With the basic cam selection information defined, let’s move forward with the next piece of the puzzle—the timing set. FE engines use a timing assembly very similar to other Ford engines, with the aforementioned cam thrust plate, an offset positioned dowel pin for locating, and a single central cam bolt for retention. The factory cam sprockets were often aluminum with molded nylon teeth for quieter operation. The chains were a link type with single-toothed sprockets. The steel lower sprocket has a light press fit onto the snout of the crankshaft and is located by a single keyway.
The original cam drive assembly also included a “C”-shaped spacer washer sandwiched between the upper sprocket and the cam itself. All current replacement timing sets incorporate this spacer into the sprocket; the spacer, if found, should be discarded during service. An oil slinger goes in front of the sprocket to reduce the amount of spray aimed toward the front seal.
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Factory Timing Sets
Link-type timing chains are comprised of multiple side plates woven together and assembled into a chain with pressed and peened pins. The side plates themselves are in contact with the single wide teeth on each sprocket; the pins do not touch the teeth. The design is simple and quite durable, but has fallen out of favor in the performance market over the past twenty years. You won’t find many of them in performance applications, but most stock replacement parts are of this design.
The early nylon-toothed sprockets are the likely culprit for the “bad rap.” The nylon would become harder and less flexible over time. That tendency, combined with the eventual loosening of the chain due to stretch and wear, caused the sprockets to shed their teeth, usually on cold startup. Replacement sets use sprockets machined completely from iron with no plastic and thus eliminate this potential problem.
Another issue faced by link-style chain systems is that the links are in contact with, and eventually wear into the sprocket teeth. Another weakness in link-style timing sets has nothing to do with the design at all; it’s more about market economics. Since they are viewed as stock replacement items, these timing sets are very low cost and therefore quality has suffered over the years. Unfortunately, imported components of questionable quality and corner cutting in both quality and manufacturing are common.
Roller Timing Systems
Roller timing sets are the norm in high-performance applications. Every roller set for the FE engine is a “double roller” design, having two identical rows of narrow teeth on each sprocket. The roller chain has only one pair of side links per segment and is driven through the connecting pins.
Roller chains can be of either an “ANSI” (American National Standards Institute) design, which has the sprocket teeth riding directly against the pins themselves, or of a “BSI” design where there are freely rotating bushings surrounding each pin. The ANSI chains are less expensive, and are sold with pins in .200- or .222-inch diameters. The “BSI”- type chains have a pin bushing diameter of .250 inch. The latter design is considered superior, and is referred to as the “Tru-Roller” series in the Cloyes literature. It is important to identify which chain you are using because the sprockets cannot be interchanged; the tooth profiles are different.
Upon initial use, all chains stretch to an extent because of construction and function of the part. Punch-formed holes in the links have something of a “point contact” until a smooth bearing surface is established. Most quality chains are “pre-stretched”; they are mounted over a set of rollers and pulled under load to a specified length.
With the notable exception of Cloyes, timing sets are generally outsourced items—sold under a marketing brand name that is often not related to the actual manufacturing source. Chains and sprockets are manufactured by numerous companies in various countries, and in a wide range of quality.
Chains can usually be identified by miniscule stampings on the links. Manufacturers of high-quality performance chains include Morse from the United States and Mexico, Renold from France, JwiS from Germany, and Daido (DiD) from Japan. Rolon from India is a common supplier for lower-cost sets.
Sprockets can be harder to identify. Cloyes makes its own, as well as private-label parts for numerous other companies. SA Gear provides many sprockets to the various marketing companies, but does not sell to consumers. There are numerous offshore sprocket suppliers as well, with quality levels ranging from excellent-appearing billet pieces to, well, just plain junk.
With such a jumbled and confusing market situation, the only thing you can do is to pick a brand based on reputation. I have gone to using exclusively Cloyes Tru-Roller timing sets. The reasons are twofold.
First is that I know who makes them and the parts are always consistent from box to box. There are no mixed parts from multiple suppliers that change with the vagaries of international currency fluctuations. Second is that the basic Tru-Roller sets simply flat-out work—no fancy quasi-billet stuff. There are only three keyways, but they always seem to fit right and deliver the timing position I’m after.
