Eaton Balancing

In attempting to squeeze out that last bit of potential output from the Ford Y-Block (and other engines), there are those items that can be applied that may not be immediately measurable but they will be done because they will not be detrimental to the power output.  One of these items is spark plug indexing which tends to vary in its benefit depending upon the application it is being applied.  Indexing the spark plugs simply insures that the spark plug ground electrode is in a specific orientation within the cylinder to promote a more beneficial flame front when the fuel is ignited.  In those cases where detonation is a risk, spark plug indexing is of a proven benefit in that the flame front will not be split by a worst case scenario of the spark plug electrode being in a position to divide the flame path.  Indexing also allows the ground electrode or strap to be intentionally positioned away from the higher heat areas it would be subjected to if randomly placed closer to the piston and/or exhaust valve which can increase the propensity for pre-ignition.  In a normal situation where a set of spark plugs are randomly installed, the spark plug straps end up running at a variety of temperatures simply from the random placements of the straps.  In this case, indexing would provide a more accurate visual means towards optimizing jetting and ignition timing by eliminating potential variances in the spark plug readings themselves.  And if running a domed piston that’s marginally close to the spark plug, then indexing also helps in preventing the ground electrode from contacting the piston and potentially closing the gap.

 Because both the spark plug threads in the Y heads and the threads on the spark plugs themselves are randomly machined in relation to the ground electrode attachment, the spark plug strap orientation will also randomly install in a myriad of positions within the combustion chamber.  To install a sparkplug so that its ground electrode is in a specific position within the combustion chamber will require trying several spark plugs in a given hole until the desired orientation is achieved.  If the heads are off the engine, it’s simply a matter of observing the electrode position and trying different spark plugs in a particular hole until the electrode resides in the desired position when tightened (see Figs. 1&2).  If the heads are on the engine, then the spark plug porcelain can be marked with a magic marker stripe that aligns with the ground strap where it attaches to the base of the spark plug.  This spark plug is then installed and tightened in the various spark plug holes until the stripe or mark falls into the desired position (see fig. 3).  This process is continued until all the cylinders have an indexed spark plug specific to each cylinder.

 

It will not be unusual to use more than a full set of spark plugs in order to have enough to properly index all eight cylinders.  The spark plugs that will not index or align for a given set of heads can potentially work on another set of heads though so just label those as not fitting a specific set of heads so they are not re-ran through the same process at a later date on the same set of heads.

 

So just where is the optimum orientation of the electrode?.  For the Ford Y-Block, the electrode ground strap will be at the highest position in the combustion chamber where the center tip is fully exposed to the oncoming piston and the compressing fuel mixture.  If taken one step further, then the electrode strap will be angled slightly towards the intake valve so that the strap is intentionally placed further from the exhaust valve (see Figs. 1,2&3).  This promotes some additional cooling of the spark plug strap as the intake charge enters the cylinder while also keeping the strap itself again cooler by not being as close to the exhaust flow leaving the engine.  The opposing thought process to this is to angle the electrode attachment towards the exhaust valve to promote some additional intake air flow.  Regardless on what you decide for the final placement, just be consistent in the methodology or thought process that you use.

 

It ends up being quite an effort to go through the process of installing that first set of indexed spark plugs.  But there is a way to capture this information so that future changes of spark plugs can be made and properly indexed without having to go through the process of checking each spark plug in each respective spark plug hole again.  All that’s needed now is a fixture that the indexed spark plug from each cylinder can be installed in and the location of each ground strap attachment position is recorded on to indicate the cylinder for which it belongs.  What has been found to be expedient and not requiring a lot of fabrication is to simply use a spark plug anti-fouler (Fig. 4) as the basis for a tool to accomplish this.  In order to make this work, each indexed spark plug is removed from its respective cylinder in the heads, installed in the anti-fouler, and the location where the ground strap or electrode is attached to the spark plugs base is marked and recorded on the side of the anti-fouler.  Personal preference is to use a metal engraver to insure the marks are permanent.  To make it easier to see the spark plug’s ground strap, the hole in the bottom of the anti-fouler is made larger (Fig. 5 & 7).  The next time a set of spark plugs is needed, the new plugs are simply screwed into the ‘tool’ and by viewing the ground strap attachment, the ‘best fit’ cylinder number marked on the tools side will indicate exactly which cylinder will get that particular spark plug.  If the ground strap aligns perfectly with the mark, then you’ve got an exact fit.  Again, you’ll likely need more than eight spark plugs to make a ‘perfect’ set for your Y engine. When the tool has outlived the set of heads it was originally marked for, it can be simply remachined to give a new surface on which to mark a new set of spark plug locations.

