Crane Cams Tech Support (Part 2)

May 22, 2009

“Bling Bling:

So a customer has a new Denali or Escalade with some “Dubs,” (rims for the old folks), and wants the speedometer to display the correct speed. The customer also notices he or she doesn’t have the power the truck had before he or she put those 26″ dubs on! So how about getting that speedometer corrected and getting that power back? Crane’s new Power Tuner can add up to 30 HP and 35 ft. lbs. of TQ at the rear wheels (for the gasoline engines). The Power Tuner will take care of any tire size change from 25″-44″, gear ratio change from 2.73-5.13, cam changes, adding a Supercharger, how firm a shift you would like, adjust tuning for the fuel you use, changing or eliminating the speed limiter, and even clearing trouble codes. Look on Crane’s Web site and find applications for the new Power Tuner by visiting the following link:

Valve Stem Diameter:

A number of the aftermarket big-block Chevrolet 396-454 V-8 cylinder heads currently being sold are equipped with 11/32″ diameter valve stems instead of the stock 3/8″ stems. When ordering valve spring retainers and valve stem locks (“split keys”) for these applications, be sure to check the valve stem diameter in order to achieve proper fit the first time.

The Harley-Davidson Twin Cam 88:

The Harley-Davidson Twin Cam 88 engine has no provision for changing cam timing. Crane Cams has solved that problem with a reversible crank sprocket, Part # 7-3000. This crank sprocket will allow you to advance the engine’s cam timing by four degrees for more bottom-end torque and acceleration, reverse it to the four-degree retard position for more top-end power, or decrease cylinder pressure if a detonation problem occurs.

Truing Lifter Bores:

One of the more popular steps in preparing a big-block Chevrolet 396-454 V-8 engine for racing (or street performance) involves truing the lifter bores to ensure their proper bank angles and squareness. Once the block has been machined, the lifter bores are often bushed back to their standard (0.842″) diameter. As it isn’t common to remove more than a few thousandths during the truing process to bring the lifter bores into spec, it is possible to save time (and money) by boring the block to use either Crane’s 0.875″ or 0.904″ diameter roller lifters and not have to bush the bores. These Ultra-Pro series rollers are offered in both centered and offset intake pushrod seat versions and provide the latest technology available in Crane’s roller lifter program. The 0.904″ versions also feature their 0.815″ diameter wheel/axle/bearing assembly which provides significant increases in strength and durability as compared with the usual size 0.750″ assemblies.

Special Grind Cams:

Special grind cams are a great options Crane offers. The company can change durations/lift/lobe separations and centerlines, etc. This is perfect for the racer who always must have the edge on the track. Because this special grind is made for a specific customer, that combination may not work for someone else. That’s why these special grind cams are a non-returnable item. For that reason, Crane wants to make sure that what you are asking for is exactly what you want.

Matching Coil and Ignition:

If you’re building a custom Harley-Davidson make sure you match your coil with the ignition you’re using. If you’re trying to build a nostalgia bike and are using a kicker or points, that would require a 5-ohm coil. Later year Shovelhead or Evolution engines with electronic ignitions take a 3-ohm coil, and if you’re going all out with the new Twin Cam 88 engine for a custom bike, that would require a special coil which has only 5-ohm resistance.

Let The Air Out:

The Gen 4 big-block Chevy must have the front lifter oil galley plugs modified by removing them and drilling a 0.030″  hole in the center of the plug before reinstalling them. This hole will bleed off any air lock in the front of the lifter galley oil passages. This air lock can cause the front lifters on each side to get air in the lifter, starve the oil to the rocker arm and, of course, make noise because the lifter will not pump up. GM started drilling the plugs in the late 1970s, early ’80s and produces a change bulletin to modify any older engines that were being rebuilt or that had dry lifters in the front of the engine. Also, the oil that then comes out of these holes will also lube the timing chain and gears as a bonus.

