mark99

Std rod lenght is used, so a far from ideal rod to stroke ratio of 1.46:1 Yeah i agree with all of that. I would always go for as longer rod to stroke ratio as is practically possible. I dont believe you are missing anything. Apples for apples that will prove to be a superior combo. RB30 engine aside, I would not choose 2.6L with 1.64 rod to stroke ratio over 2.9L with 1.46 rod to stroke ratio. In nearly all engine build some facets have to be compromised at some point. Camshaft selection nearly always highlights this. Peolpe buy stroker kits, probably for a variety of reasons. Some people have unwarranted RB30 phobia. I think some people like the idea of retaining the original block with orignal engine number. Some people like the idea that once the engine is built the install wont require any modifying or fabrication that they are not able to do. I guess what im saying is peolpes motivating factor behind choices are all different, so those that want to go the stroker option, whilst retaining the original block for whatever reason, id say that this combo works well. The extra side loads to due to poorer internal geometry from the engines i've pulled back down dont seem to be excessive to the point of causing any issue. Poor cylinder filling is mainly overcome from the get go as, inferior piston motion is negated largley by being forced induction. MOST big dollar street GTR's do very little actual work, so premature wear on anything is never usually a consideration. As an aside. We are building a V8 engine at the moment that has a rod to stroke ratio of just short of 2.2:1 for a high rpm salt lake race car. I am really interested to see how it performs.

With what rod????? Assuming a std length rb26 rod, what do you do about the following.... The .260" of piston that will stick out the top of the block. The ridiculously low comp ratio that the dish in an SR 20 piston will give you. Thats assuming you gone for a custom big end on the rod, to fix the fact that RD28 rod journals are bigger in diameter, and wider. If you then also got the rod made shorter while getting a custom rod made to fix the other issues, the piston would hit the counterweight at bottom dead centre. All this can be overcome, but; I woulndnt call the fix to the above problems minor mods

I think when momentum gtr is saying custom pistons made for the 2.9, he means; custom in the comp height (distance from gudgeon centre line to crown of the piston). That way the extra stroke to increase the capacity can be taken up by shortening the comp height from std. Yes this does work, and can/has been done. i developed it for my car. I have done a few others now, and they work really well. Yes we sell them through my workshop. Ball park pricing is $5250 for crank, rods, pistons, rings. The crank is nitrided, balanced, and has a collar fitted, the rods are Eagle, the pistons are usually JE or CP. I say ball park, because; there are a number of options; 22mm pin upgrade, plus all the usual custom piston options, plus as the pistoons are out of the states, with the dollar moving around a little latley it affects the price. Also rods are optional, Eagles, Crowers, Carrillos etc. So depending on what rods, and what piston options you want, the price will vary. Below ill give a summary of the answers to the usual questions, but ask away if you want to know something No, the crank is not as good as a brand new HKS, Tomei, etc. But for the majority of applications it is more than good enough. How many big power RB30's are out there with std cranks.... Yes the rod to stroke ratio is not ideal. The RB 26 does not have a good rod to stroke ratio to begin with, but the std rod to stroke ratio works on big power combos. Any stroker reduces rod to stroke ratio. I would prefer more capacity, with a slight decrease in rod to stroke ratio. No this is not easy to do yourself. Im not just saying this so you buy one from me. I use a lot of different machines to do this I decrease the stroke to 83.25 mm. This means it all JUST fits in. My initial engine made just over 400rwkw, and reved to 8800. The most power i know of through one of these combose is a tad over 450 awkw. In my OPINION these are a great thing for a streeter. Hope any of this is interesting of useful to some of ya........

Still got this stuff, time for it to go. Make me an offer.........

Bump

bump cmon buy someone ya love a nice xmas present.

I have one new HKS step pro 280 10.7mm intake cam for sale and I have a set of used HKS step pro cams and buckets for sale cam specs are intake 280 10.7mm exhaust 288 10.7mm These are the "best of the best". They are the billet hollow cams. much lighter and stronger than the normal cast camshafts. You can see the welch plug in the back. These are special order and an eternity wait from Japan. They are reduced base circle so you have to use thicker buckets. The used cams have not done much work, but were installed on an engine previous to when i owned them and were set up with too much spring pressure, and as a result bruised the lobes in some spots.. The lobes are "marked up". They look worse than they are, however let me be clear, they do have some marks on them, and do not LOOK like new. The cams have been in two engines of mine, and have performed faultlessly, with no noise or problems. THEY DO PERFORM WITHOUT PROBLEM. There is one broken bucket, this happend when a valve spring broke. This has been used in this condition and not caused a problem, however it would be up to the individual engine builder as to wheather they re use this. I MAY be able to organise a new one, at the buyers expense (PROBABLY around $100 - $150) Sorry for the size of the photos, i just want people to see what they look like. They are not "carved up like the photos make them look, more just "bruised" Also the suface finish in the photos look terrible, it also does not look like that. The photos make the damage look worse than it actually is. Inspection welcome, i have nothing to hide...... I would guess with the yen the way it is, 2 new cams and buckets would be $4000??? Correct me if im wrong..... Location : Adelaide Price : New cam $1500, used cams and buckets $1500 (If you want to beat me down on price on either item thats fine, lets just start at $1750, and you haggle me down to $1500) PM me Thanks Mark

