Rb30 Crank In Rb26 Block

[BoostdR]

RD28 crank sr20 pistons minor mods.

[mark99]

RD28 crank sr20 pistons minor mods.

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

[Sydneykid]

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.

A pet subject of mine, so please excuse the questions.

An RB30 has a rod stroke ratio (1.76 to 1) close to what many people consider close the ideal (1.75 to 1). Whereas the RB29 combination has a far from ideal rod stroke ratio of around 1.47 to 1 (I'm guessing around 123 mm rod length).

I know you know this, but I'll post it for other readers who may not.

In any engiune a less than ideal rod/stroke ratio has bad effects on a number of engine dynamics, including piston speed & acceleration, piston dwell at TDC and BDC, piston side loads, cylinder wall side loading and bearing loads. A low ratio like this one would mean a large rod angle, creating greater potential for accelerated wear to cylinder walls, pistons and rings. Under extrmeme conditions (high boost, high rpm) a severe rod angle can drive a piston right into the cylinder wall. The 3L F1 engines commonly had rod stroke ratios over 2 to 1, for all the same reasons, just more so because of their 20,000 rpm and high specific power outputs.

So all other things being equal, an RB30 crank in an RB30 block with RB30 length rods is going to give more horsepower, more torque, less wear and be less prone to failure than an R29, plus it is going to cost a whole lot less. So why bother with an RB29? There are a couple of good designs of 4wd sump adaptors with good qualityy oil pick up systems. The tricks to overcoming the the extra 30mm of RB30 block height are well known. Having hacked up a number of RB25/26/30 blocks I can't say that the RB26 block is superior in any area. I saw it this way back in 1999 with first RB30 in R32 I did and I still see it the same way now. What am I missing?

Cheers

Gary

[Duncan]

well in my case the only thing you are missing is the CAMS 3D regulations.

to run a 4wd sports sedan you must retain the original block. so my interest is in how I can cheaply increase capacity while retaining the standard block (by standard block they mean standard mains location, standard deck height, thats about it I think).

but this is only relevent to about 2-5 cars in this country. and I suppose most 4wd skylines will ignore this rule.

For most people, the issue is a mistaken beleif that rb30 is somehow intrinsically worse than an rb26 (probably because it was in the dodgy vl commodore not the might skyline gtr). In particular you "can't rev it as high". Personally I think that is pretty irrelevent compared to the available capacity and better rod/stroke ratio which means you would expect to make the same power with 20-30% less "stress" on the motor.

[bubba]

I haven't really seen any evidence that says you can't rev a properly built RB30 as hard you would an RB26.

[urtwhistle]

I know this is a little off topic and a little Tabooo. BUT does any 1 know of any attempts to mate a ford 4L Barra 6 to a GTR front diff/transfer case?.

you would obviously need a wicked big bulge in the bonnet IF it did work.

From what i can see after going in few XR6T's is that they make massive torque and just fry the tires with out any trouble. but if they had 4wd traction in a very light car aka GTR it would be very interesting.(every thing is light compared to the domestic Barges)

Now commence Flamage lol.

Regards

Chris

[bubba]

I hope you prepped yourself with lots of flame retardant!!

[N1GTR]

I know this is a little off topic and a little Tabooo. BUT does any 1 know of any attempts to mate a ford 4L Barra 6 to a GTR front diff/transfer case?.

you would obviously need a wicked big bulge in the bonnet IF it did work.

From what i can see after going in few XR6T's is that they make massive torque and just fry the tires with out any trouble. but if they had 4wd traction in a very light car aka GTR it would be very interesting.(every thing is light compared to the domestic Barges)

Now commence Flamage lol.

Regards

Chris

Anythings possible with the right amount of brains and cash (not in that order)

Dont know why you'd bother, there's a GTR being built right now with an RB35 DETT (thats not a typo), so for the loss of 500cc but the saving of SO much labour cost - you wouldnt bother. I know this one when put together will rev to 9000plus rpm, it will match a 2.8 rev for rev, rod stroke ratio is superior to the 2.8 strokers (like tomei,HKS) etc. That car will have the 4wd traction youre after, but its not exactly a lightweight thing like any GTR

If you wanted to go down the Ford route, youd need a custom sump plate made up, new bellhousing etc plus all the electrics and a whole shed load more - in the end as I said, the labour will be the part that hurts your credit card the most

[urtwhistle]

Yeah that's true, it was more out of curiosity then any thing. I doubt i would ever have the cash to pay some 1 to experiment with the ford idea. Me not so good at swinging zee spannerz.

hmmmmmm now I'm intrigued i wonder if the front diff in a Territory is configured to go through the sump or completely separate, i might put my head under my sisters car next time she visits.

