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Rb25/30 Engine Conversion

viator

By viator,
in Queensland

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viator Enthusiast

viator

Posted
Posted

i have been thinking about putting a rb25/30 engine in my r33 just thinking at the moment but i would like to know what opportunities or problems this could open up to me, my r33 is only going to be a everyday streeter so i am not going to go nuts on it...yet. what do you guys think?

p.s. and my performance shop gun performance has changed phone numbers since they moved to my area, their new number is ph#0738812164

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https://www.sau.com.au/forums/topic/221447-rb2530-engine-conversion/
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Col-GTSX Grand Master

Col-GTSX

Posted
Posted

where does one start.... :O

have a look at this part of the forum, this will answer all your questions or worries...

http://www.skylinesaustralia.com/forums/RB...sions-f184.html

also look at this thread about rb30 hybrid motors and results...

http://www.skylinesaustralia.com/forums/Rb...yn-t104332.html

it may also be worth just building up your rb25, as you dont have to go to a hybrid motor to make good power just ask fineline...

I personally took this option also due to wanting to make it out of an rb25, not to mention insurance and the rev'ing qualities of the rb25 vs the 30...

It a depend on your purpose of use, and what your future plans are... But have a read too...

http://www.skylinesaustralia.com/forums/Rb...yno-t55845.html

45ULT Rising Star

45ULT

Posted
Posted

rb30/25's need to be done correctly or u will end up with a pig that will be nothing but trouble. even the best 30's require constant maintenance. make sure your engine builder knows all the tricks to make it reliable.

TTT Grand Master

TTT

Posted
Posted
p.s. and my performance shop gun performance has changed phone numbers since they moved to my area, their new number is ph#0738812164

I don't get this..

is this like your OWN performance shop that you run?

or is it one that you like to use and did like a radio caller and decided to chuck in a shout out to your favourite whatever shop..?

GTRgeoff Grand Master

GTRgeoff

Posted
Posted
rb30/25's need to be done correctly or u will end up with a pig that will be nothing but trouble. even the best 30's require constant maintenance. make sure your engine builder knows all the tricks to make it reliable.

Another urban myth. Fortunately there are a lot of us on here with plenty of experience Michael so take a look in the new forum area for RB30 hybrids. Fortunately you can avoid the ones just telling furphies.....they never add all the problems that supposedly occur.

Send me an email if you want to talk about the conversion.

hayden49 Rising Star

hayden49

Posted
Posted
rb30/25's need to be done correctly or u will end up with a pig that will be nothing but trouble. even the best 30's require constant maintenance. make sure your engine builder knows all the tricks to make it reliable.

Got some evidence for this statement?

A mate of mine used a standard 200,000km+ rb30 bottom end, slapped it on the rb26 head and its been going great guns with tons of punishment.

45ULT Rising Star

45ULT

Posted
Posted
Got some evidence for this statement?

A mate of mine used a standard 200,000km+ rb30 bottom end, slapped it on the rb26 head and its been going great guns with tons of punishment.

yep i am a mechanic working for a pretty well known performance workshop and have seen many of these hybrids built by other workshops become nothing but heavy breathing, oil burners. i myself have built a 25/30 hybrid and if it wasn't for me being stupid one nite it would still be running and making decent power. each to their own..

psi Experienced

psi

Posted
Posted

I am a little confused by the above statement!

I put a turbo on an NA RB30 that had a genuine 288 000 km on it. I tried very hard to kill it, with the stock NA computer and stock auto and stock everything else the stupid thing made 175 rwp! My wife crashed it with just over 350 000 on it, and i sold it to a bloke who cained it even harder than i ever did for about a year before he wrote off his car, he pulled the head off for inspection and it still had stock pistons and nissan head gasget... he then sold the engine.. and it got cained again..

No body had rebuilt it.. so my question is this, I cant seem to remember ever seeing a really heavy oil brething RB30, what the heck do they screw up in them to do that to them?

My father in law raced RB30's for about 7 years, and most of his 'better' engines were near on stock bottom ends! I actually lent him the turbo engine minus the turbo to finish the last race of the season after he had an oil pump fail.

So surely there are some smart guys out there that can bang a good RB30 bottem end together and mate it to an RB25 head without too much bother at all. Cos I know our family has got the skills there to do it! I have read that lots of others on this forum who have done the same. Some have not even bothered with a basic re-ring or bearing check. The humble old RB30 is a VERY strong unit.

All i know is, if i ever push my RB25 to hard and it lets go, I have a good RB30 in my shed waiting, umm I mean BEGGING for a transplant.

http://www.skylinesaustralia.com/forums/Rb...yn-t104332.html

have a gwk in here!

45ULT Rising Star

45ULT

Posted
Posted

as i stated before my rb30 was fine til i was being stupid one nite and cranked way too much timing into it which broke a stock na piston before that it made 336hp without even trying running the standard rb25 computer. i am refering to the number of rb30's i have seen personally that have required rebuilding and just ran like shit. i know there are several of them running around that are fine and making awesome power. this thread was started to find out ppls experiences with the hybrids which is wat im sharing!!!

grigor Rising Star

grigor

Posted
Posted

I agree with 45ULT so here's my 2c.

