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which head is best?

Guest drift_me_silly

By Guest drift_me_silly,
in Engines & Forced Induction

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Guest drift_me_silly

Guest drift_me_silly

Posted
Posted

no msn on this machine, swapping labs in an hour...i'll try msg u then...where do you go to drift around here, who do you use for mech. work, how do you afford the sweet machines that are skylines? -i'm in the making of a career...namely mine...as i said.

in time.

blind_elk Grand Master

blind_elk

Posted
Posted

If the rules are still the same, then the head off a larger capacity engine will cause a REDUCTION in C/R when fitted to an engine of smaller capacity (presumably the combustion chambers are bigger on the bigger engine). Now, this may allow you to run more boost, but the engine will be far less tractable 'off-boost'.

It was often the practice in the days of L-series engines to do things like fitting a L-16 head on a L-18 block to get a bit more compression.

If you are after serious grunt, then trying to fit the RB20 head on the RB25 seems more the way to go. Or you could simply port / polish a RB20 head for your RB20 block so that it breaths better.

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi guys, RB25 and RB26 are 86 mm bore and RB20 is 78 mm bore. So if you try and put an RB25/26 head on an RB20 block you will have a mismatch in diameter of 8mm. The water jackets are in different places and, if I remember rightly, the oil galleries are different as well. That's why there are none around.

Want more capacity out of your RB20? Try an RB26 crank and rods and 4AGZE pistons, makes 2,336 cc's. There's a lot of info and discusion about this in the past on the forum, do a quick search. Also www.meggala.com has a lot of info as well.

Hope that helps.

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi S13 Silvia, suggestions follow your questions.............

***What do you reckon would be a good price for rb26 crank and rods?

Shop around the forum they come up from time to time, prices vary from $200 to $500

**Is it possible to use the rb20 pistons with the rb26 rods?

Never tried it, I know the gudgeon pin is larger diameter in the little end of the RB26 conrod. You could either machine the piston for a larger gudgeon pin or bush the RB26 little end for the smaller RB20 gudgeon pin. Either would probably work OK, I would lean towards the former as a larger gudgeon would be better as long as the necessary machining doesn't weaken the piston too much.

**What's the availability like on getting the rb26 crank/rods?

They come up from time to time on the forum. Be watchfull, act swiftly, as they seem to sell fairly quickly, and have your money ready.

Hope that helps.

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi drift_me_silly, check out the posts by JOnJOn he has a 2.4 litre RB20.

Watch the costs though, they add up and can easily exceed the cost of doing up an RB25DET.

Good luck, let me know how it goes.

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