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Rb25 Oil Restrictors

B0oStEr

By B0oStEr,
in Engines & Forced Induction

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B0oStEr Mentor

B0oStEr

Posted
Posted

I'm about to screw my new engine together and need to sort my restrictors.

I've done searches and read the recent threads here but there seems to be some highly regarded workshops and engine builders recommending against blocking the rear or going too small as it can affect the operation of hydraulic lifters.

On the tomei site it says their 1.5mm restrictor is unsuitable for use with hydraulic lifters and I have found referrences to rattly lifters and even cam journal failure attributed to too much restriction.

I have no doubt some measures need to be taken to control oil supply but doesn't blocking off the rear seem a bit drastic.

Any feedback from people who have experience running modified restrictors with hydraulics would be much appreciated.

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https://www.sau.com.au/forums/topic/126344-rb25-oil-restrictors/
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RB30-POWER Mentor

RB30-POWER

Posted
Posted

Can't say i would ever block one of them, not on a hydraulic top end that relies on oil for proper operation. It just doesn't sound right.

Oil is the lifeblood of the engine, who want less of it.

What spec engine are you building, estimated power, what use, track, drag or strip?

B0oStEr Mentor

B0oStEr

Posted
  • Author
Posted
Can't say i would ever block one of them, not on a hydraulic top end that relies on oil for proper operation. It just doesn't sound right.

Oil is the lifeblood of the engine, who want less of it.

What spec engine are you building, estimated power, what use, track, drag or strip?

I'm building an rb25 with rb26 internals for street and occasional track.

Oil retention in the head at sustained high revs leaves little oil in the sump and is a well known problem for all rb engines.

I intend to enlarge the oil drain holes in the head and smooth the entry to the holes so the oil can flow back to the sump better.

I'm not sure what diameter they open them out to though.

I'd like to see pics of this job completed before I do mine.

Slide Grand Master

Slide

Posted
Posted

Tomei also sell .9mm restrictors which is what i am using on my 3026

they are about $10 plus delivery each

For even oil distribution it is better to restrict both of the holes rather then blocking one completely off.

But for a rb25 not as important.

p11505luberd2.jpg

B0oStEr Mentor

B0oStEr

Posted
  • Author
Posted
Tomei also sell .9mm restrictors which is what i am using on my 3026

they are about $10 plus delivery each

For even oil distribution it is better to restrict both of the holes rather then blocking one completely off.

But for a rb25 not as important.

p11505luberd2.jpg

Where can I order them from?

I only saw the 1.5mm restrictor listed but it could be an old catalogue

Note the comments about use with rb20/25 at the bottom of the linked page.

e114_RB_oillube.html

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted (edited)

Please read this thread

http://www.skylinesaustralia.com/forums/in...howtopic=110680

There is ALL the information you need to know about putting the correct oil restrictors on your engine. I put mine in about 2 months ago now and took heaps of photos for everyone to see.

After putting in the restrictors I hardly ever get any oil blow by like i used to before and my oil light never comes on when going hard around corners or breaking heavily (which can cause bottom end failure)

IMO it is manditory that a high performance RB engine has restrictors.

Can't say i would ever block one of them, not on a hydraulic top end that relies on oil for proper operation. It just doesn't sound right.

Oil is the lifeblood of the engine, who want less of it.

What spec engine are you building, estimated power, what use, track, drag or strip?

Edited by Guilt-Toy

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