Tag Archives: FE

Camshaft and Lifter Failure Causes

Here is a list of items that are contributing factors for a flat tappet camshaft (new or otherwise) and/or lifters to experience a premature failure.

  1. Lubrication of cam and/or lifters is inadequate before first startup
  2. New engine is turned over excessively before being initially started
  3. New engine sat too long before starting it for the first time
  4. Engine is not at a sufficient rpm during camshaft break-in
  5. Valve train geometry is incorrect
  6. Valve to piston clearance inadequate
  7. Retainer to seal clearance is inadequate
  8. Valve spring coil bind
  9. Valve spring pressure is excessive
  10.  Pushrod tip angularity (at rocker adjuster)
  11.  Tight valve guides – inadequate valve guide clearance
  12.  Lifter crown radius – improperly ground
  13.  Camshaft lobe rake angle incorrect for application
  14.  Reversed camshaft rake profile – rakes on wrong side of lobe
  15.  Camshaft lobes are cut on too small a base circle – lifters too far down
  16.  Connecting rod contacting camshaft – stroker issue
  17.  Pushrods rubbing or intermediate contact within the heads
  18.  Incorrect valve lash
  19.  Rocker arm drag at shafts or trunions (oiling, clearance, etc.)
  20.  Loose cam gear retention bolt(s)
  21.  Camshaft end play is excessive
  22.  Oil quality (inadequate zinc / phosphorus content, incorrect application, etc.)
  23.  Contaminated oil (water, gasoline, particulates, etc.)
  24.  Oil pressure insufficient
  25.  Lifter bore too tight, lifter doesn’t turn or work freely
  26.  Lifter bore alignment (cam blank & block manufacturing issues)
  27.  Use of used lifters on a new camshaft or in a different block
  28.  Mixing the used lifters within an engine, not staying on same lobes
  29.  Excessive low speed idle time
  30.  Engine sat too long with open valve spring load on the lifters
  31.  Incorrect or inadequate heat treat on lobes and/or lifter faces
  32.  Valve float – bouncing and/or hammering the lifters on the lobes
  33.  Use of ARP fastener lube on the lifters and/or lobes; simply the wrong lube
  34.  Using high viscosity lube on lifter shanks; keeps lifters from free turning
  35.  Lifters are reground to the point that the original surface hardness has been compromised.
  36.  Rocker assemblies have been installed without backing off the adjusters thus jamming the lifter against the lobe due to coil bind or other interference issues.

While this list is not in any particular order of importance, any one of these items or combination of them can contribute to a cam lobe or tappet failure.

Until next time, Happy Y Motoring. Ted Eaton

Addendum:  While having an adequate level of ZDDP content in the oil is important, examination of those engines with camshaft and lifter failures finds that those failures are more often the result of other issues not related to the Zinc/Phosphate levels in the oil.  Current available oils if properly selected based on the information in the API bulletin do still have adequate amounts of Zinc/Phosphate for the older flat tappet camshafts.  The key here is to know which oils have had the Zinc/Phosphate amounts reduced and which have not.  This essentially means reading beyond the first paragraph of the API bulletin to get that information.  Ted Eaton, November 2012.

Addendum:  Items #33 & 34 added after initial publication in YBM.  Ted Eaton, May 2015.

Addendum: Items #35 & 36 added after initial publication in YBM.  Ted Eaton, Dec 2015.

This article originally published in Y-Block Magazine, Issue #112, Sep-Oct 2012, Vol 19, No.5

Neoprene Rear Seal Installation for the Y (and others)

  Y-Blocks would appear to have garnered a reputation for marking their territory when sitting still and so one of the most often asked questions is how to stop those pesky oil leaks at the rear of the engine.  Because most of these are in the area of the rear main oil seal, I’ll go through the steps I take to insure that the back end of the engine is buttoned up securely during the rebuild thereby minimizing any oil leaks from this area.  Because I use the rubber or neoprene rear main seals exclusively in those Y buildups that I do, I’ll only go into detail on using these seals and not the ‘rope’ style of seal.  While neoprene seals are available from several gasket manufacturers for the 272/292 engines, only Best Gasket offers a made to fit neoprene rear seal for the larger mained 312 engine.

  

Best Gasket and Fel Pro rear seal kits….

