If you find that you have good compression, pop off the valve cover for the missing cylinder. Check for a flat camshaft-you should be able to see this with your eyes. Turn the engine over and watch the valve lift on the intake and exhaust. They should be very similar-looking in max lift.
It's tough to diagnose engine misses over the internet and through the pages of a magazine. I hope I've given you enough clues to look in the right places. Be patient and double-check everything.
Q I recently rebuilt the 305 in my '84 Camaro Z28. I bored and stroked it to 334 cid and installed a Lunati cam (204/ 214 duration with 0.420/0.442 inch max lift) and a set of Edelbrock TES headers. All emissions equipment was reinstalled and is functioning (as it must be in New York). I am also using the stock ECM and the computer-controlled distributor and Rochester Quadrajet. I set the timing at the factory-recommended 6 degrees BTDC. Although I did not cc the heads (GM Vortec with a Vortec dual-plane manifold) I believe that the compression ratio is about 9.1:1. The stock compression ratio with the old 58cc heads was 9.5:1. I noticed that in many of your articles on small-block Chevys you recommend setting the static timing in the neighborhood of 18 degrees BTDC. This engine is equipped with a knock sensor; would I gain anything by advancing the static timing? I'm thinking that the distributor and the ECM will control my total timing no matter what I do to the static timing. Any ideas?Steve ParsellLyons Falls, NY
A You are in the right ballpark, but you missed one of the bases on the way to home plate. Yes, the ECM controls the spark advance based on a three-dimensional map of engine load, engine speed, and engine temperature. The base timing of 6 degrees is a reference value for the spark-advance table calibrated into your ECM. If you advance the static timing to, let's say, 18 degrees, the total timing that the ECM would give the engine would also be increased by 12 degrees! Have you ever checked the spark timing after you have reconnected the four-wire connector that bypasses the computer? If you have, you should have noticed the idle spark advance was up around 16 to 18 degrees, based on the engine speed and coolant temperature. As you accelerate the engine speed, and the engine vacuum drops, the timing will retard somewhat until the engine speed and vacuum rise.
You didn't mention which 305 your Camaro came with stock. The LG4 low-output 305 had a very conservative spark curve compared with the L69 H.O. 305. Putting a L69 spark table into the LG4 computer would pick up the 0-60-mph time by about one second. That shows you how conservative that calibration really is.If your engine is the LG4, increase your base timing to 10 degrees with the four-wire connector disconnected. This will step up the performance significantly. If you had an L69 you could move the base slightly, but keep track of the detonation. Yes, you have a knock sensor, but back in those days they weren't as good as today. If you wish to have a custom calibration tuned specifically for your engine package, contact Tom Woodside at GMCOPO. There is a limited number of these early chips left, and he has a good database to support your engine. You can reach Tom at 248.275.5828 (Eastern Time).
Q In this age of $3.00-plus gas, I recall an engine built by Jeff Smith for a Chevelle that used long rods out of a Ford six-cylinder. I think Duttweiler was involved. It was supercharged, small on cubic inches but big on power. Am I dreaming, or was this actually done? I'm thinking about building an engine for a project, and thought I should look into the past for info.John Alden