Spent most of the day out in the garage again getting everything buttoned up on the fuel system project. First thing up was pulling the old mechanical fuel pump.
Here’s a time saving tip for anyone that has ever spent hours trying to install a new mechanical fuel pump on a 1st generation small block Chevy. Try as you might to hold the fuel pump push rod in the up position with your finger, grease, hacksaw blade, or whatever, it inevitably falls down just as you try to insert the pump arm into the engine block opening.
Here’s the easy method. The upper passenger side motor mount boss for the old 1955 engine mounts is open to the crankcase, and in direct alignment with the fuel pump push rod. Remove the factory 3/8x16, ¾” long bolt and set it aside for reinstallation after the pump is changed. Obtain a 3/8x16 bolt that is 1.5” long. Clean the threads until they look like new, or run the bolt through a die. It’s important the threads are clean so they will easily turn in the block with just finger pressure. Run the bolt into the hole until it bottoms out on the push rod. Run it up tight with finger pressure. Avoid using a wrench or over tightening as this may ding or score the push rod. That’s all there is too it. Now you can go about removing and installing the pump with absolutely no interference from the push rod. Once the new pump is in place simply remove the long bolt and reinstall the original.
Here’s the factory bolt on the left, and a 1.5” version I threaded for the job:
Here’s a photo showing the long bolt holding the pushrod in the up position:
The new mechanical pump had to be re-clocked as the inlet/outlets were completely different than what was shown in the listing photo. After I set the new position, I checked the action on the pump and thought something might be wrong because I could easily cycle the lever by hand. It’s been a long time since I’ve held a bare fuel pump in my hands, but I didn’t think I’d gotten that much stronger with age. Sure enough when I removed the old pump, I could only cycle the lever by pressing it against the bench, which immediately made me suspect something might be wrong with the new pump. Nevertheless I went forward with the installation.
The new mechanical pump was mounted and new hard lines formed and connected. The last step was removing the plug in the tank and hooking up the hard line to the filter and electric pump. The last step was changing the fog light toggle switch to a momentary model and installing it in the dash.
The first starting test was not a roaring success.
The good news – no fuel leaks in any of the lines or connections, and the engine started right up.
The bad news – idling the engine in the driveway the engine quit running after 2-3 minutes, something it’s never done before. A quick shot with the electric pump and the engine fired right back up, and quit a few minutes later. I can only assume my worries were well founded and the new mechanical pump is defective. So tomorrow I’ll pull it off and retest with the old pump which was working perfectly.
It’s always something!