 

Another ‘tool’ option is to simply take a flat piece of material and drill and tap it to accommodate a spark plug being screwed into it (Figs. 8,9,10).  The spark plugs that have already been indexed within a given pair of heads can then be removed one at a time from their respective cylinders, installed in this new tool, and the electrode strap locations marked on the tool as to the cylinder that particular spark plug belongs.  Like with using the anti-fouler, any new spark plugs can then be installed in this tool and you will know immediately for which cylinders the new spark plugs will be suitable for.

 

Now that you’ve made a tool to assist in indexing the spark plugs without having to actually install them in the heads, it becomes important to mark the heads so that they can be reinstalled on the engine without unknowingly swapping sides.  Heads can be marked L or R, DRV or PAS, or any other markings as long as they are sufficiently identified so they can be installed back on their original sides or banks which in turn keeps the cylinder numbering on the tool the same.  Because the Y heads are already left and right specific by lieu of the temperature sending unit and the blocked water ports at the back of the heads, not doing the labeling or marking is not a show stopper on a Y engine but can be a big consideration if doing this on other engine designs.  If the heads have been inadvertently swapped, the tool no longer works as originally labeled.  If you are indexing spark plugs for several engines, then mark the tool (or anti-fouler) as to the engine or the heads for which the tool belongs (Fig. 11).    Until next time, Ted Eaton

 Originally published in the Y-Block Magazine, May-June 2008 issue, Issue #86, Vol 15, No.3

Included on that list of old racers tuning tricks is spark plug side gapping.  What’s being discussed here is not a true side gapped spark plug but a gapping procedure or electrode modification that allows the spark to actually fire off of the very edge or ‘side’ of the spark plug’s ground electrode.  In lieu of a better description, this gapping process will simply continue to be called ‘side gapping’.  Side gapping is performed even though the end result may not be measurable but a logical thought process will maintain that doing this will not be detrimental to efficiency or performance and in fact, should help it.

 

Like spark plug indexing, spark plug side gapping will vary in its benefit depending upon the application to which it is being applied.  While this procedure tends to be very effective on two stroke engines, the benefit on four stroke engines is less predictable depending in part to the combustion chamber design and air flow characteristics of the engine in question.  On both the two and four stroke engines, the immediate benefit is typically observed in engine starting where it’s quicker or with much less starter effort.  The general premise behind side gapping lies in getting the spark to fire directly on the end of the grounding electrode instead of having the spark shrouded by the electrode strap.  Doing this is typically done in conjunction with spark plug indexing in order to get as much exposure of the spark to the compressed fuel mixture as possible.

 

A typical out of the box spark plug will have the ground electrode (strap) completely covering the center post consequently shrouding or covering it to some degree.  Side gapping will simply modify this strap so the end of it is exactly in line with the centerline of the spark plug thereby putting the spark in a position to fire directly on the end of the ground electrode which in turn permits the spark to be better exposed for igniting the fuel mixture.  A variety of methods can be employed to shorten or remove the excess amount of ground electrode strap so that the new end is centered directly over the center electrode.  A grinder or file are equally effective but in either case, care must be taken to insure that the center electrode (tip) or other portions of the spark plug are not unduly damaged or altered in the process of working on the ground strap.  After the strap is appropriately modified, it will need to be deburred and then the gap reset to the desired specification.  It’s important to note that the bottom edge of the electrode where it has been shortened does need to keep a sharp edge and not be rounded in order to promote a more decisive and consistent length spark.      

 

Spark plug side gapping is just one more tuning aid that when used with the myriad of other seemingly unimportant tuning tools accumulatively adds to a measurable increase in power output that by itself would not be significant.  More simply said… “every little bit helps”.

 

Until next time, Ted Eaton

 Originally published in the Y-Block Magazine, Sept-Oct 2008 issue, Issue #88, Vol 15, No.5

  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 seal diameter for the 239, 256, 272, and 292 engines is 2.625″ while the 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.  No sealer is used on the outside diameter of the rear main seal as it is being laid into the block and the seal itself will also need to be offset at the main journal parting line by about 1/4″-3/8”.  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.

 

 

   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