5.2 Magnum Swap Part 17: A Real Firewall

by ThreeThirdsFab
October 20, 2015
In The Shop
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Welcome to part 17 of our 5.2 magnum swap, follow along as we swap a 5.2 magnum from a 1993 ZJ into our 2004 4.0 TTB WJ. This week, we fill in the holes before the motor goes in one last time.

Read The Rest
Part 1: It’s Finally Happening
Part 2: Out With the Old
Part 3: The Last of the Stock Components
Part 4: All About Brakes
Part 5: Pulling the 5.2 (time lapse)
Part 6: The Test Fit
Part 7: Cutting and (not) Fitting
Part 8: Broken and Upgraded Parts
Part 9: Leaky Plenum Gasket
Part 10: Side Projects and Summer Fun
Part 11: Setting the Motor
Part 12: Custom Exhaust & Driveline
Part 13: Cutting and Rebuilding
Part 14: Giant Radiator in a Little Jeep
Part 15: Custom Tube Bumper
Part 16: Driveshafts
Part 17: A Real Firewall
Part 18: Starting Final Assembly
Part 19: Extending The Engine Cage
Part 20: Still Assembling
Part 21: It Lives!
Part 22: Brakes and Wiring

A Real Firewall

Ever since the initial cage was built back in 2008 our firewall has been questionable. There were multiple holes left from the heat and A/C, cabin vents, and a number of other small wires and accessories we had removed. We added to the problem when we tied the engine cage into the main cage. But with nothing to burn and plenty of space to route wires we haven’t been too worried about it.

With easy access while the engine is out we finally sealed it up for good. This included the rather large holes we had to cut to squeeze the engine and new master cylinders in.

Paper templates quickly became 14 gauge cut outs that were bent, hammered, and tacked in place. We added a few more tack welds then ground it all smooth. To keep the water and dust out we sealed the inside with RTV. The outside was sealed with metal tape for heat and fire protection in accordance with Best in The Deset rules.

We also finished the steering linkage and started rebuilding the engine cage. We added a new crossbar that we previously cut out to make room for the V8 and started mocking up tubes to tie the front into the bumper.

Cleaning Fuel Injectors

We are keeping the stock fuel injectors for now since they were in pretty good shape and upgraded injectors don’t work well with OBD1 systems all of the time. They didn’t look too bad but we did want to flush them out since the donor ZJ was sitting for a few years, and the tips has some burnt oil from the Plenum gasket leak.

After removing the o-rings we searched the shop for something that would fit on the end. We found that an old piece of hose we used for the transmission lines was the perfect fit. We wrapped some electrical tape around the carb cleaner hose until it fit into the transmission line.

Some alligator clips, an old switch, and a plug from the old ZJ harness and we were good to go.

Hooked it all up, flipped the switch to activate the injector and used the pressure in the carb cleaner to blow out any debris in the injector. Switched it off, turned the injector around and did it again. After seven more times, our injectors were looking much better.

What’s Next

This week we will hopefully finish rebuilding the engine cage, mount the radiator and set the motor in place. With any luck we will be able to start the motor up early next week!

Don’t forget to check back next Tuesday for updates.