Thread: Professional engine builder tips.

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Valve to piston clearance, 0.080" intake, 0.100" exhaust minimum. Check at overlap, starting 20 degrees BTDC, each 5 degrees all the way to 20 degrees ATDC.

Tape a piece of 320 grit wet/dry paper to a piece of glass and dress the ends of all valve springs in a figure-8 pattern.

Use enough air filter element area to allow the motor to breathe. I like 120-130 square inches on a 355 Chevy.

Paint valve stem tips with indelible ink or Dykem Blue and roll the motor through several rotations to check proper pushrod length and geometry. You want the skinniest shiny mark. In other words, the least movement across the valve tip, no matter where it ends up at inboard or outboard location on the tip. Shaft rocker systems can be altered with pushrod length and shims under the stands or trimming the stands. Measure all valve lengths before having a valve job done to make certain they are the same length. A thin wafer of very hard material is inertia welded to the tip of the valve to resist wearing from the rocker arm, so if you cut the valve tip too much, you could cut right through the hard wafer and have a soft tip on the valve. Lay a straightedge across the valve stem tips to insure the valve seats are all the same depth in the head (You can only do this with certainty if you measured the length of the valves beforehand). Any of you guys who don't have a straightedge, there is a decent one available at McMaster Carr for about 50 bucks. Get the plastic case to keep it in so it doesn't get roughed up in the shop. It's another precision tool to add to your collection.

Roll pushrods on a piece of flat glass to check for straightness.

Check for interference at pivot of rocker arm through full lift. Also check for clearance between the edge of the retainer and the body of the rocker arm at all lifts.

When installing the dipstick tube, put a little Permatex #3 on the pan end of the tube, drop a header bolt into the top end and tap on the bolt head to seat the tube.
http://www.permatex.com/products/aut..._Sealant_a.htm

Trial-fit cam sprocket bolts to make sure they don't bottom-out in the cam before tightening the sprocket.

Magnaflux your pulleys. A little money spent now could save a lot of expense later. Also magnaflux the flexplate before installation. They have a tendency to crack between the bolt holes.

Check valve springs at full lift for minimum 0.010" clearance between each of the 5 coils.

Willie at Isky advised doing a compression test when installing a new cam. Wire the throttle blades wide open, mount a pressure gauge in a spark plug hole and move the cam timing around with offset bushings or whatever works for your particular motor. The idea is to adjust the cam timing to advanced and retarded until your find the highest reading on the gauge. That's where that particular cam wants to be. If you have to either advance it or retard it more than 4 degrees to get your highest reading, you have chosen the wrong cam grind (intake closing point) to match up with your static compression ratio.

Valve spring installed height can be changed with different retainers or (+/-) locks as well as cups and shims.

When using dual/triple valve springs, check closely to make sure the inner springs aren't coil binding at full lift.

If you want to paint the interior of the motor, use General Electric Glyptal
Eastwood Company: Search Results for glyptal

Get TDC nailed down on engine assembly. Also pay attention to the harmonic damper. Be cautious of offshore units, the bore may not be to spec. If the damper is not a good press fit on the crank, then it cannot transfer harmonics to the inertia ring. Always use the proper tool to install a damper.
http://www.crankshaftcoalition.com/w...op_dead_center

Mock up the distributor drive gear at the cam and the pump drive shaft length during pre-assembly. You may need a distributor with an adjustable collar.

Install studs to attach the oil pan. You'll wonder why you didn't do this years ago.

Use only premium quality oil filters from Wix, AC-Delco or equivalent. I've been made aware of problems with Fram.

Chamfer the trailing edges of oil holes in the crank.

Make certain you have adequate oil drain-back capacity in the heads. I like to epoxy brass screen over the holes to catch shrapnel from the valvetrain (use a large piece of screen placed above the holes so you don't reduce the flow capacity of the hole itself).

Using more cam will normally require more initial ignition lead at the crank. Refer to this chart from Barry Grant for the amount of ignition lead to use with the cam you're using. Where it says 20+, that means no centrifugal, lock out the weights and put the initial lead at where the total timing should be, for instance 32-34 with fast burn heads, 36-38 with conventional chambers on a small block Chevy.
Demon Selection Guide

When degreeing the cam, don't fosdick around with trying to use a hydraulic lifter to check with. It's an exercise in futility. If you have a lathe, great, if not, find a buddy with one and machine yourself a piece of solid steel rod the diameter of your lifters. It should be about 6" to 8" in length so that you can get to the end of it with your dial indicator (using a stand with integral magnet) which is mounted on the block deck. Some fellows will make the tool with two diameters, for instance Olds on one end and Ford on the other. Dress the ends off nicely. Oil the tool and just let it ride on the cam lobe with the tool in a vertical position (motor twisted on the engine stand so that the block deck is parallel with the floor).

Use a cartridge roll on your drill motor or die grinder and lightly de-burr the teeth of your cam and crank sprockets. I also like to use small Nicholson Pattern Files to deburr pieces in and on the motor. There is a set of Chinese "Needle Files" available for cheap at Harbor Freight. To prevent the file from goobering up with aluminum, rub it down with anti-sieze before you start.

If your heads have a flat area opposite the chamber, you can do yourself a world of good by setting the squish (clearance between the crown of the piston and the pad on the underside of the cylinder head with the gasket in place). Small block Chevies do well with 0.035" to 0.045". Big blocks may require a little more due to a larger bore, allowing more rock to the piston and also due to heavier components that may stretch a little more and grow a little more from heat. I am of the opinion that no motor should be put together, even a "goin' back and forth to the grocery" motor, without align honing the main bores and cutting the decks true to the main bearing bore. You can't be expected to build a performance motor if you start with dimensions that are skewed. If the block decks aren't square to the crank c/l, then the heads won't be square to the crank c/l and there is no way the intake manifold will be square to anything.

De-burring, polishing and shot-peening steel connecting rods will increase their strength by 100%.

Finally, here's the down and dirty on flat tappet cams....
http://www.crankshaftcoalition.com/w...ips_and_tricks