FinnDatsun

I should have bottom end experiencing 1.5 times the load at 10.000 rpm compared to stock parts at 7200 rpm. Let's see where the redline sets, but I think bottom end will be just fine with main journal girdle and the fact it can take 400 hp in stock form turbo. I'm more worried about the head and stock valves, what kind of acceleration they experience during high revs. To have peak power in 8500 I should be able to rev it to 9500 just for sake of power band. Otherwise I need to lower my expectations overall. One thing to consider also is that RB has 45deg angle between intake and exhaust valves in head, and by my limited research online the particular Gixxer has 40deg angle, so there is a valid risk my valve clearances to piston need to be plenty. Gixxer also has 28.5mm intake valves compared to 30mm of RB20 so I really hope aftermarket pistons have extra diameter in valve pockets to accommodate possible oversized valves. With this conrod-piston combo, deck height is exactly the same as stock RB. But reduced piston and connecting rod weight, and longer rod will be easier on piston acceleraton and load. Rod is H-beam. Not going to be ready anytime soon, but some day

Bumping this up So, I have been doing some small and big thinking and shopping for my ultimate NA RB20 fetish. So far I have: - Tomei solid lifter kit - Tomei valve springs - Tomei procam intake 270deg 9,25mm lift - Tomei procam exhaust 260deg 9,25mm lift - Adjustable cam pulleys - Crank collar - Kevlar belt - 1,0mm head gasket + OEM gasket kit Plus some proper wizardry to bottom end: - Modified Renault connecting rod with 128mm end-to-end distance - Suzuki GSXR pistons 13,0 CR Plus on intake: - 2x GSXR 750 ITB's (42mm) to be modified for 6 cyl And bits and pieces from new cam cover bolts to woodruf keys etc. etc. Sooooo... I have been looting for parts over several years and I don't anymore think about the cost of this monstrosity. Basically my aim has become to replicate Triumph Speed Triple 1050cc engine in staight-6 form. Engine geometry is shockingly similar with Triumph and half of RB20. My displacement will be 2100cc with 80mm pistons. My rod/stroke ratio will be at some 1,8 and I will lose 200g weight from moving components per cylinder, so 1,2kg moving mass in total. Plus whatever they need to machine away for balancing. CR will be something between 10 and 11 (RB has more CC in head than Gixxer), but I might need to bump it up by machining the head. Trying to set intake cam for power band target and adjust exhaust cam for feasible overlap for NA. I might have to go for GTR cams later if these are "too mild". The head will be the last big question mark in the build, mainly its flow. I will go with stock valves just for sake of minor cost reduction to avoid going bankcrupt. Some serious porting is needed. But the aim will be 240hp+ in NA at ~8500 rpm or so. I still need harmonic balancer, shims for valves and ECU. And of course all the fabricating of intake and exhaust. Plus balancing and machining. I must have lost my mind to do all this for such small engine, but it's all-in at this point. At least there is no other like it in the world lol... plz help...

I think I lost my thought, it was 2 am at the moment here. Engine has to be dynoed, and there is some sort of common practice that if you have a turbo, it should run "reasonible" boost. My first interest would be information about how the head bolts to silver top block, combustion chamber volume for CR calculation and so on, to see if it would even run. BenR seems to have all this info already and the valvetrain modification is a curiosity for now. But being able to rev never hurts now that head should have better flow figures to start with.

Vanilla Silvertop. I have some plans for bottom end but nothing has been done.

I am raising this thread to see another nice rays of sunshine after a bit of break. First of all, Hello, I'm new member in here. I actually live in Finland but I find getting any useful information in Europe way too hard so here I am. I am currently starting a build of '79 200B SSS (known as 180B in here but chassis is 810). Original L18 engine with dual carbs is not going back. Car has to have no more that 168 hp to meet legal regulations. I weighed some options in my mind and I found by accident RB20DET without turbo or manifolds for next to nothing so I bought it before anyone else had a chance. My initial idea was to make it NA as it has 212 hp stock and it is really hard to "detune" it so that it meets regulations with turbo. I stumbled upon this thread in my journey for information about RB20 heads and I have found NEO head very interesting for a swap to "silver top" RB20DET bottom end and running it NA. CR is a great mystery, but for NA I am not going below 10:1 and I prefer something 10,5:1 -ish. Something that catched my eyes was I really hope BenR could catch up if he has more information about this engine he built (and has probably scrapped it already years ago). This is still a long shot for me as the build is just about to begin with all rust problems etc. but for now, information is what I mostly need. I work as mechanical engineer so I at least have an illusion about knowing something engines and I have access to some manual machining equipment. Thanks for any info you have, I mean ANYTHING is a plus. and if someone asks, 6 cyl just for the "cool-factor" and audio. There is no good reason to do this what I can think of but hey, it's something completely different and should meet legal requirements. Cheers.