Note the guys who've had no oil usage problems have "simply slapped an Rb25 or 26 head on an Rb30 block". Obvious thing here is no re-bore.

As soon as you re-bore you have heaps of decisions to make. Like piston brand, then piston to bore clearance, rings and the biggest, bore finish. Bore finish and hone is where the oil usage saga starts and engine run-in is where it ends.

A light hone on a good Rb30 block, new rings and you'll have a good engine.

Poor hone on a re-bored block and she'll be a smoker.

I won't go into the N1 oil pump dramas but my opinion is excessive crank end float.

But as I'm an old fart (with 3-Rb30 blocks in the shed) who's done way too many transplants, I'm over the whole Rb25/30 thing.

I've discovered the Aristo.

This baby comes with a 2JZtt and low K's half cuts are quite cheap. OK you're probably stuck with an auto but it's a terrific auto and a heavy duty multi plate clutch for a manual costs a lot more than an auto shift kit.

The good points:

It's 3.0L ready to go.

The 2JZ has an excellent cambelt set-up, auto tensioner unlike the bastard Nissan idea.

She has a front facing plenum.

It will have hydraulic lash adjustment, same as the Nissan. (The Supra 2JZ will have bucket and shim same as GTR)

The only bad points I've found:

2-ceramic turbos that can let go (same as Nissan) when over boosted.

Harmonic balancer needs to be replaced ASAP, then she's fine.

Manifolding is on opposite sides to Nissan which makes it tight around the brake booster.

A stock standard Aristo will surprise you at the strip, simply no fuss or noise. Up the boost slightly and they're rocket ships. On the road, stealth+

Go the 2JZ.

psi Experienced

psi

Posted
Posted

No doubting that the 2J is an awesome machine..

But I'll be stuffed if I'm gonna drop one into my R33,

So, I'll be building what is mechanically the same type of engine, 86mm bore/stroke, twin cam head, 4 valves per cyl.

I put a turbo om my mates 2J that is the same specs as my turbo.. and now I want to upgrade the capacity even more!

I could not agree with you more in respect to the boring and honing issues! I have screwed a hone before! smoker! But I knew i made a hack job of it, and the whole 'build' was a mad rush.

The stock compression seal of the RB30 is very good, as seen by the sheer number of VL's and R31's still hooning around. every time i start gearing up for ia build, the money is needed for something else.

But the compression seal issue is not only restricked to a hybrid. In my opinion, send your hard earned $$ to somebody like SK(or similar type of person who races and pushes the limits of the engines) who knows these things backwards and get it done right the first time. He knows the clearances he is after, what pistons to use, how much they grow, what rings to give it, head gasgets.. the whole box and dice.

If you dont know all these answers, dont just buy a bunch of parts and try to get some poor bugger to put it together and expect an awesome outcome. If you do, you might end up with an engine that cost a few grand that doesn't go and smokes all the while it isn't getting there.. might as well buy a diesel! lol

Thats my 3c worth.

and like i said, want a 3L skyline, go do it!

  • 2 weeks later...
09ONE_32 Collaborator

09ONE_32

Posted
Posted
I agree with 45ULT so here's my 2c.

Note the guys who've had no oil usage problems have "simply slapped an Rb25 or 26 head on an Rb30 block". Obvious thing here is no re-bore.

As soon as you re-bore you have heaps of decisions to make. Like piston brand, then piston to bore clearance, rings and the biggest, bore finish. Bore finish and hone is where the oil usage saga starts and engine run-in is where it ends.

A light hone on a good Rb30 block, new rings and you'll have a good engine.

Poor hone on a re-bored block and she'll be a smoker.

I won't go into the N1 oil pump dramas but my opinion is excessive crank end float.

But as I'm an old fart (with 3-Rb30 blocks in the shed) who's done way too many transplants, I'm over the whole Rb25/30 thing.

I've discovered the Aristo.

This baby comes with a 2JZtt and low K's half cuts are quite cheap. OK you're probably stuck with an auto but it's a terrific auto and a heavy duty multi plate clutch for a manual costs a lot more than an auto shift kit.

The good points:

It's 3.0L ready to go.

The 2JZ has an excellent cambelt set-up, auto tensioner unlike the bastard Nissan idea.

She has a front facing plenum.

It will have hydraulic lash adjustment, same as the Nissan. (The Supra 2JZ will have bucket and shim same as GTR)

The only bad points I've found:

2-ceramic turbos that can let go (same as Nissan) when over boosted.

Harmonic balancer needs to be replaced ASAP, then she's fine.

Manifolding is on opposite sides to Nissan which makes it tight around the brake booster.

A stock standard Aristo will surprise you at the strip, simply no fuss or noise. Up the boost slightly and they're rocket ships. On the road, stealth+

Go the 2JZ.

I am in the midst of building my RB30DET and this thread has now got me a little worried...

If there are problems with re-boring RB30 blocks, wouldn't rebuilding a RB20/25/26 (with a re-bore) produce the same symptoms/problems if the re-bore wasn't done correctly? If the ring to bore clearance isn't set up correctly or if the hone pattern on the bore is not right and then engine begins to get some blow-by and starts using oil, whats the worst case scenairo? You pull down engine and re-hone the block or ditch it and grab another block and transfer all the parts over?

Just chasing a few answers for aboce questions to help me sleep better...

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