This didn't disappear into oblivion. I just got sick of e-warriors telling me "$5000, i can buy xyz jap brand for not much more than that!" or "what about the rod to stroke ratio? That must be a real problem!" etc etc. Whilst i never tried to tell anyone that this was some sort of magic combination, it seems there are a lot of people out ther with little to no experience who want to try prove there vast and expansive knowledge, that is fairly obviously gained from reading forums and reading forums only. Trust me, this combo works, and works well. Its a street car, and as such all in all is a good compromise of everything, in my opinion Paul, i certainly dont put you in that category, your results speak for themselves. As you would know, you have obviously put a lot of time into developing what is a extremley potent combo. I certainly believe with more development time, i could see substantial gains in power form my set up. Its only been on the dyno twice. Once it maxed the injectors, the second time it was tuned, made safe, and thats it . It has never even had the cam timing played with! I would be interested to hear your comments on a couple of things on my car that i reckon might be holding it back. However i would take the "pepsi challenge" with you. Run your car up, print a dyno sheet, pull the engine out, change crank and pistons to a stroker crank like mine. Put the engine back in. Then tune and re dyno. Print out another dyno sheet. I know which combo would produce a better result. Paul surely you agree that if all that is changed is capacity, and it is inceased, your car will make at least the same power, but lower in the rev range, and may even make more..... There are no "smoke and mirrors", or "special sauce" in making power. As far as the rest of the dribble on this page, seriously girls keep it on nissansilvia.com I put this info up here in the first place to share info with others, as i have gained a lot from these forums, so figured its a good idea to put back. Lets keep it on topic hey.

Spotted MissR34 going through Gawler today

1. i wasn't talking shit 2. It took a fair bit of time, i was looking at trying to see if i could do it and have it commercially viable, and for me it was worth the effort. The reason to not just use a 26 crank, is because almost with out exception no matter what your application, more capacity will be better. I did it by offset grinding the rod journals down from rb30 size to rb26 size, taking a little bit of stroke out as i went down. Final stroke was 83.2mm. i used standard length Eagle rb26 rods, i rebushed them to 22mm gudgeon pin size (but you can leave them at 21mm pin if desired) . Then used custom forged pistons. Yes the rod to stroke ratio ends up fairly poor. But it doesn't seem to to have any serious adverse effects on the engine. The car has low mounts, runs pulp, 18psi, makes 406rwkw, pulls hard from 4000, and pulls harder than an under sexed school kid from 5000 through to 8800. The engine revs freely and smoothly, and is sweet all the way through to the just short of 9000rpm rev limit. There is also counter weight modification required. Ill be the first to admit, a longer rod to stroke ratio is better, and the the OS is an awesome bit of gear. But for me it was just time, so it was certainly worth it, who wouldn't want 2.9L? It worked out that i can do the cranks finished ready to go for $2500 dollars, this is nitrided, and with a crank collar fitted. Standard rods will not clear the block, so you need an aftermarket rod like an eagle or crower, and then of course custom pistons. So all up it works out a lttle cheaper than say an HKS stage 1 kit, but most people like brand names, so i've only had a little interest. Hope that helps, feel free to ask any questions.

Im not 100% sure on this but you might find your best bet is to go with r33 rb25det cams, and change the cam angle sensor drive in the front of the cam to suit your r34 cam angle sensor. Im pretty sure r34 turbo are solid cam, where as non turbo is hydraulic, so for simplicity if you stay with hydraulic cams from other rb25 engines, other than the cam angle sensor i think they should fit straight in (any one feel free to tell me if i've over looked something else). Im not sure what the assembled height of the valve spring on the non turbo neo is like compared to the turbo rb25, i wouldn't think it could possibly be any worse, so valve springs should to be able to be sorted one way or another. If you add adjustable cam wheels, then the fact that they are "turbo cams" really should not matter, as long as the lift and duration are relatively larger than standard. Whoever tunes the car will be able to adjust the lobe seperation to suit n/a application with the cam wheels. For all intents and purposes, lobe seperation is the biggest difference between n/a cams and turbo cams, so with adjustable cam wheels, this is not such an issue. Hope that helps, but like i said dont quote me on this. Im going on memory for all of it, and i may have overlooked something. But it would be a good place to start

Dont listen to them. Cams are a personal thing some people love big cams, some people hate 'em. If you like the sound of an engine with bigger cams in it, then for an n/a engine with the mods your car alrady has on it, cams and tuning to suit are a logical step.

been spotting a nice looking stagea going through gawler lately. Think is a white pearl colour, and looks fairly slammed in to the weeds

