Cylinder Head Correction - Head Games z

15 Cylinder Head Tips And Tricks For Power And Reliability

Mike Petralia Jul 1, 2001 0 Comment(s)

Chamber Walls
Here's an area that you can port at home without fear of completely ruining your cylinder heads. The casting on the sides of both the intake and exhaust valves may already have been plunge cut by the manufacturer to ensure adequate valve clearance and good flow at low lift. However, you can improve low lift flow further by opening these areas up with a die grinder. We like to lay a copper head gasket, like this one from SCE, on the head to see just how far we can open the chamber. We use a copper gasket because its bore is perfectly round, just like the cylinder, while a composition gasket may not be round.

You don't have to use the copper gasket when you assemble the motor, just be sure that the composition gasket you use does not cover the area you opened up. Also make sure to never grind this area beyond the cylinder bore diameter. It's best to check and scribe the area you wish to grind using a gasket with a bore slightly smaller than your cylinder. When done correctly, this newly opened up area will enhance low-lift flow and will add only a small volume to the chamber, so it won't kill compression. Source: Specialty Component Engineering (SCE Gaskets), 1122 West Ave. L-12 Unit 111, Dept. SC, Lancaster, CA 93534, (800) 427-5380,

Stepped Washers
Race motors get torn down often, and constantly removing and retorquing the cylinder heads can get you stuck, literally. The problem occurs when, after repeated retorquings, the aluminum at the top of the bolt hole begins to collapse inward. This grabs the stud and won't let go. We've seen guys using an engine hoist hooked to the rocker arm studs, trying to pull the stuck heads off with no luck. Stepped washers like these from B&B Performance are the answer. After the head has been drilled with the special, stepped drill bit shown, which is also available from B&B, the steel washer gets pressed into the hole. That way the aluminum can never collapse around the stud again. Source: B&B/Steph's Performance, 699 Cross St., Lakewood, Dept. SC, NJ 08701, (732) 367-8700.

Triple Heights
We're always talking about proper valve spring height and its importance to making reliable horsepower. What do you do if your valve springs are not all correct? If your springs are too long when installed, the easiest way to shorten them is to use shims under the springs although there are other ways to correct the problem, like using these different height retainer locks from Crane. These locks can move the retainer up or down 0.050 inch. If you need to shorten spring height by more than 0.075 inch, using the -0.050 lock eliminates the need to stack multiple shims under the springs. Or if the spring is already too short when installed, you can move the retainer up by using the +0.050 lock. Source: Crane Cams, 530 Fentress Blvd., Dept. SC, Daytona Beach, FL 32114, (904) 258-6174,

Rocker Checker
You wouldn't think that there would be much to correctly installing rocker arms, but think again. There are two areas that need to be addressed when bolting on any aftermarket rocker. Both involve proper roller tip placement on the valve. Ferry's Aluminum Cylinder Head Repair has designed a rocker geometry checker to help you put the tip where it belongs. You use the geometry checker with the valve at half lift to see if the roller is centered on the valve. Ferry's tool is easy to set up and use and comes with detailed instructions and a "Zero" standard for reference. If your rockers are off, you can change the roller tip's position by lengthening or shortening your pushrods. Or if you are running shaft rockers, you'll have to shim or machine the shaft mount pedestals.

Another area to check when installing new rocker arms is if they are centered over the valve tip from side to side. Adjustable pushrod guide plates are the cure for that problem, and they can be purchased from Isky Cams (323) 770-0930, Any misalignment here could be disastrous if the roller tip slips off the valve, and since an off-center roller will try to push the valve sideways as it opens, it will cause undue heat and wear on the valve guides. Ferry's has several other unique valve train checking tools designed for the serious engine builder that can be purchased by calling (972) 557-3565 or writing to: Ferry's Aluminum Cylinder Head Repair, 710 Quietwood St., Dept. SC, Dallas, TX 75253.

A Bonus
Crane has worked closely with NASCAR and NHRA teams in developing a titanium retainer that won't fail even under the highest loads. To cure the problem Crane developed its 7-degree "Posi-Stop" retainers. The specially engineered retainers feature a stepped design to reinforce the bottom of the retainer. This increases the retainer's strength and eliminates the lock's ability to "pull through" the bottom. The Posi-Stop retainers are lightweight, come complete with machined locks, and are available to fit 5/16-, 11/32-, and 3/8-inch valves. Source: Crane Cams, 530 Fentress Blvd., Dept. SC, Daytona Beach, FL 32114, (904) 258-6174,




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