2.4 Stroker

[240240]

Just trying to figure out what all is needed for the rb20 to 24 stroker

So far I have: 82mm Pistons Rb26 Crankshaft Rb26 Con Rods

Anything else needed?

[rbsileighty]

I assume by pistons you mean the Tomei piston kit (rings etc) correct?

New bearings...

You will have to do some machining...

[Wulfgang]

Have you priced this? Can you actually source RB26 crank and rods for less than the cost of just doing an RB26 instead of RB20?

I don't have any info, but I would be interested in your estimate of how much stroking will cost.

[Sil240]

I was thinking about doing this when i rebuilt my motor, but the only thing is that you cylinder walls will be very very thin if you bore it to 82mmThats why i only bored mine to 80mmBecareful cause if you wipe the motor i dont know if you'll have any more room to re-bore

[Carl H]

rb24 is one of those things where it sounds cool to do, but isnt practical in the least.sourcing out the rb26 crank and rods is hard enough, but getting the right pistons (read: tomei; read more: 1.3k for a set) and the bottom end built is over 3k in its self......

even after the block is prepped for it you then have the problem of the rb20 head and the combustion chamber, its gonna have to be enlarged to cope with the larger bore.

which leads to another problem, the rb20 head; in a word it sucks.imagine having 2 straws, the ginormous one from mcdonalds and a coffee stirrer, blow thru both and which one is easier to blow thru?the rb20 head is the coffee stirrer, it flows terribly.

if i were you (and this is what i plan to do) is keep the rb20 bottom end, do a slight overbore to clean up the walls and rebuild it with forged pistons, then do the head up with larger valves and some porting and you will have a freer flowing head that will make the motor more responsive.increacing the rb20's displacment is kinda futile if the head cant support the airflow required, hell, the rb20 head on a rb20det sucks; only gonna be worse with more displacement. trust me on this one, ive gone over it numerous times with ppl who have done them up......

[lyon23]

They have a rb26 long lock for sale on ebay right now for about $500, the guy told me it's a good motoor just missing valve covers, intake manifold and exhaust. I also thought about the stroker idea but then I think about since I already have an rb20 installed just get a rb25 with harness and ecu and upgrade from there. It would be able to handle more power reliably. just my 2 cents. good luck.

[Shahee1]

Hey Guys ... I already started my 2.4 rebuild and I am not using Tomei PistonsI thought that would cause me problems cause I am using 4agze pistons that are 81.5mm ... they are perfect and have the right compression. I sourced my whole setup for a little over $300 ... LOL... $200 for the rods and crank $100 for the pistons or you can get forged 4agze pistons for about $600. If you fear the thin walls in the block ... just sleeve it ... You will never have to worry again about the bottom end. If you get the Tomei Head package You will definitely solve your head problem cause the head will definitely have to be reground to fit the tomei valves in the kit. The head package iis kinda pricey, but it will pay off in the longrun when you are making power to 9k!!! If you cant get the whole head package then just get the cams, springs, and retainers. My rebuild and install will be finished after X-MAS. I am only taking my time cause I bought a second block and head for about $300 from a local. I think my project is going to pay off cause I have not spent much and I will have great power handling using RB26 internals ... I would have spent more on forged internals but I know that I am not going for no more than 450HP ... Only reason I am shooting for that number is because I still have to address cooling and fuel to tame the Beast ... HAHA!!!

[Yellow4g63]

Don't forget a GTR Oil pump.

[Wulfgang]

I thought all of the oil pumps were the same. Why GTR?

[240240]

wow guys, that is some great information. In other words some of you think if I going to stroke it I might as well just get the 25?? Ill have to think about what I want to do, Im not just looking for power but rarity as well, and Shahee, Sleeving is a goood idea

Thanks everyone

[BoostFab]

wow guys, that is some great information. In other words some of you think if I going to stroke it I might as well just get the 25?? Ill have to think about what I want to do, Im not just looking for power but rarity as well, and Shahee, Sleeving is a goood idea

Thanks everyone

if you're looking for both power and rarity, rb30det would be the better route...

