Jim Smart
September 1, 2001
Photos By: Mustang Monthly Archives

Degree For Life

Few of us who build our own engines think about degreeing the camshaft during assembly. But degreeing a camshaft tells us more than just camshaft specs, according to Crane Cams. It also tells us about crankshaft, piston, and rod integrity. Degreeing in a camshaft confirms camshaft specifications one way or the other. It also helps us determine piston position as it relates to the camshaft. In a world where we take a lot for granted, this is one area we should never overlook.

Oiling Upgrades

Those of you who are building 351C, 351M, or 400M engines aren't always taking care of business during your buildups. Although it's unlikely you'll ever see a 351M or a 400M small-block in a Mustang, you can count on a 351C as a possible option from 1970-'73. These engines suffer from oil starvation at the No. 4 and the No. 5 main and rod bearings. What to do? The simplest answer comes during a rebuild. Install an oil galley restrictor plug between the No. 1 main and the No. 1 cam bearings to reduce excessive oil flow in front and to allow more volume and pressure at the No. 4 and the No. 5 main/cam bearings where it's needed more. The folks at the machine shop can help here. If your engine is already installed, another solution is to run an external line between the front and the rear oil pressure sender ports, which gets more oil to the No. 4 and the No. 5 main/rod/cam bearings.

When Not To Grind

Too many of us grind crankshafts when we don't have to. If your engine has had a healthy service life (plenty of oil changes), you don't always have to grind the crankshaft to the next size under. If the journals look good, simply have your machine shop polish then measure them, and size permitting, fit standard bearings to that healthy crank.

Wet Or Dry?

One question we hear time and time again is, do I torque fasteners wet or dry? If you're interested in an accurate torque reading, then putting a thin film of lubrication on the threads of bolts and nuts is a good idea during an engine assembly. Dry fasteners can bind, giving you an erroneous torque reading, but slippery threads won't lie.

Use A Torque Wrench

Believe it or not, some machine shops and production line rebuilders don't use a torque wrench during engine assembly. They run fasteners down with an air impact and hope for the best. Call this shooting craps with a blindfold on in a casino full of thieves; you may or may not get lucky. We torque engine fasteners to determine proper bolt stretch. When we overtighten, we risk warping castings or breaking fasteners. When we don't give it enough torque, we risk the whole monkey works coming unglued. Why torque? Because you want to be right the first time.

Got Lube?

A few of us are guilty of assembling our engines using SAE 30-weight engine oil as an assembly lubricant. But engine oil doesn't have staying power, especially if the engine sits for several months before fire-up. According to the folks at D.S.S. Competition Products, you should use assembly lube on the main, rod, and camshaft journals. Assembly lube protects all moving parts from unwanted friction during that first fire-up. Bathe the cylinder walls in assembly lube during piston installation, and smother every moving part in the lube during assembly.

Spring Height?

Only a few of us do our homework, or should we say our "headwork." When you're performing a valve job, don't forget to do all of the math while you're at it. It's a good idea to check valvespring height and pressure during an engine build. After all, you want to make sure your valvesprings and camshaft profiles match in every way. And you want to make sure there's no coil bind if you're running an aggressive camshaft. Checking it now means not having to say you're sorry to the family member who writes the checks. Most cam manufacturers, such as Crane Cams, have all the information you'll need to check this out too.

Check The Gap

One shortcoming we see repeatedly is piston-ring end gaps. All of us aren't checking piston-ring end gap during our buildups. Sometimes we check one cylinder just to ease the conscience. But we'll tell you this: no two cylinder bores and no two sets of piston rings are alike. Naegele informed us, "Check every single set of compression rings and match each set to the bore. Running a tight ring gap can cost you plenty when the engine gets warm. Running a loose gap can hurt compression and ring sealing. And don't forget to position those ring gaps 45 degrees out from each other while you're at it-at 9, 12, 3, and 6 o'clock."