more air flow .. let mw know how it goes. Quote Link to comment Share on other sites More sharing options...
Gollum Posted September 6, 2005 Share Posted September 6, 2005 I'd assume best bet would be shop manuals. But I'd also assume there to be a good amount of online info on the RB head. I wonder how well that would work NA.... would be perfect for CA. No cop could tell that it's wasn't OEM. Quote Link to comment Share on other sites More sharing options...
Phyxius Posted September 6, 2005 Share Posted September 6, 2005 I've found a guy that is going to sell me a RB26 head complete with valvetrain for about 325$ including shipping. how is the belt gear for the pump driven, and what kind of belt is it? Is it directly from the crankshaft, or some other method. You would definitley only want to use a cogged belt. Quote Link to comment Share on other sites More sharing options...
Mack Posted September 6, 2005 Author Share Posted September 6, 2005 the belt is driven directly off of the crankshaft, and it is a cogged gear. the gear teeht spacing looks almost exactly like an early to late 80's 200SX, you know the ones with the CA20E in them? also looks very similar to the VG30E timing belt, with regards to spacing and number of teeth, Ill count teeth on the crankshaft gear sometime this week to be sure. Mack Quote Link to comment Share on other sites More sharing options...
akeizm Posted September 6, 2005 Share Posted September 6, 2005 This looks very interesting. What is this Injection pump pully thing you mentioned in the 1st post? Quote Link to comment Share on other sites More sharing options...
Guest iskone Posted September 7, 2005 Share Posted September 7, 2005 If you can't find the belt in an auto parts store look in a McMaster Carr catalog. I would start with McMaster first. Good Luck! Isk Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted September 7, 2005 Share Posted September 7, 2005 Wouldnt it be easier to just throw an entie RB in it?? Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted September 7, 2005 Share Posted September 7, 2005 If it works it will be the best thing since turbocharger. Considering an OS Giken head costs 10000$ and an RB engine swap costs several thousands. Please keep us updated with your progress Quote Link to comment Share on other sites More sharing options...
Phyxius Posted September 7, 2005 Share Posted September 7, 2005 Wouldnt it be easier to just throw an entie RB in it?? easier...maybe...but this route certainly has the potential to be less expensive with more displacement. Quote Link to comment Share on other sites More sharing options...
Gollum Posted September 7, 2005 Share Posted September 7, 2005 Well, not only do you get more displacement, but it looks stock. If it can be done I'd consider it WAY before considering putting an entire RB motor in my car. If I put an RB motor in my car I'll have to swap the motor every other year to get pass smog, if I just switch the head I could pass emissions no problem as long as I could get someone to pass visualisation for me. The idea of a stock looking head on a complete stock motor is awsome. I bet 99.9% of cops wouldn't be able to tell if it was just an NA car with the NA RB25DE head Quote Link to comment Share on other sites More sharing options...
Confused Posted September 7, 2005 Share Posted September 7, 2005 I definatly need to keep updated on this one. Hope it all works. Quote Link to comment Share on other sites More sharing options...
akeizm Posted September 7, 2005 Share Posted September 7, 2005 Wouldnt it be easier to just throw an entie RB in it?? Considering you would need to change sumps, mounts, transmission and do other mods. If you could do this work I reckon it could be easier than doing a whole swap. Just really depends on what wouuld be needed for it to work. Quote Link to comment Share on other sites More sharing options...
Phyxius Posted September 8, 2005 Share Posted September 8, 2005 From what I've been able to find so far, the RB25 head has a 63cc combustion chamber on the head. I'm not sure if the RB20/26's are the same or not. That is large, and would require the use of flat top pistons to get a compression of about 7.5:1. That is about what the turbo motors are stock anyway, so it's not that big of a deal. If you wanted a higher compression, you could always mill the head or use dome pistons (which i've heard is bad for combustion chamber geometry). Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted September 9, 2005 Share Posted September 9, 2005 easier...maybe...but this route certainly has the potential to be less expensive with more displacement. More displacement? Have you not seen the specs in my signiture? I am running a 3L RB! Quote Link to comment Share on other sites More sharing options...
Phyxius Posted September 9, 2005 Share Posted September 9, 2005 More displacement? Have you not seen the specs in my signiture? I am running a 3L RB! I was talking about more dispacement in stock form. To get an RB30 with another head and install it in a z would probably take nearly $10k. If this method works it should cost less than a quarter of that at MOST. I'm hoping to do it for less that a tenth of that. $1000 for all the advantages of an RB doesn't sound too bad to me. Keep in mind, most of us are in the US and RB's of any sort are much less common here. Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted September 12, 2005 Share Posted September 12, 2005 I was talking about more dispacement in stock form. To get an RB30 with another head and install it in a z would probably take nearly $10k. If this method works it should cost less than a quarter of that at MOST. I'm hoping to do it for less that a tenth of that. $1000 for all the advantages of an RB doesn't sound too bad to me. Keep in mind' date=' most of us are in the US and RB's of any sort are much less common here.[/quote'] Yep good call on everything above, i am spending truck loads! But mostly on all the bolts on's ie, turbo, w/gate, big i/c, front facing inlet plenum, big t/b, BOV, injectors, fuel rail, fuel pumps, reg, surge tank, ECU. So as you can see, none of the above mentioned items relate to the actual engine itself or g/box etc. And i have at least $7k in above parts already!!! And even if you use an RB head on an L block, you will still need the majority of above items if you are going to make decent power. If you are able to do this swap for $1k, GO FOR IT!! Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted September 12, 2005 Share Posted September 12, 2005 RB30E block + RB26DETT head = fun ill be having soon! even still ill be watching this thread mike Quote Link to comment Share on other sites More sharing options...
Phyxius Posted September 12, 2005 Share Posted September 12, 2005 Yep good call on everything above' date=' i am spending truck loads! But mostly on all the bolts on's ie, turbo, w/gate, big i/c, front facing inlet plenum, big t/b, BOV, injectors, fuel rail, fuel pumps, reg, surge tank, ECU. So as you can see, none of the above mentioned items relate to the actual engine itself or g/box etc. And i have at least $7k in above parts already!!! And even if you use an RB head on an L block, you will still need the majority of above items if you are going to make decent power. If you are able to do this swap for $1k, GO FOR IT!![/quote'] yeah...i already have some of that stuff though...1000$ is VERY optimistic...but that never hurt anyone, right? lol Quote Link to comment Share on other sites More sharing options...
evildky Posted September 12, 2005 Share Posted September 12, 2005 I have wondered about the head off of the RB20ET it's not a twin cam so it might line up better and it's a crossflow so it should be a marked improvement and being a singlecam the timing chain guides wouldn't be a huge issue another benefit the RB20ET is older and less desirable, it'd be harder to find but shoud be a LOT cheaper! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.