September 2025 – Eaton Balancing

Roller Timing Chain Failures

The Rollmaster true roller timing sets have been available for a number of years now for the Ford Y-Block family of engines. These have been a big plus for those engine builders that go to the extra effort of degreeing in the camshafts as the lower crankshaft gear is keyed for nine different camshaft timing positions. Before these Rollmaster timing sets came to market, degreeing in the camshafts on the Y involved offset keys or broaching new keyway slots in the crankshaft or camshaft timing gears. The offset keys were always questionable strength wise regardless if the valve spring pressures were increased or not. The practice of broaching new keyway slots in the gears is not an exact science when it comes to getting the new keyway in the exact ‘right’ location. The Rollmaster timing sets eliminates those prior difficulties.

What showed up in this shop last year were two different Ford Y engines with Rollmaster timing chain sets that were on the verge of coming apart. The roller chain side plates that hold the links or pins in place were coming off of the chains. These two engines were in the shop for other reasons and the side plates that hold the links being missing from the chains had not become an issue in causing any kind of catastrophic failure in that area …. yet. The first engine this was noticed on had a side plate simply laying in the front of the oil pan when the timing cover was removed which was an immediate alert that something was amiss. Had it not been for the appearance of that piece laying in the oil pan, there’s a good chance that missing side plate may have gone un-noticed as that side plate had come loose from the chain at the back or block side of the chain. Upon removing the chain from the engine, it’s noticed that a second side plate is also missing from the back side of the chain. Searching around in the oil pan finds that other missing side plate. If not noticing that side plate lying in the pan and unless the chain was being removed, those missing side plates would have likely have gone unnoticed. For that particular engine, the chain was simply replaced with a new timing set and everyone was left wondering why there was a failure on that chain. That timing set is simply tagged accordingly and stored on a shelf for the time being as it’s an anomaly without an immediate reason for the failure.

It’s less than six months later when another Y comes into the shop in short block form from an estate sale as a potential engine build for a customer. That engine also has a Rollmaster timing set installed, and a cursory examination finds a side plate missing from one of the links. Again, this missing side plate is on the back or block side of the timing chain. It’s not going to be noticed unless you are looking for it. Same drill as before as the timing set is replaced with a new one and the camshaft is appropriately re-degreed in.

This is two potential chain failures in a short period of time which begs the question “What’s going on?” A major clue is that the missing side plates are from the backsides of both chains. There are no obvious wear marks on the block or protrusions that could be hitting the chain so that’s ruled out. The upper and lower gears are also in vertical alignment with each other so that’s not a consideration either. A more thorough examination of the chains on their backsides shows several other side plates on the verge of coming loose. First thoughts are maybe a defective chain but that’s lowered on the list of probable reasons when looking at the history of both engines. Both engines had been built elsewhere and based on the lower crankshaft gears being in non-zero keyway locations, both engines had had their camshafts previously degreed in. In looking at the chains in detail, there are only certain areas of the chain where the roller link pins are barely holding the side plates in place which is driving to the conclusion that the chains were damaged during the prior cam degree in operations.

After a round table discussion, here’s the most probable scenario as to what happened. These are two different engines and from two different locales so we are dealing with two different individuals or engine builders. These builders had installed the timing sets and after initially degreeing them in found that the camshafts needed to be moved in which to re-phase them. To make this happen, the upper and lower gears were removed or pried forward by using some kind of wide bladed pry bars and those pry bars put pressure directly on the roller link pins. Those pins were then simply pressed forward with pressure exerted against them and allowed the pins to be pushed so that the pins were now flush with the side plates. At that point, the pressure is adequate enough to then force the timing gears forward in which to remove the chain and relocate the crank gear position in which to change the cam timing. Once that operation was complete, the side plates were not pushed off the pins but were only being marginally held in place at that point in time. The roller pins are effectively now flush with the side plates with only a minimal amount of crimp or crush holding the side plates in place. Once the engines are up and running, the major amount of crimp on the pins that holds those side plates in place was gone and the side plates simply fell off the pins and into the oil pan. Hard to say exactly how long it took for those side plates to fall off as both engines had some miles on them. It was mentioned that there was as much as 3500 miles on one of them. The exact mileage or run time on the other engine is unknown but based on the cylinder and bearing wear, it was low mileage also.

Having worked with roller timing chains on other engines for a good number of years, this was the first instance I’ve been exposed to with side plates coming off of the roller pin links. And in this instance, it was two different Ford Y engines in a very short period of time. But it does show a weakness in the roller link type of timing chains if particular care is not taken when removing them from the engine. The same could be said for also installing them if pressure is put on the chains rather than the gears to get them pushed into place.

