The previous owner had installed...
The previous owner had installed the engine. After careful inspection, it was apparent that everything had to be taken apart and reassembled. Why reuse a 30-year-old engine-mount-to-block bolt and then add a flat washer and a lock washer on top of the seated bolt head? Note the oversized washers and lack of washer on the engine-mount-to-frame-mount bolt, as well the unfilled gap between the parts. The gap will allow the metal to bend during torquing, thereby reducing tension in the bolt, and in a short time the metal will flex and fatigue, causing the bolt to quickly loosen. These errors exemplify what happens when you put a lot of money and effort into the big stuff and then cheap out on what keeps the whole thing together.
We'd come to love our Wrangler YJ. It had proven itself a likable and competent friend for family outings in the Adirondacks. Even my wife was beginning to understand this four-wheeling thing, having ignored my warning and burying the Jeep on the road to Otter Creek. She called me at camp for help, and I had to negotiate the trail in her mother's four-door Blazer to extricate the YJ. Heck, even her mother thought the whole thing was cool. It was with sentimental tears that I decided to sell the YJ to help fund the purchase of a TJ.
I had come across a half-completed TJ V-8 conversion project that needed a new home and seemed the perfect rig for our adventures. It ran and was driveable, but needed much buttoning up to be trailworthy. After all, this was someone else's idea, started with great gusto, but the job was far from finished. No transfer-case linkage, no gauges, leaking a little here and there. Almost done, no big deal, right? Well, you know how it goes.
Once I had the TJ in the garage and took a close look, it became obvious I'd need to take a few steps back. Good intentions are not enough when you're talking safety, reliability, and money. The previous owner had put together the right parts: low-mileage TJ, small-block Chevy, TH400 tranny, Advance Adapters transfer case/transmission mount, engine mount, and headers. The problem was that all the parts had been assembled using questionable hardware and assembly methods in an otherwise stout drivetrain arrangement. So out came all the fasteners from the motor mount to the driveshafts. Every nut and bolt was scrutinized and replaced with the correct size and grade, then reassembled with a liberal dose of Loctite.
 The Grade 2 flat washers had...  The Grade 2 flat washers had deformed during tightening. This deformation results in a false torque tension relationship and defeats the use of higher-grade bolts. Nylon insert nuts are good at keeping the nut from falling off but can easily loosen resulting in a loss of clamping force. |  Here are the new engine-mount...  Here are the new engine-mount fasteners. Grade 5 nuts and bolts, plus hardened flat washers for the Chevy side, and metric 10.2-grade hardware for the Jeep side. Lock washers are generally useless, while flat washers reduce friction and spread the force evenly. Find a hardware supplier who knows what he is talking about and has technical information on what he sells. Torque each bolt to specification based on fastener size and grade. Make sure you know whether it is a "wet" (oiled) or "dry" torque spec. |  Washers are sized to either...  Washers are sized to either USS or SAE standards. USS-sized washers have a larger ID than the SAE, sometimes too large for the bolt. Though harder to find, a good supplier will stock a wide variety of hardened SAE washers. |