   Oil leaks at the back of the Y can likely be from one of several locations.  These include the rear main seal itself, the side seals on the seal retainer, the oil pan bolts, the oil galley plugs, the cam plug, and residuals seeping down from the top and back of the engine.  And let’s not forget the oil pump as it can also be a contributor but this particular leak is easier to spot than most.  The key here is to get these areas sealed up during the initial engine assembly so they are not a problem once the engine is in the vehicle and running.

    The oil galley plugs at the back of the block are 3/8” NPT (National Pipe Thread) and will require a nominal amount of sealer on the threads.  For sealer, Permatex #2, a thin film of RTV, ‘high tack’, or teflon tape can be used.  The key here is that some form of sealer must be used in lieu of simply relying on a dry fit of the tapered thread design of the screw in plugs being used.

 

   The cam plug at the back of the block is typically installed at the machine shop but does need some form of sealer on it during installation.  Installing it dry just increases the chances for an oil leak in that area. 

 

   Before installing the rear seal half into the block and laying the crankshaft into the bearings, check the seal groove depth both in the block and the rear seal retainer.  It’s been passed along that the groove depth on a particular 312 block was deeper than normal which made the rear seal fit too low in the groove.  Another instance was the groove depth in a 272 block being too shallow.  Both cases were problems when it came to neoprene seal installation in these particular engines.  To check this, simply lay the neoprene seal firmly in the upper and lower grooves with the neoprene seal ends level with where the cap fits the block and insure that the seal ends are flush with the block or edge of the cap.  If the seal ends are lower than the block or edge of the seal retainer, then it’s either the incorrect seal for the application or a seal groove that’s too deep.  If the seal half sits considerably higher at the block than normal when firmly putting it in the groove, then the possibility exists that the groove is too shallow or the incorrect seal for the application.  These may be cases where a rope seal must be used.

 

The crankshaft journal diameter for the seals for the 239, 256, 272, and 292 engines is 2.625″ while the journal seal diameter for the 312 engine is 2.750″.  Because of this there are two different neoprene seals available for these engines.  Trying to use a 292 neoprene seal kit in a 312 engine will redefine what a rear seal leak really is as the seal ends will have a gapping hole in them.

 

Assuming the block being used has passed the groove depth test, a rear seal half will need to be laid into its groove at the back of the block before laying the crankshaft into the bearings.  The lip of the seal “must” be facing forward or towards the inside of the engine.  While no sealer is used on the outside diameter of the rear main seal before installing it in the block or the retaining cap, coating the outer edge of the seal halves with white grease can help to seal any small imperfections within the groove or seal that might be an oil leak otherwise.  At this point, the seal half being laid into the block will need to be offset at the main journal parting line by about 1/4″-3/8”.  This allows the retaining cap to self align so that the seal ends can actually butt to each other.  Be sure that the lips on the seals are lubed prior to installing the crankshaft as installing dry can cause premature seal wear.  A small amount of KW Copper Coat sealer is put on the block where the rear seal retainer fits.  This will take care of any seepage that can potentially occur between the retainer and the the block mating surface.  Take care not to put any sealer on the neoprene seal itself.

Offsetting the rear seal halves.

 

   After the crankshaft has been laid into the bearings and the main caps torqued to specification, the rear seal retainer can then be readied for installation.  KW Copper Coat or similar type of sealer is applied to the retainer flats where it mates to the block.  At this point, the remaining rear seal half is laid into the retainer groove with emphasis being put on insuring that the lip of the seal faces the inside of the engine when the retainer is bolted in place.  The offset in the seal where it sticks up on one side of the retainer will also need to match the offset of the seal half that’s already in the block.  Again, use no sealer on the backside of the seal that installs in the rear seal retainer groove.

 Sealer on bottom of retainer…..

 

  Before actually installing the seal retainer in the block, it must be determined which side seal design is being used as this will have a bearing on when the retainer itself is installed.  If using the Best Gasket brand orange seals which are both soft and compressible, then the side seals and retainer are installed together as a unit into the block.  If using the black rubber seals that uses ‘nails’ or small diameter rods, then the retainer is installed into the block without the side seals first being in place.  Regardless of which seal design is being used, the leading edge of the block where the retainer starts being fitted into place should have the edge ‘broken’ with a file to facilitate the side seals starting in at this point easier.  It’s desirable that the filing of this edge took place before final block cleaning to reduce the risk of metal filings within the new engine.

 Chamfer detail…..