Valve Lash:

On Ford 1971-74 2000cc I4 camshafts and Ford 1974-87 2300cc I4 engines equipped with mechanical followers, the valve lash is measured between the camshaft and the follower, not the follower and the valve stem. Measuring incorrectly can result in incorrect valve timing and a probable reduction in performance and reliability.

Chevy 60 Degree V-6 Camshafts:

The Chevrolet 60 degree V-6 camshafts listed in Crane’s current catalog are for distributor equipped engines only. In 1991 and later applications, some vehicles used a version of this engine that was distributorless. In these instances, these camshafts will not install and function properly. However, Crane can regrind distributorless type camshafts to their specifications. Please contact Crane’s Tech Department at (386) 258-6174 for more information.

GM’s Gear Marking Compound:

General Motors sells a compound to aid the inspection of the gear mating. It is GM “Gear Marking Compound,” Part #1052351, and is available at GM dealerships. This compound can be used in many applications, such as inspecting a ring and pinion gear or mating the cam distributor drive gear. To use it to check a distributor, the compound must be brushed all the way around the distributor drive gear. Then, install the distributor into the engine using whatever gasket and hold-down device you plan on running. Tighten the distributor in place. Use your hand to hold the distributor rotor to provide some resistance to the rotation of the distributor (this is to simulate the load on the distributor drive gears). Now, hand turn the engine over at least two full turns of the crankshaft. (Remember, it takes two crankshaft revolutions to generate one camshaft revolution.) Then carefully remove the distributor and inspect the wear pattern marked on the compound. You may find that the distributor location might need to be spaced up or down to move the wear pattern as close to the center of the distributor gear as possible. (Some distributors have adjustable hold-down collars to assist in this adjustment.) Next, you want to see how the teeth are mating to determine whether the gear lash is too tight or too loose. In certain cases, there are oversized distributor gears available that can be used to assist in the gear lash adjustment.

Installing Reground Cams and Lash Caps on 4.6L-5.4L Fords:

You must measure the amount of clearance between the roller rocker arm and the base circle of the cam. This will ensure that you have the correct clearance for your reground cams. When the cams are reground, the size of the base circle is reduced, which means you will have to run lash caps to make up the difference. Since you have changed the size of the cam, you will want to make sure you have the same clearances as before. To do this, compress the lifter until it is solid and then install the rocker arm and cam. You are looking to get between 0.018″-0.032″ of clearance between the roller rocker arm and the base circle of the cam. This will ensure that the rocker will stay in place while the engine is being assembled. If you have a clearance larger than 0.032″, you will need to put a shim under the lifter to get your clearances correct.

Oil Restrictors:

Crane doesn’t recommend running oil restrictors because they will starve the top end of a motor. This lack of oil will not prevent the components from being lubricated or cooled by the flow of oil, which is necessary to remove the heat created from pressure and friction. This, in turn, will create excessive wear and shorten the life of the springs, valves, guides, rockers, lifters, etc. On Crane’s Shaft Mount rockers, oil is necessary to the longevity and life of the bearings. So, if you do run oil restrictors, you must open up the restrictors to 0.100″ to ensure that you’re applying enough oil to the rockers.

Mopar Ultra Pro Roller Lifters:

With all of the new Ultra Pro roller lifters that Crane has recently released for Chevrolet and Ford applications, some of the Chrysler-oriented folks are wondering about availability for their engines. The good news is that Crane actually did all of the development work on the Ultra Pro series in Chrysler applications, especially in the harsh environments of supercharged alcohol and Top Fuel drag racing. Crane first released 8620-bodied lifters for these usages more than 15 years ago and have now upgraded them all to the new Monel pin retained locking bar retention system. To maintain the identity of these familiar items, we elected not to change their part numbers, but to stay with the current 66542, 66543, 66550, 66554, 66547, 66548, 140550, etc. numbered offerings. The 2005 Crane Master Catalog details all of the numbers by application, and explains the differences between the Standard, Pro Series and Ultra-Pro roller lifters.