Work in Gawler, live in Mawson Lakes

Precision Shims 0397230199

Im from Rhemac Motors, we are a performance engine machining shop. Prices for a built engine really would vary, depending on brands of parts used, std rods or aftermarket, how big a cams etc etc. PM me a phone number and i can call you. But ball park, crank and custom CP pistons, pins and rings $4000. By the time you did a whole engine and assembled it, start around $9000 - $10000 depending on what options, and then go from there with yet more options. Ill try take some pics on the weekend and post em up

Sorry in the delay with updates, been absolutely flat out.... I put bigger injectors in and the car ended up making 406rwkw @ 18 pounds on pump fuel. Any more boost and it only picked up small amounts of kw and started to heat the air, not sure if the turbos are maxed out or if something in the induction setup is causing a restriction... not sure if my cooler is big enough. I've got another dyno sheet but its done in shoot 8 insted of shoot 6 so the torque figure is different due to the different ramp rate?? ( i dont know much about dynos). The power curve looks identical, just goes a few kw higher... To drive, the car is nice and broad and controllable in power delivery,pulls well from 3000 rpm and hard from 4500 through to 8500rpm... Ive two more cranks almost ready to go, and more started for those that are interested. Please PM if you are intersested, so we can discuss options. It can be set up with std rods, or after market, 21mm or 22mm pins. My car will be on display at Adelaide auto salon, as will a 2.9l short engine. As usual any questions, comments or ideas just shoot Mark

Hey guys, once again thanks for the interest, when i started this thread i thought the interest would centre aronud the gt-rs turbos, as these are always the centre of debate... Again though please dont think im trying to say what i've done is ultimately better than using a brand new jap brand stroker crank, most of those cranks are a real nice bit of gear. However, value for money i may be able to compete on. For me it was just time as i have all the equipment at my disposal, but im in the midst of trying to figure if i can do this conversion at a cost that is both economical to me and to customers. To do this ill have to be well under the price of those kits. Im thinking that this conversion is good for people who've just trashed a crank through oil surge, and are looking at building a new bottom end, and need another crank anyway. One other thing to think on is while my crank is not fully counterweighted, this may be a good thing for a drag application, as fully counterweighted cranks are quite heavy. Lightweight cranks are always limited life but for drag work often this is not a worry

Thanks for the interest guys. Yeah really broad power was what i was after for street use. Gav, for that price is that a fully counter weighted or semi counter weighted crank? While i agree horses for courses, im hoping the cost to be sustantially less than that. Pete, at this stage, the same as any rb30 crank, so far what i have done seems to have no adverse effects on the crank, but iil keep you posted.

You mean copy an OS or buy one? Buying one no, too much, but copying yes. Thats my next project, sort of a copy of both OS and Kakimoto high block... Already got the first few things cut. But gotta finish this first.

Yeah, what SK said. Basically longer rod to storke ratio is better. However due to me wanting to retain the factory block yet increase the stroke, something had to compromised, thus the low rod to stoke ratio. But i dont cosider it too big a trade off, its not that much worse than other jap brand stokers, yet gives me more capacity at vastly reduced price. The other thing to note is that some the benefits of longer rod to stroke, ie better cylinder filling, are most notable on engines with very poor breathing, ie restrictive induction and heads. Something a turbo charged engine has less to worry about. So whist in an ideal world i would have preferred a longer rod to stroke ratio, in the real world, for what i wanted, std block, more capacity, affordability, something had to give Oh and redline is 8000 at the moment, but will be raised once bigger injectors go in.

The crank is de-stroked slightly, and heavily modified, using std rb26 shells (rb30 big ends are larger than rb26). Yeah the ring lands are fine, the pin is high, but no higher than on a lot of other long stroke engies. Details on the crank mods sound vague, but i dont have exact measurments of what i did. i made templates of the shapes i made everything so i can do it again, and am in the process of figuring out if i can offer the conversion at an economical price (there are a lot of hours of labour in the modifications). To do all the mods you need a lathe, mill, crank grinder and engine balancer. But should still be able to do something vastly cheaper than japanese alternatives.

I modified the crank, so that i could use a 26 block, instead of an rb 30 block, so that all the outside components would fit up with out modification. The pistons are a custom order, with 22mm pin, the only rod modificatonn, is re-bushing to 22mm pin

hey guys, to answer some of the questions, its a modified rb 30 crank, eagle rb26 rods, this may sound strange but i dont even know what BP on that dyno chart means (im an engine machinist, and know very little about dyno set up), only just got the car back so not sure what rpm it hits full boost at but ill let you know.

As the title says here is a dyno sheet for a set gt-rs's on a 2.9l gtr engine. It needs bigger injectors as you can see it hasn't fallen over yet. Will post another sheet once the bigger injectors go in. all the usual mods have been done, including these relavant ones; gt-rs turbos uas extrude honed manifolds ces race style dumps and front pipe trust tr exhaust hks 280 10.7 intake, 288 11.0 exhaust cams 1mm o/s intake valves cnc ported head cp forged pistons eagle h beam rods stroker crank power fc z 32 afms any questions just ask. this run is at 16 pounds, pump fuel and injectors at max duty cycle