Cloyes offers Tru-Roller sets with reduced center-to-center distances of .010 and .005 inch. These are intended to address issues caused by excessive line boring but I’ve rarely had to use them. On several occasions, customers have requested the reduced center-to-center sets from other manufact-urers to correct a perceived loose-chain problem. However, the standard Cloyes timing chains and parts remedied the problem.
Billet, 9 Keyway and Thrust Bearings
You can purchase some really cool-sounding timing sets these days for your FE project. There are sets with nine keyways instead of only three. There are sets with billet-cam sprockets. There are sets with thrust washers and thrust bearings. In my experience, most of these innovations don’t offer much of an advantage, considering the added cost and complexity.
While the nine-keyway deal sounds like a great idea to really dial in your cam timing, it makes a coupleassumptions. The first is that the key slots are all labeled according to their actual function. Having tried a number of these over the years, it seems that they are usually labeled at random, so you wear out your wrenches trying to find the one that gets you what you desire. The second assumption is that you are going to notice whether the cam is installed at the perfect spot or if it’s a degree off. The truth hurts a bit— nobody other than a NASCAR team or a Pro Stock builder will be able to document whether any position is “right or wrong” until they’ve run the engine with multiple settings. While we all strive for perfection, the ideal for cam timing is to get a good-fitting system that is reliable, predictable, and consistent.
Billet sprockets look great hanging on the wall in a blister package. But beyond that they have no real functional advantage over a properly made hardened cast or machined steel sprocket. In 40 years, I have yet to see a double-roller cam sprocket that caused a failure, so the material has proven to be pretty good for the task. The machines that form the teeth and center machining are identical, so there is no dimensional advantage. All crank sprockets have (or should have) hardened teeth on a steel base.
Cloyes sells its infinitely adjustable “Hex-A-Just” timing set for the FE. As fond as I am of the traditional Cloyes set, the Hex-A-Just is not one of my favorites because it uses the fuel-pump eccentric as an adjuster, and pivots around the center bolt. The design counts on the center fastener for tightening and holding the cam position. The dowel pin is allowed to move in a slot in the sprocket and no longer serves as the locating device. Many folks use this system with good results, but I’m just not comfortable with it.
The thrust-washer and thrustbearing kits strike me as a solution looking for a problem. Originally offered as a repair part for smallblock Chevrolet engines, cam thrust washers can be used to fix a block with a worn thrust surface. This was never a problem on Ford engines, which used a thrust plate to handle the cam loads; but if you have debris induced wear, just replace the plate. Thrust bearings, using Torringtonstyle flat rollers, are theoretically useful in a flat-tappet-cam application with the cam-lobe-angle-induced rearward loads. Most race engines have a roller cam and, thus, noangle- induced loading. The simple Ford thrust plate seems to work just fine. Blue Thunder sells a bronze thrust plate if you’re concerned with steel cam compatibility.
Gear-to-gear-type cam drives have largely fallen out of favor over the past 20 years because they offer no real performance advantages. But some folks really like the sound of the blower-like “whine” that they produce. As far as I know, the only supplier for an FE gear drive is Milodon. It is a system that fits under the stock timing cover and requires that a couple additional holes be drilled into the front of the block. If you plan to run one, you should acquire the system and do the drilling and tapping before block assembly.
The belt drive is considered the best part to use in a drag-racing environment. It is relatively easy to install, provides reliable and consistent performance, and unmatched tuning capability. While performance advantages are sometimes touted by various belt-drive suppliers, they would be incremental at best, and largely offset by the added drag from the required camshaft seal.
The great advantage of a beltdrive system is that it allows camtiming changes in a couple of minutes, with the engine completely assembled. The billet timing cover supplied with an FE belt drive is sealed, while the sprockets and belt are on the outside of the engine. With a belt drive on your engine, in the dyno cell, you can optimize cam timing in a few quick pulls. Cam timing is adjusted as follows. Loosen the half-dozen fasteners around the perimeter of the cam sprocket and align the appropriate marks while “bumping” the crank around with a wrench. It takes five minutes, tops. Those same tests and changes would take hours with a factory-style chain system.
Written by Barry Robotnik and Republished with Permission of CarTech Inc
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In addition, the belt-drive system allows for much easier cam changes. Only the cam sprocket and center section of the front cover need to be removed; the damper and the cover itself can remain in place.