1963 Ford SHC 427 V-8 Camshafts:

As the nostalgia market expands daily, there are many folks looking for camshafts for the 1963 Ford SHC 427 V-8 engines. Original cams (either cast or billet) are tough to come by, but there is another option. Roto Faze Products in Torrance, California (310/325-8844) has produced new round lobe 8620 steel billet camshaft cores for these powerplants and offers them to those fortunate enough to have a Cammer. Once you obtain the cores, you can forward them to Crane for rough grinding, heat treating and finish grinding to any of our dedicated profiles. As Crane was instrumental in the original aftermarket development of this engine in the racing arena, the company can reproduce any of its original grinds and also offers many new profiles for applications ranging from mild street to all-out drag racing.

502 Gen 6 Big-Block Chevy Marine Engine Cam Firing Order:

If you’re thinking about replacing the camshaft in a 502 Gen 6 big-block Chevy marine engine and would like to try a different firing order, call Crane Cams and get the part number for your new cam designed for the 8.1L engine. The 8.1L camshaft will fit right into a Gen 6 502, but you will have the new firing order of 1, 8, 7, 2, 6, 5, 4, 3. The cams are interchangeable as long as you install your plug wires to match the firing order you have.

Changing From Iron to Aluminum Cylinder Heads:

When changing to aluminum cylinder heads from your trusty old cast iron pieces, you not only lighten up the engine, but you can also affect the ignition timing requirements. Even though you might have the same exact static compression ratio as with your old iron heads, the aluminum heads dissipate heat much more effectively, resulting in a similar effect to lowering the compression ratio from 0.5 to 1 full point depending on your overall combination. Therefore, with aluminum heads, you can usually run a higher compression ratio and/or more ignition timing, as the tendency towards detonation will decrease. An aluminum block will also contribute to this effect, though not as significantly. We’ve discussed the valve lash/lifter preload situation with aluminum heads in recent Tech Tips, so refer back to those when setting your valves.

Oil Drip:

To ensure better oiling on your small-block Ford, drill a .030″ (1/32″) hole in the plug above the distributor gear under the timing cover. This will make a fast drip on the distributor gear, which will extend the life of both the gears. This can also help prevent a cutting edge from occurring on the cam gear if you’re running a high-volume oil pump.

Flat Tappet Going Flat:

First of all, the hydraulic or mechanical flat tappet lifters need to rotate in the lifter bore to get an even wear pattern. This will keep the cam and lifters running smoothly. So, setup will be important on a flat tappet cam. Spring pressure can be too high and not allow the lifter(s) to rotate in the bore during break-in. So if you are running dual springs, you will need to remove the inner springs to reduce the pressure on the lifters during break-in. Also, do not run a synthetic type of oil for break-in. Before the installation of the cam and lifters, do not soak or pump up the hydraulic lifters! This will only make the lifter lock up and cause more problems when setting a pre-load into the lifters. Of course, you will need to apply the assembly lube (Part #99002-1 is 1 oz.) to the cam lobes and lifters. Using break-in lube (#99003-1 is 8 oz.) in the oil is another great precaution to take since oil formulations have changed during the past few years. On the hydraulic lifters, you will need to set a preload into the lifter between 0.020″-0.060″. If you do not set any preload into the lifter and run it at zero lash, you have now tried to make the hydraulic into a mechanical lifter, which will pump up the hydraulic lifter, again causing a load on the lifter face. After you have set your pre-load (hydraulic) or lash setting (mechanical), you will need to make sure you prime the engine and get oil up through every rocker arm, even if this takes a half-hour (big-block Chevy). Another precaution to help you during break-in is to take some white-out or paint and put a small stripe on the top of every pushrod. Before you start up the vehicle, use a clear or cut-away valve cover to watch the pushrods. After start up, watch all of those pushrods and make sure they are all spinning. If the pushrods are spinning, the lifters are also spinning, and there should be no problem through the break-in period. Remember to keep your RPMs between 1,500-3,000 and vary the RPM. Do not leave the engine at a set RPM! Varying the RPM will change the oil splash to the lifters. Also make sure your break-in period is no shorter than 20 minutes (and up to 30 minutes).