Fun With Cam Sprockets and a Home Made Spanner Wrench

Start at noon, and be done by 6:00PM, right? I figured the timing belt replacement shouldn't take longer than six hours. I thought wrong.

It was going fine, although a little behind schedule by the time I got to the cam sprockets. I needed to remove the bolt so I could take them off and replace the cam seals. I tried my impact wrench on the front cam, while holding the sprocket with some channel locks. That didn't work. I needed a very large spanner wrench.

I checked youtube to see how other people removed the cam sprockets. I saw some videos where these guys made contraptions using the old timing belt to hold the sprocket. The belt broke on at least one of the videos. I was going to need something that wouldn't break the first time.

I found the Lisle Universal Cam Adjuster Tool for $42, but it looked too wimpy. The ATD Tools 8614 Variable Pin Spanner Wrench for $54 with only a 1 lb shipping weight was definitely not going to hold back the torque I needed.

I finally dismissed the idea of finding an appropriate tool at the auto parts store, or even at a hardware store. I've never seen a spanner wrench of the kind I was going to need. I needed a Tim "The Toolman" Taylor's kind of spanner wrench for this job.

Thankfully, Home Depot had the materials I needed to build my own for less than $30.

(1) 1/4" thick steel, 1.5" wide x 48" long
(1) 1/4" thick steel, 1.5" wide x 36" long
(3) 5/8" x 2" bolts
(4) 5/8" nuts
(6) 5/8" flat washers

I already had a stepper bit and a drill press, so drilling 5/8" holes into the steel was no problem. Here's the finished product.

Home Made Spanner Wrench

I didn't need the extra length on the 36" bar, and could have just cut 12" off the 48" bar and had plenty of leverage, but this worked and it looks like it'll be able to handle all the torque I can muster. Plus, I can maneuver the spanner wrench from one end using the extra length on the short bar.

 If you look closely, you can see that I used two nuts on the pivot, for hopefully obvious reasons.

Back to the timing belt job, Mom was waiting while I was working, so it had to get done that night. This spanner wrench worked very well. I was able to put my longest breaker bar on the bolt with the spanner wrench holding the sprockets and with some effort, broke the bolts free. After that, it was all routine. I replaced the cam and crank seals, the water pump, and got the new timing belt on.

There were no instructions specific to this application, and I never figured out why the mark for the crank on the belt was off by five teeth. The belt had white line marks that lined up perfectly for the cams, but the white line on the belt for the crank pulley was off by five teeth. It didn't line up when I flipped the belt around either. Oh well. It's probably because the belt doesn't touch the crank pulley at the mark when they're all lined up.

I lined up the cam and crank marks before pulling the old belt off and made sure the marks were lined up perfectly before pulling the pin on the tensioner. I tried to keep it quiet, except for when I had to tighten the crank pulley bolt with an impact wrench. At least the neighbors can be grateful that it wasn't them out under the hood until late.

As the time passed, I had to go slowly and carefully to make sure I didn't miss anything like filling the coolant back up before sending Mom on her way. I finally got done at 12:55 AM.