Cold lash numbers on aluminum cylinder heads and/or aluminum cylinder blocks can vary greatly from the hot figures. When hot, aluminum moves around significantly more than cast-iron, causing valve lash figures to become decidedly different. Chevrolet offers this advice: "Cold-lash all aluminum engines .010 inch tighter than hot lash specifications." Generally speaking, you can use this as a starting point. Some aluminum head/iron block combinations are very close to an all-iron engine in terms of cold lash while others might be anywhere from .005 to .010 inch tighter. Do what we do: Contact your cam grinder and ask for a specific cold lash number for your particular combination.
No Fire in the Hole
A quick test for a misfiring cylinder on a header-equipped engine is to spray a little water on each header tube up near the exhaust port while the engine is running. The misfiring cylinder will have a lower temperature, which shows up on the cylinder where the water evaporates the slowest.
All the engine "how-to" stories say to always run a tap through the head-bolt holes when swapping heads or rebuilding an engine. There are, however, a number of different taps. ARP offers taps that clean the threads but don't remove material, leaving more iron in the block for thread overlap with the head bolts, which will prevent pulled threads.
The Big Bang
If you're running nitrous on your engine and you inadvertently fill the cylinders with nitrous while the engine is off, don't try to start the engine-an explosion can occur! Remove the coil wire, fully open the carburetor throttle blades, and crank the engine for 10-15 seconds before starting it. This purges the engine of any nitrous.
Having trouble keeping your floor mats in place? Glue a couple of small pieces of Velcro(r) to the backside. The Velcro(r) will bite into the carpeting and keep the mat where it's supposed to be, instead of bunched up under your gas pedal, or worse yet-under your brake pedal.
If your radio crackles every time you change the volume or the station, take the knob off and spray some aerosol tuner cleaner in along the control shaft. Tuner cleaner evaporates after it does its job and leaves no residue. You can buy it at most electronics stores
Most cam-break-in lubricants are molydisulfide concoctions. We recommend that you use them. But remember that they can easily plug an oil filter within 20 minutes of operation. When the filter is plugged, it will typically by-pass, and the result will be copious quantities of dirt inside the engine. After breaking in the camshaft (or a new engine), replace the filter after 20 minutes of running time. It's cheap insurance.
You Are Getting Sleepy
Common aerosol starting fluid (like ether) makes a great grease and wax remover, after sanding, in preparing small parts for painting. Simply hang the part with a piece of wire, spray it, and let it dry while you shake the can of paint. Make sure you use it in a well-ventilated area, away from any source of flame. In other words: No smoking!
When installing steel connecting rods, measure bearing surfaces at least twice-once at the 12:00 o'clock position and again at the 6:00 o'clock position. Remember that clearances vary, according to the application. Typically, you need 0.001 inch clearance per 1.000 inch of crank pin diameter.
More Solid Steel Info
Clean all steel connecting rod reciprocating parts thoroughly. The idea is to remove all dirt and foreign oils. Spread the rod bolt assembly lube on the threads and be sure to spread the lube under the head of the bolt prior to beginning the tightening sequence.
When You Get to 9, You've Gone too FarDon't use metal stamps to number connecting rods! They may disturb the roundness of the connecting rod bore. Instead, paint toolmaker's layout die on the rod and rod cap. Inscribe the numbers.