Pro-Billet Main Caps - SR20

Pro-Billet Main Caps - SR20
Price: $125.00
Availability: Pre-Order

This product has a minimum quantity of 5

*All prices exclude GST(Tax) and will be calculated during checkout. International customers do not pay tax*

*Pictures are for illustration purposes only and may differ to your order*


Intro special = $105 + GST (One set saves you $110.00 !)

Delivery ~December

International guys (everyone outside of Australia) our website sucks and can't process your order, so
please Contact Us for a shipping quote and good ol' fashion personalised service, AND you don't have to pay GST (no added tax)!





An engine builder contracted us to engineer and manufacture a solution to the OEM standard main cap cracking and splitting, or they flex and allow the crank to slightly walk under high boost pressure / high power applications. Now they're available to the public.

They wanted specific features, and combined with our engineering you get:

  • Billet 4000-series chromium-molybdenum high-tensile steel
    • Tempered and treated for increased hardness and toughness
  • CNC machined to an accuracy of 0.03mm
    • More accurate than required by the International Standards Organisation "ISO"
  • Full size with reinforced centre
  • Deleted the threaded hole as this is the main stress-riser causing crack propagation
  • No engraving because this causes premature failure; in engineering terms it is known as "notch sensitivity"


SR20 SR20DET Billet Main Caps

SR20 SR20DET Billet Main Caps
SR20 Pro-Billet main caps font and left, OEM Nissan back and right




  1. Requires line/tunnel boring.
  2. Suits standard girdle.
  3. Suits standard main bolts.
  4. Suits aftermarket studs and can be enlarged to suit 1/2" studs.
  5. Suits standard 17mm bearings.
  6. Suits oversized 19mm (GTi-R) bearings.
  7. Suits SR20, SR20DE, SR20DET, SR20VE, SR20VET, and stroker kits 2.1L, 2.2L, 2.3L, 2.4L


SR20 SR20DET Billet Main Caps
Alpha Omega Racing front, OEM Nissan back

SR20 SR20DET Billet Main Caps
OEM Nissan left, SR20 Pro-Billet main caps right (no threaded hole or cutouts in the middle)




A billet girdle / brace is NOT a bad idea, and an integrated billet main caps + girdle is an even better idea!!

But the cost of these braces + install + studs + machining to accept 1/2" studs + line bore + GTi-R bearing upgrades + modifying your gearbox to accept it + other stuff your engine builders recommends (such as sleeves, x-ray, crack testing) = you're close to the cost of a full-billet block.

Either keep it simple with these Pro-Billet main caps, or go all the way. Good luck!


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