[rbsileighty]

if you're looking for both power and rarity, rb30det would be the better route...

Still thing this is a bit tall for a S-body... unless you have a lot of ground clearance... or a cowl.

Rare would be a VQ35DE too... all depends on how deep your pockets are...

[T4 RB25det]

there was a guy in florida who had an rb30det in an s14 with the RB tophat mount kit and the only thing he had to do is cut the webbing off the bottom of the hood to clear the motor.

[Yellow4g63]

I thought all of the oil pumps were the same. Why GTR?

Nope not all pumps are the same. If your planing on reving it out to 9k you might have to get something better than a factory GTR oil pump. The Jun pump might be what you want. But who knows a shimmed GTR oil pump could keep it safe up there.

[Carl H]

Hey Guys ... I already started my 2.4 rebuild and I am not using Tomei PistonsI thought that would cause me problems cause I am using 4agze pistons that are 81.5mm ... they are perfect and have the right compression. I sourced my whole setup for a little over $300 ... LOL... $200 for the rods and crank $100 for the pistons or you can get forged 4agze pistons for about $600. If you fear the thin walls in the block ... just sleeve it ... You will never have to worry again about the bottom end. If you get the Tomei Head package You will definitely solve your head problem cause the head will definitely have to be reground to fit the tomei valves in the kit. The head package iis kinda pricey, but it will pay off in the longrun when you are making power to 9k!!! If you cant get the whole head package then just get the cams, springs, and retainers. My rebuild and install will be finished after X-MAS. I am only taking my time cause I bought a second block and head for about $300 from a local. I think my project is going to pay off cause I have not spent much and I will have great power handling using RB26 internals ... I would have spent more on forged internals but I know that I am not going for no more than 450HP ... Only reason I am shooting for that number is because I still have to address cooling and fuel to tame the Beast ... HAHA!!!

and i hate you.but yah if you are going for the moon (read 9k redline) then yah, the n1 pumps wont cut it and you will def need a uprated aftermarket pump.

[Shahee1]

WOW!!! Look at the minds clicking on this forum ... I love a lively forum!!! Great way to start the day .... AHHHHHH!!!! LOL ... WHASSSUPP CARL!!! Don't Hate me ... You made me, you're my hero ... LOL ... we were supposed to do this project at the same time ... but seriously ... I was only throwing the 9k rev-limit out there to drive home the drivetrain strength point (a little zealous huh???) .... redline will only be about 7800 - 8200 with the longer stroke ... not sure til I get the car running and tuned ... Most likely closer to 7800 ... I am only looking to upgrade my powerband without changing motors and buying everything all over again ... if I go 2.5 or 2.6 I will have to rebuild for reliability anyways cause you are not sure of the shape of the motors ... so why not rebuild for reliability and power on the RB20DET if you already have it and it was really cheap. I mean I know at least 4 people that have bought their rb20 for under $1k ... try and find a rb25 for that price ... better yet a rb26!!!! NOT!!! The crank and rods in the rb20 are good up to a certain point ... same for 25 ... but we all know what stock 26 parts are capable of ... their parts make for a great cheap OEM-like build that has mounds of potential after the build ... I May Nismo oil and water pump ... that is what Tomie uses in their build. Come on 240240 go through with it ... come to the darkside ... HEEHEEE ... plus a nice RB30DET costs about 10k in parts ... maybe more ...

[driftjunke]

Hmm, I have a 20 with knock, a 25 with broken valve, a 26 broken valve ,and 30 block. Was going to use the 26 block to do the 2.4 stroker, but the broke valves detroyed #6 so we're just using the head for the 30 block, but we're debating on destroking the 25 using the 20 crank and rods, and stroking the 20 with the 25 crank and rods. Gonna do something, might just go ahead and order the new 26 crank and rods and use our other spare 20 block. It's be fun to see the frankstein RB motors and what they could do.

E