When Joe Craine saw this problem, he had a quick solution for removing the gears for cam timing adjustments. He obtained some wide bladed pry bars and modified them with recessed slots on their ends. These slots fit around the pins and allow the gears to be pushed forward without any pressure on the pins and only on the side plates. You still have to be careful in the placement of these modified pry bars when placing them on the chain but when placed properly behind the chains, it eliminates the possibility of the pins being used as the point of contact for pushing the gears forward. In lieu of making some slotted bars for removing the chain and gears forward, simply catching the side plates at their edges will also work but this does not give the same working surface area that’s presented when using Joe’s modified tools.

With all that being said, just be careful in how those chains are being removed and avoid putting any pressure on the roller link pins.

Until next time, Happy Y Motoring. Ted Eaton.

Note: This article was originally published in The Y-Block Magazine, issue #151, Mar-Apr 2019.

Ford Y-Blk Distributor Hold Downs

Who’d have ever thought that something as simple as the distributor hold down on the Y would require an article in which to point out some manufacturing differences on them? But differences there are.

For the first eight years of Ford Y production, the Y used a simple stamped steel piece to keep the distributor snugged in place. If you have dealt with these over a period of time, you have found some of these that became distorted to the point that they would not keep the distributor tight. It’s the distorted distributor hold downs that make it difficult to maintain the ignition timing on some engines as the distributors are still able to move or ‘creep’ after being tightened down.

Comes 1963, Ford starts using a cast iron distributor hold down which replaces the older stamp steel units. For the Y, that fixes the problem with the distributors loosening up. From all appearances, that cast iron distributor hold down was originally developed for the small block Ford engines and some engineer had an Ah ha moment and applied it to the current production of Ford Y engines still being used in the pickups and larger trucks.

The aftermarket hold downs for the SBF, while still being cast, also have some ribs or ‘teeth’ to help further hold the distributor in place.

So now when I do a Y build, I will instead use one of the small block Ford ‘iron’ distributor hold downs to eliminate the possibility that the distributor might loosen up later. Until next time, happy Y motoring. Ted Eaton

Note: Originally written to be published in The Y-Block Magazine, Issue #180. The discontinuation of that publication did keep that from happening. Ted Eaton.

More Power for a 1954 239

It boggles the mind as to how many 1954 Ford and Mercury cars and pickups are still out there running with their original 239 and 256 engines. But with it now being over seventy years since those engines were introduced, the need for parts and/or the rebuilding of those engines does become necessary even for those that are not driven much each year. While some of those 1954 Ford vehicles have been upgraded to a later model Y engine, there’s still a significant number of them out there still running the original engines. I normally shy away from rebuilding the 1954 Y engines due to the scarcity of some of the 1954 only parts that are on those engines. Some of those parts includes the camshaft, camshaft bearings, oil pumps, water pumps, and fuel pumps.

But my arm is twisted and I take on this particular 239 build. In this instance, the customer would like to rebuild the original engine just for purposes of retaining the original block and heads. And I do like the idea of recycling parts that are rebuildable. This 239 comes from a 1954 Ford F100 pickup and arrives into the shop with complaints of being lack luster in performance and in need of a rebuild. While this engine has been previously rebuilt at least once before and possibly twice, it is again well worn and in need of another rebuild. The customer would also like the original rated power levels increased and provides a 1954 Mercury 256 four-barrel intake to be installed on the engine during the freshening up process.

A tear down of the engine finds that the cylinders are already a well-worn 0.040” over and the crankshaft journals are now at 0.030” and 0.040” undersize. With the scarcity of 0.040” or more undersize bearings, this engine presents an opportunity to install a later model crankshaft with more stroke to make for a quick increase in both the cubic inches and the compression ratio. An 0.080” overbore is found to clean up the existing bores and a quick check of the cylinder wall thickness finds that the remaining wall thickness will be more than adequate for this build.

Rather than use an original 3.1” stroke crankshaft, the plan is to go with a 312 crankshaft (3.44″ stroke) with the mains cut down to the 292 standard main size. A quick combustion chamber measurement of the original heads and some even quicker math indicates that the compression ratio with a 312 crankshaft and zero deck will still be shy of 8:1. With a new set of custom metric ringed pistons in hand, the block is bored and after being torque plate honed, the final cylinder size is 3.580”. After mocking up the engine with the piston and connecting rod assemblies, the decks are machined ~0.015” for a zero deck clearance for the pistons.

