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Rb30 Head On 25 Block


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You seem to like quoting a lot of stuff yourself, like quoting paper without actually knowing what you're on about yourself.

Well sir what field of work are you actually in? Yes I quote stuff but I do know what I am talking about after years in the trade you get a certain nitch at working with cars. Also I quote stuff as I don't want to blur the meaning of the original writer and do not want to take credit for someone else.

Edited by pf.
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How come the school zones are still active if it seems like school holidays on here?? :blink:

its probably uni holidays.

Someone claims they know what they're talking about in building engines... Still wants advice off "backyarders" on how to build engine... Lol

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its probably uni holidays.

Someone claims they know what they're talking about in building engines... Still wants advice off "backyarders" on how to build engine... Lol

Did you read my first post, obviously not I asked for any advice so I can fast track this project otherwise it will be a matter of trial and error. But so far all you have done is argue against the idea because you believe it is a bad idea. Nearly every other person has said do it and post back results which I will have to do, but you sir have kept this attitude up that you have a superior knowledge over myself. I asked politely at the start of the thread if no one could delve into the topic of why but you sir did so I replied in a just way against your unfounded theories that you tried ever so hard to thrust upon me.

Edited by pf.
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It would seem easy enough, if the block is VCT then block off the VCT oil feed and put 1-1.2mm restrictors in the other 2, use RB30 head bolts/studs for correct length for head, the hardest bit I can think of would be the correct length of the timing belt as no one I could think of would have done this before so you will have the figure that out for yourself after the head is fitted

the RB30 head has a smaller combustion chamber the the 25/26 heads ( not sure about the NEO head, I believe it has a smaller chamber then the normal 25 head ) so the comp ratio will be higher, so checking the valve clearance would be a good idea

that said I stand by my previous post as it's not a great idea, they went to twin cam for a reason/reasons, but I love a slapper engine and am interested to see how this turns out, GL :thumbsup:

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It would seem easy enough, if the block is VCT then block off the VCT oil feed and put 1-1.2mm restrictors in the other 2, use RB30 head bolts/studs for correct length for head, the hardest bit I can think of would be the correct length of the timing belt as no one I could think of would have done this before so you will have the figure that out for yourself after the head is fitted

the RB30 head has a smaller combustion chamber the the 25/26 heads ( not sure about the NEO head, I believe it has a smaller chamber then the normal 25 head ) so the comp ratio will be higher, so checking the valve clearance would be a good idea

that said I stand by my previous post as it's not a great idea, they went to twin cam for a reason/reasons, but I love a slapper engine and am interested to see how this turns out, GL :thumbsup:

Yea I have not put much thought into this as of yet (the finer details) I hear you about blocking off the vct feeds. With the belt this is one thing I was thinking of today I am guessing I just have to reverse the figures from a rb25/30 so the extra length required will be subtracted instead. But I think I may be able to use a rb20e belt if gates make one.

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easiest way would be fit head then cut an old belt and run it around then measure it/count the teeth, then search for a belt

PS if it isn't a Nissan replacement belt then make sure the teeth profile is right, when I searched for a belt for my 26/30 I found that one of the belts commonly use for this combo is not the correct profile

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easiest way would be fit head then cut an old belt and run it around then measure it/count the teeth, then search for a belt

PS if it isn't a Nissan replacement belt then make sure the teeth profile is right, when I searched for a belt for my 26/30 I found that one of the belts commonly use for this combo is not the correct profile

Thanks heaps I normally only use the right part for the right car, but have done a few matchup jobs in my time.

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Did you read my first post, obviously not I asked for any advice so I can fast track this project otherwise it will be a matter of trial and error. But so far all you have done is argue against the idea because you believe it is a bad idea. Nearly every other person has said do it and post back results which I will have to do, but you sir have kept this attitude up that you have a superior knowledge over myself. I asked politely at the start of the thread if no one could delve into the topic of why but you sir did so I replied in a just way against your unfounded theories that you tried ever so hard to thrust upon me.

Dude, everyone has said to not do it in here, you know, the kids who play with RBs all day?

The only ones saying do it are the ones who are going to be ready to piss them selves laughing when you make about 150HP...

Feel free, go ahead and do, we'll be here waiting to laugh...

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My RB30E made 109rwkW on a dyno, it's standard with GTS1 cam and GTS2 extractors.

Dropping $10k into it would easily make 250rwkW :P


Do it hero, and post results (so we can laugh at you). By the time you're done, you could have bought an RB25DET.

You came here for advice, you got it, you don't like it so you're going to fight us? Kids these days...

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Dude, everyone has said to not do it in here, you know, the kids who play with RBs all day?

The only ones saying do it are the ones who are going to be ready to piss them selves laughing when you make about 150HP...

Feel free, go ahead and do, we'll be here waiting to laugh...

*grabs chair and waits*

Make sure to post build photos

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My RB30E made 109rwkW on a dyno, it's standard with GTS1 cam and GTS2 extractors.

Dropping $10k into it would easily make 250rwkW :P

Do it hero, and post results (so we can laugh at you). By the time you're done, you could have bought an RB25DET.

You came here for advice, you got it, you don't like it so you're going to fight us? Kids these days...

I never tried to start a fight I asked for advice I have received some but I have also received comments from a smart a#$ that tried to question my reasons. I asked for the thread not to go down this path I just want advice like some I received from XKLABA thanks :).

Like I have already stated I am building a turbo engine the engine I want advice on is a N/A engine.

BTW what may cost you 10k does not mean I will pay 10k for the same it's called trade prices and accounts at parts shops also it makes it easy when you have a work shop.

Edited by pf.
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*grabs chair and waits*

Make sure to post build photos

Yea i'll have to start soon as it seems you guys have started to get a interest in this. First thing will be a acid bath I guess then i'll see what is next.

Oh yea a bore on the 25 block is farked so i'll have to find some oversized N/A pistons as it is a turbo block. I will have to weigh up the cost of new rods over resizing mine vs the performance gain.

Edited by pf.
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ask gerg_r31 or have a look at his R31 N/A thread. That was with an RB26 head though.

There was an interesting discussion on Performance Forums about 2 valve vs 4 valve incidentally, though I believe it might have been more a comparison of V8 head design.

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My note will be a lil bit more potent than that ;)

Also what is with all the youtube clips with people starting engines cold reving them without load?????

m3 with supersprint exhaust what I want but cant afford atm. Edited by pf.
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ask gerg_r31 or have a look at his R31 N/A thread. That was with an RB26 head though.

There was an interesting discussion on Performance Forums about 2 valve vs 4 valve incidentally, though I believe it might have been more a comparison of V8 head design.

Really I might have to go and check that out it sounds interesting.

Is that the 26/30 that made only 160kw.

If you wonder why I say only what I mean is that those figures sound very low for the perceived power it should make on paper. I myself thought how can a 26 head on a 3l block only make that much power when some 202's come close or better they aren't even crossflow.

Refer back to the stats I quoted in a post of the m20 160kw should be doable with a 30 head so why spend the extra on a 26 head if I am not going to spin the engine past 8k?

Edited by pf.
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