A Matter of Timing

[Barrman]

I have a HEI on my 396 Big block. I love it. It works so good, that I don't even think about the distributor. The last time I did was in June of 2006. We all played in the mud at the 2006 National FE in WITC. I made a post FE trip to the car wash and the truck wouldn't start again. The module in the HEI shorted out and I replaced it, set the timing and forgot about it.

That fall, I trailered a M715 for Pistolnut more than 500 miles to and from the Texas FE. Getting 10-11 mpg doing it. The next year I barely got 11 mpg without the M715 and trailer making the same trip to the 2007 Texas FE. I wasn't getting 10 mpg last spring when I rejetted the carb in preperation for the 2008 FE in Colorado. It was still running ok though. Once I changed the jets, it ran bad here, but ok in BV. At least ok compared to my 7K + altitude expectations.

We got home, I put the jets back to where they were and it just never really ran right. So, I kept driving it to work every few weeks, pulling the carb off, changing something, using the Gas Analyser to set the mixture and then see if it was better. I might get better acceleration or idle or cruise or high rpm, but never all at the same time. I also had been doing a lot of M35 driving and just tended to ignore the M715 since it was small and just wasn't fun to drive anymore. The more I drove the whistler, the more I convinced myself that I needed a turbo diesel in the M715.

A week or so ago, I had the M715 in my class bringing parts in for the various projects in my room. One of my students asked a question about timing and timing lights. So, I hooked up the light and fired off the 396. I couldn't believe it! My static timing was almost right at 0 degrees. I had set it at 8 degrees and not touched it. Then I started thinking about when I had set it? June, 2006. I pulled and tugged on it. It was tight and wouldn't move. We pulled the cap and the mechanical advance worked and wasn't stuck or flopping. Vacuum worked as well.

We set the timing like I liked it, set the mixture and I drove it home. WOW! It was like a different truck. The awesome sounding idle was back, neck snapping acceleration and effortless cruising too. I started making excuses to drive it.

However, we were in the mid to upper 80's last week and weekend. The hard top had to go. I almost, but not quite talked Jennifer into going to church in it Sunday. (Like I said, I wanted to drive it everywhere again) Of course, I pulled the top last weekend, a front blew in Wednesday morning, we have gotten 2-1/2" of rain since and the temperature hasn't been over 42 degrees either. Which is the most rain we have had in 18 months.

Anyway, my point was this. If your stock or modified truck just doesn't seem to be itself anymore, check the timing. It might startle you.

[hiker]

Well said !!

[randyscycle]

Good point. THe HEI's were also famous for the flyweights in the mechanical advance to wear out and either stick in the full advance position, or the springs to come off and render the whole thing inoperative.

I'm not sure of they still offer it, but NAPA used to sell a kit to replace the weights, springs and little plastic bushings.