Using a 312 crankshaft will mandate using a connecting rod with a shorter bolt design and there are three oem rods that fits that requirement; those are the 6.252” 312 ECZ and 292 C1TE truck rods and the longer 6.324” 292 C2AE rods. The longer C2AE rods are selected for this build which pushes the wrist pin in the piston ~0.072” closer to the piston top versus using the shorter ECZ or C1TE rods. The compression height (wrist pin location) on the new pistons is 1.712” versus 1.875” on the original pistons. To go along with the shorter length rod bolts, the camshaft will also need to be upgraded to the smaller journal 1955 and up camshaft so that the connecting rods will clear the cam lobes. If using an original big journal camshaft with anything other than the original 3.1” stroke crankshaft, then connecting rod to camshaft interference comes to the forefront. The combination of small journal camshaft, short length bolt connecting rods, a 312 crankshaft, and an 0.080” overbore for the EBU-E block is a doable combination for this engine and will make for 277 cubic inches when finished.

Because the original large journal camshaft is being replaced with a later model smaller journal camshaft, the cam bearings must be fabricated from scratch. These are made from bearing brass and are machined for a 0.002” press fit into the block. There is some variance in the hole sizes within the cam bores in the block and that requires that each bearing is made specifically for each cam bore hole. Where I would normally put a groove in the center cam bore of the block to redirect the oil to the top end, in this instance I did put the groove on the outer O.D. of the new bearing for the top end oil. The new bearings being ~1/8” thick permitted this. The replacement camshaft has a grooved center journal versus the original camshaft being cross-drilled but with the cam bearing now being grooved on its outer diameter, only one oil hole is put in the center bearing. The groove at the center camshaft journal no longer provides any additional oiling to the top end of the engine. To eliminate the possibility of too much oil to the top end, 0.078” restrictors are installed in the appropriate stand at the bottom of each rocker arm assembly.

With the change in camshaft, the distributor is also being upgraded. The original Load-O-Matic distributor with its 13 tooth gear is being upgraded to a modern electronic billet distributor with a 14 tooth gear. That distributor change also requires a ¼” hex drive oil pump and a corresponding intermediate oil shaft. An ARP oil pump drive is being used as those are now the same price as the replacement oil drives; the ARP unit is definitely a heavier duty piece. Had it been desired to retain the original L-O-M distributor, then it would have been necessary to replace the original 13 tooth gear with the later model 14 tooth gear. In that instance, the original slotted oil pump drive and slotted tang oil pump could have been retained. Another option would have been to use a 1957 and up Y distributor but that would have required the subsequent oil drive and oil pump change as well.

The rotating assembly consisting of the freshly machined 312 crankshaft, connecting rods freshly resized with new ARP bolts, custom Diamond pistons and metric rings, and bearings is electronically balanced. The bobweight value for this new combination is 1860 grams versus the stock bobweight value being in the neighborhood of 2000 grams. That lighter rotating assembly will allow the engine to accelerate quicker in the vehicle as well as remove some of the stress that was originally present at both the connecting rod bearings and bolts.

The stock EBU-6015-F cylinder heads are treated to a fresh valve job. They are checked for straightness and found to be okay thus not requiring any milling. Checking the square pads under the exhaust ports finds those pads at ~1.005” suggesting that this set of heads have never been milled. Of note here is that the 1954 engines use a washered 14mm spark plug versus all newer oem Ford Y-Block heads using 18mm tapered seat spark plugs. Also worth noting is that the ’54 heads are specific to the ’54 blocks and the head gaskets are also specific to the ’54 engines. The ’54 head gaskets are not suitable for the later model engines due to both the bore and coolant hole locations being different.

The original 1.43:1 rocker arm assemblies have the locking nut adjusters and are disassembled and cleaned. The rocker arm tips are machined so that they have fresh valve stem contacting pads. With new rocker shafts in hand, the assemblies are reassembled. The original rocker arm overflow tubes are retained in lieu of pressurizing the rocker arm assemblies. As mentioned earlier, 0.078” restrictors are installed in each assembly to help control the amount of oil going to the top end of the engine. The factory oil restriction at the center cam bearing has been eliminated and with the addition of the groove on the outer side of the center cam bearing, there will now be an excess of oil to the top end if not using the added restrictors.

ARP grade eight head bolts are used in lieu of the factory grade 5/6 bolts.

The short block assembly goes together without any hiccups. The Hy-Lift Johnson tappets are installed first and then the camshaft. A custom ground Isky camshaft is selected and is a replacement for the 1957 V8 camshafts. The specs are as follows:
238° – Advertised duration
208° – Duration at 0.050”
0.284”– Lobe lift
0.406” – Calculated total lift at valve
112° – As ground lobe centerline
107° – Installed intake lobe centerline

A neoprene real main seal is used in lieu of using an original type rope seal. The six quarts with filter rear sump oil pan is modified with the addition of a baffle to prevent oil starvation during heavy braking. The timing cover is upgraded to a newer version which will accommodate the ’55 and newer water pump and fuel pump.

