Grassroots Motorsports
Issue link: http://grassrootsmotorsports.epubxp.com/i/501675
HOW TO: ENGINE SWAPS 10 STEP 10: BUILD A JIG Miata engine mounts are made of fexible rubber, so we started with fresh, brand-new ones. These mounts needed to ft perfectly, because an imprecise ft could lead to extra stresses and early failure. Our solution was to build a jig from the Miata subframe to make sure our cradle ft as intended. STEP 11: TEST-FIT THE CRADLE Our little jig allowed us to test-fit and adjust the cradle until it fit per- fectly with both the engine and our U-shaped mounts. STEP 12: REINFORCE THE SUBFRAME Time to turn our attention back to those U-shaped pieces. We wanted our mounts to bolt in, so we drilled the U-shaped pieces for half-inch bolts. Now, an important detail: Since the MGB's sub- frame is hollow, we needed to reinforce it with short tubes. Locking fasteners wouldn't be enough, since bolts need to stretch to properly fasten. Bypassing these reinforcement tubes is a critical mistake in many fabrications. Without them it's not possible to properly tighten the bolts, and problems will follow. The hollow subframe will be crushed and prevent the fasteners from achieving proper torque. Rather than weld our tubes directly to the MGB's subframe, we frst welded them to plates. This will make it easier to align everything. 11 12 Grassroots Motorsports 140