FJ40 Rebuild

Wednesday, February 01, 2006


starting the engine

My dad was down in Phoenix for a week, so I put him to work helping me get the motor finished up and running. Actually, he was doing a lot more than helping me - he pretty much had all of the knowledge and know-how (not to mention a big box of parts), and I was just sort of the wrench-fetcher. My dad had aquired a Rochester Quadrajet carb off of a 1972 Blazer and it looked to be in great shape, so that was one of the first items we tackled. Quadrajet Installed

The distributor was an HEI unit out of a 1977 Chevy 1/2 Ton pickup. My dad had tested it before he sent it down, and it had a good strong spark. Most of the old wires were in good shape, so we just used those for this test. HEI Distributor

The water pump and alternator were already installed, so we put on the belt and that was done. We also installed a new mechanical fuel pump and bent up a custom metal fuel line to the carburetor. Fuel Pump

We mounted the radiator and then had the not-very-fun task of finding the correct radiator hoses. On our first attempt, the bottom hose we got ended up being the right length and shape, but didnt fit the water pump outlet correctly. We didnt know what upper hose would work, so had to settle for a flexible hose. However, the flexible hose also didnt fit over the thermostat housing correctly. We had to make a return trip to Napa, where the parts guys let up go upstairs and just browse all of their hoses. We found two that seemed like they would work, and when we returned home to try them out, both were a perfect fit. (For reference, the upper hose is Napa part number 7884, and the lower is 7651). Upper Radiator Hose

  Lower Radiator Hose

I re-used the stock Toyota oil pressure sending unit and temperature sending unit. The temperature sending unit screwed right in with a small adapter, but the oil pressure sending unit took a little bit of creative use of fittings to get things to connect up properly. I also installed the electric fan control module into the head, although we didnt hook up the rest of the wiring for this test (we just wired up the fan directly to a switch). Temperature Sending Unit

  Oil Sending Unit

  Electric Fan Control

Finally, we wired up my stock instrument cluster so we could keep an eye on oil pressure and engine temperature. We also wired in some standard house AC switches to simulate the ignition (one to fire the starter, and one to the distributor so we could kill the power). There wasnt a fuse anywhere in the whole mess. Not probably the typical way of doing things, but it ended up working out really well for this test. All Wired Up and Ready to Go

After finding out that no Napa or Checker stores in all of Phoenix had an oil pump priming tool for sale or rent, I finally found one at an Autozone. However, when we went to use it, something wasnt right. The tool wouldnt catch on the oil pump and kept slipping. We took it out and compared it to the distributor and found that the tooth that engages the gear was too large to fit into the groove. Frustrated, we finally ended up disassembling the tool and grinding down the flange, then putting the tool all back together. After our modification, it worked flawlessly. As we spun up the drill, the oil pressure gauge began to rise. Once we knew we had pressure, we put the distributor back on for the final time. We roughly set the timing using top dead center and then it was the moment of truth.

The Moment of Truth

We hit the switch to turn on power to the distributor. Then I hit the switch to fire the starter. It cranked and cranked, but wouldnt fire. After much deliberation, we determined that the carb wasnt getting any fuel. We checked a few fittings and fixed the problem. Time to try again. This time, we hit the switch, and the motor fired and started! I had been waiting for that moment for almost a year and a half! My dad quickly dialed in the timing and the engine was running great. It sounds incredible and we only had one small leak that simply required tightening a hose clamp.

I was very excited to finally have an engine that ran. However, the joy was short-lived. After making a few adjustments, when we tried to fire it up again - nothing. The engine wouldnt fire. Argh! We determined that there was no spark. The distributor that was working so well and just had plenty of spark a few minutes earlier was no longer working. It was getting late and I was frustrated, so we called it a night and tackled it again in the morning.

The next morning, we did a few tests to try to isolate the problem. We figured it was either the coil, capacitor, or electronic module in the distributor. In order to avoid driving back and forth to the parts store all day, we just bought all three parts (my dad is going to put an HEI in his landcruiser soon, so any extra parts would not go to waste). We changed them out, one-by-one, so we could see what the root of the problem was. First the coil - reassemble and...nothing. Then the capacitor and terminal...nothing. Finally, we replaced the electronics module and put it all back together. I had bad thoughts of it still not starting, but I crossed my fingers anyway. I flicked the switch and the engine fired up - what a huge relief!