Get RED Hot Specials now from our on line store, we can and will supply you the best products, click here to access the store.


If we do not have the product in stock we will deliver with in 2 to 3 weeks.

Lapping your side plates

At Racing Boys we offer you a very accurate process referred to as lapping to the face of a side housing. While some shops use conventional grinding equipment to resurface side housings or even face to face by hand, we believe the best way to achieve a superior finish is to lap each surface to a minimal tolerance on our world class lapping table.

Lapping TableLapping Table
Providing a smooth and best quality surface allows the best sealing and the least amount of wear of the corner seals and side seals. Our lapping process has proven to offer one of the best finishes currently in South Africa.

This new lapped surface provides optimal oil retention and the least amount of friction. We aim to remove a maximum of .0025’ to minimize reducing the thickness of the housing and to retain the nitride factory hardness built into the first layers of the plat.

Cost is R250-00 per side

The most significant change found in the 1986-95 side housings (as compared to pre-86 and RX-8 housings) is the placement of inner and outer O-ring grooves onto these housings This change makes it more difficult to lap and re-use these side housings. Because we recommend removing no more than .002" of material from each side housing surface to maintain the integrity of the O-ring grooves, it is possible that unacceptable "wear grooves" may remain after lapping, necessitating replacement with a new housing. In the case of 1974 to 1985 side housings, removal of up to .008" per side is allowable to remove damage or corrosion.

Mazda has used a gas nitriding process on the side housings to increase wear durability since 1979. Gas nitriding is a surface treatment that is typically only .001" to .002" thick in this particular application. While lapping a side housing surface effectively removes this nitriding, engine wear is not greatly accelerated should you choose to rebuild with properly lapped housings.
We recommend that side housings always be re-surfaced on a lapping table as part of a thorough engine rebuild. While it is possible to grind side housings, few grinding shops can match the superior surface finish a lapping table provides. We offer our customers side housing lapping services to assure properly resurfaced housings. Source

Lapping Rotory Side Plates Gallery