RB35 hey? RB30 with big crank and big sleeves that's 1 hell of an increase in capacity. ok maybe an exaggeration with the light weight comment, but they aint no 1900kg ford fairlane either.

ok sorry for leading every 1 off topic.

regards

Chris

[mark99]

An RB30 has a rod stroke ratio (1.76 to 1) close to what many people consider close the ideal (1.75 to 1). Whereas the RB29 combination has a far from ideal rod stroke ratio of around 1.47 to 1 (I'm guessing around 123 mm rod length).

Std rod lenght is used, so a far from ideal rod to stroke ratio of 1.46:1

I know you know this, but I'll post it for other readers who may not.

In any engiune a less than ideal rod/stroke ratio has bad effects on a number of engine dynamics, including piston speed & acceleration, piston dwell at TDC and BDC, piston side loads, cylinder wall side loading and bearing loads. A low ratio like this one would mean a large rod angle, creating greater potential for accelerated wear to cylinder walls, pistons and rings. Under extrmeme conditions (high boost, high rpm) a severe rod angle can drive a piston right into the cylinder wall. The 3L F1 engines commonly had rod stroke ratios over 2 to 1, for all the same reasons, just more so because of their 20,000 rpm and high specific power outputs.

Yeah i agree with all of that. I would always go for as longer rod to stroke ratio as is practically possible.

So all other things being equal, an RB30 crank in an RB30 block with RB30 length rods is going to give more horsepower, more torque, less wear and be less prone to failure than an R29, plus it is going to cost a whole lot less. So why bother with an RB29? There are a couple of good designs of 4wd sump adaptors with good qualityy oil pick up systems. The tricks to overcoming the the extra 30mm of RB30 block height are well known. Having hacked up a number of RB25/26/30 blocks I can't say that the RB26 block is superior in any area. I saw it this way back in 1999 with first RB30 in R32 I did and I still see it the same way now. What am I missing?

Cheers

Gary

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.

[ZILR-34]

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.

your spot on mate. the reason people go for stroker kits is to retaining the original block "keeps the vaule of the car" as for myself i have a R34 GTR VspecII and not wanting to go the RB30 block.

what you guys think about this stroker kit from racespec?

http://racespec.com.au/product_info.php?cP...products_id=698

$7900 for a 2.9L

cheers

bill

[TiTAN]

the only reason it would retain higher value would be due to the extra cost involved in using a stroker (3x the price for the internals) vs forged 30 pistons rods and a sump adaptor.

[Adriano]

No, the stroker 2.9 will retain more value as the gearbox will still be in one piece compared to the rb30

[Duncan]

lol

personally I don't get the concept of the jap stroker cranks, you are paying literally 3x as much as something based on an easily available local product.

but hey if you've got the cash to spend on an inferior solution.....go for it!

[NXTIME]

That Rb29 stroker kit from Race pace looks great for $7,900. It has similar specs to the Apexi 2.9L kit, but the Apexi kit is better (IMHO).

[BoostdR]

RD28 crank sr20 pistons minor mods.

Ops, i meant to say SR20 Rods not pistons

[R31Nismoid]

That Rb29 stroker kit from Race pace looks great for $7,900. It has similar specs to the Apexi 2.9L kit, but the Apexi kit is better (IMHO).

Racespec - Not Racepace

No way a Racepace 2.9ltr would cost 8k

[daisu]

your spot on mate. the reason people go for stroker kits is to retaining the original block "keeps the vaule of the car" as for myself i have a R34 GTR VspecII and not wanting to go the RB30 block.

Why not just keep the original block boxed up in your shed, then when it comes time to sell put the original block back in.

[GT-RZ]

Best way is too keep the original engine stock and build up another monster. I always sell my cars stock rather than modified then sell the bits off individually if you want or transfer to a different car.

Never get your money back when you sell with or without mods or different engines in it.

[TiTAN]

unless you happen to get some miracle price in the first place (or buy something thats going up in value aka not a skyline) you never get your money back on a car modified or kept bog stock.