The only supplier for belt-drive systems for the FE is Danny Bee. While expensive at nearly $1,000, the system is of very high quality, and includes everything necessary to make the conversion. Instructions are a bit sketchy but you can use the ones for the more popular 460 Ford kit. The only thing to look out for is the lower sprocket, which may need to be shortened to provide proper belt alignment on certain factory crankshafts— notably the 391 truck forging.
Timing Covers, Damper Spacers and Pointers
There are a few different factory timing covers, but they effectively interchange with one another. All FE timing covers mount the same way and include a spot for the timing pointer and the front crankshaft seal. They have a flat surface at the bottom with 5/16-18 threaded holes for four of the oil-pan bolts, and a side opening with a pair of 3/8-16 threaded holes to mount the mechanical fuel pump. Four 5/16- inch fasteners secure the cover to the block around the upper circle, and four 3/8-inch fasteners secure the lower half. Several of the mounting fasteners extend into either water or oil—I recommend using a dab of sealant on assembly.
The earliest FE engines used a sheetmetal cover—an item not often seen on performance engines. The vast majority of FEs have a diecast aluminum timing cover. The earlier version has two small fasteners retaining the timing pointer. Later ones use a small fastener for one end of the pointer and have an extended portion of the casting to allow a longer 3/8-inch bolt to hold the other end.
Most FE dampers have the timing marks engraved on them, thus the pointers have a simple angled end. The two pointers are functionally interchangeable, providing the appropriate cover is used. But some 427 engines only had a scribed line on the damper, with the coordinating pointer having a range of timing positions; these pointers are unique and valuable.
The front seal on an FE is pressed into the timing cover from the rear. It seals against the damper spacer, a cylindrical sleeve that slides over the crankshaft before the damper itself is pressed into place. The damper spacer is located by the same keyway that located the crankshaft timing sprocket. It is pretty common for the damper spacer to develop a worn-in ridge where the seal rides, causing oil leakage. Slide-on repair sleeves are available, as are replacement damper spacers, in both aluminum and steel. If installing a repair sleeve, remember to lubricate the seal surface. Centering the damper spacer in the seal before bolting down the timing cover can help prevent premature seal wear and subsequent leakage.
The damper used on factory FE engines is of conventional design— an inner hub, a bonded elastomer layer, and an outer ring. Some early dampers had a pulley groove machined into the outer ring, but most have pulleys bolted to the front hub section. As noted above, most FE dampers have the timing marks engraved on their outer ring. FE dampers are located by a single 1/4- inch keyway in the crank.
Although a large array of factory parts is available, their relative merits and part numbers are best kept within the context of a restorationtype build. Most of these are now approaching or exceeding 40 years in age. The rubber has long since surpassed its service life and will show signs of cracking and wear. With aftermarket replacements being readily available and inexpensive, there is no reason to reuse an original part unless you are doing a restoration or are on a restrictive budget.
The least-expensive offshore dampers from Professional Products are suitable for street use, and are likely better than a worn-out factory piece. They have timing marks around the perimeter and come with a universal pointer that fits the common timing cover.
Romac products offer the next step up in quality. An Australian company, Romac supplies a very nice-looking reproduction of the factory 427 damper, as well as a topquality performance damper with an aluminum outer ring. Although cosmetically pleasing, its silver color is hard to read with a timing light. Both are SFI certified, making them legal for use in NHRA drag-racing venues.
The best dampers are likely from ATI. As a supplier to the majority of professional race teams, the quality of ATI dampers is well established. The only issue, beyond the higher but appropriate price, is that its FE damper is a variation on other parts. It has an outer ring from a 460, which means that the timing marks are off by a few degrees, but timing needs to be checked anyway in a race engine. Also, the hub has the big-block Chevrolet bolt pattern; thus, FE-specific pulleys require modification.
Damper mounting bolts on FE engines are large at 5/8 inch and rarely strip out. ARP sells replacement bolts with the required big washer. The bolt on a 391 truck crank is larger yet (3/4 inch), but ARP sells a bolt for the KB hemi that works just fine. These must be tightened to specs and used with red Loctite for final assembly, or they will come loose.
Written by Barry Robotnik and Republished with Permission of CarTech Inc