   When using the Best Gasket orange side seals, the outside surfaces of the seals or the faces of the seals that contact the block are lightly oiled.  A small dab of RTV on the end of the seals is also of a benefit in insuring that there is not a gap for oil seepage at the block and where the seal retainer itself mates to it.  With a pair of long bolts or studs inserted both into the seal retainer retention bolt holes in the block and the seal retainer itself, the seal retainer is pushed into place while putting inward pressure on the side seals to insure that they stay in place while the retainer slides into place.  With the retainer fully seated, the side seals are expected to be either flush or slightly below the pan rail surface.  If the side seals protrude above the pan rail surface, then the seal retainer will need to be pulled back out and reinstalled to insure adequate insertion of the side seals.  Torque the real seal retainer to 23-28 ft-lbs when satisfied with the side seal fit.

 

  

   The use of the black rubber seals with their accompanying ‘nails’ presents a slightly different scenario.  The retainer with the installed rear seal half and aforementioned KW Copper Coat application is installed into the block without the side seals in place.  Torque the rear seal retainer to 23-28 ft-lbs.

 

   Before inserting the black side seals, put a small amount of RTV into each of the side seal holes.  This RTV will be pushed down and ahead of the seals to insure a solid and leak free seal at the mating surface of the block where the side seals reside at the main journal parting line.  At this point, install the side seals into the holes and push or tap them down until the seals bottom out.  It may be necessary to grind a small bevel or chamfer on the leading edge of the rubber seals to facilitate starting them in their holes.  The nails are then installed on the retainer side of the side seals and are simply tapped into place with a small hammer.  Installing the nails on the block side of the side seals will almost guaranatee an oil leak so take due diligence in insuring that the nails are on the retainer side of the seals.  As a side note, if an excess of RTV is used in the holes, it may be pushed out the front and rear sides of the retainer as the side seals are being pushed into place.  This excess should be allowed to thoroughly dry before trimming or cutting off the excess amounts so it is flush with the block and/or retainer. 

 

 

 

 

 

 A small dab of RTV seals the deal….

 

  And a quick note on the oil pumps.  There are two styles of pumps and subsequently two methods employed in their manufacture to minimize oil leakage between the oil pump housing and the plate that covers the gears.  The spur-gear style of pump incorporates a very thin paper gasket while the gerotor style of pump uses a rubber ‘O’ ring.  In either of these, it’s important that due diligence be applied when servicing either style of oil pump to insure that all surfaces are clean and flat.  New gaskets and/or ‘O’ rings are a prerequisite.  Using a sequential and even tightening sequence when fastening the pump to the block with its related gasket is also recommended.

  When it comes to oil leaks on the Y-Block family of engines, another often overlooked detail is the two oil pan bolts that locate into the rear oil seal retainer.  These two threaded holes are open to the crankcase and are prone to leakage around the oil pan bolts if sealer is not used on the threads.  Ideally, it’s best to use the factory supplied studs at this location but a fair number of these engines have had these studs removed over the course of time.  When reinstalling the studs, be sure to use some form of thread sealer where the stud goes into the retainer.  If just using pan bolts at this location, then use a small amount of RTV or other suitable sealer on the threads.

 

   And here’s a word of caution with using RTV.  Use only enough to get the job done regardless of where it’s being used.  Excessive amounts of RTV can be pushed into the inside of the engine and if dislodged and in a worst case situation, can make its way into and through the oil pump where it can eventually plug or stop up an oil galley in the block or crankshaft.

 

   While these are not the only approved steps or methods available for sealing up the back of these engines, these are the steps that I’ve found to have a very high success rate.  A special thanks goes to Bill Phelps in Dallas Texas for prompting me to jump this article ahead of the others that are forthcoming.

 

Until next time, Ted Eaton.

Originally published in the Y-Block Magazine, Jul-Aug 2008 issue, Issue #87, Vol 15, No.4

Altering Rocker Arm Ratio By Varying The Length Of The Pushrods

Fig A.A unique feature with the shaft mounted rocker arms such as those found on the Y-Block (as well as the FE, MEL,  and LYB) Ford engines is that the solid lifter or lash adjusting versions can be measurably variable in the rocker arm ratio depending upon where the lash adjusting screw is positioned within its range of travel. Where changing the pushrod length on the stud mounted or trunion type of rocker arm affects the geometry of the rocker and not the rocker arm ratio, changing the pushrod length on the shaft mounted Y-Block rocker allows for some deviation from the advertised amount of rocker arm ratio. This in turn allows some flexibility in rocker arm ratio tuning without having to purchase specific rockers for this purpose. What makes this possible is that the contact point for the pushrod at the bottom of the adjustment screw changes in relationship to the center of the pivot point (shaft) as the adjusting screw is moved up or down. (see illustration)

Depending upon the year model, Y’s can be found with rocker arms that have an advertised ratio of 1.43:1 or 1.54:1. Measurements performed on these rockers shows that the advertised ratio is more closely achieved when the adjusting screws are approximately half way down or midpoint in their adjustment travel. When the rocker adjusting screws are taken towards their extreme ends of adjustment, then the ratios do deviate from this advertised value. This same phenomenon is also seen on the aftermarket roller rockers that are available for the Y.

