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R32 Rb26 Camtech 272S?

Dauntess

By Dauntess,
in Engines & Forced Induction

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Beer Baron Grand Master

Beer Baron

Posted
Posted

honestly, I would not upgrade cams in an RB26 to anything without doing valve springs. valve springs get tired and the last thing you want is your 100,000km old springs now having to deal with more lift. so yeah, if doing cams (regardless of the lift - they all have more lift than standard) do springs at the same time.

  • 1 month later...
GTRNUR Grand Master

GTRNUR

Posted
Posted (edited)

Unless you want to pull the head off the engine so you can clearence it without worrying about debris falling into the engine, then forget about high lift cams. If it requires clearencing, its far from a drop in affair.

Unless as TO4 says, the cams might use a smaller base circle, which means re-shimming the valves. Not a task for the typical back yarder. A reduced base circle cam runs the same peak lobe height as a 9.15mm cam, but runs the back of the lobe (base circle) at a reduce diameter. Thicker shims are added to raise the bucket further off the valve. This translates to more lift at the valve, with no need for clearencing.

But I really agree with beer baron. 272's should have a step 2 spring and are typically used in engines that rev to 9k. The whole point of longer duration cams is to move the peak torque point further up the rev range. Running 272's with standard springs will give you 2 results.

1. A reduced usable RPM power band

2. A wonky idle.

Add any meaningful level of boost and you start getting valve float with standard spring/standard 8.7mm cams at around 7500. Higher lift and duration will bring that RPM level down considerably.

Edited by GTRNUR
T04GTR Grand Master

T04GTR

Posted
Posted

new valve springs should be used. id recomend supertech. cheap and really good. also not hard on the valve train. tomie do +1mm buckets for the 30mm base circle cams. (putting to thick a adjusting shim can have issues)

either way its a $1300 exercise just for the bits, but a nessesary expence) if you are not chasing huge power just get pon cams.

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