The heads are bolted to the engine with a new set of grade eight ARP bolts which are torqued to 75 lbs/ft for the short bolts and 80 lbs/ft for the longer bolts. Whereas the original grade five top row of bolts were all the same lengths, the new set of bolts are of two different lengths for the top row with the end bolts being slightly longer than the three center bolts. The new ARP head bolts use hardened washers versus the original bolts not using any washers. Best Gasket head gaskets specific to the 1954 engines are used and these are 0.045” thick versus the original steel shim gaskets being 0.025” thick. But with the addition of the grade eight head bolts and the composite head gaskets, a retorque of the head bolts after the engine has been fired up will not be required.

The rocker arm assemblies are bolted to the cylinder heads and when using the original pushrods, it’s found that they are on the short side when using the original oil deflection trays under the rocker arms. The original pushrods have an effective length of 7.975” and are changed out to the ’57 version pushrods which are 8.100” in effective length. The smaller base circle on the new camshaft along with using the valve train oil trays explains why the longer pushrods are required. In the grand scheme of things, the pushrods could have been another 0.100” longer and been even better suited to this application but what is already being used will be okay. This engine is to be a daily runner and getting every iota of performance out of it is not a priority.

The original two-barrel intake manifold goes to the way side and is replaced by the provided 1954 Mercury 256 four barrel EBY-D intake manifold. The four holes at the carburetor base of the manifold are machined so that they are two ovals. This is similar to the modification that is performed on the later model ECZ-B 4V iron intake manifolds as it does help to increase the air flow within the manifold. A machined adapter on top of this will allow a more modern four-barrel carburetor to be used. In this particular instance, a Summit 500 cfm carburetor is selected. A Carter M4008 mechanical fuel pump for a 390 Ford is being used to supply the fuel. This particular fuel pump has a cartridge type filter and cannister already attached to it thus eliminating the need for an inline fuel filter.

With six quarts of conventional grade Valvoline 10W-30 oil added to the crankcase, the engine is prelubed. Plenty of oil is evident at the top end of the engine including a good flow from the rocker arm overflow tubes so no issues there. The distributor is installed and the valve covers are bolted in place. The engine is now ready to be put on the dyno for break in and tuning purposes. With the fuel added to the float bowls through the vent tubes, a couple swings of the throttle puts some fuel into the engine. After waiting the prerequisite ten seconds so the fuel can be allowed to vaporize, the engine starts up immediately. No drama there but with the distributor installed so that the initial ignition timing is set at 25° BTDC, no problems with the initial startup were expected. The engine is brought up to 2000 rpms and with some load put on the engine, both the camshaft and the rings are broken in. The total ignition timing is set to 38° BTDC during this same time frame.

While the break-in period itself went without any issues, it’s during the first dyno run for a power check that a problem comes to the forefront. The oil pressure is exceeding 100 psi and is creating an oil leak at the oil filter area. Upon closer examination, the oil filter has actually deformed and has ballooned as a result of the excessive oil pressure. Removal of the oil pump finds that the spring at the oil relief valve in the new Melling spur gear oil pump is too long. The coil bind of the spring is preventing the relief valve from fully opening and exposing the bypass hole within the pump. Another slightly shorter spring is used and that high oil pressure problem goes away. The oil pressure is now limited to 55 psi.

The 500 cfm Summit carb is running on the lean side at idle and with the idle adjustment screws being turned out 3 full turns, there’s still not enough idle fuel. The idle bleeds within the fuel discharge nozzles are switched out from the supplied 0.046” bleeds to 0.043” bleeds and that restores the idle fuel adjustment. Subsequent dyno runs on the engine has the horsepower peaking at 205 at 4700 rpm and the torque peaking at 282 @ 3400 rpm. Not too shabby for an engine that originally left the factory rated at 130HP and 214 lb/ft torque. This engine is now ready for installation back into its 1954 Ford pickup. The dyno sheet can be found at the end of this article.

So, there you have it. A 239 now becomes 277 cubic inches and is upgraded with some of the newer parts that are more readily available. Whereas the compression ratio was 6.91:1 upon arriving for rebuilding, it’s now at 7.71:1 with the 312 crankshaft and composite head gaskets. With over a fifty percent increase in the available power than when originally produced, this will be one very good running 1954 Ford pickup. Until next time, happy Y motoring. Ted Eaton.

Note: Originally written to be published in The Y-Block Magazine, Issue #172, Sep-Oct 2022. Was rescheduled to be in issue YBM #174 but issue #173 was the last one to be mailed out before the YBM ceased all publication. Ted Eaton.