Fig A.This rocker ratio variability can be measured several different ways. In the past, I have used an adjustable length pushrod so that the rocker adjustment screw could be varied and then measuring the net lift at the valve while maintaining zero lash. With the cam lobe lift being known, it’s just a simple matter of dividing the lift at the valve by the cam lobe lift to obtain the real time rocker arm ratio. This particular measurement is performed after achieving optimum rocker arm geometry which is effectively done by altering the rocker stand heights. Rocker arm geometry will also affect the net valve lift if the rocker shafts themselves are not at their optimum height. This has been covered in detail in a separate technical article.

To facilitate an easier method of rocker arm ratio measurements, a simple fixture with two dial indicators was fabricated that would simulate the rocker as mounted on a head. This would facilitate much quicker back to back testing of the different rocker arms without having to dry assemble the rockers on a workable head in order to simulate their movement through the various scenarios. Based on measurements taken on several different rocker arms, some trends in the observations become apparent. If the adjuster is at the top of its adjustment range, then an increase in rocker ratio would be observed. Conversely, if the adjuster is at the bottom of its range or screwed all the way in, then there would be decrease in rocker ratio. The following chart summarizes the measurements and are converted to rocker arm ratio values.

Adjuster down all the way. Adjuster at the mid point position. Adjuster at the top of its travel.
1.43:1 Y Rocker 1.370 1.425 1.472
1.54:1 Y Rocker 1.438 1.500 1.560
1.6:1 Dove Rckr 1.528 1.599 1.670

Having the ability to change to different rocker ratios opens up more tuning options regarding performance and/or efficiency of an engine. There are instances where it would be ideal to either increase or reduce the rocker ratio on either or both valves depending upon the camshaft and the specific application that the engine is being used. This myriad of combinations would be another chapter in itself so that will be left for another day. What must be remembered at this time is that the net valve lift is greatly affected by changes in rocker ratio as well as the speed in which the valve is being lifted from its seat. As an example for a particular scenario, I’ll use the Isky T-505 camshaft for the Y which has an advertised valve lift of 0.505”. This is calculated using a 1.5:1 rocker and if a 1.43 rocker is utilized, then this lift drops to a nominal 0.481” lift and reduces even further to 0.461” if the pushrod is shortened as much as possible. On the other side of the spectrum are the aftermarket 1.6 rockers for the Y which would allow the gross valve lift on this same camshaft to increase to 0.539” lift and if the pushrod is lengthened as much as the rocker adjustment will tolerate, then 0.562” lift. The valve lash would be subtracted from all these equations for actual lift at the valve.

This range in rocker arm variability does create some interesting scenarios that can keep an engine from running at its peak potential or become a potential source for breakage or engine damage. An example is an engine that has one head milled more than the other but has not had the pushrods adjusted appropriately in which to compensate can effectively be running different rocker arm ratios from side to side. And yet another instance is where mismatched heads from different years are on the same engine with a subsequent different height of the rocker shafts on each side. Although either of these scenarios could be checked by just visibly insuring that the rocker arm adjustment screws are sitting in approximately the same location on both banks of rockers, it is advisable to do an actual check of the net valve lifts at the valves. Milling the heads to increase the compression ratio also effectively increases the rocker arm ratio in that the adjustment screws must be moved up in order to use the same length pushrods. In this particular case, if the valve to piston clearance was already marginal then the valve is automatically positioned closer to the piston by the amount the head was milled. What compounds this is that the rocker ratio also increased if the same length pushrods are retained which effectively puts more lift at the valve which left unchecked could ultimately be just the amount that allows the valve to contact the piston.

As always, I hope this topic did not thoroughly confuse you but instead did help to enlighten you on just another nuance with these engines.

Until next time, Happy Motoring. Ted Eaton.

Originally published in the Y-Block Magazine, Nov-Dec 2005, Issue #71.